[PATCH v7 0/3] Add LED1202 LED Controller

[PATCH v7 0/3] Add LED1202 LED Controller

[Vicentiu Galanopulo]

The LED1202 is a 12-channel low quiescent current LED driver with:
  * Supply range from 2.6 V to 5 V
  * 20 mA current capability per channel
  * 1.8 V compatible I2C control interface
  * 8-bit analog dimming individual control
  * 12-bit local PWM resolution
  * 8 programmable patterns

Internal volatile memory allows the user to store up to 8 different patterns,
each pattern is a particular output configuration in terms of PWM
duty-cycle (on 4096 steps). Analog dimming (on 256 steps) is per channel but
common to all patterns. Each device tree LED node will have a corresponding
entry in /sys/class/leds with the label name. The brightness property
corresponds to the per channel analog dimming, while the patterns[1-8] to the
PWM dimming control.  

Vicentiu Galanopulo (3):
  Documentation:leds: Add leds-st1202.rst
  dt-bindings: leds: Add LED1202 LED Controller
  leds: Add LED1202 I2C driver

 .../devicetree/bindings/leds/st,led1202.yaml  | 132 +++++
 Documentation/leds/index.rst                  |   1 +
 Documentation/leds/leds-st1202.rst            |  36 ++
 drivers/leds/Kconfig                          |  11 +
 drivers/leds/Makefile                         |   1 +
 drivers/leds/leds-st1202.c                    | 510 ++++++++++++++++++
 6 files changed, 691 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/st,led1202.yaml
 create mode 100644 Documentation/leds/leds-st1202.rst
 create mode 100644 drivers/leds/leds-st1202.c

-- 
2.39.3 (Apple Git-145)

[PATCH v7 1/3] Documentation:leds: Add leds-st1202.rst

[Vicentiu Galanopulo]

Add usage for sysfs hw_pattern entry for leds-st1202

Signed-off-by: Vicentiu Galanopulo <vicentiu.galanopulo@remote-tech.co.uk>
---
 Documentation/leds/index.rst       |  1 +
 Documentation/leds/leds-st1202.rst | 36 ++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 Documentation/leds/leds-st1202.rst

diff --git a/Documentation/leds/index.rst b/Documentation/leds/index.rst
index 3ade16c18328..0ab0a2128a11 100644
--- a/Documentation/leds/index.rst
+++ b/Documentation/leds/index.rst
@@ -28,4 +28,5 @@ LEDs
    leds-mlxcpld
    leds-mt6370-rgb
    leds-sc27xx
+   leds-st1202.rst
    leds-qcom-lpg
diff --git a/Documentation/leds/leds-st1202.rst b/Documentation/leds/leds-st1202.rst
new file mode 100644
index 000000000000..e647966e496c
--- /dev/null
+++ b/Documentation/leds/leds-st1202.rst
@@ -0,0 +1,36 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+============================================
+Kernel driver for STMicroelectronics LED1202
+============================================
+
+/sys/class/leds/<led>/hw_pattern
+--------------------------------
+
+Specify a hardware pattern for the ST1202 LED. The LED
+controller implements 12 low-side current generators
+with independent dimming control. Internal volatile memory
+allows the user to store up to 8 different patterns.
+Each pattern is a particular output configuration in terms
+of PWM duty-cycle and duration (ms).
+
+To be compatible with the hardware pattern
+format, maximum 8 tuples of brightness (PWM) and duration must
+be written to hw_pattern.
+
+- Min pattern duration: 22 ms
+- Max pattern duration: 5660 ms
+
+The format of the hardware pattern values should be:
+"brightness duration brightness duration ..."
+
+/sys/class/leds/<led>/repeat
+----------------------------
+
+Specify a pattern repeat number, which is common for all channels.
+Default is 1; negative numbers and 0 are invalid.
+
+This file will always return the originally written repeat number.
+
+When the 255 value is written to it, all patterns will repeat
+indefinitely.
-- 
2.39.3 (Apple Git-145)

[PATCH v7 2/3] dt-bindings: leds: Add LED1202 LED Controller

[Vicentiu Galanopulo]

The LED1202 is a 12-channel low quiescent current LED driver with:
  * Supply range from 2.6 V to 5 V
  * 20 mA current capability per channel
  * 1.8 V compatible I2C control interface
  * 8-bit analog dimming individual control
  * 12-bit local PWM resolution
  * 8 programmable patterns

If the led node is present in the controller then the channel is
set to active.

