mfd: fsl imx25 Touchscreen ADC driver

From: Markus Pargmann <[email protected]>

This is a driver for the imx25 ADC/TSC module. It controls the touchscreen conversion queue and creates a touchscreen input device. The driver currently only supports 4 wire touchscreens. The driver uses a simple conversion queue of precharge, touch detection, X measurement, Y measurement, precharge and another touch detection.

This driver uses the regmap from the parent to setup some touch specific settings in the core driver and setup a idle configuration with touch detection.

Signed-off-by Markus Pargmann <[email protected]>

Signed-off-by Denis Carikli <[email protected]>

---
Changelog v3->v4:
- Reworked the probe to handle the IRQ and the clock removal order correctly.
- Some code and style cleanups.

Changelog v2->v3:
- Fixed the 'Senitel' typo.
- Fixed input_report_key to report 1 for BTN_TOUCH events.
- Removed useless explicit casts.
- Also disable clock when devm_request_threaded_irq failed.

---
 .../bindings/input/touchscreen/fsl-mx25-tcq.txt    |   29 +
 drivers/input/touchscreen/Kconfig                  |    6 +
 drivers/input/touchscreen/Makefile                 |    1 +
 drivers/input/touchscreen/fsl-imx25-tcq.c          |  584 ++++++++++++++++++++
 4 files changed, 620 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/input/touchscreen/fsl-mx25-tcq.txt
 create mode 100644 drivers/input/touchscreen/fsl-imx25-tcq.c

Documentation/devicetree/bindings/input/touchscreen/fsl-mx25-tcq.txt new file +29 -0

new file mode 100644
index 0000000..4214a99
@@ -0,0 +1,29 @@
+Freescale mx25 TS conversion queue module
+
+mx25 touchscreen conversion queue module which controls the ADC unit of the
+mx25 for attached touchscreens.
+
+Required properties:
+ - compatible: Should be "fsl,imx25-tcq".
+ - reg: Memory range of the device.
+ - interrupts: Should be the interrupt number associated with this module within
+   the tscadc unit (<0>).
+ - interrupt-parent: Should be a phandle to the tscadc unit.
+ - fsl,wires: Should be '<4>' or '<5>'
+
+Optional properties:
+ - fsl,pen-debounce: Pen debounce time.
+ - fsl,pen-threshold: Pen-down threshold for the touchscreen.
+ - fsl,settling-time: Settling time in nanoseconds.
+
+This device includes two conversion queues which can be added as subnodes.
+The first queue is for the touchscreen, the second for general purpose ADC.
+
+Example:
+	tsc: tcq at 50030400 {
+		compatible = "fsl,imx25-tcq";
+		reg = <0x50030400 0x60>;
+		interrupt-parent = <&tscadc>;
+		interrupts = <0>;
+		fsl,wires = <4>;
+	};

drivers/input/touchscreen/Kconfig +6 -0

index a23a94b..a2290b9 100644
@@ -699,6 +699,12 @@ config TOUCHSCREEN_USB_COMPOSITE
 	  To compile this driver as a module, choose M here: the
 	  module will be called usbtouchscreen.
 
+config TOUCHSCREEN_MX25
+	tristate "Freescale i.MX25 touchscreen input driver"
+	depends on MFD_MX25_TSADC
+	help
+	  Enable support for touchscreen connected to your i.MX25.
+
 config TOUCHSCREEN_MC13783
 	tristate "Freescale MC13783 touchscreen input driver"
 	depends on MFD_MC13XXX

drivers/input/touchscreen/Makefile +1 -0

index 126479d..537d591 100644
@@ -38,6 +38,7 @@ obj-$(CONFIG_TOUCHSCREEN_INEXIO)	+= inexio.o
 obj-$(CONFIG_TOUCHSCREEN_INTEL_MID)	+= intel-mid-touch.o
 obj-$(CONFIG_TOUCHSCREEN_LPC32XX)	+= lpc32xx_ts.o
 obj-$(CONFIG_TOUCHSCREEN_MAX11801)	+= max11801_ts.o
+obj-$(CONFIG_TOUCHSCREEN_MX25)		+= fsl-imx25-tcq.o
 obj-$(CONFIG_TOUCHSCREEN_MC13783)	+= mc13783_ts.o
 obj-$(CONFIG_TOUCHSCREEN_MCS5000)	+= mcs5000_ts.o
 obj-$(CONFIG_TOUCHSCREEN_MIGOR)		+= migor_ts.o

