Re: [PATCH v3 2/2] leds: Add LED1202 I2C driverr

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Le 21/07/2024 à 12:33, Vicentiu Galanopulo a écrit :
The LED1202 is a 12-channel low quiescent current LED driver.
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 active=1 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@xxxxxxxxxxxxxxxxx>
---

Hi,

...

diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 18afbb5a23ee..e665af45e363 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_LEDS_IP30)			+= leds-ip30.o
  obj-$(CONFIG_LEDS_IPAQ_MICRO)		+= leds-ipaq-micro.o
  obj-$(CONFIG_LEDS_IS31FL319X)		+= leds-is31fl319x.o
  obj-$(CONFIG_LEDS_IS31FL32XX)		+= leds-is31fl32xx.o
+obj-$(CONFIG_LEDS_ST1202)		+= leds-st1202.o

v3 has apparently s/ll1202/st1202/, so now this entry should be a few lines below to keep it sorted.

  obj-$(CONFIG_LEDS_LM3530)		+= leds-lm3530.o
  obj-$(CONFIG_LEDS_LM3532)		+= leds-lm3532.o
  obj-$(CONFIG_LEDS_LM3533)		+= leds-lm3533.o
diff --git a/drivers/leds/leds-st1202.c b/drivers/leds/leds-st1202.c
new file mode 100644
index 000000000000..2c1b3c918b2c
--- /dev/null
+++ b/drivers/leds/leds-st1202.c
@@ -0,0 +1,899 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * LED driver for STMicroelectronics LED1202 chip
+ *
+ * Copyright (C) 2024 Remote-Tech Ltd. UK
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/leds.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/gpio.h>
+#include <linux/delay.h>

Nitpick: usually it is preferred to have #include alphabetically sorted.

+
+#define ST1202_DEVICE_ID		0x00
+#define ST1202_DEV_ENABLE		0x01
+#define ST1202_CHAN_ENABLE_LOW		0x02
+#define ST1202_CHAN_ENABLE_HIGH		0x03
+#define ST1202_CONFIG_REG		0x04
+#define ST1202_ILED_REG0		0x09
+#define ST1202_PATTERN_REP		0x15
+#define ST1202_PATTERN_DUR		0x16
+#define ST1202_PATTERN_PWM		0x1E
+#define ST1202_CLOCK_REG		0xE0
+
+/* PATS: Pattern sequence feature enable */
+#define ST1202_CONFIG_REG_PATS		BIT(7)
+/**

Why a /** here?
Does it generate a warning when building the doc?

+ * PATSR: Pattern sequence runs (self-clear
+ * when sequence is finished)

Also, I think that the whole omment would fit on a single line.

+ */
+#define ST1202_CONFIG_REG_PATSR		BIT(6)
+#define ST1202_CHAN_DISABLE_ALL		0x00
+#define ST1202_PATTERN_REP_INF_LOOP	0xFF
+
+#define ST1202_NAME_LENGTH		32
+#define ST1202_CURRENT_AMPS_MAX		20
+#define ST1202_MILLIS_PATTERN_DUR	5660
+#define ST1202_UINT8_MAX		255
+#define ST1202_BUF_SIZE			16
+
+
+#define ST1202_LED_CHANNEL_0		0
+#define ST1202_LED_CHANNEL_1		1
+#define ST1202_LED_CHANNEL_2		2
+#define ST1202_LED_CHANNEL_3		3
+#define ST1202_LED_CHANNEL_4		4
+#define ST1202_LED_CHANNEL_5		5
+#define ST1202_LED_CHANNEL_6		6
+#define ST1202_LED_CHANNEL_7		7
+#define ST1202_LED_CHANNEL_8		8
+#define ST1202_LED_CHANNEL_9		9
+#define ST1202_LED_CHANNEL_10		10
+#define ST1202_LED_CHANNEL_11		11

Maybe ST1202_MAP_ALL_PATTERNS_TO_LEDNUM could use hard-coded numbers to save these (mostly useless, IMHO) lines? (see next comment)

ST1202_MAP_EXT_ATTR_TO_ALL_PATTERNS_ARRAY already uses hard-coded numbers.