Signed-off-by: Vicentiu Galanopulo <vicentiu.galanopulo@remote-tech.co.uk>
---
 .../devicetree/bindings/leds/st,led1202.yaml  | 132 ++++++++++++++++++
 1 file changed, 132 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/st,led1202.yaml

diff --git a/Documentation/devicetree/bindings/leds/st,led1202.yaml b/Documentation/devicetree/bindings/leds/st,led1202.yaml
new file mode 100644
index 000000000000..f1e5e4efaa3a
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/st,led1202.yaml
@@ -0,0 +1,132 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/st,led1202.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ST LED1202 LED controllers
+
+maintainers:
+  - Vicentiu Galanopulo <vicentiu.galanopulo@remote-tech.co.uk>
+
+description: |
+  The LED1202 is a 12-channel low quiescent current LED controller
+  programmable via I2C; The output current can be adjusted separately
+  for each channel by 8-bit analog and 12-bit digital dimming control.
+  Datasheet available at
+  https://www.st.com/en/power-management/led1202.html
+
+properties:
+  compatible:
+    const: st,led1202
+
+  reg:
+    maxItems: 1
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+patternProperties:
+  "^led@[0-9a-f]$":
+    type: object
+    $ref: common.yaml#
+    unevaluatedProperties: false
+
+    properties:
+      reg:
+        minimum: 0
+        maximum: 11
+
+    required:
+      - reg
+
+required:
+  - compatible
+  - reg
+  - "#address-cells"
+  - "#size-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/leds/common.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        led-controller@58 {
+            compatible = "st,led1202";
+            reg = <0x58>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            led@0 {
+                reg = <0x0>;
+                function = LED_FUNCTION_STATUS;
+                color = <LED_COLOR_ID_RED>;
+                function-enumerator = <1>;
+            };
+
+            led@1 {
+                reg = <0x1>;
+                function = LED_FUNCTION_STATUS;
+                color = <LED_COLOR_ID_GREEN>;
+                function-enumerator = <2>;
+            };
+
+            led@2 {
+                reg = <0x2>;
+                function = LED_FUNCTION_STATUS;
+                color = <LED_COLOR_ID_BLUE>;
+                function-enumerator = <3>;
+            };
+
+            led@3 {
+                reg = <0x3>;
+                function = LED_FUNCTION_STATUS;
+                color = <LED_COLOR_ID_RED>;
+                function-enumerator = <4>;
+            };
+
+            led@4 {
+                reg = <0x4>;
+                function = LED_FUNCTION_STATUS;
+                color = <LED_COLOR_ID_GREEN>;
+                function-enumerator = <5>;
+            };
+
+            led@5 {
+                reg = <0x5>;
+                function = LED_FUNCTION_STATUS;
+                color = <LED_COLOR_ID_BLUE>;
+                function-enumerator = <6>;
+            };
+
+            led@6 {
+                reg = <0x6>;
+                function = LED_FUNCTION_STATUS;
+                color = <LED_COLOR_ID_RED>;
+                function-enumerator = <7>;
+            };
+
+            led@7 {
+                reg = <0x7>;
+                function = LED_FUNCTION_STATUS;
+                color = <LED_COLOR_ID_GREEN>;
+                function-enumerator = <8>;
+            };
+
+            led@8 {
+                reg = <0x8>;
+                function = LED_FUNCTION_STATUS;
+                color = <LED_COLOR_ID_BLUE>;
+                function-enumerator = <9>;
+            };
+        };
+    };
+...
-- 
2.39.3 (Apple Git-145)

[PATCH v7 3/3] leds: Add LED1202 I2C driver

[Vicentiu Galanopulo]

The output current can be adjusted separately for each channel by 8-bit
analog (current sink input) and 12-bit digital (PWM) dimming control. The
LED1202 implements 12 low-side current generators with independent dimming
control.
Internal volatile memory allows the user to store up to 8 different patterns,
each pattern is a particular output configuration in terms of PWM
duty-cycle (on 4096 steps). Analog dimming (on 256 steps) is per channel but
common to all patterns. Each device tree LED node will have a corresponding
entry in /sys/class/leds with the label name. The brightness property
corresponds to the per channel analog dimming, while the patterns[1-8] to the
PWM dimming control.

Signed-off-by: Vicentiu Galanopulo <vicentiu.galanopulo@remote-tech.co.uk>
---
 drivers/leds/Kconfig       |  11 +
 drivers/leds/Makefile      |   1 +
 drivers/leds/leds-st1202.c | 510 +++++++++++++++++++++++++++++++++++++
 3 files changed, 522 insertions(+)
 create mode 100644 drivers/leds/leds-st1202.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index b784bb74a837..c4fdacc00066 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -931,6 +931,17 @@ config LEDS_LM36274
 	  Say Y to enable the LM36274 LED driver for TI LMU devices.
 	  This supports the LED device LM36274.
 
