misc: Add Allwinner Q8 tablet hardware manager

Allwinnner A13 / A23 / A33 based Q8 tablets are popular cheap 7" tablets of which a new batch is produced every few weeks. Each batch uses a different mix of touchscreen, accelerometer and wifi peripherals.

Given that each batch is different creating a devicetree for each variant is not desirable. This commit adds a Q8 tablet hardware manager which auto-detects the touchscreen and accelerometer so that a single generic dts can be used for these tablets.

The wifi is connected to a discoverable bus (sdio or usb) and will be autodetected by the mmc resp. usb subsystems.

Signed-off-by Hans de Goede <[email protected]>

---

.../misc/allwinner,sunxi-q8-hardwaremgr.txt        |  52 +++
drivers/misc/Kconfig                               |  12 +
drivers/misc/Makefile                              |   1 +
drivers/misc/q8-hardwaremgr.c                      | 512 +++++++++++++++++++++
4 files changed, 577 insertions(+)

create mode 100644 Documentation/devicetree/bindings/misc/allwinner,sunxi-q8-hardwaremgr.txt create mode 100644 drivers/misc/q8-hardwaremgr.c

Documentation/devicetree/bindings/misc/allwinner,sunxi-q8-hardwaremgr.txt new file +52 -0

new file mode 100644
index 0000000..f428bf5
@@ -0,0 +1,52 @@
+Q8 tablet hardware manager
+--------------------------
+
+Allwinnner A13 / A23 / A33 based Q8 tablets are popular cheap 7" tablets of
+which a new batch is produced every few weeks. Each batch uses a different
+mix of touchscreen, accelerometer and wifi peripherals.
+
+Given that each batch is different creating a devicetree for each variant is
+not desirable. The Q8 tablet hardware manager bindings are bindings for an os
+module which auto-detects the touchscreen so that a single
+generic dts can be used for these tablets.
+
+The wifi is connected to a discoverable bus and will be autodetected by the os.
+
+Required properties:
+ - compatible         : "allwinner,sunxi-q8-hardwaremgr"
+ - touchscreen        : phandle of a template touchscreen node, this must be a
+		        child node of the touchscreen i2c bus
+
+Optional properties:
+ - touchscreen-supply : regulator phandle for the touchscreen vdd supply
+
+touschreen node required properties:
+ - interrupt-parent   : phandle pointing to the interrupt controller
+			serving the touchscreen interrupt
+ - interrupts         : interrupt specification for the touchscreen interrupt
+ - power-gpios        : Specification for the pin connected to the touchscreen's
+			enable / wake pin. This needs to be driven high to
+			enable the touchscreen controller
+
+Example:
+
+/ {
+	hwmgr {
+		compatible = "allwinner,sunxi-q8-hardwaremgr";
+		touchscreen = <&touchscreen>;
+		touchscreen-supply = <&reg_ldo_io1>;
+	};
+};
+
+&i2c0 {
+	touchscreen: touchscreen at 0 {
+		interrupt-parent = <&pio>;
+		interrupts = <1 5 IRQ_TYPE_EDGE_FALLING>; /* PB5 */
+		power-gpios = <&pio 7 1 GPIO_ACTIVE_HIGH>; /* PH1 */
+		/*
+		 * Enabled by sunxi-q8-hardwaremgr if it detects a
+		 * known model touchscreen.
+		 */
+		status = "disabled";
+	};
+};

drivers/misc/Kconfig +12 -0

index a216b46..c3e7772 100644
@@ -804,6 +804,18 @@ config PANEL_BOOT_MESSAGE
 	  An empty message will only clear the display at driver init time. Any other
 	  printf()-formatted message is valid with newline and escape codes.
 
+config Q8_HARDWAREMGR
+	tristate "Allwinner Q8 tablet hardware manager"
+	depends on GPIOLIB || COMPILE_TEST
+	depends on I2C
+	depends on OF
+	default	n
+	help
+	  This option enables support for autodetecting the touchscreen
+	  on Allwinner Q8 tablets.
+
+	  If unsure, say N.
+

source "drivers/misc/c2port/Kconfig"
source "drivers/misc/eeprom/Kconfig"
source "drivers/misc/cb710/Kconfig"

drivers/misc/Makefile +0 -0

index 7410c6d..cac76b7 100644
@@ -57,6 +57,7 @@ obj-$(CONFIG_ECHO)		+= echo/

obj-$(CONFIG_VEXPRESS_SYSCFG) += vexpress-syscfg.o
obj-$(CONFIG_CXL_BASE) += cxl/
obj-$(CONFIG_PANEL) += panel.o
+obj-$(CONFIG_Q8_HARDWAREMGR) += q8-hardwaremgr.o

lkdtm-$(CONFIG_LKDTM) += lkdtm_core.o
lkdtm-$(CONFIG_LKDTM) += lkdtm_bugs.o

drivers/misc/q8-hardwaremgr.c new file +95 -0

new file mode 100644
index 0000000..e75625e
@@ -0,0 +1,512 @@
+/*
+ * Allwinner q8 formfactor tablet hardware manager
+ *
+ * Copyright (C) 2016 Hans de Goede <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <asm/unaligned.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+
+/*
+ * We can detect which touchscreen controller is used automatically,
+ * but some controllers can be wired up differently depending on the
+ * q8 PCB variant used, so they need different firmware files / settings.
+ *
+ * We allow the user to specify a firmware_variant to select a config
+ * from a list of known configs. We also allow overriding each setting
+ * individually.
+ */
+
+static int touchscreen_variant = -1;
+module_param(touchscreen_variant, int, 0444);
+MODULE_PARM_DESC(touchscreen_variant, "Touchscreen variant 0-x, -1 for auto");
+
+static int touchscreen_width = -1;
+module_param(touchscreen_width, int, 0444);
+MODULE_PARM_DESC(touchscreen_width, "Touchscreen width, -1 for auto");
+
+static int touchscreen_height = -1;
+module_param(touchscreen_height, int, 0444);
+MODULE_PARM_DESC(touchscreen_height, "Touchscreen height, -1 for auto");
+
+static int touchscreen_invert_x = -1;
+module_param(touchscreen_invert_x, int, 0444);
+MODULE_PARM_DESC(touchscreen_invert_x, "Touchscreen invert x, -1 for auto");
+
+static int touchscreen_invert_y = -1;
+module_param(touchscreen_invert_y, int, 0444);
+MODULE_PARM_DESC(touchscreen_invert_y, "Touchscreen invert y, -1 for auto");
+
+static int touchscreen_swap_x_y = -1;
+module_param(touchscreen_swap_x_y, int, 0444);
+MODULE_PARM_DESC(touchscreen_swap_x_y, "Touchscreen swap x y, -1 for auto");
+
+static char *touchscreen_fw_name;
+module_param(touchscreen_fw_name, charp, 0444);
+MODULE_PARM_DESC(touchscreen_fw_name, "Touchscreen firmware filename");
+
+#define TOUCHSCREEN_POWER_ON_DELAY	20
+#define SILEAD_REG_ID			0xFC
+#define EKTF2127_RESPONSE		0x52
+#define EKTF2127_REQUEST		0x53
+#define EKTF2127_WIDTH			0x63
+
+enum touchscreen_model {
+	touchscreen_unknown,
+	gsl1680_a082,
+	gsl1680_b482,
+	ektf2127,
+	zet6251,
+};
+
+struct q8_hardwaremgr_data {
+	struct device *dev;
+	bool touchscreen_needs_regulator;
+	enum touchscreen_model touchscreen_model;
+	int touchscreen_addr;
+	int touchscreen_variant;
+	int touchscreen_width;
+	int touchscreen_height;
+	int touchscreen_invert_x;
+	int touchscreen_invert_y;
+	int touchscreen_swap_x_y;
+	const char *touchscreen_compatible;
+	const char *touchscreen_fw_name;
+};
+
+typedef int (*probe_func)(struct q8_hardwaremgr_data *data,