drivers/input/touchscreen/fsl-imx25-tcq.c new file +584 -0

new file mode 100644
index 0000000..5ebeff8
@@ -0,0 +1,584 @@
+/*
+ * Copyright 2014 Markus Pargmann, Pengutronix <[email protected]>
+ * Based on driver from 2011:
+ *   Juergen Beisert, Pengutronix <[email protected]>
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * This is the driver for the imx25 TCQ (Touchscreen Conversion Queue)
+ * connected to the imx25 ADC.
+ */
+
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/input.h>
+#include <linux/mfd/imx25-tsadc.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+static const char mx25_tcq_name[] = "mx25-tcq";
+
+enum mx25_tcq_mode {
+	MX25_TS_4WIRE,
+};
+
+struct mx25_tcq_priv {
+	struct regmap *regs;
+	struct regmap *core_regs;
+	struct input_dev *idev;
+	enum mx25_tcq_mode mode;
+	unsigned int pen_threshold;
+	unsigned int sample_count;
+	unsigned int expected_samples;
+	unsigned int pen_debounce;
+	unsigned int settling_time;
+	struct clk *clk;
+	int irq;
+};
+
+static struct regmap_config mx25_tcq_regconfig = {
+	.fast_io = true,
+	.max_register = 0x5c,
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+};
+
+static struct of_device_id mx25_tcq_ids[] = {
+	{ .compatible = "fsl,imx25-tcq", },
+	{ /* Sentinel */ }
+};
+
+#define TSC_4WIRE_PRE_INDEX 0
+#define TSC_4WIRE_X_INDEX 1
+#define TSC_4WIRE_Y_INDEX 2
+#define TSC_4WIRE_POST_INDEX 3
+#define TSC_4WIRE_LEAVE 4
+
+#define MX25_TSC_DEF_THRESHOLD 80
+#define TSC_MAX_SAMPLES 16
+
+
+enum mx25_adc_configurations {
+	MX25_CFG_PRECHARGE = 0,
+	MX25_CFG_TOUCH_DETECT,
+	MX25_CFG_X_MEASUREMENT,
+	MX25_CFG_Y_MEASUREMENT,
+};
+
+#define MX25_PRECHARGE_VALUE (\
+			MX25_ADCQ_CFG_YPLL_OFF | \
+			MX25_ADCQ_CFG_XNUR_OFF | \
+			MX25_ADCQ_CFG_XPUL_HIGH | \
+			MX25_ADCQ_CFG_REFP_INT | \
+			MX25_ADCQ_CFG_IN_XP | \
+			MX25_ADCQ_CFG_REFN_NGND2 | \
+			MX25_ADCQ_CFG_IGS)
+
+#define MX25_TOUCH_DETECT_VALUE (\
+			MX25_ADCQ_CFG_YNLR | \
+			MX25_ADCQ_CFG_YPLL_OFF | \
+			MX25_ADCQ_CFG_XNUR_OFF | \
+			MX25_ADCQ_CFG_XPUL_OFF | \
+			MX25_ADCQ_CFG_REFP_INT | \
+			MX25_ADCQ_CFG_IN_XP | \
+			MX25_ADCQ_CFG_REFN_NGND2 | \
+			MX25_ADCQ_CFG_PENIACK)
+
+static void imx25_setup_queue_cfgs(struct mx25_tcq_priv *priv,
+		unsigned int settling_time)
+{
+	u32 precharge_cfg =
+			MX25_PRECHARGE_VALUE |
+			MX25_ADCQ_CFG_SETTLING_TIME(settling_time);
+	u32 touch_detect_cfg =
+			MX25_TOUCH_DETECT_VALUE |
+			MX25_ADCQ_CFG_NOS(1) |
+			MX25_ADCQ_CFG_SETTLING_TIME(settling_time);
+
+	regmap_write(priv->core_regs, MX25_TSC_TICR, precharge_cfg);
+
+	/* PRECHARGE */
+	regmap_write(priv->regs, MX25_ADCQ_CFG(MX25_CFG_PRECHARGE),
+			precharge_cfg);
+
+	/* TOUCH_DETECT */
+	regmap_write(priv->regs, MX25_ADCQ_CFG(MX25_CFG_TOUCH_DETECT),
+			touch_detect_cfg);
+
+	/* X Measurement */
+	regmap_write(priv->regs, MX25_ADCQ_CFG(MX25_CFG_X_MEASUREMENT),
+			MX25_ADCQ_CFG_YPLL_OFF |
+			MX25_ADCQ_CFG_XNUR_LOW |
+			MX25_ADCQ_CFG_XPUL_HIGH |
+			MX25_ADCQ_CFG_REFP_XP |
+			MX25_ADCQ_CFG_IN_YP |
+			MX25_ADCQ_CFG_REFN_XN |
+			MX25_ADCQ_CFG_NOS(priv->sample_count) |
+			MX25_ADCQ_CFG_SETTLING_TIME(settling_time));
+
+	/* Y Measurement */
+	regmap_write(priv->regs, MX25_ADCQ_CFG(MX25_CFG_Y_MEASUREMENT),
+			MX25_ADCQ_CFG_YNLR |
+			MX25_ADCQ_CFG_YPLL_HIGH |
+			MX25_ADCQ_CFG_XNUR_OFF |
+			MX25_ADCQ_CFG_XPUL_OFF |
+			MX25_ADCQ_CFG_REFP_YP |
+			MX25_ADCQ_CFG_IN_XP |
+			MX25_ADCQ_CFG_REFN_YN |
+			MX25_ADCQ_CFG_NOS(priv->sample_count) |
+			MX25_ADCQ_CFG_SETTLING_TIME(settling_time));
+
+	/* Enable the touch detection right now */
+	regmap_write(priv->core_regs, MX25_TSC_TICR, touch_detect_cfg |
+			MX25_ADCQ_CFG_IGS);
+}
+
+static int imx25_setup_queue_4wire(struct mx25_tcq_priv *priv,
+		unsigned settling_time, int *items)
+{
+	imx25_setup_queue_cfgs(priv, settling_time);
+
+	/* Setup the conversion queue */
+	regmap_write(priv->regs, MX25_ADCQ_ITEM_7_0,
+			MX25_ADCQ_ITEM(0, MX25_CFG_PRECHARGE) |
+			MX25_ADCQ_ITEM(1, MX25_CFG_TOUCH_DETECT) |
+			MX25_ADCQ_ITEM(2, MX25_CFG_X_MEASUREMENT) |
+			MX25_ADCQ_ITEM(3, MX25_CFG_Y_MEASUREMENT) |
+			MX25_ADCQ_ITEM(4, MX25_CFG_PRECHARGE) |
+			MX25_ADCQ_ITEM(5, MX25_CFG_TOUCH_DETECT));
+
+	/* We measure X/Y with 'sample_count' number of samples and execute a
+	 * touch detection twice, with 1 sample each */
+	priv->expected_samples = priv->sample_count * 2 + 2;
+	*items = 6;
+
+	return 0;
+}
+
+static void mx25_tcq_disable_touch_irq(struct mx25_tcq_priv *priv)
+{
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_PDMSK,
+			MX25_ADCQ_CR_PDMSK);
+}
+
+static void mx25_tcq_enable_touch_irq(struct mx25_tcq_priv *priv)
+{
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_PDMSK, 0);
+}
+
+static void mx25_tcq_disable_fifo_irq(struct mx25_tcq_priv *priv)
+{
+	regmap_update_bits(priv->regs, MX25_ADCQ_MR, MX25_ADCQ_MR_FDRY_IRQ,
+			MX25_ADCQ_MR_FDRY_IRQ);
+}
+
+static void mx25_tcq_enable_fifo_irq(struct mx25_tcq_priv *priv)
+{
+	regmap_update_bits(priv->regs, MX25_ADCQ_MR, MX25_ADCQ_MR_FDRY_IRQ, 0);
+}
+
+static void mx25_tcq_force_queue_start(struct mx25_tcq_priv *priv)
+{