+config LEDS_ST1202
+	tristate "LED Support for STMicroelectronics LED1202 I2C chips"
+	depends on LEDS_CLASS
+	depends on I2C
+	depends on OF
+	select LEDS_TRIGGERS
+	help
+	  Say Y to enable support for LEDs connected to LED1202
+	  LED driver chips accessed via the I2C bus.
+	  Supported devices include LED1202.
+
 config LEDS_TPS6105X
 	tristate "LED support for TI TPS6105X"
 	depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 18afbb5a23ee..e8b39ef760cc 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -81,6 +81,7 @@ obj-$(CONFIG_LEDS_POWERNV)		+= leds-powernv.o
 obj-$(CONFIG_LEDS_PWM)			+= leds-pwm.o
 obj-$(CONFIG_LEDS_REGULATOR)		+= leds-regulator.o
 obj-$(CONFIG_LEDS_SC27XX_BLTC)		+= leds-sc27xx-bltc.o
+obj-$(CONFIG_LEDS_ST1202)		+= leds-st1202.o
 obj-$(CONFIG_LEDS_SUN50I_A100)		+= leds-sun50i-a100.o
 obj-$(CONFIG_LEDS_SUNFIRE)		+= leds-sunfire.o
 obj-$(CONFIG_LEDS_SYSCON)		+= leds-syscon.o
diff --git a/drivers/leds/leds-st1202.c b/drivers/leds/leds-st1202.c
new file mode 100644
index 000000000000..f278e528c73f
--- /dev/null
+++ b/drivers/leds/leds-st1202.c
@@ -0,0 +1,510 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * LED driver for STMicroelectronics LED1202 chip
+ *
+ * Copyright (C) 2024 Remote-Tech Ltd. UK
+ */
+
+#include <linux/ctype.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/i2c.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+
+#define ST1202_CHAN_DISABLE_ALL            0x00
+#define ST1202_CHAN_ENABLE_HIGH            0x03
+#define ST1202_CHAN_ENABLE_LOW             0x02
+#define ST1202_CONFIG_REG                  0x04
+/* PATS: Pattern sequence feature enable */
+#define ST1202_CONFIG_REG_PATS             BIT(7)
+/* PATSR: Pattern sequence runs (self-clear when sequence is finished) */
+#define ST1202_CONFIG_REG_PATSR            BIT(6)
+#define ST1202_CONFIG_REG_SHFT             BIT(3)
+#define ST1202_DEV_ENABLE                  0x01
+#define ST1202_DEV_ENABLE_ON               BIT(0)
+#define ST1202_DEV_ENABLE_RESET            BIT(7)
+#define ST1202_DEVICE_ID                   0x00
+#define ST1202_ILED_REG0                   0x09
+#define ST1202_MAX_LEDS                    12
+#define ST1202_MAX_PATTERNS                8
+#define ST1202_MILLIS_PATTERN_DUR_MAX      5660
+#define ST1202_MILLIS_PATTERN_DUR_MIN      22
+#define ST1202_PATTERN_DUR                 0x16
+#define ST1202_PATTERN_PWM                 0x1E
+#define ST1202_PATTERN_REP                 0x15
+
+struct st1202_led {
+	struct fwnode_handle *fwnode;
+	struct led_classdev led_cdev;
+	struct st1202_chip *chip;
+	bool is_active;
+	int led_num;
+};
+
+struct st1202_chip {
+	struct i2c_client *client;
+	struct mutex lock;
+	struct st1202_led leds[ST1202_MAX_LEDS];
+};
+
+static struct st1202_led *cdev_to_st1202_led(struct led_classdev *cdev)
+{
+	return container_of(cdev, struct st1202_led, led_cdev);
+}
+
+static int st1202_read_reg(struct st1202_chip *chip, int reg, uint8_t *val)
+{
+	int ret;
+
+	ret = i2c_smbus_read_byte_data(chip->client, reg);
+	if (ret < 0)
+		return ret;
+
+	*val = (uint8_t)ret;
+	return 0;
+}
+
+static int st1202_write_reg(struct st1202_chip *chip, int reg, uint8_t val)
+{
+	return i2c_smbus_write_byte_data(chip->client, reg, val);
+}
+
+static uint8_t st1202_prescalar_to_miliseconds(unsigned int value)
+{
+	return value/ST1202_MILLIS_PATTERN_DUR_MIN - 1;
+}
+
+static int st1202_pwm_pattern_write(struct st1202_chip *chip, int led_num,
+					int pattern, unsigned int value)
+{
+	u8 value_l, value_h;
+	int ret;
+
+	value_l = (u8)value;
+	value_h = (u8)(value >> 8);
+
+	/*
+	 *  Datasheet: Register address low = 1Eh + 2*(xh) + 18h*(yh),
+	 *  where x is the channel number (led number) in hexadecimal (x = 00h .. 0Bh)
+	 *  and y is the pattern number in hexadecimal (y = 00h .. 07h)
+	 */
+	ret = st1202_write_reg(chip, (ST1202_PATTERN_PWM + (led_num * 2) + 0x18 * pattern),
+				value_l);
+	if (ret != 0) {
+		dev_err(&chip->client->dev, "Failed writing value %d to register [0x%x], error: %d\n",
+			value_l, ST1202_PATTERN_PWM + (led_num * 2) + 0x18 * pattern, ret);
+		return ret;
+	}
+
+	/*
+	 * Datasheet: Register address high = 1Eh + 01h + 2(xh) +18h*(yh),
+	 * where x is the channel number in hexadecimal (x = 00h .. 0Bh)
+	 * and y is the pattern number in hexadecimal (y = 00h .. 07h)
+	 */
+	ret = st1202_write_reg(chip, (ST1202_PATTERN_PWM + 0x1 + (led_num * 2) + 0x18 * pattern),
+				value_h);
+	if (ret != 0) {
+		dev_err(&chip->client->dev, "Failed writing value %d to register [0x%x], error: %d\n",
+			value_h, ST1202_PATTERN_PWM + 0x1 + (led_num * 2) + 0x18 * pattern, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int st1202_duration_pattern_write(struct st1202_chip *chip, int pattern,
+					unsigned int value)
+{
+	int ret;
+
+	ret = st1202_write_reg(chip, (ST1202_PATTERN_DUR + pattern),
+				st1202_prescalar_to_miliseconds(value));
+	if (ret != 0) {
+		dev_err(&chip->client->dev, "Writing to register [0x%x] failed, value %u\n",
+			ST1202_PATTERN_DUR + pattern, value);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void st1202_brightness_set(struct led_classdev *led_cdev,