drivers/misc/q8-hardwaremgr.c new file +88 -0

+static int q8_hardwaremgr_probe_touchscreen(struct q8_hardwaremgr_data *data,
+					    struct i2c_adapter *adap)
+{
+	struct i2c_client *client;
+	unsigned char buff[24];
+	__le32 chip_id;
+	int ret;
+
+	msleep(TOUCHSCREEN_POWER_ON_DELAY);
+
+	/* Check for silead touchsceen at addr 0x40 */
+	client = i2c_new_dummy(adap, 0x40);
+	if (!client)
+		return -ENOMEM;
+
+	ret = i2c_smbus_read_i2c_block_data(client, SILEAD_REG_ID,
+					    sizeof(chip_id), (u8 *)&chip_id);
+	if (ret == sizeof(chip_id)) {
+		switch (le32_to_cpu(chip_id)) {
+		case 0xa0820000:
+			data->touchscreen_addr = 0x40;
+			data->touchscreen_compatible = "silead,gsl1680";
+			data->touchscreen_model = gsl1680_a082;
+			dev_info(data->dev, "Found Silead touchscreen ID: 0xa0820000\n");
+			break;
+		case 0xb4820000:
+			data->touchscreen_addr = 0x40;
+			data->touchscreen_compatible = "silead,gsl1680";
+			data->touchscreen_model = gsl1680_b482;
+			dev_info(data->dev, "Found Silead touchscreen ID: 0xb4820000\n");
+			break;
 
+		default:
+			dev_warn(data->dev, "Found Silead touchscreen with unknown ID: 0x%08x\n",
+				 le32_to_cpu(chip_id));
+		}
+		ret = 0;
+	}
+	i2c_unregister_device(client);
+	if (ret == 0 || ret == -ETIMEDOUT /* Bus stuck bail immediately */)
+		return ret;
+
+	/* Check for Elan eKTF2127 touchsceen at addr 0x15 */
+	client = i2c_new_dummy(adap, 0x15);
+	if (!client)
+		return -ENOMEM;
+
+	do {
+		/* Read hello, ignore data, depends on initial power state */
+		ret = i2c_master_recv(client, buff, 4);
+		if (ret != 4)
+			break;
+
+		/* Request width */
+		buff[0] = EKTF2127_REQUEST;
+		buff[1] = EKTF2127_WIDTH;
+		buff[2] = 0x00;
+		buff[3] = 0x00;
+		ret = i2c_master_send(client, buff, 4);
+		if (ret != 4)
+			break;
+
+		msleep(20);
+
+		/* Read response */
+		ret = i2c_master_recv(client, buff, 4);
+		if (ret != 4)
+			break;
+			
+		if (buff[0] == EKTF2127_RESPONSE && buff[1] == EKTF2127_WIDTH) {
+			data->touchscreen_addr = 0x15;
+			data->touchscreen_compatible = "elan,ektf2127";
+			data->touchscreen_model = ektf2127;
+			dev_info(data->dev, "Found Elan eKTF2127 touchscreen\n");
+			ret = 0;
+		}
+	} while (0);
+	i2c_unregister_device(client);
+	if (ret == 0 || ret == -ETIMEDOUT /* Bus stuck bail immediately */)
+		return ret;
+
+	/* Check for Zeitec zet6251 touchsceen at addr 0x76 */
+	client = i2c_new_dummy(adap, 0x76);
+	if (!client)
+		return -ENOMEM;
+
+	/*
+	 * We only do a simple read finger data packet test, because some
+	 * versions require firmware to be loaded. If not firmware is loaded