ST1202_LED_CHANNEL_7 could be renamed to something meaningful for its use in st1202_channel_activate().

+#define ST1202_MAX_LEDS			12
+
+#define ST1202_PATTERN_0		0
+#define ST1202_PATTERN_1		1
+#define ST1202_PATTERN_2		2
+#define ST1202_PATTERN_3		3
+#define ST1202_PATTERN_4		4
+#define ST1202_PATTERN_5		5
+#define ST1202_PATTERN_6		6
+#define ST1202_PATTERN_7		7
+#define ST1202_PATTERNS_NR		8

These 9 #define semm to be used.

Either update ST1202_MAP_ALL_PATTERNS_TO_LEDNUM which uses hard-coded pattern numbers or remove these useless #define.

I think that removing it is fine enough.

+
+/**

Why a /** kerneldoc here?

In fact, all comments in the file seem to be kerneldoc style. I'm pretty sure that make kerneldoc complains about it.

+ * There are 12 leds (channels) and 8 patterns
+ * create this struct as to represent the complete
+ * 12 X 8 matrix
+ */
+struct st1202_led_pattern_map {
+	u8 led_num;
+	u8 pattern;
+};
+
+struct st1202_led {
+	struct led_classdev led_cdev;
+	struct st1202_chip *chip;
+	int led_num;
+	char name[ST1202_NAME_LENGTH];
+	int is_active;

Keeping led_num close to is_active would save a few bytes.

Should is_active be a bool?

+};
+
+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);
+

Nitpick : remove this empty line?

+	if (ret < 0)
+		return ret;
+
+	*val = (uint8_t)ret;
+	return 0;
+}

...

+static int st1202_pwm_pattern_read(struct st1202_chip *chip, int led_num,
+					int pattern, u16 *value)
+{
+	u8 value_l, value_h;
+	int ret;
+
+	/**
+	 *  Datasheet: Register address low = 1Eh + 2*(xh) + 18h*(yh),
+	 *  where x is the channel number (led number) in hexadecimal (x = 00h .. 0Bh) and
+	 *  and y is the pattern number in hexadecimal (y = 00h .. 07h)
+	 */
+	ret = st1202_read_reg(chip, (ST1202_PATTERN_PWM + (led_num * 2) + 0x18 * pattern),
+				&value_l);
+	if (ret != 0) {
+		dev_err(&chip->client->dev, "Reading pattern PWM register [0x%x] failed, error: %d\n",
+			(ST1202_PATTERN_PWM + (led_num * 2) + 0x18 * pattern), ret);
+		return ret;
+	}

Maybe having a function or a macro for computing
	ST1202_PATTERN_PWM + (led_num * 2) + 0x18 * pattern
and
	ST1202_PATTERN_PWM + 0x1 + (led_num * 2) + 0x18 * pattern

would increase readaility and avoid comment duplication.

+
+	/**
+	 * 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_read_reg(chip, (ST1202_PATTERN_PWM + 0x1 + (led_num * 2) + 0x18 * pattern),
+					&value_h);
+	if (ret != 0) {
+		dev_err(&chip->client->dev, "Reading pattern PWM register [0x%x] failed, error: %d\n",
+			(ST1202_PATTERN_PWM + 0x1 + (led_num * 2) + 0x18 * pattern), ret);
+		return ret;
+	}
+
+	*value = (u16)value_h << 8 | value_l;
+	return 0;
+}

...

+static ssize_t st1202_duration_pattern_show(struct device *dev,
+					struct device_attribute *attr, char *buf)
+{
+	struct st1202_chip *chip;
+	struct dev_ext_attribute *eattr;
+	struct st1202_led_pattern_map *map;
+
+	u8 duration;
+	int led_num, pattern, ret;
+
+	chip = dev_get_drvdata(dev->parent);
+	eattr = container_of(attr, struct dev_ext_attribute, attr);
+	map = (struct st1202_led_pattern_map *)eattr->var;
+
+	led_num = (int)map->led_num;
+	pattern = (int)map->pattern;
+
+	if (led_num < 0 || led_num >= ST1202_MAX_LEDS) {

Can this happen?