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FQS,
+			MX25_ADCQ_CR_FQS);
+
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FQS, 0);
+}
+
+static void mx25_tcq_force_queue_stop(struct mx25_tcq_priv *priv)
+{
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FQS, 0);
+}
+
+static void mx25_tcq_fifo_reset(struct mx25_tcq_priv *priv)
+{
+	u32 tcqcr;
+
+	regmap_read(priv->regs, MX25_ADCQ_CR, &tcqcr);
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FRST,
+			MX25_ADCQ_CR_FRST);
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FRST,
+			0);
+	regmap_write(priv->regs, MX25_ADCQ_CR, tcqcr);
+}
+
+static void mx25_tcq_re_enable_touch_detection(struct mx25_tcq_priv *priv)
+{
+	/* stop the queue from looping */
+	mx25_tcq_force_queue_stop(priv);
+
+	/* for a clean touch detection, preload the X plane */
+	regmap_write(priv->core_regs, MX25_TSC_TICR, MX25_PRECHARGE_VALUE);
+
+	/* waste some time now to pre-load the X plate to high voltage */
+	mx25_tcq_fifo_reset(priv);
+
+	/* re-enable the detection right now */
+	regmap_write(priv->core_regs, MX25_TSC_TICR, MX25_TOUCH_DETECT_VALUE |
+			MX25_ADCQ_CFG_IGS);
+
+	regmap_update_bits(priv->regs, MX25_ADCQ_SR, MX25_ADCQ_SR_PD,
+			MX25_ADCQ_SR_PD);
+
+	/* enable the pen down event to be a source for the interrupt */
+	regmap_update_bits(priv->regs, MX25_ADCQ_MR, MX25_ADCQ_MR_PD_IRQ, 0);
+
+	/* lets fire the next IRQ if someone touches the touchscreen */
+	mx25_tcq_enable_touch_irq(priv);
+}
+
+static int mx25_tcq_create_event_for_4wire(struct mx25_tcq_priv *priv,
+		u32 *sample_buf, int samples)
+{
+	unsigned int x_pos = 0;
+	unsigned int y_pos = 0;
+	unsigned int touch_pre = 0;
+	unsigned int touch_post = 0;
+	unsigned i;
+	int ret = 0;
+
+	for (i = 0; i < samples; i++) {
+		unsigned int index = MX25_ADCQ_FIFO_ID(sample_buf[i]);
+		unsigned int val = MX25_ADCQ_FIFO_DATA(sample_buf[i]);
+
+		switch (index) {
+		case 1:
+			touch_pre = val;
+			break;
+		case 2:
+			x_pos = val;
+			break;
+		case 3:
+			y_pos = val;
+			break;
+		case 5:
+			touch_post = val;
+			break;
+		default:
+			ret = -EINVAL;
+			break;
+		}
+	}
+
+	if (ret == 0 && samples != 0) {
+		/*
+		 * only if both touch measures are below a treshold,
+		 * the position is valid
+		 */
+		if (touch_pre < priv->pen_threshold &&
+					touch_post < priv->pen_threshold) {
+			/* valid samples, generate a report */
+			x_pos /= priv->sample_count;
+			y_pos /= priv->sample_count;
+			input_report_abs(priv->idev, ABS_X, x_pos);
+			input_report_abs(priv->idev, ABS_Y, y_pos);
+			input_report_key(priv->idev, BTN_TOUCH, 1);
+			input_sync(priv->idev);
+
+			/* get next sample */
+			mx25_tcq_force_queue_start(priv);
+			mx25_tcq_enable_fifo_irq(priv);
+		} else if (touch_pre >= priv->pen_threshold &&
+				touch_post >= priv->pen_threshold) {
+			/*
+			 * if both samples are invalid,
+			 * generate a release report
+			 */
+			input_report_key(priv->idev, BTN_TOUCH, 0);
+			input_sync(priv->idev);
+			mx25_tcq_re_enable_touch_detection(priv);
+		} else {
+			/*
+			 * if only one of both touch measurements are
+			 * below the threshold, still some bouncing
+			 * happens. Take additional samples in this
+			 * case to be sure
+			 */
+			mx25_tcq_force_queue_start(priv);
+			mx25_tcq_enable_fifo_irq(priv);
+		}
+	}
+
+	return ret;
+}
+
+static irqreturn_t mx25_tcq_irq_thread(int irq, void *dev_id)
+{
+	struct mx25_tcq_priv *priv = dev_id;
+	u32 sample_buf[TSC_MAX_SAMPLES];
+	int samples = 0;
+
+	/* read all samples */
+	while (1) {
+		u32 stats;
+
+		regmap_read(priv->regs, MX25_ADCQ_SR, &stats);
+		if (stats & MX25_ADCQ_SR_EMPT)
+			break;
+
+		if (samples < TSC_MAX_SAMPLES) {
+			regmap_read(priv->regs, MX25_ADCQ_FIFO,
+							&sample_buf[samples]);
+			++samples;
+		} else {
+			u32 discarded;
+			/* discard samples */
+			regmap_read(priv->regs, MX25_ADCQ_FIFO, &discarded);
+		}
+	}
+
+	mx25_tcq_create_event_for_4wire(priv, sample_buf, samples);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t mx25_tcq_irq(int irq, void *dev_id)
+{
+	struct mx25_tcq_priv *priv = dev_id;
+	u32 stat;
+	int ret = IRQ_HANDLED;
+
+	regmap_read(priv->regs, MX25_ADCQ_SR, &stat);
+
+	if (stat & (MX25_ADCQ_SR_FRR | MX25_ADCQ_SR_FUR | MX25_ADCQ_SR_FOR))
+		mx25_tcq_fifo_reset(priv);
+
+	if (stat & MX25_ADCQ_SR_PD) {
+		mx25_tcq_disable_touch_irq(priv);
+		mx25_tcq_force_queue_start(priv);
+		mx25_tcq_enable_fifo_irq(priv);
+	}
+
+	if (stat & MX25_ADCQ_SR_FDRY) {
+		mx25_tcq_disable_fifo_irq(priv);
+		ret = IRQ_WAKE_THREAD;
+	}
+
+	regmap_update_bits(priv->regs, MX25_ADCQ_SR, MX25_ADCQ_SR_FRR |
+			MX25_ADCQ_SR_FUR | MX25_ADCQ_SR_FOR | MX25_ADCQ_SR_PD |
+			MX25_ADCQ_SR_EOQ,
+			MX25_ADCQ_SR_FRR |
+			MX25_ADCQ_SR_FUR | MX25_ADCQ_SR_FOR | MX25_ADCQ_SR_PD |
+			MX25_ADCQ_SR_EOQ);
+
+	return ret;
+}
+
+/* configure the statemachine for a 4-wire touchscreen */
+static int mx25_tcq_init(struct mx25_tcq_priv *priv)
+{
+	u32 tgcr;
+	unsigned int ipg_div;
+	unsigned int adc_period;
+	unsigned int debounce_cnt;
+	unsigned int settling_time;
+	int itemct;