drivers/misc/q8-hardwaremgr.c new file +272 -0

+	i2c_unregister_device(client);
+	if (ret == 0 || ret == -ETIMEDOUT /* Bus stuck bail immediately */)
+		return ret;
+
+	return -ENODEV;
+}
+
+static int q8_hardwaremgr_do_probe(struct q8_hardwaremgr_data *data,
+				   const char *prefix, probe_func func)
+{
+	struct device *dev = data->dev;
+	struct device_node *np;
+	struct i2c_adapter *adap;
+	struct regulator *reg;
+	struct gpio_desc *gpio;
+	int ret = 0;
+
+	np = of_parse_phandle(dev->of_node, prefix, 0);
+	if (!np) {
+		dev_err(dev, "Error %s not set\n", prefix);
+		return -EINVAL;
+	}
+
+	adap = of_get_i2c_adapter_by_node(np->parent);
+	if (!adap) {
+		ret = -EPROBE_DEFER;
+		goto put_node;
+	}
+
+	reg = regulator_get_optional(dev, prefix);
+	if (IS_ERR(reg)) {
+		ret = PTR_ERR(reg);
+		if (ret == -EPROBE_DEFER)
+			goto put_adapter;
+		reg = NULL;
+	}
+
+	gpio = fwnode_get_named_gpiod(&np->fwnode, "power-gpios");
+	if (IS_ERR(gpio)) {
+		ret = PTR_ERR(gpio);
+		if (ret == -EPROBE_DEFER)
+			goto put_reg;
+		gpio = NULL;
+	}
+
+	/* First try with only the power gpio driven high */
+	if (gpio) {
+		ret = gpiod_direction_output(gpio, 1);
+		if (ret)
+			goto put_gpio;
+	}
+
+	dev_info(dev, "Looking for %s without a regulator\n", prefix);
+	ret = func(data, adap);
+	if (ret != 0 && reg) {
+		/* Second try, also enable the regulator */
+		ret = regulator_enable(reg);
+		if (ret)
+			goto restore_gpio;
+
+		dev_info(dev, "Looking for %s with a regulator\n", prefix);
+		ret = func(data, adap);
+		if (ret == 0)
+			data->touchscreen_needs_regulator = true; 
+
+		regulator_disable(reg);
+	}
+	ret = 0; /* Not finding a device is not an error */
+
+restore_gpio:
+	if (gpio)
+		gpiod_direction_output(gpio, 0);
+put_gpio:
+	if (gpio)
+		gpiod_put(gpio);
+put_reg:
+	if (reg)
+		regulator_put(reg);
+put_adapter:
+	i2c_put_adapter(adap);
+
+put_node:
+	of_node_put(np);
+
+	return ret;
+}
+
+static void q8_hardwaremgr_apply_gsl1680_a082_variant(
+	struct q8_hardwaremgr_data *data)
+{
+	if (touchscreen_variant != -1) {
+		data->touchscreen_variant = touchscreen_variant;
+	} else {
+		if (of_machine_is_compatible("allwinner,sun8i-a33"))
+			data->touchscreen_variant = 1;
+		else
+			data->touchscreen_variant = 0;
+	}
+
+	switch (data->touchscreen_variant) {
+	default:
+		dev_warn(data->dev, "Error unknown touchscreen_variant %d using 0\n",
+			 touchscreen_variant);
+		/* Fall through */
+	case 0:
+		data->touchscreen_width = 1024;
+		data->touchscreen_height = 600;
+		data->touchscreen_fw_name = "gsl1680-a082-q8-700.fw";
+		break;
+	case 1:
+		data->touchscreen_width = 480;
+		data->touchscreen_height = 800;
+		data->touchscreen_swap_x_y = 1;
+		data->touchscreen_fw_name = "gsl1680-a082-q8-a70.fw";
+		break;
+	}
+}
+
+static void q8_hardwaremgr_apply_gsl1680_b482_variant(
+	struct q8_hardwaremgr_data *data)
+{
+	if (touchscreen_variant != -1)
+		data->touchscreen_variant = touchscreen_variant;
+
+	switch (data->touchscreen_variant) {
+	default:
+		dev_warn(data->dev, "Error unknown touchscreen_variant %d using 0\n",
+			 touchscreen_variant);
+		/* Fall through */
+	case 0:
+		data->touchscreen_width = 960;
+		data->touchscreen_height = 640;
+		data->touchscreen_fw_name = "gsl1680-b482-q8-d702.fw";
+		break;
+	case 1:
+		data->touchscreen_width = 960;
+		data->touchscreen_height = 640;
+		data->touchscreen_fw_name = "gsl1680-b482-q8-a70.fw";
+		break;
+	}
+}
+
+static void q8_hardwaremgr_issue_gsl1680_warning(
+	struct q8_hardwaremgr_data *data)
+{
+	dev_warn(data->dev, "gsl1680 touchscreen may require kernel cmdline parameters to function properly\n");
+	dev_warn(data->dev, "Try q8_hardwaremgr.touchscreen_invert_x=1 if x coordinates are inverted\n");
+	dev_warn(data->dev, "Try q8_hardwaremgr.touchscreen_variant=%d if coordinates are all over the place\n",
+		 !data->touchscreen_variant);
+
+#define	show(x) \
+	dev_info(data->dev, #x " %d (%s)\n", data->x, \
+		 (x == -1) ? "auto" : "user supplied")
+
+	show(touchscreen_variant);
+	show(touchscreen_width);
+	show(touchscreen_height);
+	show(touchscreen_invert_x);
+	show(touchscreen_invert_y);
+	show(touchscreen_swap_x_y);
+	dev_info(data->dev, "touchscreen_fw_name %s (%s)\n",
+		 data->touchscreen_fw_name,
+		 (touchscreen_fw_name == NULL) ? "auto" : "user supplied");
+#undef show
+}
+
+static void q8_hardwaremgr_apply_touchscreen(struct q8_hardwaremgr_data *data)
+{
+	struct device *dev = data->dev;
+	struct of_changeset cset;
+	struct device_node *np;
+
+	switch (data->touchscreen_model) {
+	case touchscreen_unknown:
+		return;
+	case gsl1680_a082:
+		q8_hardwaremgr_apply_gsl1680_a082_variant(data);
+		break;
+	case gsl1680_b482:
+		q8_hardwaremgr_apply_gsl1680_b482_variant(data);
+		break;
+	case ektf2127:
+	case zet6251:
+		/* These have only 1 variant */
+		break;
+	}
+
+	if (touchscreen_width != -1)
+		data->touchscreen_width = touchscreen_width;
+
+	if (touchscreen_height != -1)
+		data->touchscreen_height = touchscreen_height;
+
+	if (touchscreen_invert_x != -1)
+		data->touchscreen_invert_x = touchscreen_invert_x;
+
+	if (touchscreen_invert_y != -1)
+		data->touchscreen_invert_y = touchscreen_invert_y;
+
+	if (touchscreen_swap_x_y != -1)
+		data->touchscreen_swap_x_y = touchscreen_swap_x_y;
+
+	if (touchscreen_fw_name)
+		data->touchscreen_fw_name = touchscreen_fw_name;
+
+	if (data->touchscreen_model == gsl1680_a082 ||
+	    data->touchscreen_model == gsl1680_b482)
+		q8_hardwaremgr_issue_gsl1680_warning(data);
+
+	np = of_parse_phandle(data->dev->of_node, "touchscreen", 0);
+	/* Never happens already checked in q8_hardwaremgr_do_probe() */
+	if (WARN_ON(!np))
+		return;
+
+	of_changeset_init(&cset);
+	of_changeset_add_property_u32(&cset, np, "reg", data->touchscreen_addr);
+	of_changeset_add_property_string(&cset, np, "compatible",
+					 data->touchscreen_compatible);
+
+	if (data->touchscreen_width)
+		of_changeset_add_property_u32(&cset, np, "touchscreen-size-x",
+					      data->touchscreen_width);
+	if (data->touchscreen_height)
+		of_changeset_add_property_u32(&cset, np, "touchscreen-size-y",
+					      data->touchscreen_height);
+	if (data->touchscreen_invert_x)
+		of_changeset_add_property_bool(&cset, np,
+					       "touchscreen-inverted-x");
+	if (data->touchscreen_invert_y)
+		of_changeset_add_property_bool(&cset, np,
+					       "touchscreen-inverted-y");
+	if (data->touchscreen_swap_x_y)
+		of_changeset_add_property_bool(&cset, np,
+					       "touchscreen-swapped-x-y");
+	if (data->touchscreen_fw_name)
+		of_changeset_add_property_string(&cset, np, "firmware-name",
+						 data->touchscreen_fw_name);
+	if (data->touchscreen_needs_regulator) {
+		struct property *p;
+
+		p = of_find_property(dev->of_node, "touchscreen-supply", NULL);
+		/* Never happens already checked in q8_hardwaremgr_do_probe() */
+		if (WARN_ON(!p))
+			return;
+
+		of_changeset_add_property_copy(&cset, np, "vddio-supply",
+					       p->value, p->length);
+	}
+
+	of_changeset_update_property_string(&cset, np, "status", "okay");
+	of_changeset_apply(&cset);
+
+	of_node_put(np);
+}
+
+static int q8_hardwaremgr_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct q8_hardwaremgr_data *data;
+	int ret = 0;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->dev = &pdev->dev;
+
+	ret = q8_hardwaremgr_do_probe(data, "touchscreen",
+				      q8_hardwaremgr_probe_touchscreen);
+	if (ret)
+		goto error;
+

drivers/misc/q8-hardwaremgr.c new file +27 -0

+	q8_hardwaremgr_apply_touchscreen(data);
+
+error:
+	kfree(data);
+
+	return ret;
+}
+
+static const struct of_device_id q8_hardwaremgr_of_match[] = {
+	{ .compatible = "allwinner,sunxi-q8-hardwaremgr", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, q8_hardwaremgr_of_match);
+
+static struct platform_driver q8_hardwaremgr_driver = {
+	.driver = {
+		.name	= "q8-hardwaremgr",
+		.of_match_table = of_match_ptr(q8_hardwaremgr_of_match),
+	},
+	.probe	= q8_hardwaremgr_probe,
+};
+
+module_platform_driver(q8_hardwaremgr_driver);
+
+MODULE_DESCRIPTION("Allwinner q8 formfactor tablet hardware manager");
+MODULE_AUTHOR("Hans de Goede <[email protected]>");
+MODULE_LICENSE("GPL");

Signature · 1 line

2.9.3

Hi Hans,

Quoted 222 lines · Hans de Goede

Allwinnner A13 / A23 / A33 based Q8 tablets are popular cheap 7" tablets of which a new batch is produced every few weeks. Each batch uses a different mix of touchscreen, accelerometer and wifi peripherals.