+		dev_err(dev, "Invalid led number: %d (out of range). Possible values 0..11\n",

Maybe, over-engineering things, but this hard coded 11, coud be %d and ST1202_MAX_LEDS - 1.

If you change it, this pattern is used in several messages.

+			led_num);
+		goto validity_exit;
+	}
+
+	mutex_lock(&chip->lock);
+	ret = st1202_duration_pattern_read(chip, pattern, &duration);
+	if (ret != 0)
+		goto exit;
+
+exit:
+	mutex_unlock(&chip->lock);
+validity_exit:
+	return sysfs_emit(buf, "Pattern[%d][led(channel)%d]: DURATION = %d ms\n",
+		pattern, led_num, st1202_prescalar_to_miliseconds(duration));

Maybe reorder this code to:
- have the mutex_unlock, just after st1202_duration_pattern_read() and before if (ret != 0) - display something else in case of error? Right now we display potentially some garbage without saying so.

+}
+
+static ssize_t st1202_duration_pattern_store(struct device *dev, struct device_attribute *attr,
+						const char *buf, size_t count)
+{
+	struct st1202_chip *chip;
+	struct dev_ext_attribute *eattr;
+	struct st1202_led_pattern_map *map;
+
+	unsigned long duration;
+	char duration_str[ST1202_BUF_SIZE];
+	int led_num, pattern, ret;
+
+	chip = dev_get_drvdata(dev->parent);
+	eattr = container_of(attr, struct dev_ext_attribute, attr);
+	map = (struct st1202_led_pattern_map *)eattr->var;
+
+	led_num = (int)map->led_num;
+	pattern = (int)map->pattern;
+
+	if (led_num < 0 || led_num >= ST1202_MAX_LEDS) {

Can this happen?

+		dev_err(dev, "Invalid led number: %d (out of range). Possible values 0..11\n",
+			led_num);
+		return count;
+	}
+
+	if (!count)
+		return -EINVAL;
+
+	ret = sscanf(buf, "%s", duration_str);
+	if (ret == 0) {
+		dev_err(dev, "sscanf failed with error :%d\n", ret);
+		return ret;
+	}
+
+	ret = kstrtoul(duration_str, 10, &duration);
+	if (ret)
+		return ret;
+
+	mutex_lock(&chip->lock);
+
+	ret = st1202_duration_pattern_write(chip, pattern, duration);
+	if (ret != 0)
+		goto exit;
+
+	ret = st1202_write_reg(chip, ST1202_CONFIG_REG,
+				(ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_PATSR | pattern));
+	if (ret != 0)
+		dev_err(dev, "Failed writing value %ld to register [0x%x], error: %d\n",
+			(ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_PATSR | pattern),
+			ST1202_CONFIG_REG, ret);
+
+exit:
+	mutex_unlock(&chip->lock);
+	return count;
+}
+
+static ssize_t st1202_patt_seq_rep_show(struct device *dev,
+					struct device_attribute *attr, char *buf)
+{
+	struct st1202_chip *chip;
+	unsigned int ret;
+	u8 value;
+
+	chip = dev_get_drvdata(dev);
+
+	mutex_lock(&chip->lock);
+
+	ret = st1202_read_reg(chip, ST1202_PATTERN_REP, &value);
+	if (ret != 0)
+		dev_err(dev, "Reading register [0x%x] failed, error: %d\n",
+			ST1202_PATTERN_REP, ret);
+
+	mutex_unlock(&chip->lock);
+	return sysfs_emit(buf, "Pattern sequence register, repetition value = %d (times)\n",
+			 value);

Maybe reorder this code to:
- have the mutex_unlock, just after st1202_read_reg() and before if (ret != 0) - display something else in case of error? Right now we display potentially some garbage without saying so.

