mfd: rt4831: Adds support for Richtek RT4831

From: ChiYuan Huang <[email protected]>

Adds DT binding document for Richtek RT4831 backlight.

Signed-off-by ChiYuan Huang <[email protected]>

Reviewed-by Daniel Thompson <[email protected]>

---
Resend this v6 patch series to loop devicetree reviewers.

For next, need to add the below line

Reviewed-by Daniel Thompson <[email protected]>

---
 .../leds/backlight/richtek,rt4831-backlight.yaml   | 65 ++++++++++++++++++++++
 include/dt-bindings/leds/rt4831-backlight.h        | 23 ++++++++
 2 files changed, 88 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml
 create mode 100644 include/dt-bindings/leds/rt4831-backlight.h

Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml new file +11 -0

new file mode 100644
index 00000000..4da6a66
@@ -0,0 +1,65 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/backlight/richtek,rt4831-backlight.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Richtek RT4831 Backlight
+
+maintainers:
+  - ChiYuan Huang <[email protected]>
+

Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml new file +29 -0

+    minimum: 0
+    maximum: 2048
+
+  richtek,pwm-enable:
+    description: |
+      Specify the backlight dimming following by PWM duty or by SW control.
+    type: boolean
+
+  richtek,bled-ovp-sel:
+    description: |
+      Backlight OVP level selection, currently support 17V/21V/25V/29V.
+    $ref: /schemas/types.yaml#/definitions/uint8
+    default: 1
+    minimum: 0
+    maximum: 3
+
+  richtek,channel-use:
+    description: |
+      Backlight LED channel to be used.
+      BIT 0/1/2/3 is used to indicate led channel 1/2/3/4 enable or disable.
+    $ref: /schemas/types.yaml#/definitions/uint8
+    minimum: 1
+    maximum: 15
+
+required:
+  - compatible
+  - richtek,channel-use
+
+additionalProperties: false

include/dt-bindings/leds/rt4831-backlight.h new file +23 -0

new file mode 100644
index 00000000..125c635
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
+/*
+ * This header provides constants for rt4831 backlight bindings.
+ *
+ * Copyright (C) 2020, Richtek Technology Corp.
+ * Author: ChiYuan Huang <[email protected]>
+ */
+
+#ifndef _DT_BINDINGS_RT4831_BACKLIGHT_H
+#define _DT_BINDINGS_RT4831_BACKLIGHT_H
+
+#define RT4831_BLOVPLVL_17V	0
+#define RT4831_BLOVPLVL_21V	1
+#define RT4831_BLOVPLVL_25V	2
+#define RT4831_BLOVPLVL_29V	3
+
+#define RT4831_BLED_CH1EN	(1 << 0)
+#define RT4831_BLED_CH2EN	(1 << 1)
+#define RT4831_BLED_CH3EN	(1 << 2)
+#define RT4831_BLED_CH4EN	(1 << 3)
+#define RT4831_BLED_ALLCHEN	((1 << 4) - 1)
+
+#endif /* _DT_BINDINGS_RT4831_BACKLIGHT_H */

Signature · 1 line

2.7.4

Quoted 35 lines

From: ChiYuan Huang <[email protected]>

Adds DT binding document for Richtek RT4831 backlight.

Signed-off-by ChiYuan Huang <[email protected]>

Reviewed-by Daniel Thompson <[email protected]>

---
Resend this v6 patch series to loop devicetree reviewers.

For next, need to add the below line

Reviewed-by Daniel Thompson <[email protected]>

---
 .../leds/backlight/richtek,rt4831-backlight.yaml   | 65 ++++++++++++++++++++++
 include/dt-bindings/leds/rt4831-backlight.h        | 23 ++++++++
 2 files changed, 88 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml
 create mode 100644 include/dt-bindings/leds/rt4831-backlight.h

Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml new file +11 -0

new file mode 100644
index 00000000..4da6a66
@@ -0,0 +1,65 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/backlight/richtek,rt4831-backlight.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Richtek RT4831 Backlight
+
+maintainers:
+  - ChiYuan Huang <[email protected]>
+

Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml line 21

Quoted 10 lines

Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml new file +10 -0

+description: |
+  RT4831 is a mutifunctional device that can provide power to the LCD display
+  and LCD backlight.
+
+  For the LCD backlight, it can provide four channel WLED driving capability.
+  Each channel driving current is up to 30mA
+
+  Datasheet is available at
+  https://www.richtek.com/assets/product_file/RT4831A/DS4831A-05.pdf
+

Need to reference common backlight schema:

allOf:
- $ref: common.yaml#

Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml line 29

Quoted 8 lines

Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml new file +8 -0

+properties:
+  compatible:
+    const: richtek,rt4831-backlight
+
+  default-brightness:
+    description: |
+      The default brightness that applied to the system on start-up.
+    $ref: /schemas/types.yaml#/definitions/uint32

Drop description and $ref. Covered in common.yaml.

Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml line 36

Quoted 7 lines

Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml new file +7 -0

+    minimum: 0
+    maximum: 2048
+
+  max-brightness:
+    description: |
+      The max brightness for the H/W limit
+    $ref: /schemas/types.yaml#/definitions/uint32

And here.

Quoted 53 lines

Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml new file +29 -0

+    minimum: 0
+    maximum: 2048
+
+  richtek,pwm-enable:
+    description: |
+      Specify the backlight dimming following by PWM duty or by SW control.
+    type: boolean
+
+  richtek,bled-ovp-sel:
+    description: |
+      Backlight OVP level selection, currently support 17V/21V/25V/29V.
+    $ref: /schemas/types.yaml#/definitions/uint8
+    default: 1
+    minimum: 0
+    maximum: 3
+
+  richtek,channel-use:
+    description: |
+      Backlight LED channel to be used.
+      BIT 0/1/2/3 is used to indicate led channel 1/2/3/4 enable or disable.
+    $ref: /schemas/types.yaml#/definitions/uint8
+    minimum: 1
+    maximum: 15
+
+required:
+  - compatible
+  - richtek,channel-use
+
+additionalProperties: false

include/dt-bindings/leds/rt4831-backlight.h new file +18 -0

new file mode 100644
index 00000000..125c635
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
+/*
+ * This header provides constants for rt4831 backlight bindings.
+ *
+ * Copyright (C) 2020, Richtek Technology Corp.
+ * Author: ChiYuan Huang <[email protected]>
+ */
+
+#ifndef _DT_BINDINGS_RT4831_BACKLIGHT_H
+#define _DT_BINDINGS_RT4831_BACKLIGHT_H
+
+#define RT4831_BLOVPLVL_17V  0
+#define RT4831_BLOVPLVL_21V  1
+#define RT4831_BLOVPLVL_25V  2
+#define RT4831_BLOVPLVL_29V  3
+
+#define RT4831_BLED_CH1EN    (1 << 0)
+#define RT4831_BLED_CH2EN    (1 << 1)

Quoted 8 lines

include/dt-bindings/leds/rt4831-backlight.h new file +5 -1

+#define RT4831_BLED_CH3EN    (1 << 2)
+#define RT4831_BLED_CH4EN    (1 << 3)
+#define RT4831_BLED_ALLCHEN  ((1 << 4) - 1)
+
+#endif /* _DT_BINDINGS_RT4831_BACKLIGHT_H */
--

2.7.4

From: ChiYuan Huang <[email protected]>

Adds DT binding document for Richtek RT4831.

Signed-off-by ChiYuan Huang <[email protected]>

---
Resend this v6 patch series to loop devicetree reviewers.

---
 .../devicetree/bindings/mfd/richtek,rt4831.yaml    | 90 ++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mfd/richtek,rt4831.yaml

Quoted 4 lines

From: ChiYuan Huang <[email protected]>

Adds DT binding document for Richtek RT4831.

Quoted 8 lines

Signed-off-by ChiYuan Huang <[email protected]>

---
Resend this v6 patch series to loop devicetree reviewers.

---
 .../devicetree/bindings/mfd/richtek,rt4831.yaml    | 90 ++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mfd/richtek,rt4831.yaml

Reviewed-by Rob Herring <[email protected]>

From: ChiYuan Huang <[email protected]>

Adds support for Richtek RT4831 backlight.

Signed-off-by ChiYuan Huang <[email protected]>

Reviewed-by Daniel Thompson <[email protected]>

---
Resend this v6 patch series to loop devicetree reviewers.

For next, if the typo in Kconfig 'common' to 'commonly' can be added the below line

Reviewed-by Daniel Thompson <[email protected]>

---

 drivers/video/backlight/Kconfig            |   8 ++
 drivers/video/backlight/Makefile           |   1 +
 drivers/video/backlight/rt4831-backlight.c | 203 +++++++++++++++++++++++++++++
 3 files changed, 212 insertions(+)
 create mode 100644 drivers/video/backlight/rt4831-backlight.c

drivers/video/backlight/Kconfig +8 -0

index d83c87b..de96441 100644
@@ -289,6 +289,14 @@ config BACKLIGHT_QCOM_WLED
 	  If you have the Qualcomm PMIC, say Y to enable a driver for the
 	  WLED block. Currently it supports PM8941 and PMI8998.
 