+				enum led_brightness value)
+{
+	struct st1202_led *led;
+	struct st1202_chip *chip;
+	int ret;
+
+	led = cdev_to_st1202_led(led_cdev);
+	chip = led->chip;
+
+	mutex_lock(&chip->lock);
+
+	ret = st1202_write_reg(chip, ST1202_ILED_REG0 + led->led_num, value);
+	if (ret != 0)
+		dev_err(&chip->client->dev, "Reading register [0x%x] failed, error: %d\n",
+			ST1202_ILED_REG0 + led->led_num, ret);
+
+	mutex_unlock(&chip->lock);
+}
+
+static enum led_brightness st1202_brightness_get(struct led_classdev *led_cdev)
+{
+	struct st1202_led *led;
+	struct st1202_chip *chip;
+	u8 value = 0;
+	int ret;
+
+	led = cdev_to_st1202_led(led_cdev);
+	chip = led->chip;
+
+	mutex_lock(&chip->lock);
+
+	ret = st1202_read_reg(chip, ST1202_ILED_REG0 + led->led_num,
+				&value);
+	if (ret != 0)
+		dev_err(&chip->client->dev, "Reading register [0x%x] failed, error: %d\n",
+			ST1202_ILED_REG0 + led->led_num, ret);
+
+	mutex_unlock(&chip->lock);
+
+	return value;
+}
+
+static int st1202_channel_set(struct st1202_chip *chip, int led_num, bool active)
+{
+	u8 chan_low, chan_high;
+	int ret;
+
+	mutex_lock(&chip->lock);
+
+	if (led_num <= 7) {
+		ret = st1202_read_reg(chip, ST1202_CHAN_ENABLE_LOW, &chan_low);
+		if (ret < 0) {
+			dev_err(&chip->client->dev, "Failed reading register [0x%x], error: %d\n",
+				ST1202_CHAN_ENABLE_LOW, ret);
+			goto exit;
+		}
+
+		chan_low = active ? chan_low | BIT(led_num) : chan_low & ~BIT(led_num);
+
+		ret = st1202_write_reg(chip, ST1202_CHAN_ENABLE_LOW, chan_low);
+		if (ret < 0) {
+			dev_err(&chip->client->dev, "Failed writing to register [0x%x], error: %d\n",
+				ST1202_CHAN_ENABLE_LOW, ret);
+			goto exit;
+		}
+	} else {
+		ret = st1202_read_reg(chip, ST1202_CHAN_ENABLE_HIGH, &chan_high);
+		if (ret < 0) {
+			dev_err(&chip->client->dev, "Failed reading register [0x%x], error: %d\n",
+				ST1202_CHAN_ENABLE_HIGH, ret);
+			goto exit;
+		}
+
+		chan_high = active ? chan_high | (BIT(led_num) >> 8) :
+					chan_high & ~(BIT(led_num) >> 8);
+
+		ret = st1202_write_reg(chip, ST1202_CHAN_ENABLE_HIGH, chan_high);
+		if (ret < 0)
+			dev_err(&chip->client->dev, "Failed writing to register [0x%x], error: %d\n",
+				ST1202_CHAN_ENABLE_HIGH, ret);
+	}
+
+exit:
+	mutex_unlock(&chip->lock);
+	return ret;
+}
+
+static int st1202_led_set(struct led_classdev *ldev, enum led_brightness value)
+{
+	struct st1202_led *led;
+	struct st1202_chip *chip;
+	int ret;
+
+	led = cdev_to_st1202_led(ldev);
+	chip = led->chip;
+
+	ret = st1202_channel_set(chip, led->led_num, value == LED_OFF ? false : true);
+
+	return ret;
+}
+
+static int st1202_led_pattern_clear(struct led_classdev *ldev)
+{
+	struct st1202_led *led;
+	struct st1202_chip *chip;
+	int ret;
+
+	led = cdev_to_st1202_led(ldev);
+	chip = led->chip;
+
+	mutex_lock(&chip->lock);
+
+	for (int patt = 0; patt < ST1202_MAX_PATTERNS; patt++) {
+		ret = st1202_pwm_pattern_write(chip, led->led_num, patt, LED_OFF);
+		if (ret != 0)
+			goto exit;
+
+		ret = st1202_duration_pattern_write(chip, patt, ST1202_MILLIS_PATTERN_DUR_MIN);
+		if (ret != 0)
+			goto exit;
+	}
+
+exit:
+	mutex_unlock(&chip->lock);
+
+	return ret;
+}
+
+static int st1202_led_pattern_set(struct led_classdev *ldev,
+				  struct led_pattern *pattern,
+				  u32 len, int repeat)
+{
+	struct st1202_led *led;
+	struct st1202_chip *chip;
+	int ret;
+
+	led = cdev_to_st1202_led(ldev);
+	chip = led->chip;
+
+	if (len > ST1202_MAX_PATTERNS)
+		return -EINVAL;
+
+	mutex_lock(&chip->lock);
+
+	for (int patt = 0; patt < len; patt++) {
+		if (pattern[patt].delta_t < ST1202_MILLIS_PATTERN_DUR_MIN ||
+			pattern[patt].delta_t > ST1202_MILLIS_PATTERN_DUR_MAX) {
+			ret = -EINVAL;
+			goto exit;
+		}
+
+		ret = st1202_pwm_pattern_write(chip, led->led_num, patt, pattern[patt].brightness);
+		if (ret != 0)
+			goto exit;
+
+		ret = st1202_duration_pattern_write(chip, patt, pattern[patt].delta_t);
+		if (ret != 0)
+			goto exit;
+	}
+
+	ret = st1202_write_reg(chip, ST1202_PATTERN_REP, repeat);
+	if (ret != 0) {
+		dev_err(&chip->client->dev, "Writing register [0x%x] failed, error: %d\n",
+			ST1202_PATTERN_REP, ret);
+		goto exit;
+	}
+
+	ret = st1202_write_reg(chip, ST1202_CONFIG_REG,
+				(ST1202_CONFIG_REG_PATSR | ST1202_CONFIG_REG_PATS |
+				ST1202_CONFIG_REG_SHFT));
+	if (ret != 0) {
+		dev_err(&chip->client->dev, "Failed writing value %ld to register [0x%x], error: %d\n",
+			(ST1202_CONFIG_REG_PATSR | ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_SHFT),
+			ST1202_CONFIG_REG, ret);
+		goto exit;
+	}
+
+exit:
+	mutex_unlock(&chip->lock);
+
+	return ret;
+}
+
+static int st1202_dt_init(struct st1202_chip *chip)
+{
+	struct device *dev = &chip->client->dev;
+	struct st1202_led *led;
+	int err, reg;
+
+	for_each_available_child_of_node_scoped(dev_of_node(dev), child) {
+		struct led_init_data init_data = {};
+
+		err = of_property_read_u32(child, "reg", &reg);
+		if (err) {
+			of_node_put(child);
+			return dev_err_probe(dev, err, "Invalid register, error: %d\n", err);
+		}
+