+}
+
+static ssize_t st1202_patt_seq_rep_store(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t count)
+{
+	struct st1202_chip *chip;
+	unsigned int ret;
+	unsigned long duration;
+
+	chip = dev_get_drvdata(dev);
+
+	if (!count)
+		return -EINVAL;
+
+	ret = kstrtoul(buf, 10, &duration);
+	if (ret)
+		return ret;
+
+	mutex_lock(&chip->lock);
+
+	ret = st1202_write_reg(chip, ST1202_PATTERN_REP, duration);
+	if (ret != 0)
+		dev_err(dev, "Writing register [0x%x] failed, error: %d\n",
+			ST1202_PATTERN_REP, ret);
+
+	mutex_unlock(&chip->lock);
+	return count;
+}
+
+static ssize_t st1202_channel_mA_current_show(struct device *dev,
+						struct device_attribute *attr,
+						char *buf)
+{
+	struct st1202_chip *chip;
+	struct dev_ext_attribute *eattr;
+	u8 value;
+	int led_num, ret;
+
+	chip = dev_get_drvdata(dev->parent);
+	eattr = container_of(attr, struct dev_ext_attribute, attr);
+	led_num = (int)eattr->var;

This does not compile for me.
based on other similar pattern, should it be

	map = (struct st1202_led_pattern_map *)eattr->var;

	led_num = (int)map->led_num;
?

+
+	if (led_num < 0 || led_num >= ST1202_MAX_LEDS) {

Can this happen?

+		dev_err(dev, "Invalid led number: %d (out of range). Possible values 0..11\n",
+				led_num);
+		return -EINVAL;
+	}
+
+	mutex_lock(&chip->lock);
+
+	ret = st1202_read_reg(chip, ST1202_ILED_REG0 + led_num, &value);
+	if (ret != 0)
+		dev_err(dev, "Reading analog dimming register [0x%x] failed, error: %d\n",
+			led_num, ret);
+
+	mutex_unlock(&chip->lock);
+	return sysfs_emit(buf, "Channel[%d] = %d mA\n", led_num,
+			 st1202_prescalar_to_miliamps(value));

Same comment as in other show() function.

+}
+
+static ssize_t st1202_pwm_pattern_show(struct device *dev,
+					struct device_attribute *attr, char *buf)
+{
+	struct st1202_chip *chip;
+	struct dev_ext_attribute *eattr;
+	struct st1202_led_pattern_map *map;
+
+	u16 value;
+	int led_num, pattern, ret;
+
+	chip = dev_get_drvdata(dev->parent);
+	eattr = container_of(attr, struct dev_ext_attribute, attr);
+	map = (struct st1202_led_pattern_map *)eattr->var;
+
+	led_num = (int)map->led_num;
+	pattern = (int)map->pattern;
+
+	if (led_num < 0 || led_num >= ST1202_MAX_LEDS) {

Can this happen?

+		dev_err(dev, "Invalid led number: %d (out of range). Possible values 0..11\n",
+			led_num);
+		goto validity_exit;
+	}
+
+	mutex_lock(&chip->lock);
+
+	ret = st1202_pwm_pattern_read(chip, led_num, pattern, &value);
+	if (ret != 0)
+		goto exit;
+
+exit:
+	mutex_unlock(&chip->lock);
+validity_exit:
+	return sysfs_emit(buf, "Pattern[%d][led(channel) %d]: PWM = 0x%03X\n",
+		pattern, led_num, value);

Same comment as in other show() function.

+}
+
+static ssize_t st1202_pwm_pattern_store(struct device *dev, struct device_attribute *attr,
+					const char *buf, size_t count)
+{
+	struct st1202_chip *chip;
+	struct dev_ext_attribute *eattr;
+	struct st1202_led_pattern_map *map;
+	unsigned int pwm_value;
+	int led_num, pattern, ret;
+
+	chip = dev_get_drvdata(dev->parent);
+	eattr = container_of(attr, struct dev_ext_attribute, attr);
+	map = (struct st1202_led_pattern_map *)eattr->var;
+
+	led_num = (int)map->led_num;
+	pattern = (int)map->pattern;
+
+	if (led_num < 0 || led_num >= ST1202_MAX_LEDS) {

Can this happen?