+config BACKLIGHT_RT4831
+	tristate "Richtek RT4831 Backlight Driver"
+	depends on MFD_RT4831
+	help
+	  This enables support for Richtek RT4831 Backlight driver.
+	  It's common used to drive the display WLED. There're four channels
+	  inisde, and each channel can provide up to 30mA current.
+
 config BACKLIGHT_SAHARA
 	tristate "Tabletkiosk Sahara Touch-iT Backlight Driver"
 	depends on X86

drivers/video/backlight/Makefile +1 -0

index 685f3f1..cae2c83 100644
@@ -49,6 +49,7 @@ obj-$(CONFIG_BACKLIGHT_PANDORA)		+= pandora_bl.o
 obj-$(CONFIG_BACKLIGHT_PCF50633)	+= pcf50633-backlight.o
 obj-$(CONFIG_BACKLIGHT_PWM)		+= pwm_bl.o
 obj-$(CONFIG_BACKLIGHT_QCOM_WLED)	+= qcom-wled.o
+obj-$(CONFIG_BACKLIGHT_RT4831)		+= rt4831-backlight.o
 obj-$(CONFIG_BACKLIGHT_SAHARA)		+= kb3886_bl.o
 obj-$(CONFIG_BACKLIGHT_SKY81452)	+= sky81452-backlight.o
 obj-$(CONFIG_BACKLIGHT_TOSA)		+= tosa_bl.o

drivers/video/backlight/rt4831-backlight.c new file +203 -0

new file mode 100644
index 00000000..42155c7
@@ -0,0 +1,203 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <dt-bindings/leds/rt4831-backlight.h>
+#include <linux/backlight.h>
+#include <linux/bitops.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+#define RT4831_REG_BLCFG	0x02
+#define RT4831_REG_BLDIML	0x04
+#define RT4831_REG_ENABLE	0x08
+
+#define RT4831_BLMAX_BRIGHTNESS	2048
+
+#define RT4831_BLOVP_MASK	GENMASK(7, 5)
+#define RT4831_BLOVP_SHIFT	5
+#define RT4831_BLPWMEN_MASK	BIT(0)
+#define RT4831_BLEN_MASK	BIT(4)
+#define RT4831_BLCH_MASK	GENMASK(3, 0)
+#define RT4831_BLDIML_MASK	GENMASK(2, 0)
+#define RT4831_BLDIMH_MASK	GENMASK(10, 3)
+#define RT4831_BLDIMH_SHIFT	3
+
+struct rt4831_priv {
+	struct device *dev;
+	struct regmap *regmap;
+	struct backlight_device *bl;
+};
+
+static int rt4831_bl_update_status(struct backlight_device *bl_dev)
+{
+	struct rt4831_priv *priv = bl_get_data(bl_dev);
+	int brightness = backlight_get_brightness(bl_dev);
+	unsigned int enable = brightness ? RT4831_BLEN_MASK : 0;
+	u8 v[2];
+	int ret;
+
+	if (brightness) {
+		v[0] = (brightness - 1) & RT4831_BLDIML_MASK;
+		v[1] = ((brightness - 1) & RT4831_BLDIMH_MASK) >> RT4831_BLDIMH_SHIFT;
+
+		ret = regmap_raw_write(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
+		if (ret)
+			return ret;
+	}
+
+	return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLEN_MASK, enable);
+
+}
+
+static int rt4831_bl_get_brightness(struct backlight_device *bl_dev)
+{
+	struct rt4831_priv *priv = bl_get_data(bl_dev);
+	unsigned int val;
+	u8 v[2];
+	int ret;
+
+	ret = regmap_read(priv->regmap, RT4831_REG_ENABLE, &val);
+	if (ret)
+		return ret;
+
+	if (!(val & RT4831_BLEN_MASK))
+		return 0;
+
+	ret = regmap_raw_read(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
+	if (ret)
+		return ret;
+
+	ret = (v[1] << RT4831_BLDIMH_SHIFT) + (v[0] & RT4831_BLDIML_MASK) + 1;
+
+	return ret;
+}
+
+static const struct backlight_ops rt4831_bl_ops = {
+	.options = BL_CORE_SUSPENDRESUME,
+	.update_status = rt4831_bl_update_status,
+	.get_brightness = rt4831_bl_get_brightness,
+};
+
+static int rt4831_parse_backlight_properties(struct rt4831_priv *priv,
+					     struct backlight_properties *bl_props)
+{
+	struct device *dev = priv->dev;
+	u8 propval;
+	u32 brightness;
+	unsigned int val = 0;
+	int ret;
+
+	/* common properties */
+	ret = device_property_read_u32(dev, "max-brightness", &brightness);
+	if (ret)
+		brightness = RT4831_BLMAX_BRIGHTNESS;
+
+	bl_props->max_brightness = min_t(u32, brightness, RT4831_BLMAX_BRIGHTNESS);
+
+	ret = device_property_read_u32(dev, "default-brightness", &brightness);
+	if (ret)
+		brightness = bl_props->max_brightness;
+
+	bl_props->brightness = min_t(u32, brightness, bl_props->max_brightness);
+
+	/* vendor properties */
+	if (device_property_read_bool(dev, "richtek,pwm-enable"))
+		val = RT4831_BLPWMEN_MASK;
+
+	ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLPWMEN_MASK, val);
+	if (ret)
+		return ret;
+
+	ret = device_property_read_u8(dev, "richtek,bled-ovp-sel", &propval);
+	if (ret)
+		propval = RT4831_BLOVPLVL_21V;
+
+	propval = min_t(u8, propval, RT4831_BLOVPLVL_29V);
+	ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLOVP_MASK,
+				 propval << RT4831_BLOVP_SHIFT);
+	if (ret)
+		return ret;
+
+	ret = device_property_read_u8(dev, "richtek,channel-use", &propval);
+	if (ret) {
+		dev_err(dev, "richtek,channel-use DT property missing\n");
+		return ret;
+	}
+
+	if (!(propval & RT4831_BLCH_MASK)) {
+		dev_err(dev, "No channel specified\n");
+		return -EINVAL;
+	}
+
+	return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLCH_MASK, propval);
+}
+
+static int rt4831_bl_probe(struct platform_device *pdev)
+{
+	struct rt4831_priv *priv;
+	struct backlight_properties bl_props = { .type = BACKLIGHT_RAW,
+						 .scale = BACKLIGHT_SCALE_LINEAR };
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = &pdev->dev;
+
+	priv->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!priv->regmap) {
+		dev_err(&pdev->dev, "Failed to init regmap\n");
+		return -ENODEV;
+	}
+
+	ret = rt4831_parse_backlight_properties(priv, &bl_props);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to parse backlight properties\n");
+		return ret;
+	}
+
+	priv->bl = devm_backlight_device_register(&pdev->dev, pdev->name, &pdev->dev, priv,
+						  &rt4831_bl_ops, &bl_props);
+	if (IS_ERR(priv->bl)) {
+		dev_err(&pdev->dev, "Failed to register backlight\n");
+		return PTR_ERR(priv->bl);
+	}
+
+	backlight_update_status(priv->bl);
+	platform_set_drvdata(pdev, priv);
+
+	return 0;
+}
+
+static int rt4831_bl_remove(struct platform_device *pdev)
+{
+	struct rt4831_priv *priv = platform_get_drvdata(pdev);
+	struct backlight_device *bl_dev = priv->bl;
+
+	bl_dev->props.brightness = 0;
+	backlight_update_status(priv->bl);
+
+	return 0;
+}
+
+static const struct of_device_id __maybe_unused rt4831_bl_of_match[] = {
+	{ .compatible = "richtek,rt4831-backlight", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, rt4831_bl_of_match);
+
+static struct platform_driver rt4831_bl_driver = {
+	.driver = {
+		.name = "rt4831-backlight",
+		.of_match_table = rt4831_bl_of_match,
+	},
+	.probe = rt4831_bl_probe,
+	.remove = rt4831_bl_remove,
+};
+module_platform_driver(rt4831_bl_driver);
+
+MODULE_AUTHOR("ChiYuan Huang <[email protected]>");
+MODULE_LICENSE("GPL v2");