+	int ret;
+
+	regmap_read(priv->core_regs, MX25_TSC_TGCR, &tgcr);
+	ipg_div = max_t(unsigned int, 4, MX25_TGCR_GET_ADCCLK(tgcr));
+	adc_period = clk_get_rate(priv->clk) / (ipg_div * 2 + 2);
+	debounce_cnt = DIV_ROUND_UP(priv->pen_debounce, adc_period * 8) - 1;
+	settling_time = DIV_ROUND_UP(priv->settling_time, adc_period);
+
+
+	/* Reset */
+	regmap_write(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_QRST |
+			MX25_ADCQ_CR_FRST);
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_QRST |
+			MX25_ADCQ_CR_FRST, 0);
+
+	/* up to 128 * 8 ADC clocks are possible */
+	if (debounce_cnt > 127)
+		debounce_cnt = 127;
+
+	ret = imx25_setup_queue_4wire(priv, 0x0, &itemct);
+	if (ret)
+		return ret;
+
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_LITEMID_MASK |
+			MX25_ADCQ_CR_WMRK_MASK,
+			MX25_ADCQ_CR_LITEMID(itemct - 1) |
+			MX25_ADCQ_CR_WMRK(priv->expected_samples - 1));
+
+	/* setup debounce count */
+	regmap_update_bits(priv->core_regs, MX25_TSC_TGCR,
+			MX25_TGCR_PDBTIME_MASK,
+			MX25_TGCR_PDBTIME(debounce_cnt));
+
+	/* enable debounce */
+	regmap_update_bits(priv->core_regs, MX25_TSC_TGCR, MX25_TGCR_PDBEN,
+			MX25_TGCR_PDBEN);
+	regmap_update_bits(priv->core_regs, MX25_TSC_TGCR, MX25_TGCR_PDEN,
+			MX25_TGCR_PDEN);
+
+	/* enable the engine on demand */
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_QSM_FQS,
+			MX25_ADCQ_CR_QSM_FQS);
+
+	mx25_tcq_re_enable_touch_detection(priv);
+
+	return 0;
+}
+
+static int mx25_tcq_parse_dt(struct platform_device *pdev,
+		struct mx25_tcq_priv *priv)
+{
+	struct device_node *np = pdev->dev.of_node;
+	u32 wires;
+	int ret;
+
+	/* Setup defaults */
+	priv->pen_threshold = 500;
+	priv->sample_count = 3;
+	priv->pen_debounce = 1000000;
+	priv->settling_time = 250000;
+
+	ret = of_property_read_u32(np, "fsl,wires", &wires);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to find fsl,wires properties\n");
+		return ret;
+	}
+
+	if (wires == 4) {
+		priv->mode = MX25_TS_4WIRE;
+	} else {
+		dev_err(&pdev->dev, "%u-wire mode not supported\n", wires);
+		return -EINVAL;
+	}
+
+	/* These are optional, we don't care about the return values */
+	of_property_read_u32(np, "fsl,pen-threshold", &priv->pen_threshold);
+	of_property_read_u32(np, "fsl,settling-time", &priv->settling_time);
+	of_property_read_u32(np, "fsl,pen-debounce", &priv->pen_debounce);
+
+	return 0;
+}
+
+static int mx25_tcq_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct input_dev *idev;
+	struct mx25_tcq_priv *priv;
+	struct mx25_tsadc *tsadc = dev_get_drvdata(pdev->dev.parent);
+	struct resource *res;
+	void __iomem *mem;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	mem = devm_ioremap_resource(dev, res);
+	if (!mem)
+		return -ENOMEM;
+
+	ret = mx25_tcq_parse_dt(pdev, priv);
+	if (ret)
+		return ret;
+
+	priv->regs = devm_regmap_init_mmio(dev, mem, &mx25_tcq_regconfig);
+	if (IS_ERR(priv->regs)) {
+		dev_err(dev, "Failed to initialize regmap\n");
+		return PTR_ERR(priv->regs);
+	}
+
+	priv->irq = platform_get_irq(pdev, 0);
+	if (priv->irq <= 0) {
+		dev_err(dev, "Failed to get IRQ\n");
+		return priv->irq;
+	}
+
+	idev = devm_input_allocate_device(dev);
+	if (!idev) {
+		dev_err(dev, "Failed to allocate input device\n");
+		return -ENOMEM;
+	}
+
+	idev->name = mx25_tcq_name;
+	idev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+	idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
+	input_set_abs_params(idev, ABS_X, 0, 0xfff, 0, 0);
+	input_set_abs_params(idev, ABS_Y, 0, 0xfff, 0, 0);
+
+	idev->id.bustype = BUS_HOST;
+
+	ret = input_register_device(idev);
+	if (ret) {
+		dev_err(dev, "Failed to register input device\n");
+		return ret;
+	}
+
+	priv->idev = idev;
+
+	priv->core_regs = tsadc->regs;
+	if (!priv->core_regs)
+		return -EINVAL;
+
+	priv->clk = tsadc->clk;
+	if (!priv->clk)
+		return -EINVAL;
+
+	ret = clk_prepare_enable(priv->clk);
+	if (ret) {
+		dev_err(dev, "Failed to enable ipg clock\n");
+		return ret;
+	}
+
+	ret = request_threaded_irq(priv->irq, mx25_tcq_irq, mx25_tcq_irq_thread,
+				   IRQF_ONESHOT, pdev->name, priv);
+	if (ret) {
+		dev_err(dev, "Failed requesting IRQ\n");
+		goto err_clk_unprepare;
+	}
+
+	ret = mx25_tcq_init(priv);
+	if (ret) {
+		dev_err(dev, "Failed to init tcq\n");
+		goto error_free_irq;
+	}
+
+	platform_set_drvdata(pdev, priv);
+
+	return 0;
+
+error_free_irq:
+	free_irq(priv->irq, priv);
+err_clk_unprepare:
+	clk_disable_unprepare(priv->clk);
+	return ret;
+}
+
+static int mx25_tcq_remove(struct platform_device *pdev)
+{
+	struct mx25_tcq_priv *priv = platform_get_drvdata(pdev);
+
+	free_irq(priv->irq, priv);
+	clk_disable_unprepare(priv->clk);
+
+	return 0;
+}
+
+static struct platform_driver mx25_tcq_driver = {
+	.driver		= {
+		.name	= "mx25-tcq",
+		.owner	= THIS_MODULE,
+		.of_match_table = mx25_tcq_ids,
+	},
+	.probe		= mx25_tcq_probe,
+	.remove		= mx25_tcq_remove,
+};
+module_platform_driver(mx25_tcq_driver);
+
+MODULE_DESCRIPTION("TS input driver for Freescale mx25");
+MODULE_AUTHOR("Markus Pargmann <[email protected]>");
+MODULE_LICENSE("GPL v2");