Given that each batch is different creating a devicetree for each variant is not desirable. This commit adds a Q8 tablet hardware manager which auto-detects the touchscreen and accelerometer so that a single generic dts can be used for these tablets.

The wifi is connected to a discoverable bus (sdio or usb) and will be autodetected by the mmc resp. usb subsystems.

Signed-off-by Hans de Goede <[email protected]>

---

.../misc/allwinner,sunxi-q8-hardwaremgr.txt        |  52 +++
drivers/misc/Kconfig                               |  12 +
drivers/misc/Makefile                              |   1 +
drivers/misc/q8-hardwaremgr.c                      | 512 +++++++++++++++++++++
4 files changed, 577 insertions(+)

create mode 100644 Documentation/devicetree/bindings/misc/allwinner,sunxi-q8-hardwaremgr.txt create mode 100644 drivers/misc/q8-hardwaremgr.c

Documentation/devicetree/bindings/misc/allwinner,sunxi-q8-hardwaremgr.txt new file +52 -0

new file mode 100644
index 0000000..f428bf5
@@ -0,0 +1,52 @@
+Q8 tablet hardware manager
+--------------------------
+
+Allwinnner A13 / A23 / A33 based Q8 tablets are popular cheap 7" tablets of
+which a new batch is produced every few weeks. Each batch uses a different
+mix of touchscreen, accelerometer and wifi peripherals.
+
+Given that each batch is different creating a devicetree for each variant is
+not desirable. The Q8 tablet hardware manager bindings are bindings for an os
+module which auto-detects the touchscreen so that a single
+generic dts can be used for these tablets.
+
+The wifi is connected to a discoverable bus and will be autodetected by the os.
+
+Required properties:
+ - compatible         : "allwinner,sunxi-q8-hardwaremgr"
+ - touchscreen        : phandle of a template touchscreen node, this must be a
+		        child node of the touchscreen i2c bus
+
+Optional properties:
+ - touchscreen-supply : regulator phandle for the touchscreen vdd supply
+
+touschreen node required properties:
+ - interrupt-parent   : phandle pointing to the interrupt controller
+			serving the touchscreen interrupt
+ - interrupts         : interrupt specification for the touchscreen interrupt
+ - power-gpios        : Specification for the pin connected to the touchscreen's
+			enable / wake pin. This needs to be driven high to
+			enable the touchscreen controller
+
+Example:
+
+/ {
+	hwmgr {
+		compatible = "allwinner,sunxi-q8-hardwaremgr";
+		touchscreen = <&touchscreen>;
+		touchscreen-supply = <&reg_ldo_io1>;
+	};
+};
+
+&i2c0 {
+	touchscreen: touchscreen at 0 {
+		interrupt-parent = <&pio>;
+		interrupts = <1 5 IRQ_TYPE_EDGE_FALLING>; /* PB5 */
+		power-gpios = <&pio 7 1 GPIO_ACTIVE_HIGH>; /* PH1 */
+		/*
+		 * Enabled by sunxi-q8-hardwaremgr if it detects a
+		 * known model touchscreen.
+		 */
+		status = "disabled";
+	};
+};

drivers/misc/Kconfig +12 -0

index a216b46..c3e7772 100644
@@ -804,6 +804,18 @@ config PANEL_BOOT_MESSAGE
 	  An empty message will only clear the display at driver init time. Any other
 	  printf()-formatted message is valid with newline and escape codes.
 
+config Q8_HARDWAREMGR
+	tristate "Allwinner Q8 tablet hardware manager"
+	depends on GPIOLIB || COMPILE_TEST
+	depends on I2C
+	depends on OF
+	default	n
+	help
+	  This option enables support for autodetecting the touchscreen
+	  on Allwinner Q8 tablets.
+
+	  If unsure, say N.
+

source "drivers/misc/c2port/Kconfig"
source "drivers/misc/eeprom/Kconfig"
source "drivers/misc/cb710/Kconfig"

drivers/misc/Makefile +0 -0

index 7410c6d..cac76b7 100644
@@ -57,6 +57,7 @@ obj-$(CONFIG_ECHO)		+= echo/

obj-$(CONFIG_VEXPRESS_SYSCFG) += vexpress-syscfg.o
obj-$(CONFIG_CXL_BASE) += cxl/
obj-$(CONFIG_PANEL) += panel.o
+obj-$(CONFIG_Q8_HARDWAREMGR) += q8-hardwaremgr.o

lkdtm-$(CONFIG_LKDTM) += lkdtm_core.o
lkdtm-$(CONFIG_LKDTM) += lkdtm_bugs.o

drivers/misc/q8-hardwaremgr.c new file +99 -0

new file mode 100644
index 0000000..e75625e
@@ -0,0 +1,512 @@
+/*
+ * Allwinner q8 formfactor tablet hardware manager
+ *
+ * Copyright (C) 2016 Hans de Goede <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <asm/unaligned.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+
+/*
+ * We can detect which touchscreen controller is used automatically,
+ * but some controllers can be wired up differently depending on the
+ * q8 PCB variant used, so they need different firmware files / settings.
+ *
+ * We allow the user to specify a firmware_variant to select a config
+ * from a list of known configs. We also allow overriding each setting
+ * individually.
+ */
+
+static int touchscreen_variant = -1;
+module_param(touchscreen_variant, int, 0444);
+MODULE_PARM_DESC(touchscreen_variant, "Touchscreen variant 0-x, -1 for auto");
+
+static int touchscreen_width = -1;
+module_param(touchscreen_width, int, 0444);
+MODULE_PARM_DESC(touchscreen_width, "Touchscreen width, -1 for auto");
+
+static int touchscreen_height = -1;
+module_param(touchscreen_height, int, 0444);
+MODULE_PARM_DESC(touchscreen_height, "Touchscreen height, -1 for auto");
+
+static int touchscreen_invert_x = -1;
+module_param(touchscreen_invert_x, int, 0444);
+MODULE_PARM_DESC(touchscreen_invert_x, "Touchscreen invert x, -1 for auto");
+
+static int touchscreen_invert_y = -1;
+module_param(touchscreen_invert_y, int, 0444);
+MODULE_PARM_DESC(touchscreen_invert_y, "Touchscreen invert y, -1 for auto");
+
+static int touchscreen_swap_x_y = -1;
+module_param(touchscreen_swap_x_y, int, 0444);
+MODULE_PARM_DESC(touchscreen_swap_x_y, "Touchscreen swap x y, -1 for auto");
+
+static char *touchscreen_fw_name;
+module_param(touchscreen_fw_name, charp, 0444);
+MODULE_PARM_DESC(touchscreen_fw_name, "Touchscreen firmware filename");
+
+#define TOUCHSCREEN_POWER_ON_DELAY	20
+#define SILEAD_REG_ID			0xFC
+#define EKTF2127_RESPONSE		0x52
+#define EKTF2127_REQUEST		0x53
+#define EKTF2127_WIDTH			0x63
+
+enum touchscreen_model {
+	touchscreen_unknown,
+	gsl1680_a082,
+	gsl1680_b482,
+	ektf2127,
+	zet6251,
+};
+
+struct q8_hardwaremgr_data {
+	struct device *dev;
+	bool touchscreen_needs_regulator;
+	enum touchscreen_model touchscreen_model;
+	int touchscreen_addr;
+	int touchscreen_variant;
+	int touchscreen_width;
+	int touchscreen_height;
+	int touchscreen_invert_x;
+	int touchscreen_invert_y;
+	int touchscreen_swap_x_y;
+	const char *touchscreen_compatible;
+	const char *touchscreen_fw_name;
+};
+
+typedef int (*probe_func)(struct q8_hardwaremgr_data *data,
+			  struct i2c_adapter *adap);
+
+#if 0
+	ret = i2c_smbus_xfer(adap, 0x40, 0, I2C_SMBUS_WRITE, 0,