Signature · 1 line

2.7.4

Quoted 4 lines

From: ChiYuan Huang <[email protected]>

Adds support for Richtek RT4831 backlight.

Quoted 8 lines

Signed-off-by ChiYuan Huang <[email protected]>

Reviewed-by Daniel Thompson <[email protected]>

---
Resend this v6 patch series to loop devicetree reviewers.

For next, if the typo in Kconfig 'common' to 'commonly' can be added the below line

Reviewed-by Daniel Thompson <[email protected]>

---

This isn't the best way to handle feedback from multiple maintainers.

It is great to see you are keeping track of feedback. However it doesn't make sense to RESEND an old patchset and acknowledge that you haven't fixed a typo yet.

It would be better to fix the typo and to resend a v7.

Daniel.

Quoted 241 lines

 drivers/video/backlight/Kconfig            |   8 ++
 drivers/video/backlight/Makefile           |   1 +
 drivers/video/backlight/rt4831-backlight.c | 203 +++++++++++++++++++++++++++++
 3 files changed, 212 insertions(+)
 create mode 100644 drivers/video/backlight/rt4831-backlight.c

drivers/video/backlight/Kconfig +8 -0

index d83c87b..de96441 100644
@@ -289,6 +289,14 @@ config BACKLIGHT_QCOM_WLED
        If you have the Qualcomm PMIC, say Y to enable a driver for the
        WLED block. Currently it supports PM8941 and PMI8998.
 