+		led = &chip->leds[reg];
+		led->is_active = true;
+		led->fwnode = of_fwnode_handle(child);
+
+		led->led_cdev.max_brightness = U8_MAX;
+		led->led_cdev.brightness_set_blocking = st1202_led_set;
+		led->led_cdev.pattern_set = st1202_led_pattern_set;
+		led->led_cdev.pattern_clear = st1202_led_pattern_clear;
+		led->led_cdev.default_trigger = "pattern";
+
+		init_data.fwnode = led->fwnode;
+		init_data.devicename = "st1202";
+		init_data.default_label = ":";
+		err = devm_led_classdev_register_ext(dev,
+					&led->led_cdev, &init_data);
+		if (err < 0) {
+			dev_err_probe(dev, err,
+				"Failed to register LED class dev, error: %d\n", err);
+			return err;
+		}
+		led->led_cdev.brightness_set = st1202_brightness_set;
+		led->led_cdev.brightness_get = st1202_brightness_get;
+	}
+
+	return 0;
+}
+
+static int st1202_setup(struct st1202_chip *chip)
+{
+	int ret;
+
+	mutex_lock(&chip->lock);
+	/*
+	 * Once the supply voltage is applied, the LED1202 executes some internal checks,
+	 * afterwords it stops the oscillator and puts the internal LDO in quiescent mode.
+	 * To start the device, EN bit must be set inside the “Device Enable” register at
+	 * address 01h. As soon as EN is set, the LED1202 loads the adjustment parameters
+	 * from the internal non-volatile memory and performs an auto-calibration procedure
+	 * in order to increase the output current precision.
+	 * Such initialization lasts about 6.5 ms.
+	 */
+
+	/* Reset the chip during setup */
+	ret = st1202_write_reg(chip, ST1202_DEV_ENABLE, ST1202_DEV_ENABLE_RESET);
+	if (ret < 0) {
+		dev_err_probe(&chip->client->dev, -EIO,
+				"Failed to write to register [0x%x], error: %d\n",
+				ST1202_DEV_ENABLE, ret);
+		goto exit;
+	}
+
+	/* Enable phase-shift delay feature */
+	ret = st1202_write_reg(chip, ST1202_CONFIG_REG, ST1202_CONFIG_REG_SHFT);
+	if (ret < 0) {
+		dev_err_probe(&chip->client->dev, -EIO,
+				"Failed to write to register [0x%x], error: %d\n",
+				ST1202_CONFIG_REG, ret);
+		goto exit;
+	}
+
+	/* Enable the device */
+	ret = st1202_write_reg(chip, ST1202_DEV_ENABLE, ST1202_DEV_ENABLE_ON);
+	if (ret < 0) {
+		dev_err_probe(&chip->client->dev, -EIO,
+				"Failed to write to register [0x%x], error: %d\n",
+				ST1202_DEV_ENABLE, ret);
+		goto exit;
+	}
+
+	/* Duration of initialization */
+	usleep_range(6500, 10000);
+
+	/* Deactivate all LEDS (channels) and activate only the ones found in Device Tree */
+	ret = st1202_write_reg(chip, ST1202_CHAN_ENABLE_LOW, ST1202_CHAN_DISABLE_ALL);
+	if (ret < 0) {
+		dev_err_probe(&chip->client->dev, -EIO,
+				"Failed writing to register [0x%x], error: %d\n",
+				ST1202_CHAN_ENABLE_LOW, ret);
+		goto exit;
+	}
+
+	ret = st1202_write_reg(chip, ST1202_CHAN_ENABLE_HIGH, ST1202_CHAN_DISABLE_ALL);
+	if (ret < 0) {
+		dev_err_probe(&chip->client->dev, -EIO,
+				"Failed writing to register [0x%x], error: %d\n",
+				ST1202_CHAN_ENABLE_HIGH, ret);
+		goto exit;
+	}
+
+	ret = st1202_write_reg(chip, ST1202_CONFIG_REG,
+				ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_PATSR);
+	if (ret < 0) {
+		dev_err_probe(&chip->client->dev, -EIO,
+				"Failed writing to register [0x%lx], error: %d\n",
+				ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_PATSR, ret);
+		goto exit;
+	}
+
+exit:
+	mutex_unlock(&chip->lock);
+	return ret;
+}
+
+static int st1202_probe(struct i2c_client *client)
+{
+	struct st1202_chip *chip;
+	struct st1202_led *led;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+		return dev_err_probe(&client->dev, -EIO, "SMBUS Byte Data not Supported\n");
+
+	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, chip);
+
+	devm_mutex_init(&client->dev, &chip->lock);
+	chip->client = client;
+
+	ret = st1202_dt_init(chip);
+	if (ret < 0)
+		return ret;
+
+	ret = st1202_setup(chip);
+	if (ret < 0)
+		return ret;
+
+	for (int i = 0; i < ST1202_MAX_LEDS; i++) {
+		led = &chip->leds[i];
+		led->chip = chip;
+		led->led_num = i;
+
+		if (led->is_active) {
+			ret = st1202_channel_set(led->chip, led->led_num, true);
+			if (ret < 0) {
+				return dev_err_probe(&client->dev, -EIO,
+					"Failed to activate LED channel, error: %d\n", ret);
+			}
+
+			ret = st1202_led_pattern_clear(&led->led_cdev);
+			if (ret < 0) {
+				return dev_err_probe(&client->dev, -EIO,
+					"Failed to clear LED pattern, error: %d\n", ret);
+			}
+		}
+	}
+
+	return 0;
+}
+
+static const struct i2c_device_id st1202_id[] = {
+	{ "st1202-i2c" },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(i2c, st1202_id);
+
+static const struct of_device_id st1202_dt_ids[] = {
+	{ .compatible = "st,led1202", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, st1202_dt_ids);
+
+static struct i2c_driver st1202_driver = {
+	.driver = {
+		.name = "leds-st1202",
+		.of_match_table = of_match_ptr(st1202_dt_ids),
+	},
+	.probe = st1202_probe,
+	.id_table = st1202_id,
+};
+module_i2c_driver(st1202_driver);
+
+MODULE_AUTHOR("Remote Tech LTD");
+MODULE_DESCRIPTION("STMicroelectronics LED1202 : 12-channel constant current LED driver");
+MODULE_LICENSE("GPL");
-- 
2.39.3 (Apple Git-145)