drivers/misc/q8-hardwaremgr.c line 105

Quoted 6 lines

drivers/misc/q8-hardwaremgr.c new file +6 -0

+			     I2C_SMBUS_QUICK, NULL);
+	if (ret < 0)
+		return -ENODEV;
+
+#endif
+

^^^ crud?

Quoted 89 lines

drivers/misc/q8-hardwaremgr.c new file +88 -0

+static int q8_hardwaremgr_probe_touchscreen(struct q8_hardwaremgr_data *data,
+					    struct i2c_adapter *adap)
+{
+	struct i2c_client *client;
+	unsigned char buff[24];
+	__le32 chip_id;
+	int ret;
+
+	msleep(TOUCHSCREEN_POWER_ON_DELAY);
+
+	/* Check for silead touchsceen at addr 0x40 */
+	client = i2c_new_dummy(adap, 0x40);
+	if (!client)
+		return -ENOMEM;
+
+	ret = i2c_smbus_read_i2c_block_data(client, SILEAD_REG_ID,
+					    sizeof(chip_id), (u8 *)&chip_id);
+	if (ret == sizeof(chip_id)) {
+		switch (le32_to_cpu(chip_id)) {
+		case 0xa0820000:
+			data->touchscreen_addr = 0x40;
+			data->touchscreen_compatible = "silead,gsl1680";
+			data->touchscreen_model = gsl1680_a082;
+			dev_info(data->dev, "Found Silead touchscreen ID: 0xa0820000\n");
+			break;
+		case 0xb4820000:
+			data->touchscreen_addr = 0x40;
+			data->touchscreen_compatible = "silead,gsl1680";
+			data->touchscreen_model = gsl1680_b482;
+			dev_info(data->dev, "Found Silead touchscreen ID: 0xb4820000\n");
+			break;
 
+		default:
+			dev_warn(data->dev, "Found Silead touchscreen with unknown ID: 0x%08x\n",
+				 le32_to_cpu(chip_id));
+		}
+		ret = 0;
+	}
+	i2c_unregister_device(client);
+	if (ret == 0 || ret == -ETIMEDOUT /* Bus stuck bail immediately */)
+		return ret;
+
+	/* Check for Elan eKTF2127 touchsceen at addr 0x15 */
+	client = i2c_new_dummy(adap, 0x15);
+	if (!client)
+		return -ENOMEM;
+
+	do {
+		/* Read hello, ignore data, depends on initial power state */
+		ret = i2c_master_recv(client, buff, 4);
+		if (ret != 4)
+			break;
+
+		/* Request width */
+		buff[0] = EKTF2127_REQUEST;
+		buff[1] = EKTF2127_WIDTH;
+		buff[2] = 0x00;
+		buff[3] = 0x00;
+		ret = i2c_master_send(client, buff, 4);
+		if (ret != 4)
+			break;
+
+		msleep(20);
+
+		/* Read response */
+		ret = i2c_master_recv(client, buff, 4);
+		if (ret != 4)
+			break;
+			
+		if (buff[0] == EKTF2127_RESPONSE && buff[1] == EKTF2127_WIDTH) {
+			data->touchscreen_addr = 0x15;
+			data->touchscreen_compatible = "elan,ektf2127";
+			data->touchscreen_model = ektf2127;
+			dev_info(data->dev, "Found Elan eKTF2127 touchscreen\n");
+			ret = 0;
+		}
+	} while (0);
+	i2c_unregister_device(client);
+	if (ret == 0 || ret == -ETIMEDOUT /* Bus stuck bail immediately */)
+		return ret;
+
+	/* Check for Zeitec zet6251 touchsceen at addr 0x76 */
+	client = i2c_new_dummy(adap, 0x76);
+	if (!client)
+		return -ENOMEM;
+
+	/*
+	 * We only do a simple read finger data packet test, because some
+	 * versions require firmware to be loaded. If not firmware is loaded

drivers/misc/q8-hardwaremgr.c line 203

Quoted 10 lines

drivers/misc/q8-hardwaremgr.c new file +10 -0

+	 * the buffer will be filed with 0xff, so we ignore the contents.
+	 */
+	ret = i2c_master_recv(client, buff, 24);
+	if (ret == 24) {
+		data->touchscreen_addr = 0x76;
+		data->touchscreen_compatible = "zeitec,zet6251";
+		data->touchscreen_model = zet6251;
+		dev_info(data->dev, "Found Zeitec zet6251 touchscreen\n");
+		ret = 0;
+	}

I can understand having a switch here since it?s quite complicated but it would be better to have a structure that defines them i.e.

struct touchscreen_detect_data {
	u32 chip_id;
	int addr;
	const char *compatible;
	enum touchscreen_model model;

};

static const struct touchscreen_detect_data ts_detect_data[] = {
	{
		.chip_id = 0xa0820000,
		.addr = 0x40,
		.compatible = ?silead,gsl1680?,
		.model = gsl1680_a082,
	}, ...
};

And so on, and restructuring by having different paths by touchscreen model type.