+config BACKLIGHT_RT4831
+     tristate "Richtek RT4831 Backlight Driver"
+     depends on MFD_RT4831
+     help
+       This enables support for Richtek RT4831 Backlight driver.
+       It's common used to drive the display WLED. There're four channels
+       inisde, and each channel can provide up to 30mA current.
+
 config BACKLIGHT_SAHARA
      tristate "Tabletkiosk Sahara Touch-iT Backlight Driver"
      depends on X86

drivers/video/backlight/Makefile +1 -0

index 685f3f1..cae2c83 100644
@@ -49,6 +49,7 @@ obj-$(CONFIG_BACKLIGHT_PANDORA)             += pandora_bl.o
 obj-$(CONFIG_BACKLIGHT_PCF50633)     += pcf50633-backlight.o
 obj-$(CONFIG_BACKLIGHT_PWM)          += pwm_bl.o
 obj-$(CONFIG_BACKLIGHT_QCOM_WLED)    += qcom-wled.o
+obj-$(CONFIG_BACKLIGHT_RT4831)               += rt4831-backlight.o
 obj-$(CONFIG_BACKLIGHT_SAHARA)               += kb3886_bl.o
 obj-$(CONFIG_BACKLIGHT_SKY81452)     += sky81452-backlight.o
 obj-$(CONFIG_BACKLIGHT_TOSA)         += tosa_bl.o