Signature · 1 line

1.7.9.5

From: Markus Pargmann <[email protected]>

This is a conversion queue driver for the mx25 SoC. It uses the central ADC which is used by two seperate independent queues. This driver prepares different conversion configurations for each possible input. For a conversion it creates a conversionqueue of one item with the correct configuration for the chosen channel. It then executes the queue once and disables the conversion queue afterwards.

The reference voltages are configurable through devicetree subnodes, depending on the connections of the ADC inputs.

Signed-off-by Markus Pargmann <[email protected]>

Signed-off-by Denis Carikli <[email protected]>

---
Changelog v3->v4:
- Reworked the ADC reference voltage bindings.
- IIO_CHAN_INFO_SCALE is now handled.
- Lot of code and style cleanups.
- Tested by watching WIPER become 0 when the touchscreen is touched.

Changelog v2->v3:
- Fixed compilation: I forgott to tell that this IIO patch was untested in the previous cover letter. Now it is tested at runtime:
I left the touchscreen connected but I configured the TSC as an ADC instead, set the refp to internal reference, and the refn to ngnd_adc(3) for the first 4 channels(xp,yp,xn,yn) and observed the values changing while touching the resistive 4-wire touchscreen.
- MX25_IIO_CHAN now became MX25_GCQ_CHAN and its .address is now gone and the code using it adapted.
- The instances of struct iio_dev were renamed from idev to indio_dev.
- regmap_read return value is now checked in mx25_gcq_read_raw.
- Comparisons with MX25_NUM_CFGS are now fixed
- Cosmetics fix in a multiline comment.