Quoted 276 lines

drivers/misc/q8-hardwaremgr.c new file +276 -0

+	i2c_unregister_device(client);
+	if (ret == 0 || ret == -ETIMEDOUT /* Bus stuck bail immediately */)
+		return ret;
+
+	return -ENODEV;
+}
+
+static int q8_hardwaremgr_do_probe(struct q8_hardwaremgr_data *data,
+				   const char *prefix, probe_func func)
+{
+	struct device *dev = data->dev;
+	struct device_node *np;
+	struct i2c_adapter *adap;
+	struct regulator *reg;
+	struct gpio_desc *gpio;
+	int ret = 0;
+
+	np = of_parse_phandle(dev->of_node, prefix, 0);
+	if (!np) {
+		dev_err(dev, "Error %s not set\n", prefix);
+		return -EINVAL;
+	}
+
+	adap = of_get_i2c_adapter_by_node(np->parent);
+	if (!adap) {
+		ret = -EPROBE_DEFER;
+		goto put_node;
+	}
+
+	reg = regulator_get_optional(dev, prefix);
+	if (IS_ERR(reg)) {
+		ret = PTR_ERR(reg);
+		if (ret == -EPROBE_DEFER)
+			goto put_adapter;
+		reg = NULL;
+	}
+
+	gpio = fwnode_get_named_gpiod(&np->fwnode, "power-gpios");
+	if (IS_ERR(gpio)) {
+		ret = PTR_ERR(gpio);
+		if (ret == -EPROBE_DEFER)
+			goto put_reg;
+		gpio = NULL;
+	}
+
+	/* First try with only the power gpio driven high */
+	if (gpio) {
+		ret = gpiod_direction_output(gpio, 1);
+		if (ret)
+			goto put_gpio;
+	}
+
+	dev_info(dev, "Looking for %s without a regulator\n", prefix);
+	ret = func(data, adap);
+	if (ret != 0 && reg) {
+		/* Second try, also enable the regulator */
+		ret = regulator_enable(reg);
+		if (ret)
+			goto restore_gpio;
+
+		dev_info(dev, "Looking for %s with a regulator\n", prefix);
+		ret = func(data, adap);
+		if (ret == 0)
+			data->touchscreen_needs_regulator = true;
+
+		regulator_disable(reg);
+	}
+	ret = 0; /* Not finding a device is not an error */
+
+restore_gpio:
+	if (gpio)
+		gpiod_direction_output(gpio, 0);
+put_gpio:
+	if (gpio)
+		gpiod_put(gpio);
+put_reg:
+	if (reg)
+		regulator_put(reg);
+put_adapter:
+	i2c_put_adapter(adap);
+
+put_node:
+	of_node_put(np);
+
+	return ret;
+}
+
+static void q8_hardwaremgr_apply_gsl1680_a082_variant(
+	struct q8_hardwaremgr_data *data)
+{
+	if (touchscreen_variant != -1) {
+		data->touchscreen_variant = touchscreen_variant;
+	} else {
+		if (of_machine_is_compatible("allwinner,sun8i-a33"))
+			data->touchscreen_variant = 1;
+		else
+			data->touchscreen_variant = 0;
+	}
+
+	switch (data->touchscreen_variant) {
+	default:
+		dev_warn(data->dev, "Error unknown touchscreen_variant %d using 0\n",
+			 touchscreen_variant);
+		/* Fall through */
+	case 0:
+		data->touchscreen_width = 1024;
+		data->touchscreen_height = 600;
+		data->touchscreen_fw_name = "gsl1680-a082-q8-700.fw";
+		break;
+	case 1:
+		data->touchscreen_width = 480;
+		data->touchscreen_height = 800;
+		data->touchscreen_swap_x_y = 1;
+		data->touchscreen_fw_name = "gsl1680-a082-q8-a70.fw";
+		break;
+	}
+}
+
+static void q8_hardwaremgr_apply_gsl1680_b482_variant(
+	struct q8_hardwaremgr_data *data)
+{
+	if (touchscreen_variant != -1)
+		data->touchscreen_variant = touchscreen_variant;
+
+	switch (data->touchscreen_variant) {
+	default:
+		dev_warn(data->dev, "Error unknown touchscreen_variant %d using 0\n",
+			 touchscreen_variant);
+		/* Fall through */
+	case 0:
+		data->touchscreen_width = 960;
+		data->touchscreen_height = 640;
+		data->touchscreen_fw_name = "gsl1680-b482-q8-d702.fw";
+		break;
+	case 1:
+		data->touchscreen_width = 960;
+		data->touchscreen_height = 640;
+		data->touchscreen_fw_name = "gsl1680-b482-q8-a70.fw";
+		break;
+	}
+}
+
+static void q8_hardwaremgr_issue_gsl1680_warning(
+	struct q8_hardwaremgr_data *data)
+{
+	dev_warn(data->dev, "gsl1680 touchscreen may require kernel cmdline parameters to function properly\n");
+	dev_warn(data->dev, "Try q8_hardwaremgr.touchscreen_invert_x=1 if x coordinates are inverted\n");
+	dev_warn(data->dev, "Try q8_hardwaremgr.touchscreen_variant=%d if coordinates are all over the place\n",
+		 !data->touchscreen_variant);
+
+#define	show(x) \
+	dev_info(data->dev, #x " %d (%s)\n", data->x, \
+		 (x == -1) ? "auto" : "user supplied")
+
+	show(touchscreen_variant);
+	show(touchscreen_width);
+	show(touchscreen_height);
+	show(touchscreen_invert_x);
+	show(touchscreen_invert_y);
+	show(touchscreen_swap_x_y);
+	dev_info(data->dev, "touchscreen_fw_name %s (%s)\n",
+		 data->touchscreen_fw_name,
+		 (touchscreen_fw_name == NULL) ? "auto" : "user supplied");
+#undef show
+}
+
+static void q8_hardwaremgr_apply_touchscreen(struct q8_hardwaremgr_data *data)
+{
+	struct device *dev = data->dev;
+	struct of_changeset cset;
+	struct device_node *np;
+
+	switch (data->touchscreen_model) {
+	case touchscreen_unknown:
+		return;
+	case gsl1680_a082:
+		q8_hardwaremgr_apply_gsl1680_a082_variant(data);
+		break;
+	case gsl1680_b482:
+		q8_hardwaremgr_apply_gsl1680_b482_variant(data);
+		break;
+	case ektf2127:
+	case zet6251:
+		/* These have only 1 variant */
+		break;
+	}
+
+	if (touchscreen_width != -1)
+		data->touchscreen_width = touchscreen_width;
+
+	if (touchscreen_height != -1)
+		data->touchscreen_height = touchscreen_height;
+
+	if (touchscreen_invert_x != -1)
+		data->touchscreen_invert_x = touchscreen_invert_x;
+
+	if (touchscreen_invert_y != -1)
+		data->touchscreen_invert_y = touchscreen_invert_y;
+
+	if (touchscreen_swap_x_y != -1)
+		data->touchscreen_swap_x_y = touchscreen_swap_x_y;
+
+	if (touchscreen_fw_name)
+		data->touchscreen_fw_name = touchscreen_fw_name;
+
+	if (data->touchscreen_model == gsl1680_a082 ||
+	    data->touchscreen_model == gsl1680_b482)
+		q8_hardwaremgr_issue_gsl1680_warning(data);
+
+	np = of_parse_phandle(data->dev->of_node, "touchscreen", 0);
+	/* Never happens already checked in q8_hardwaremgr_do_probe() */
+	if (WARN_ON(!np))
+		return;
+
+	of_changeset_init(&cset);
+	of_changeset_add_property_u32(&cset, np, "reg", data->touchscreen_addr);
+	of_changeset_add_property_string(&cset, np, "compatible",
+					 data->touchscreen_compatible);
+
+	if (data->touchscreen_width)
+		of_changeset_add_property_u32(&cset, np, "touchscreen-size-x",
+					      data->touchscreen_width);
+	if (data->touchscreen_height)
+		of_changeset_add_property_u32(&cset, np, "touchscreen-size-y",
+					      data->touchscreen_height);
+	if (data->touchscreen_invert_x)
+		of_changeset_add_property_bool(&cset, np,
+					       "touchscreen-inverted-x");
+	if (data->touchscreen_invert_y)
+		of_changeset_add_property_bool(&cset, np,
+					       "touchscreen-inverted-y");
+	if (data->touchscreen_swap_x_y)
+		of_changeset_add_property_bool(&cset, np,
+					       "touchscreen-swapped-x-y");
+	if (data->touchscreen_fw_name)
+		of_changeset_add_property_string(&cset, np, "firmware-name",
+						 data->touchscreen_fw_name);
+	if (data->touchscreen_needs_regulator) {
+		struct property *p;
+
+		p = of_find_property(dev->of_node, "touchscreen-supply", NULL);
+		/* Never happens already checked in q8_hardwaremgr_do_probe() */
+		if (WARN_ON(!p))
+			return;
+
+		of_changeset_add_property_copy(&cset, np, "vddio-supply",
+					       p->value, p->length);
+	}
+
+	of_changeset_update_property_string(&cset, np, "status", "okay");
+	of_changeset_apply(&cset);
+
+	of_node_put(np);
+}
+
+static int q8_hardwaremgr_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct q8_hardwaremgr_data *data;
+	int ret = 0;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->dev = &pdev->dev;
+
+	ret = q8_hardwaremgr_do_probe(data, "touchscreen",
+				      q8_hardwaremgr_probe_touchscreen);
+	if (ret)
+		goto error;
+
+	/*
+	 * Our pinctrl may conflict with the pinctrl of the detected devices
+	 * we're adding, so remove it before adding detected devices.
+	 */