drivers/video/backlight/rt4831-backlight.c new file +198 -0

new file mode 100644
index 00000000..42155c7
@@ -0,0 +1,203 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <dt-bindings/leds/rt4831-backlight.h>
+#include <linux/backlight.h>
+#include <linux/bitops.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+#define RT4831_REG_BLCFG     0x02
+#define RT4831_REG_BLDIML    0x04
+#define RT4831_REG_ENABLE    0x08
+
+#define RT4831_BLMAX_BRIGHTNESS      2048
+
+#define RT4831_BLOVP_MASK    GENMASK(7, 5)
+#define RT4831_BLOVP_SHIFT   5
+#define RT4831_BLPWMEN_MASK  BIT(0)
+#define RT4831_BLEN_MASK     BIT(4)
+#define RT4831_BLCH_MASK     GENMASK(3, 0)
+#define RT4831_BLDIML_MASK   GENMASK(2, 0)
+#define RT4831_BLDIMH_MASK   GENMASK(10, 3)
+#define RT4831_BLDIMH_SHIFT  3
+
+struct rt4831_priv {
+     struct device *dev;
+     struct regmap *regmap;
+     struct backlight_device *bl;
+};
+
+static int rt4831_bl_update_status(struct backlight_device *bl_dev)
+{
+     struct rt4831_priv *priv = bl_get_data(bl_dev);
+     int brightness = backlight_get_brightness(bl_dev);
+     unsigned int enable = brightness ? RT4831_BLEN_MASK : 0;
+     u8 v[2];
+     int ret;
+
+     if (brightness) {
+             v[0] = (brightness - 1) & RT4831_BLDIML_MASK;
+             v[1] = ((brightness - 1) & RT4831_BLDIMH_MASK) >> RT4831_BLDIMH_SHIFT;
+
+             ret = regmap_raw_write(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
+             if (ret)
+                     return ret;
+     }
+
+     return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLEN_MASK, enable);
+
+}
+
+static int rt4831_bl_get_brightness(struct backlight_device *bl_dev)
+{
+     struct rt4831_priv *priv = bl_get_data(bl_dev);
+     unsigned int val;
+     u8 v[2];
+     int ret;
+
+     ret = regmap_read(priv->regmap, RT4831_REG_ENABLE, &val);
+     if (ret)
+             return ret;
+
+     if (!(val & RT4831_BLEN_MASK))
+             return 0;
+
+     ret = regmap_raw_read(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
+     if (ret)
+             return ret;
+
+     ret = (v[1] << RT4831_BLDIMH_SHIFT) + (v[0] & RT4831_BLDIML_MASK) + 1;
+
+     return ret;
+}
+
+static const struct backlight_ops rt4831_bl_ops = {
+     .options = BL_CORE_SUSPENDRESUME,
+     .update_status = rt4831_bl_update_status,
+     .get_brightness = rt4831_bl_get_brightness,
+};
+
+static int rt4831_parse_backlight_properties(struct rt4831_priv *priv,
+                                          struct backlight_properties *bl_props)
+{
+     struct device *dev = priv->dev;
+     u8 propval;
+     u32 brightness;
+     unsigned int val = 0;
+     int ret;
+
+     /* common properties */
+     ret = device_property_read_u32(dev, "max-brightness", &brightness);
+     if (ret)
+             brightness = RT4831_BLMAX_BRIGHTNESS;
+
+     bl_props->max_brightness = min_t(u32, brightness, RT4831_BLMAX_BRIGHTNESS);
+
+     ret = device_property_read_u32(dev, "default-brightness", &brightness);
+     if (ret)
+             brightness = bl_props->max_brightness;
+
+     bl_props->brightness = min_t(u32, brightness, bl_props->max_brightness);
+
+     /* vendor properties */
+     if (device_property_read_bool(dev, "richtek,pwm-enable"))
+             val = RT4831_BLPWMEN_MASK;
+
+     ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLPWMEN_MASK, val);
+     if (ret)
+             return ret;
+
+     ret = device_property_read_u8(dev, "richtek,bled-ovp-sel", &propval);
+     if (ret)
+             propval = RT4831_BLOVPLVL_21V;
+
+     propval = min_t(u8, propval, RT4831_BLOVPLVL_29V);
+     ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLOVP_MASK,
+                              propval << RT4831_BLOVP_SHIFT);
+     if (ret)
+             return ret;
+
+     ret = device_property_read_u8(dev, "richtek,channel-use", &propval);
+     if (ret) {
+             dev_err(dev, "richtek,channel-use DT property missing\n");
+             return ret;
+     }
+
+     if (!(propval & RT4831_BLCH_MASK)) {
+             dev_err(dev, "No channel specified\n");
+             return -EINVAL;
+     }
+
+     return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLCH_MASK, propval);
+}
+
+static int rt4831_bl_probe(struct platform_device *pdev)
+{
+     struct rt4831_priv *priv;
+     struct backlight_properties bl_props = { .type = BACKLIGHT_RAW,
+                                              .scale = BACKLIGHT_SCALE_LINEAR };
+     int ret;
+
+     priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+     if (!priv)
+             return -ENOMEM;
+
+     priv->dev = &pdev->dev;
+
+     priv->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+     if (!priv->regmap) {
+             dev_err(&pdev->dev, "Failed to init regmap\n");
+             return -ENODEV;
+     }
+
+     ret = rt4831_parse_backlight_properties(priv, &bl_props);
+     if (ret) {
+             dev_err(&pdev->dev, "Failed to parse backlight properties\n");
+             return ret;
+     }
+
+     priv->bl = devm_backlight_device_register(&pdev->dev, pdev->name, &pdev->dev, priv,
+                                               &rt4831_bl_ops, &bl_props);
+     if (IS_ERR(priv->bl)) {
+             dev_err(&pdev->dev, "Failed to register backlight\n");
+             return PTR_ERR(priv->bl);
+     }
+
+     backlight_update_status(priv->bl);
+     platform_set_drvdata(pdev, priv);
+
+     return 0;
+}
+
+static int rt4831_bl_remove(struct platform_device *pdev)
+{
+     struct rt4831_priv *priv = platform_get_drvdata(pdev);
+     struct backlight_device *bl_dev = priv->bl;
+
+     bl_dev->props.brightness = 0;
+     backlight_update_status(priv->bl);
+
+     return 0;
+}
+
+static const struct of_device_id __maybe_unused rt4831_bl_of_match[] = {
+     { .compatible = "richtek,rt4831-backlight", },
+     {}
+};
+MODULE_DEVICE_TABLE(of, rt4831_bl_of_match);
+
+static struct platform_driver rt4831_bl_driver = {
+     .driver = {
+             .name = "rt4831-backlight",
+             .of_match_table = rt4831_bl_of_match,
+     },
+     .probe = rt4831_bl_probe,
+     .remove = rt4831_bl_remove,

Quoted 8 lines

drivers/video/backlight/rt4831-backlight.c new file +5 -1

+};
+module_platform_driver(rt4831_bl_driver);
+
+MODULE_AUTHOR("ChiYuan Huang <[email protected]>");
+MODULE_LICENSE("GPL v2");
--

2.7.4

Hi,

Daniel Thompson <[email protected]> 於 2021年4月26日 週一 下午6:19寫道：

Quoted 17 lines · cy_huang

Quoted 4 lines

From: ChiYuan Huang <[email protected]>

Adds support for Richtek RT4831 backlight.

Quoted 8 lines

Signed-off-by ChiYuan Huang <[email protected]>

Reviewed-by Daniel Thompson <[email protected]>

---
Resend this v6 patch series to loop devicetree reviewers.

For next, if the typo in Kconfig 'common' to 'commonly' can be added the below line

Reviewed-by Daniel Thompson <[email protected]>

---

This isn't the best way to handle feedback from multiple maintainers.

Quoted 5 lines

It is great to see you are keeping track of feedback. However it doesn't make sense to RESEND an old patchset and acknowledge that you haven't fixed a typo yet.