+		dev_err(dev, "Invalid led number: %d (out of range). Possible values 0..11\n",
+			led_num);
+		return count;
+	}
+
+	if (!count)
+		return -EINVAL;
+
+	ret = sscanf(buf, "%X", &pwm_value);
+	if (ret == 0) {
+		dev_err(dev, "sscanf failed with error :%d\n", ret);
+		return ret;
+	}
+
+	mutex_lock(&chip->lock);
+
+	ret = st1202_pwm_pattern_write(chip, led_num, pattern, pwm_value);
+	if (ret != 0)
+		goto exit;
+
+	ret = st1202_write_reg(chip, ST1202_CONFIG_REG,
+				(ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_PATSR | pattern));
+	if (ret != 0)
+		dev_err(dev, "Failed writing value %ld to register [0x%x], error: %d\n",
+			(ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_PATSR | pattern),
+			ST1202_CONFIG_REG, ret);
+
+exit:
+	mutex_unlock(&chip->lock);
+	return count;
+}
+
+static struct device_attribute dev_attr_st1202_patt_seq_rep = __ATTR(pattern_seq_rep,
+								0644,
+								st1202_patt_seq_rep_show,
+								st1202_patt_seq_rep_store);
+
+#define ST1202_EXT_ATTR(patt, lednum)	\
+(&((struct st1202_led_pattern_map[]){	\
+	{.led_num = lednum,		\
+	.pattern = patt}		\
+})[0])
+
+#define ST1202_PATT_EXT_ATTR(pattern, led_num)							\
+static struct dev_ext_attribute dev_ext_attr_patt_pwm_##pattern##led_num = {			\
+	.attr =  __ATTR(pwm_pattern##pattern, 0644,						\
+			st1202_pwm_pattern##_show, st1202_pwm_pattern##_store),			\
+	.var = (void *) ST1202_EXT_ATTR(pattern, led_num),					\
+};												\
+static struct dev_ext_attribute dev_ext_attr_patt_duration_##pattern##led_num = {		\
+	.attr =  __ATTR(duration_pattern##pattern, 0644,					\
+			st1202_duration_pattern##_show, st1202_duration_pattern##_store),	\
+	.var = (void *) ST1202_EXT_ATTR(pattern, led_num),					\
+};
+
+#define ST1202_LED_CURRENT_EXTATTR(led_num)							\
+static struct dev_ext_attribute dev_attr_current_mA##led_num =  {				\
+	.attr = __ATTR(current_mA, 0444, st1202_channel_mA_current_show, NULL),		\
+	.var = (void *)led_num, };

Ending }; could be on its own line.
\ alignement could be improved in the #define.