---
  .../devicetree/bindings/iio/adc/fsl,imx25-gcq.txt  |   51 +++
  drivers/iio/adc/Kconfig                            |    7 +
  drivers/iio/adc/Makefile                           |    1 +
  drivers/iio/adc/fsl-imx25-gcq.c                    |  371 ++++++++++++++++++++
  include/dt-bindings/iio/adc/fsl-imx25-gcq.h        |   11 +
  5 files changed, 441 insertions(+)

create mode 100644 Documentation/devicetree/bindings/iio/adc/fsl,imx25-gcq.txt create mode 100644 drivers/iio/adc/fsl-imx25-gcq.c
create mode 100644 include/dt-bindings/iio/adc/fsl-imx25-gcq.h

Documentation/devicetree/bindings/iio/adc/fsl,imx25-gcq.txt new file +51 -0

new file mode 100644
index 0000000..e4a7170
@@ -0,0 +1,51 @@
+Freescale i.MX25 ADC GCQ device
+
+This is a generic conversion queue device that can convert any of the
+analog inputs using the ADC unit of the i.MX25.
+
+Required properties:
+ - compatible: Should be "fsl,imx25-gcq".
+ - reg: Should be the register range of the module.
+ - interrupts: Should be the interrupt number of the module.
+   Typically this is <1>.
+ - interrupt-parent: phandle to the tsadc module of the i.MX25.
+ - #address-cells: Should be <1> (setting for the subnodes)
+ - #size-cells: Should be <0> (setting for the subnodes)
+
+Optional properties:
+ - vref-supply: The regulator supplying the ADC refrence voltage.
+   Required when at least one subnode uses the external reference.
+
+Sub-nodes:
+Optionally you can define subnodes which define the reference voltage
+for the analog inputs.
+
+Required properties for subnodes:
+ - reg: Should be the number of the analog input.
+     0: xp
+     1: yp
+     2: xn
+     3: yn
+     4: wiper
+     5: inaux0
+     6: inaux1
+     7: inaux2
+ - fsl,adc-ref: specifies the reference input as defined in
+     <dt-bindings/iio/adc/fsl-imx25-gcq.h>
+     MX25_ADC_REF_INT and MX25_ADC_REF_EXT flags are supported.
+
+Example:
+
+	adc: adc@50030800 {
+		compatible = "fsl,imx25-gcq";
+		reg = <0x50030800 0x60>;
+		interrupt-parent = <&tscadc>;
+		interrupts = <1>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		inaux@5 {
+			reg = <5>;
+			fsl,adc-ref = <MX25_ADC_REF_INT>;
+		};
+	};

drivers/iio/adc/Kconfig +7 -0

index a80d236..58efb8d 100644
@@ -125,6 +125,13 @@ config EXYNOS_ADC
  	  of SoCs for drivers such as the touchscreen and hwmon to use to share
  	  this resource.
 
+config FSL_MX25_ADC
+	tristate "Freescale MX25 ADC driver"
+	depends on MFD_MX25_TSADC
+	help
+	  Generic Conversion Queue driver used for general purpose ADC in the
+	  MX25. This driver supports single measurements using the MX25 ADC.
+
  config LP8788_ADC
  	tristate "LP8788 ADC driver"
  	depends on MFD_LP8788

drivers/iio/adc/Makefile +1 -0

index 9d60f2d..2767fd6 100644
@@ -14,6 +14,7 @@ obj-$(CONFIG_AD7887) += ad7887.o
  obj-$(CONFIG_AD799X) += ad799x.o
  obj-$(CONFIG_AT91_ADC) += at91_adc.o
  obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
+obj-$(CONFIG_FSL_MX25_ADC) += fsl-imx25-gcq.o
  obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
  obj-$(CONFIG_MAX1363) += max1363.o
  obj-$(CONFIG_MCP320X) += mcp320x.o