It would be better to fix the typo and to resend a v7.

You can refer to the below reply
https://lkml.org/lkml/2021/4/23/229

Quoted 241 lines

Quoted 241 lines

 drivers/video/backlight/Kconfig            |   8 ++
 drivers/video/backlight/Makefile           |   1 +
 drivers/video/backlight/rt4831-backlight.c | 203 +++++++++++++++++++++++++++++
 3 files changed, 212 insertions(+)
 create mode 100644 drivers/video/backlight/rt4831-backlight.c

drivers/video/backlight/Kconfig +8 -0

index d83c87b..de96441 100644
@@ -289,6 +289,14 @@ config BACKLIGHT_QCOM_WLED
        If you have the Qualcomm PMIC, say Y to enable a driver for the
        WLED block. Currently it supports PM8941 and PMI8998.
 
+config BACKLIGHT_RT4831
+     tristate "Richtek RT4831 Backlight Driver"
+     depends on MFD_RT4831
+     help
+       This enables support for Richtek RT4831 Backlight driver.
+       It's common used to drive the display WLED. There're four channels
+       inisde, and each channel can provide up to 30mA current.
+
 config BACKLIGHT_SAHARA
      tristate "Tabletkiosk Sahara Touch-iT Backlight Driver"
      depends on X86

drivers/video/backlight/Makefile +1 -0

index 685f3f1..cae2c83 100644
@@ -49,6 +49,7 @@ obj-$(CONFIG_BACKLIGHT_PANDORA)             += pandora_bl.o
 obj-$(CONFIG_BACKLIGHT_PCF50633)     += pcf50633-backlight.o
 obj-$(CONFIG_BACKLIGHT_PWM)          += pwm_bl.o
 obj-$(CONFIG_BACKLIGHT_QCOM_WLED)    += qcom-wled.o
+obj-$(CONFIG_BACKLIGHT_RT4831)               += rt4831-backlight.o
 obj-$(CONFIG_BACKLIGHT_SAHARA)               += kb3886_bl.o
 obj-$(CONFIG_BACKLIGHT_SKY81452)     += sky81452-backlight.o
 obj-$(CONFIG_BACKLIGHT_TOSA)         += tosa_bl.o