Re: [PATCH v7 3/3] leds: Add LED1202 I2C driver

[Christophe JAILLET]

Le 18/11/2024 à 15:54, Vicentiu Galanopulo a écrit :
> The output current can be adjusted separately for each channel by 8-bit
> analog (current sink input) and 12-bit digital (PWM) dimming control. The
> LED1202 implements 12 low-side current generators with independent dimming
> control.
> Internal volatile memory allows the user to store up to 8 different patterns,
> each pattern is a particular output configuration in terms of PWM
> duty-cycle (on 4096 steps). Analog dimming (on 256 steps) is per channel but
> common to all patterns. Each device tree LED node will have a corresponding
> entry in /sys/class/leds with the label name. The brightness property
> corresponds to the per channel analog dimming, while the patterns[1-8] to the
> PWM dimming control.
> 
> Signed-off-by: Vicentiu Galanopulo <vicentiu.galanopulo@remote-tech.co.uk>
...

> +static int st1202_write_reg(struct st1202_chip *chip, int reg, uint8_t val)
> +{
> +	return i2c_smbus_write_byte_data(chip->client, reg, val);
> +}

Many duplicated message could be saved if errors where logged directly 
in st1202_write_reg() and st1202_read_reg()

This would simplify a lot the callers that would only need to return 
directly.

> +
> +static uint8_t st1202_prescalar_to_miliseconds(unsigned int value)
> +{
> +	return value/ST1202_MILLIS_PATTERN_DUR_MIN - 1;

Can value be 0?
If yes, should the return value be clamped?

> +}

...