drivers/misc/q8-hardwaremgr.c line 485

Quoted 6 lines

drivers/misc/q8-hardwaremgr.c new file +6 -0

+	if (dev->pins) {
+		devm_pinctrl_put(dev->pins->p);
+		devm_kfree(dev, dev->pins);
+		dev->pins = NULL;
+	}
+

Hmm, that?s weird for sure. How can it happen?

Allwinnner A13 / A23 / A33 based Q8 tablets are popular cheap 7" tablets of which a new batch is produced every few weeks. Each batch uses a different mix of touchscreen, accelerometer and wifi peripherals.

Given that each batch is different creating a devicetree for each variant is not desirable. This commit adds a Q8 tablet hardware manager which auto-detects the touchscreen and accelerometer so that a single generic dts can be used for these tablets.

The wifi is connected to a discoverable bus (sdio or usb) and will be autodetected by the mmc resp. usb subsystems.

Signed-off-by Hans de Goede <[email protected]>

---
 .../misc/allwinner,sunxi-q8-hardwaremgr.txt        |  52 +++
 drivers/misc/Kconfig                               |  12 +
 drivers/misc/Makefile                              |   1 +
 drivers/misc/q8-hardwaremgr.c                      | 512 +++++++++++++++++++++
 4 files changed, 577 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/misc/allwinner,sunxi-q8-hardwaremgr.txt
 create mode 100644 drivers/misc/q8-hardwaremgr.c

Documentation/devicetree/bindings/misc/allwinner,sunxi-q8-hardwaremgr.txt new file +11 -0

new file mode 100644
index 0000000..f428bf5
@@ -0,0 +1,52 @@
+Q8 tablet hardware manager
+--------------------------
+
+Allwinnner A13 / A23 / A33 based Q8 tablets are popular cheap 7" tablets of
+which a new batch is produced every few weeks. Each batch uses a different
+mix of touchscreen, accelerometer and wifi peripherals.
+
+Given that each batch is different creating a devicetree for each variant is
+not desirable. The Q8 tablet hardware manager bindings are bindings for an os
+module which auto-detects the touchscreen so that a single
+generic dts can be used for these tablets.

Documentation/devicetree/bindings/misc/allwinner,sunxi-q8-hardwaremgr.txt new file +31 -0

+
+touschreen node required properties:
+ - interrupt-parent   : phandle pointing to the interrupt controller
+                       serving the touchscreen interrupt
+ - interrupts         : interrupt specification for the touchscreen interrupt
+ - power-gpios        : Specification for the pin connected to the touchscreen's
+                       enable / wake pin. This needs to be driven high to
+                       enable the touchscreen controller
+
+Example:
+
+/ {
+       hwmgr {
+               compatible = "allwinner,sunxi-q8-hardwaremgr";
+               touchscreen = <&touchscreen>;
+               touchscreen-supply = <&reg_ldo_io1>;
+       };
+};
+
+&i2c0 {
+       touchscreen: touchscreen at 0 {
+               interrupt-parent = <&pio>;
+               interrupts = <1 5 IRQ_TYPE_EDGE_FALLING>; /* PB5 */
+               power-gpios = <&pio 7 1 GPIO_ACTIVE_HIGH>; /* PH1 */
+               /*
+                * Enabled by sunxi-q8-hardwaremgr if it detects a
+                * known model touchscreen.
+                */
+               status = "disabled";
+       };
+};

Quoted 44 lines · Hans de Goede

Allwinnner A13 / A23 / A33 based Q8 tablets are popular cheap 7" tablets of which a new batch is produced every few weeks. Each batch uses a different mix of touchscreen, accelerometer and wifi peripherals.

Given that each batch is different creating a devicetree for each variant is not desirable. This commit adds a Q8 tablet hardware manager which auto-detects the touchscreen and accelerometer so that a single generic dts can be used for these tablets.

The wifi is connected to a discoverable bus (sdio or usb) and will be autodetected by the mmc resp. usb subsystems.

Signed-off-by Hans de Goede <[email protected]>

---
 .../misc/allwinner,sunxi-q8-hardwaremgr.txt        |  52 +++
 drivers/misc/Kconfig                               |  12 +
 drivers/misc/Makefile                              |   1 +
 drivers/misc/q8-hardwaremgr.c                      | 512 +++++++++++++++++++++
 4 files changed, 577 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/misc/allwinner,sunxi-q8-hardwaremgr.txt
 create mode 100644 drivers/misc/q8-hardwaremgr.c

Documentation/devicetree/bindings/misc/allwinner,sunxi-q8-hardwaremgr.txt new file +16 -0

new file mode 100644
index 0000000..f428bf5
@@ -0,0 +1,52 @@
+Q8 tablet hardware manager
+--------------------------
+
+Allwinnner A13 / A23 / A33 based Q8 tablets are popular cheap 7" tablets of
+which a new batch is produced every few weeks. Each batch uses a different
+mix of touchscreen, accelerometer and wifi peripherals.
+
+Given that each batch is different creating a devicetree for each variant is
+not desirable. The Q8 tablet hardware manager bindings are bindings for an os
+module which auto-detects the touchscreen so that a single
+generic dts can be used for these tablets.
+
+The wifi is connected to a discoverable bus and will be autodetected by the os.
+
+Required properties:
+ - compatible         : "allwinner,sunxi-q8-hardwaremgr"

Documentation/devicetree/bindings/misc/allwinner,sunxi-q8-hardwaremgr.txt line 21

Quoted 5 lines

Documentation/devicetree/bindings/misc/allwinner,sunxi-q8-hardwaremgr.txt new file +5 -0

+ - touchscreen        : phandle of a template touchscreen node, this must be a
+                       child node of the touchscreen i2c bus
+
+Optional properties:
+ - touchscreen-supply : regulator phandle for the touchscreen vdd supply

While I said I think you should be using overlays here, you could also do it without.