drivers/iio/adc/fsl-imx25-gcq.c new file +132 -0

new file mode 100644
index 0000000..1e95553
@@ -0,0 +1,371 @@
+/*
+ * Copyright 2014 Markus Pargmann, Pengutronix <[email protected]>
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * This is the driver for the imx25 GCQ (Generic Conversion Queue)
+ * connected to the imx25 ADC.
+ */
+
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/iio/iio.h>
+#include <linux/mfd/imx25-tsadc.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <dt-bindings/iio/adc/fsl-imx25-gcq.h>
+
+#define MX25_GCQ_TIMEOUT (msecs_to_jiffies(2000))
+
+enum mx25_gcq_cfgs {
+	MX25_CFG_XP = 0,
+	MX25_CFG_YP,
+	MX25_CFG_XN,
+	MX25_CFG_YN,
+	MX25_CFG_WIPER,
+	MX25_CFG_INAUX0,
+	MX25_CFG_INAUX1,
+	MX25_CFG_INAUX2,
+	MX25_NUM_CFGS,
+};
+
+struct mx25_gcq_priv {
+	struct regmap *regs;
+	struct completion completed;
+	unsigned int settling_time;
+	struct clk *clk;
+	int irq;
+	struct regulator *ext_vref;
+	u32 channel_vref_mv[MX25_NUM_CFGS];
+};
+
+#define MX25_CQG_CHAN(chan, id) {\
+	.type = IIO_VOLTAGE,\
+	.indexed = 1,\
+	.channel = chan,\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\
+	.datasheet_name = id,\
+}
+
+static const struct iio_chan_spec mx25_gcq_channels[MX25_NUM_CFGS] = {
+	MX25_CQG_CHAN(0, "xp"),
+	MX25_CQG_CHAN(1, "yp"),
+	MX25_CQG_CHAN(2, "xn"),
+	MX25_CQG_CHAN(3, "yn"),
+	MX25_CQG_CHAN(4, "wiper"),
+	MX25_CQG_CHAN(5, "inaux0"),
+	MX25_CQG_CHAN(6, "inaux1"),
+	MX25_CQG_CHAN(7, "inaux2"),
+};
+
+static void mx25_gcq_disable_eoq(struct mx25_gcq_priv *priv)
+{
+	regmap_update_bits(priv->regs, MX25_ADCQ_MR, MX25_ADCQ_MR_EOQ_IRQ,
+			   MX25_ADCQ_MR_EOQ_IRQ);
+}
+
+static void mx25_gcq_enable_eoq(struct mx25_gcq_priv *priv)
+{
+	regmap_update_bits(priv->regs, MX25_ADCQ_MR,
+			   MX25_ADCQ_MR_EOQ_IRQ, 0);
+}
+
+static irqreturn_t mx25_gcq_irq(int irq, void *data)
+{
+	struct mx25_gcq_priv *priv = data;
+	u32 stats;
+
+	regmap_read(priv->regs, MX25_ADCQ_SR, &stats);
+
+	if (stats & MX25_ADCQ_SR_EOQ) {
+		mx25_gcq_disable_eoq(priv);
+		complete(&priv->completed);
+	}
+
+	/* Disable conversion queue run */
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FQS, 0);
+
+	/* Acknowledge all possible irqs */
+	regmap_write(priv->regs, MX25_ADCQ_SR, MX25_ADCQ_SR_FRR |
+				 MX25_ADCQ_SR_FUR | MX25_ADCQ_SR_FOR |
+				 MX25_ADCQ_SR_EOQ | MX25_ADCQ_SR_PD);
+
+	return IRQ_HANDLED;
+}
+
+static int mx25_gcq_read_raw(struct iio_dev *indio_dev,
+		struct iio_chan_spec const *chan, int *val, int *val2,
+		long mask)
+{
+	struct mx25_gcq_priv *priv = iio_priv(indio_dev);
+	long timeout;
+	u32 data;
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		mutex_lock(&indio_dev->mlock);
+
+		/* Setup the configuration we want to use */
+		regmap_write(priv->regs, MX25_ADCQ_ITEM_7_0,
+			     MX25_ADCQ_ITEM(0, chan->channel));
+
+		mx25_gcq_enable_eoq(priv);
+
+		/* Trigger queue for one run */
+		regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FQS,
+				   MX25_ADCQ_CR_FQS);
+
+		timeout = wait_for_completion_interruptible_timeout(
+			&priv->completed, MX25_GCQ_TIMEOUT);
+		if (timeout < 0) {
+			dev_err(&indio_dev->dev,
+					 "ADC wait for measurement failed\n");

drivers/iio/adc/fsl-imx25-gcq.c new file +22 -0

+		*val = priv->channel_vref_mv[chan->channel];
+		*val2 = 12;
+		return IIO_VAL_FRACTIONAL_LOG2;
+
+	default:
+		return -EINVAL;
+	}
+out:
+	mutex_unlock(&indio_dev->mlock);
+	return ret;
+}
+
+static const struct iio_info mx25_gcq_iio_info = {
+	.read_raw = mx25_gcq_read_raw,
+};
+
+static const struct regmap_config mx25_gcq_regconfig = {
+	.max_register = 0x5c,
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+};