> +static int st1202_dt_init(struct st1202_chip *chip)
> +{
> +	struct device *dev = &chip->client->dev;
> +	struct st1202_led *led;
> +	int err, reg;
> +
> +	for_each_available_child_of_node_scoped(dev_of_node(dev), child) {
> +		struct led_init_data init_data = {};
> +
> +		err = of_property_read_u32(child, "reg", &reg);
> +		if (err) {
> +			of_node_put(child);

The _scoped version of the iterator is used, so I think that this 
of_node_put() is not needed.

> +			return dev_err_probe(dev, err, "Invalid register, error: %d\n", err);

No need to duplicate err. dev_err_probe() already prints it, in a human 
readble form.

> +		}
> +
> +		led = &chip->leds[reg];
> +		led->is_active = true;
> +		led->fwnode = of_fwnode_handle(child);
> +
> +		led->led_cdev.max_brightness = U8_MAX;
> +		led->led_cdev.brightness_set_blocking = st1202_led_set;
> +		led->led_cdev.pattern_set = st1202_led_pattern_set;
> +		led->led_cdev.pattern_clear = st1202_led_pattern_clear;
> +		led->led_cdev.default_trigger = "pattern";
> +
> +		init_data.fwnode = led->fwnode;
> +		init_data.devicename = "st1202";
> +		init_data.default_label = ":";
> +		err = devm_led_classdev_register_ext(dev,
> +					&led->led_cdev, &init_data);
> +		if (err < 0) {
> +			dev_err_probe(dev, err,
> +				"Failed to register LED class dev, error: %d\n", err);

No need to duplicate err. dev_err_probe() already prints it, in a human 
readble form.

Also return dev_err_probe() would save a few lines.

> +			return err;
> +		}
> +		led->led_cdev.brightness_set = st1202_brightness_set;
> +		led->led_cdev.brightness_get = st1202_brightness_get;
> +	}
> +
> +	return 0;
> +}
> +
> +static int st1202_setup(struct st1202_chip *chip)
> +{
> +	int ret;
> +
> +	mutex_lock(&chip->lock);

if guard(mutex)(&chip->lock); was used you could return directly in all 
error paths below.

Same applies in several functions above.

> +	/*
> +	 * Once the supply voltage is applied, the LED1202 executes some internal checks,
> +	 * afterwords it stops the oscillator and puts the internal LDO in quiescent mode.
> +	 * To start the device, EN bit must be set inside the “Device Enable” register at
> +	 * address 01h. As soon as EN is set, the LED1202 loads the adjustment parameters
> +	 * from the internal non-volatile memory and performs an auto-calibration procedure
> +	 * in order to increase the output current precision.
> +	 * Such initialization lasts about 6.5 ms.
> +	 */
> +
> +	/* Reset the chip during setup */
> +	ret = st1202_write_reg(chip, ST1202_DEV_ENABLE, ST1202_DEV_ENABLE_RESET);
> +	if (ret < 0) {
> +		dev_err_probe(&chip->client->dev, -EIO,
> +				"Failed to write to register [0x%x], error: %d\n",
> +				ST1202_DEV_ENABLE, ret);

Why return -EIO if you have an error code in ret?
If you return ret, the ", error: %d\n", ret" part can be removed

Same everywhere in this function

> +		goto exit;
> +	}
> +
> +	/* Enable phase-shift delay feature */
> +	ret = st1202_write_reg(chip, ST1202_CONFIG_REG, ST1202_CONFIG_REG_SHFT);
> +	if (ret < 0) {
> +		dev_err_probe(&chip->client->dev, -EIO,
> +				"Failed to write to register [0x%x], error: %d\n",
> +				ST1202_CONFIG_REG, ret);
> +		goto exit;
> +	}
> +
> +	/* Enable the device */
> +	ret = st1202_write_reg(chip, ST1202_DEV_ENABLE, ST1202_DEV_ENABLE_ON);
> +	if (ret < 0) {
> +		dev_err_probe(&chip->client->dev, -EIO,
> +				"Failed to write to register [0x%x], error: %d\n",
> +				ST1202_DEV_ENABLE, ret);
> +		goto exit;
> +	}
> +
> +	/* Duration of initialization */
> +	usleep_range(6500, 10000);
> +
> +	/* Deactivate all LEDS (channels) and activate only the ones found in Device Tree */
> +	ret = st1202_write_reg(chip, ST1202_CHAN_ENABLE_LOW, ST1202_CHAN_DISABLE_ALL);
> +	if (ret < 0) {
> +		dev_err_probe(&chip->client->dev, -EIO,
> +				"Failed writing to register [0x%x], error: %d\n",
> +				ST1202_CHAN_ENABLE_LOW, ret);
> +		goto exit;
> +	}
> +
> +	ret = st1202_write_reg(chip, ST1202_CHAN_ENABLE_HIGH, ST1202_CHAN_DISABLE_ALL);
> +	if (ret < 0) {
> +		dev_err_probe(&chip->client->dev, -EIO,
> +				"Failed writing to register [0x%x], error: %d\n",
> +				ST1202_CHAN_ENABLE_HIGH, ret);
> +		goto exit;
> +	}
> +
> +	ret = st1202_write_reg(chip, ST1202_CONFIG_REG,
> +				ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_PATSR);
> +	if (ret < 0) {
> +		dev_err_probe(&chip->client->dev, -EIO,
> +				"Failed writing to register [0x%lx], error: %d\n",
> +				ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_PATSR, ret);
> +		goto exit;
> +	}
> +
> +exit:
> +	mutex_unlock(&chip->lock);
> +	return ret;
> +}
> +
> +static int st1202_probe(struct i2c_client *client)
> +{
> +	struct st1202_chip *chip;
> +	struct st1202_led *led;
> +	int ret;
> +
> +	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
> +		return dev_err_probe(&client->dev, -EIO, "SMBUS Byte Data not Supported\n");
> +
> +	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
> +	if (!chip)
> +		return -ENOMEM;
> +
> +	i2c_set_clientdata(client, chip);