+
+#define ST1202_MAP_ALL_PATTERNS_TO_LEDNUM(led_num)		\
+ST1202_PATT_EXT_ATTR(0, led_num)				\
+ST1202_PATT_EXT_ATTR(1, led_num)				\
+ST1202_PATT_EXT_ATTR(2, led_num)				\
+ST1202_PATT_EXT_ATTR(3, led_num)				\
+ST1202_PATT_EXT_ATTR(4, led_num)				\
+ST1202_PATT_EXT_ATTR(5, led_num)				\
+ST1202_PATT_EXT_ATTR(6, led_num)				\
+ST1202_PATT_EXT_ATTR(7, led_num)				\
+ST1202_LED_CURRENT_EXTATTR(led_num)
+
+ST1202_MAP_ALL_PATTERNS_TO_LEDNUM(ST1202_LED_CHANNEL_0)
+ST1202_MAP_ALL_PATTERNS_TO_LEDNUM(ST1202_LED_CHANNEL_1)
+ST1202_MAP_ALL_PATTERNS_TO_LEDNUM(ST1202_LED_CHANNEL_2)
+ST1202_MAP_ALL_PATTERNS_TO_LEDNUM(ST1202_LED_CHANNEL_3)
+ST1202_MAP_ALL_PATTERNS_TO_LEDNUM(ST1202_LED_CHANNEL_4)
+ST1202_MAP_ALL_PATTERNS_TO_LEDNUM(ST1202_LED_CHANNEL_5)
+ST1202_MAP_ALL_PATTERNS_TO_LEDNUM(ST1202_LED_CHANNEL_6)
+ST1202_MAP_ALL_PATTERNS_TO_LEDNUM(ST1202_LED_CHANNEL_7)
+ST1202_MAP_ALL_PATTERNS_TO_LEDNUM(ST1202_LED_CHANNEL_8)
+ST1202_MAP_ALL_PATTERNS_TO_LEDNUM(ST1202_LED_CHANNEL_9)
+ST1202_MAP_ALL_PATTERNS_TO_LEDNUM(ST1202_LED_CHANNEL_10)
+ST1202_MAP_ALL_PATTERNS_TO_LEDNUM(ST1202_LED_CHANNEL_11)
+
+#define ST1202_EXT_ATTR_LED_PWM(patt, lednum)			\
+&dev_ext_attr_patt_pwm_##patt##lednum.attr.attr,		\
+&dev_ext_attr_patt_duration_##patt##lednum.attr.attr
+
+#define ST1202_MAP_EXT_ATTR_TO_ALL_PATTERNS_ARRAY(lednum)			\
+static struct attribute *led_attrs##lednum[] = {				\
+	ST1202_EXT_ATTR_LED_PWM(0, lednum),					\
+	ST1202_EXT_ATTR_LED_PWM(1, lednum),					\
+	ST1202_EXT_ATTR_LED_PWM(2, lednum),					\
+	ST1202_EXT_ATTR_LED_PWM(3, lednum),					\
+	ST1202_EXT_ATTR_LED_PWM(4, lednum),					\
+	ST1202_EXT_ATTR_LED_PWM(5, lednum),					\
+	ST1202_EXT_ATTR_LED_PWM(6, lednum),					\
+	ST1202_EXT_ATTR_LED_PWM(7, lednum),					\
+	&dev_attr_current_mA##lednum.attr.attr,					\
+	NULL									\
+};										\
+static struct attribute_group led_attr_group##lednum = {			\

static const struct?

+	.attrs = led_attrs##lednum,						\
+};										\
+static const struct attribute_group *st1202_led_groups##lednum[] = {		\
+	&led_attr_group##lednum,						\
+	NULL									\
+};
+
+ST1202_MAP_EXT_ATTR_TO_ALL_PATTERNS_ARRAY(0)
+ST1202_MAP_EXT_ATTR_TO_ALL_PATTERNS_ARRAY(1)
+ST1202_MAP_EXT_ATTR_TO_ALL_PATTERNS_ARRAY(2)
+ST1202_MAP_EXT_ATTR_TO_ALL_PATTERNS_ARRAY(3)
+ST1202_MAP_EXT_ATTR_TO_ALL_PATTERNS_ARRAY(4)
+ST1202_MAP_EXT_ATTR_TO_ALL_PATTERNS_ARRAY(5)
+ST1202_MAP_EXT_ATTR_TO_ALL_PATTERNS_ARRAY(6)
+ST1202_MAP_EXT_ATTR_TO_ALL_PATTERNS_ARRAY(7)
+ST1202_MAP_EXT_ATTR_TO_ALL_PATTERNS_ARRAY(8)
+ST1202_MAP_EXT_ATTR_TO_ALL_PATTERNS_ARRAY(9)
+ST1202_MAP_EXT_ATTR_TO_ALL_PATTERNS_ARRAY(10)
+ST1202_MAP_EXT_ATTR_TO_ALL_PATTERNS_ARRAY(11)

...

+static int st1202_dt_init(struct st1202_chip *chip)
+{
+	struct device_node *np, *child;
+	struct st1202_led *led;
+	int err, reg;
+
+	np = dev_of_node(&chip->client->dev);
+
+	for_each_child_of_node(np, child) {

for_each_child_of_node_scoped() would simplify error handling paths.

+		err = of_property_read_u32(child, "reg", &reg);
+		if (err) {
+			of_node_put(child);
+			dev_err(&chip->client->dev, "Failed to get child node, error: %d\n", err);

Nitpick: return dev_err_probe()?
(same for other calls below)

+			return err;
+		}
+		if (reg < 0 || reg >= ST1202_MAX_LEDS) {
+			of_node_put(child);
+			dev_err(&chip->client->dev, "Invalid led number: %d (out of range). Possible values 0..11\n",
+				reg);
+			return -EINVAL;
+		}
+
+		led = &chip->leds[reg];
+		led->led_cdev.name = of_get_property(child, "label", NULL) ?:
+							child->name;
+
+		err = of_property_read_u32(child, "active", &led->is_active);

If is_active is changed to a bool, of_property_read_bool()?