drivers/iio/adc/fsl-imx25-gcq.c new file +190 -0

+	 * configuration for each input
+	 */
+	for (i = 0; i < MX25_NUM_CFGS; ++i)
+		regmap_write(priv->regs, MX25_ADCQ_CFG(i),
+			     MX25_ADCQ_CFG_YPLL_OFF |
+			     MX25_ADCQ_CFG_XNUR_OFF |
+			     MX25_ADCQ_CFG_XPUL_OFF |
+			     MX25_ADCQ_CFG_REFP_INT |
+			     (i << 4) |
+			     MX25_ADCQ_CFG_REFN_NGND2);
+
+	for_each_child_of_node(np, child) {
+		u32 reg;
+		u32 refp;
+		u32 adc_ref;
+
+		ret = of_property_read_u32(child, "reg", &reg);
+		if (ret) {
+			dev_err(dev, "Failed to get reg property\n");
+			return ret;
+		}
+
+		if (reg >= MX25_NUM_CFGS) {
+			dev_err(dev,
+				"reg value is greater than the number of available configuration registers\n");
+			return -EINVAL;
+		}
+
+		ret = of_property_read_u32(child, "fsl,adc-ref", &adc_ref);
+		if (ret) {
+			dev_err(dev, "Failed to get fsl,adc-ref property\n");
+			return ret;
+		}
+
+		if (adc_ref != MX25_ADC_REF_INT &&
+		    adc_ref != MX25_ADC_REF_EXT) {
+			dev_err(dev, "Invalid fsl,adc-refp property value %d\n",
+				adc_ref);
+			return -EINVAL;
+		}
+
+		switch (adc_ref) {
+		case MX25_ADC_REF_EXT:
+			if (IS_ERR_OR_NULL(priv->ext_vref)) {
+				dev_err(dev,
+					"No regulator found for the external vref\n");
+				return -EINVAL;
+			}
+			priv->channel_vref_mv[reg] =
+				regulator_get_voltage(priv->ext_vref);
+			refp = MX25_ADCQ_CFG_REFP_EXT;
+			break;
+		case MX25_ADC_REF_INT:
+			priv->channel_vref_mv[reg] = 2500;
+			refp = MX25_ADCQ_CFG_REFP_INT;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		regmap_update_bits(priv->regs, MX25_ADCQ_CFG(reg),
+				   MX25_ADCQ_CFG_REFP_MASK |
+				   MX25_ADCQ_CFG_REFN_MASK, (refp << 7) |
+				   (MX25_ADCQ_CFG_REFN_NGND << 2));
+	}
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR,
+			   MX25_ADCQ_CR_FRST | MX25_ADCQ_CR_QRST,
+			   MX25_ADCQ_CR_FRST | MX25_ADCQ_CR_QRST);
+
+	regmap_write(priv->regs, MX25_ADCQ_CR,
+		     MX25_ADCQ_CR_PDMSK |
+		     MX25_ADCQ_CR_QSM_FQS);
+
+	return 0;
+}
+
+static int mx25_gcq_probe(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev;
+	struct mx25_gcq_priv *priv;
+	struct mx25_tsadc *tsadc = dev_get_drvdata(pdev->dev.parent);
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+	void __iomem *mem;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*priv));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	priv = iio_priv(indio_dev);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	mem = devm_ioremap_resource(dev, res);
+	if (!mem)
+		return -ENOMEM;
+
+	priv->regs = devm_regmap_init_mmio(dev, mem, &mx25_gcq_regconfig);
+	if (IS_ERR(priv->regs)) {
+		dev_err(dev, "Failed to initialize regmap\n");
+		return PTR_ERR(priv->regs);
+	}
+
+	init_completion(&priv->completed);
+
+	/* Optional external regulator */
+	priv->ext_vref = devm_regulator_get(&pdev->dev, "vref");
+	if (!IS_ERR_OR_NULL(priv->ext_vref)) {
+		ret = regulator_enable(priv->ext_vref);
+		if (ret)
+			return ret;
+	}
+
+	ret = mx25_gcq_setup_cfgs(pdev, priv);
+	if (ret)
+		return ret;
+
+	priv->clk = tsadc->clk;
+	ret = clk_prepare_enable(priv->clk);
+	if (ret) {
+		dev_err(dev, "Failed to enable clock\n");
+		return ret;
+	}
+
+	priv->irq = platform_get_irq(pdev, 0);
+	if (priv->irq <= 0) {
+		dev_err(dev, "Failed to get IRQ\n");
+		ret = priv->irq;
+		goto err_clk_unprepare;
+	}
+
+	ret = request_irq(priv->irq, mx25_gcq_irq, 0, pdev->name, priv);
+	if (ret) {
+		dev_err(dev, "Failed requesting IRQ\n");
+		goto err_clk_unprepare;
+	}
+
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->channels = mx25_gcq_channels;
+	indio_dev->num_channels = ARRAY_SIZE(mx25_gcq_channels);
+	indio_dev->info = &mx25_gcq_iio_info;
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(dev, "Failed to register iio device\n");
+		goto err_irq_free;
+	}
+
+	platform_set_drvdata(pdev, priv);
+
+	return 0;
+
+err_irq_free:
+	free_irq(priv->irq, (void *)priv);
+err_clk_unprepare:
+	clk_disable_unprepare(priv->clk);
+	return ret;
+}
+
+static int mx25_gcq_remove(struct platform_device *pdev)
+{
+	struct mx25_gcq_priv *priv = platform_get_drvdata(pdev);
+	struct iio_dev *indio_dev = iio_priv_to_dev(pdev);
+
+	iio_device_unregister(indio_dev);
+	free_irq(priv->irq, priv);
+	clk_disable_unprepare(priv->clk);
+
+	return 0;
+}
+
+static struct of_device_id mx25_gcq_ids[] = {
+	{ .compatible = "fsl,imx25-gcq", },
+	{ /* Sentinel */ }
+};
+
+static struct platform_driver mx25_gcq_driver = {
+	.driver		= {
+		.name	= "mx25-gcq",
+		.owner	= THIS_MODULE,
+		.of_match_table = mx25_gcq_ids,
+	},
+	.probe		= mx25_gcq_probe,
+	.remove		= mx25_gcq_remove,
+};
+module_platform_driver(mx25_gcq_driver);
+
+MODULE_DESCRIPTION("ADC driver for Freescale mx25");
+MODULE_AUTHOR("Markus Pargmann <[email protected]>");
+MODULE_LICENSE("GPL v2");

include/dt-bindings/iio/adc/fsl-imx25-gcq.h new file +11 -0

new file mode 100644
index 0000000..486dce7
@@ -0,0 +1,11 @@
+/*
+ * This header provides constants for configuring the I.MX25 ADC
+ */
+
+#ifndef _DT_BINDINGS_IIO_ADC_FS_IMX25_GCQ_H
+#define _DT_BINDINGS_IIO_ADC_FS_IMX25_GCQ_H
+
+#define MX25_ADC_REF_INT	0 /* Internal voltage reference */
+#define MX25_ADC_REF_EXT	1 /* External voltage reference */
+
+#endif

drivers/mfd/Kconfig +0 -0

index af0e83f..d354547 100644

drivers/mfd/Kconfig +2 -0

+	return 0;
+}

drivers/mfd/Kconfig +5 -0

+		.of_match_table = of_match_ptr(mx25_tsadc_ids),
+	},
+	.probe = mx25_tsadc_probe,
+};
+module_platform_driver(mx25_tsadc_driver);