However, this node has to go. It is not h/w, and you are putting it here purely to instantiate a driver.

For the
touchscreen property, surely you know where the touchscreen is located in the DT?

If not, of_find_node_by_name()?

For touchscreen-supply, I
assume this is to turn on the supply so you can talk to the touch controller. There's no reason the supply can't just be in the touchscreen node itself.

Quoted 32 lines

Documentation/devicetree/bindings/misc/allwinner,sunxi-q8-hardwaremgr.txt new file +31 -0

+
+touschreen node required properties:
+ - interrupt-parent   : phandle pointing to the interrupt controller
+                       serving the touchscreen interrupt
+ - interrupts         : interrupt specification for the touchscreen interrupt
+ - power-gpios        : Specification for the pin connected to the touchscreen's
+                       enable / wake pin. This needs to be driven high to
+                       enable the touchscreen controller
+
+Example:
+
+/ {
+       hwmgr {
+               compatible = "allwinner,sunxi-q8-hardwaremgr";
+               touchscreen = <&touchscreen>;
+               touchscreen-supply = <&reg_ldo_io1>;
+       };
+};
+
+&i2c0 {
+       touchscreen: touchscreen at 0 {
+               interrupt-parent = <&pio>;
+               interrupts = <1 5 IRQ_TYPE_EDGE_FALLING>; /* PB5 */
+               power-gpios = <&pio 7 1 GPIO_ACTIVE_HIGH>; /* PH1 */
+               /*
+                * Enabled by sunxi-q8-hardwaremgr if it detects a
+                * known model touchscreen.
+                */
+               status = "disabled";
+       };
+};

Hi,

Quoted 45 lines · Rob Herring

Quoted 44 lines · Hans de Goede

Allwinnner A13 / A23 / A33 based Q8 tablets are popular cheap 7" tablets of which a new batch is produced every few weeks. Each batch uses a different mix of touchscreen, accelerometer and wifi peripherals.

Given that each batch is different creating a devicetree for each variant is not desirable. This commit adds a Q8 tablet hardware manager which auto-detects the touchscreen and accelerometer so that a single generic dts can be used for these tablets.

The wifi is connected to a discoverable bus (sdio or usb) and will be autodetected by the mmc resp. usb subsystems.

Signed-off-by Hans de Goede <[email protected]>

---

.../misc/allwinner,sunxi-q8-hardwaremgr.txt        |  52 +++
drivers/misc/Kconfig                               |  12 +
drivers/misc/Makefile                              |   1 +
drivers/misc/q8-hardwaremgr.c                      | 512 +++++++++++++++++++++
4 files changed, 577 insertions(+)

create mode 100644 Documentation/devicetree/bindings/misc/allwinner,sunxi-q8-hardwaremgr.txt create mode 100644 drivers/misc/q8-hardwaremgr.c

Documentation/devicetree/bindings/misc/allwinner,sunxi-q8-hardwaremgr.txt new file +16 -0

new file mode 100644
index 0000000..f428bf5
@@ -0,0 +1,52 @@
+Q8 tablet hardware manager
+--------------------------
+
+Allwinnner A13 / A23 / A33 based Q8 tablets are popular cheap 7" tablets of
+which a new batch is produced every few weeks. Each batch uses a different
+mix of touchscreen, accelerometer and wifi peripherals.
+
+Given that each batch is different creating a devicetree for each variant is
+not desirable. The Q8 tablet hardware manager bindings are bindings for an os
+module which auto-detects the touchscreen so that a single
+generic dts can be used for these tablets.
+
+The wifi is connected to a discoverable bus and will be autodetected by the os.
+
+Required properties:
+ - compatible         : "allwinner,sunxi-q8-hardwaremgr"

Quoted 8 lines

Documentation/devicetree/bindings/misc/allwinner,sunxi-q8-hardwaremgr.txt line 21

Quoted 5 lines

Documentation/devicetree/bindings/misc/allwinner,sunxi-q8-hardwaremgr.txt new file +5 -0

+ - touchscreen        : phandle of a template touchscreen node, this must be a
+                       child node of the touchscreen i2c bus
+
+Optional properties:
+ - touchscreen-supply : regulator phandle for the touchscreen vdd supply

While I said I think you should be using overlays here, you could also do it without.

Good, because I believe that doing things without overlays will be much easier. If you look at the actual implementation you will see that it sets a lot of properties (touchscreen width, height, inversion, axis-swapping, firmware-name) based on various sources, the explosion of possible overlays from this is huge, and if we're going to runtime patch the overlays then why use them at all and not just runtime generate all the info ?

Quoted 2 lines

However, this node has to go. It is not h/w, and you are putting it here purely to instantiate a driver.

With "this" in "this node has to go", do you mean the node with the "allwinner,sunxi-q8-hardwaremgr" compatible, or do you mean the touchscreen template node ?

Quoted 4 lines

For the
touchscreen property, surely you know where the touchscreen is located in the DT?

Nope q8 tablets come with A13, A23 or A33 SoCs, A23/A33 are pin compatible with each other, but the A13 is not, this leads to the touchscreen being on a different i2c bus, so I cannot hardcode things, likewise the power-gpios and interrupt found in the touchscreen node differ between the A13 vs A23/A33.

I actually had a touchscreen-i2c-bus property containing a phandle to the i2c controller for the bus which has the touchscreen in an earlier revision + touchscreen-gpios and touchscreen-supply properties, I can switch to that if you prefer that over having a touchscreen template node.

Quoted 1 line

If not, of_find_node_by_name()?

Still a bit confused about what you do not like, (touchscreen template node vs q8-hardwaremgr node).

I guess (based on context) you do not want the
q8-hardwaremgr node ?

So the q8-hardwaremgr code should activate based on the machine compatible I presume?

How does that
work with module autoloading ?

If you do not want the q8-hardwaremgr node and thus no touchscreen property them yes I can use of_find_node_by_name(), but I thought that was generally frowned up on?

Quoted 4 lines

For touchscreen-supply, I
assume this is to turn on the supply so you can talk to the touch controller. There's no reason the supply can't just be in the touchscreen node itself.

Only a few q8 tablets actually use the regulator, so the hardwaremgr first tries detecting the touchscreen without it, and only if it does not find anything then tries with it, and adds a property to the touchscreen node for it, but I guess I can do this other way around and have it be present in the (incomplete / template) touchscreen node and delete it from it if not necessary.

Hi All,

Here is a first RFC for the q8 tablet hw-manager I've been talking about for a while now.

The touchscreen part is finished, I'll start working on the accelerometer bits next.

Note that this requires the "of: changesets: Introduce changeset helper methods" patch from Pantelis. If that is still not upstream when I'm ready to post a non RFC, I'll post a new version of that myself.

Quoted 5 lines · Hans de Goede

Hi All,

Here is a first RFC for the q8 tablet hw-manager I've been talking about for a while now.

Quoted 2 lines

The touchscreen part is finished, I'll start working on the accelerometer bits next.

This at least partially overlaps with the "overlay manager" just posted. A dev board having different devices attached and a production device have 2nd source components are not really different problems. We need a common solution and can't have each platform making up their own scheme.