+		if (err) {
+			of_node_put(child);
+			dev_err(&chip->client->dev, "Failed to get child node, 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);

Using guard(mutex)(&chip->lock) would simplify code below and allow using return dev_error_probe().

The mutex_lock()/mutex_unlock() in the middle of the function looks useless to me, the probe has not completed yet and we can sleep within a mutex.

+
+	/**
+	 * 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.

Formatting could be slightly improve to better match the 80-char limit, without adding any new LoC.

+	 */
+
+	/* reset the chip during setup */
+	ret = st1202_write_reg(chip, ST1202_DEV_ENABLE, BIT(7));
+	if (ret < 0) {
+		dev_err(&chip->client->dev, "Failed writing to register [0x%x], error: %d\n",
+			ST1202_DEV_ENABLE, ret);
+	goto exit;

1 tabulation missing.

+	}
+
+	/* enable the device */
+	ret = st1202_write_reg(chip, ST1202_DEV_ENABLE, BIT(0));
+	if (ret < 0) {
+		dev_err(&chip->client->dev, "Failed writing to register [0x%x], error: %d\n",
+			ST1202_DEV_ENABLE, ret);
+		goto exit;
+	}
+
+	mutex_unlock(&chip->lock);
+
+	/* duration of initialization */
+	usleep_range(6500, 10000);
+
+	mutex_lock(&chip->lock);
+	/* set Pattern sequence repetition register to inifite loop */
+	ret = st1202_write_reg(chip, ST1202_PATTERN_REP, ST1202_PATTERN_REP_INF_LOOP);
+	if (ret < 0) {
+		dev_err(&chip->client->dev, "Failed writing to register [0x%x], error: %d\n",
+			ST1202_PATTERN_REP, ret);
+		goto exit;
+	}
+	/* deactivate all leds (channels) and activate only the device tree active ones */
+	ret = st1202_write_reg(chip, ST1202_CHAN_ENABLE_LOW, ST1202_CHAN_DISABLE_ALL);
+	if (ret < 0) {
+		dev_err(&chip->client->dev, "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(&chip->client->dev, "Failed writing to register [0x%x], error: %d\n",
+			ST1202_CHAN_ENABLE_HIGH, 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;
+	int i;
+
+	dev_info(&client->dev, "ST1202 I2C driver");

Not sure this is useful.

+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
+		dev_err(&client->dev, "SMBUS Byte Data not Supported\n");
+		return -EIO;
+	}
+
+	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;
+
+	/* Device tree setup */
+	ret = st1202_dt_init(chip);
+	if (ret < 0)
+		goto exit;
+
+	/* Configuration setup */
+	ret = st1202_setup(chip);
+	if (ret < 0)
+		goto exit;
+
+	for (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_activate(led->chip, led->led_num);
+			if (ret < 0) {
+				dev_err(&client->dev, "Failed to register LED class dev, error: %d\n",
+					ret);
+				goto exit;
+			}
+
+			led->led_cdev.groups = st1202_led_groups[i];
+
+			ret = devm_led_classdev_register(&client->dev,
+						    &led->led_cdev);
+			if (ret < 0) {
+				dev_err(&client->dev, "Failed to register LED class dev, error: %d\n",
+					ret);
+				goto exit;
+			}
+		}
+	}
+
+	client->dev.driver->dev_groups = st1202_device_groups;
+	return 0;
+
+exit:
+	for (i = 0; i < ST1202_MAX_LEDS; i++)
+		devm_led_classdev_unregister(&client->dev,  &chip->leds[i].led_cdev);
+	mutex_destroy(&chip->lock);
+	devm_kfree(&client->dev, chip);

All these clean-up functions should already be called by the framework and could be removed.

So direct return and return dev_error_probe() could be used above

+	return ret;
+}

...

CJ





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