Is it needed?
(There is no i2c_get_clientdata())

> +
> +	devm_mutex_init(&client->dev, &chip->lock);
> +	chip->client = client;
> +
> +	ret = st1202_dt_init(chip);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = st1202_setup(chip);
> +	if (ret < 0)
> +		return ret;
> +
> +	for (int i = 0; i < ST1202_MAX_LEDS; i++) {
> +		led = &chip->leds[i];
> +		led->chip = chip;
> +		led->led_num = i;
> +
> +		if (led->is_active) {
> +			ret = st1202_channel_set(led->chip, led->led_num, true);
> +			if (ret < 0) {
> +				return dev_err_probe(&client->dev, -EIO,
> +					"Failed to activate LED channel, error: %d\n", ret);
> +			}

Why return -EIO if you have an error code in ret?
If you return ret, the ", error: %d\n", ret" part can be removed

Also some { } could be removed.

> +
> +			ret = st1202_led_pattern_clear(&led->led_cdev);
> +			if (ret < 0) {
> +				return dev_err_probe(&client->dev, -EIO,
> +					"Failed to clear LED pattern, error: %d\n", ret);

Why return -EIO if you have an error code in ret?
If you return ret, the ", error: %d\n", ret" part can be removed

Also some { } could be removed.

> +			}
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id st1202_id[] = {
> +	{ "st1202-i2c" },
> +	{ /* sentinel */ },

Nitpick: no need for ending comma after a terminator

> +};
> +MODULE_DEVICE_TABLE(i2c, st1202_id);
> +
> +static const struct of_device_id st1202_dt_ids[] = {
> +	{ .compatible = "st,led1202", },
> +	{ /* sentinel */ },

Nitpick: no need for ending comma after a terminator

> +};
> +MODULE_DEVICE_TABLE(of, st1202_dt_ids);
...

CJ

Re: [PATCH v7 3/3] leds: Add LED1202 I2C driver

[Vicentiu Galanopulo]

On Thu, Nov 21, 2024 at 06:10:00PM +0100, Vicentiu Galanopulo wrote:
> On Mon, Nov 18, 2024 at 09:13:32PM +0100, Christophe JAILLET wrote:
> > Le 18/11/2024 à 15:54, Vicentiu Galanopulo a écrit :
> > > The output current can be adjusted separately for each channel by 8-bit
> > > analog (current sink input) and 12-bit digital (PWM) dimming control. The
> > > LED1202 implements 12 low-side current generators with independent dimming
> > > control.
> > > Internal volatile memory allows the user to store up to 8 different patterns,
> > > each pattern is a particular output configuration in terms of PWM
> > > duty-cycle (on 4096 steps). Analog dimming (on 256 steps) is per channel but
> > > common to all patterns. Each device tree LED node will have a corresponding
> > > entry in /sys/class/leds with the label name. The brightness property
> > > corresponds to the per channel analog dimming, while the patterns[1-8] to the
> > > PWM dimming control.
> > > 
> > > Signed-off-by: Vicentiu Galanopulo <vicentiu.galanopulo@remote-tech.co.uk>
> > ...

Sorry for resending this, I pasted wrong in the previous one and didn't notice


> > > +{
> > > +	return value/ST1202_MILLIS_PATTERN_DUR_MIN - 1;
> > 
> > Can value be 0?
> > If yes, should the return value be clamped?
> 
 No, it's called in st1202_duration_pattern_write, which is mostly a wrapper,
 called in 2 places:
 line 225: ret = st1202_duration_pattern_write(chip, patt, ST1202_MILLIS_PATTERN_DUR_MIN);
 line 258: ret = st1202_duration_pattern_write(chip, patt, pattern[patt].delta_t); 
 
 for line 258, I make sure in line 250:
                          if (pattern[patt].delta_t < ST1202_MILLIS_PATTERN_DUR_MIN ||
 				pattern[patt].delta_t > ST1202_MILLIS_PATTERN_DUR_MAX)
 			           return -EINVAL;
 that it respects the range provided by the datasheet and supported by the chip.
 
>  
> > 
> > Is it needed?
> > (There is no i2c_get_clientdata())
> 
 Indeed, not needed so removed.
> 
>  
> > > +
> > 
> > CJ
> 
 Thank you very much for thanking the time to review!
 
 Kindest regards,
 Vicentiu