drivers/video/backlight/rt4831-backlight.c new file +198 -0

new file mode 100644
index 00000000..42155c7
@@ -0,0 +1,203 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <dt-bindings/leds/rt4831-backlight.h>
+#include <linux/backlight.h>
+#include <linux/bitops.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+#define RT4831_REG_BLCFG     0x02
+#define RT4831_REG_BLDIML    0x04
+#define RT4831_REG_ENABLE    0x08
+
+#define RT4831_BLMAX_BRIGHTNESS      2048
+
+#define RT4831_BLOVP_MASK    GENMASK(7, 5)
+#define RT4831_BLOVP_SHIFT   5
+#define RT4831_BLPWMEN_MASK  BIT(0)
+#define RT4831_BLEN_MASK     BIT(4)
+#define RT4831_BLCH_MASK     GENMASK(3, 0)
+#define RT4831_BLDIML_MASK   GENMASK(2, 0)
+#define RT4831_BLDIMH_MASK   GENMASK(10, 3)
+#define RT4831_BLDIMH_SHIFT  3
+
+struct rt4831_priv {
+     struct device *dev;
+     struct regmap *regmap;
+     struct backlight_device *bl;
+};
+
+static int rt4831_bl_update_status(struct backlight_device *bl_dev)
+{
+     struct rt4831_priv *priv = bl_get_data(bl_dev);
+     int brightness = backlight_get_brightness(bl_dev);
+     unsigned int enable = brightness ? RT4831_BLEN_MASK : 0;
+     u8 v[2];
+     int ret;
+
+     if (brightness) {
+             v[0] = (brightness - 1) & RT4831_BLDIML_MASK;
+             v[1] = ((brightness - 1) & RT4831_BLDIMH_MASK) >> RT4831_BLDIMH_SHIFT;
+
+             ret = regmap_raw_write(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
+             if (ret)
+                     return ret;
+     }
+
+     return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLEN_MASK, enable);
+
+}
+
+static int rt4831_bl_get_brightness(struct backlight_device *bl_dev)
+{
+     struct rt4831_priv *priv = bl_get_data(bl_dev);
+     unsigned int val;
+     u8 v[2];
+     int ret;
+
+     ret = regmap_read(priv->regmap, RT4831_REG_ENABLE, &val);
+     if (ret)
+             return ret;
+
+     if (!(val & RT4831_BLEN_MASK))
+             return 0;
+
+     ret = regmap_raw_read(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
+     if (ret)
+             return ret;
+
+     ret = (v[1] << RT4831_BLDIMH_SHIFT) + (v[0] & RT4831_BLDIML_MASK) + 1;
+
+     return ret;
+}
+
+static const struct backlight_ops rt4831_bl_ops = {
+     .options = BL_CORE_SUSPENDRESUME,
+     .update_status = rt4831_bl_update_status,
+     .get_brightness = rt4831_bl_get_brightness,
+};
+
+static int rt4831_parse_backlight_properties(struct rt4831_priv *priv,
+                                          struct backlight_properties *bl_props)
+{
+     struct device *dev = priv->dev;
+     u8 propval;
+     u32 brightness;
+     unsigned int val = 0;
+     int ret;
+
+     /* common properties */
+     ret = device_property_read_u32(dev, "max-brightness", &brightness);
+     if (ret)
+             brightness = RT4831_BLMAX_BRIGHTNESS;
+
+     bl_props->max_brightness = min_t(u32, brightness, RT4831_BLMAX_BRIGHTNESS);
+
+     ret = device_property_read_u32(dev, "default-brightness", &brightness);
+     if (ret)
+             brightness = bl_props->max_brightness;
+
+     bl_props->brightness = min_t(u32, brightness, bl_props->max_brightness);
+
+     /* vendor properties */
+     if (device_property_read_bool(dev, "richtek,pwm-enable"))
+             val = RT4831_BLPWMEN_MASK;
+
+     ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLPWMEN_MASK, val);
+     if (ret)
+             return ret;
+
+     ret = device_property_read_u8(dev, "richtek,bled-ovp-sel", &propval);
+     if (ret)
+             propval = RT4831_BLOVPLVL_21V;
+
+     propval = min_t(u8, propval, RT4831_BLOVPLVL_29V);
+     ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLOVP_MASK,
+                              propval << RT4831_BLOVP_SHIFT);
+     if (ret)
+             return ret;
+
+     ret = device_property_read_u8(dev, "richtek,channel-use", &propval);
+     if (ret) {
+             dev_err(dev, "richtek,channel-use DT property missing\n");
+             return ret;
+     }
+
+     if (!(propval & RT4831_BLCH_MASK)) {
+             dev_err(dev, "No channel specified\n");
+             return -EINVAL;
+     }
+
+     return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLCH_MASK, propval);
+}
+
+static int rt4831_bl_probe(struct platform_device *pdev)
+{
+     struct rt4831_priv *priv;
+     struct backlight_properties bl_props = { .type = BACKLIGHT_RAW,
+                                              .scale = BACKLIGHT_SCALE_LINEAR };
+     int ret;
+
+     priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+     if (!priv)
+             return -ENOMEM;
+
+     priv->dev = &pdev->dev;
+
+     priv->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+     if (!priv->regmap) {
+             dev_err(&pdev->dev, "Failed to init regmap\n");
+             return -ENODEV;
+     }
+
+     ret = rt4831_parse_backlight_properties(priv, &bl_props);
+     if (ret) {
+             dev_err(&pdev->dev, "Failed to parse backlight properties\n");
+             return ret;
+     }
+
+     priv->bl = devm_backlight_device_register(&pdev->dev, pdev->name, &pdev->dev, priv,
+                                               &rt4831_bl_ops, &bl_props);
+     if (IS_ERR(priv->bl)) {
+             dev_err(&pdev->dev, "Failed to register backlight\n");
+             return PTR_ERR(priv->bl);
+     }
+
+     backlight_update_status(priv->bl);
+     platform_set_drvdata(pdev, priv);
+
+     return 0;
+}
+
+static int rt4831_bl_remove(struct platform_device *pdev)
+{
+     struct rt4831_priv *priv = platform_get_drvdata(pdev);
+     struct backlight_device *bl_dev = priv->bl;
+
+     bl_dev->props.brightness = 0;
+     backlight_update_status(priv->bl);
+
+     return 0;
+}
+
+static const struct of_device_id __maybe_unused rt4831_bl_of_match[] = {
+     { .compatible = "richtek,rt4831-backlight", },
+     {}
+};
+MODULE_DEVICE_TABLE(of, rt4831_bl_of_match);
+
+static struct platform_driver rt4831_bl_driver = {
+     .driver = {
+             .name = "rt4831-backlight",
+             .of_match_table = rt4831_bl_of_match,
+     },
+     .probe = rt4831_bl_probe,
+     .remove = rt4831_bl_remove,

Quoted 8 lines

Quoted 8 lines

drivers/video/backlight/rt4831-backlight.c new file +5 -1

+};
+module_platform_driver(rt4831_bl_driver);
+
+MODULE_AUTHOR("ChiYuan Huang <[email protected]>");
+MODULE_LICENSE("GPL v2");
--

2.7.4