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Message-ID: <e886e2a3-7e00-44db-a512-1f2f7e7b99d7@t-8ch.de>
Date: Wed, 26 Jun 2024 13:20:56 +0200
From: Thomas Weißschuh <thomas@...ch.de>
To: Vicentiu Galanopulo <vicentiu.galanopulo@...ote-tech.co.uk>
Cc: pavel@....cz, lee@...nel.org, linux-kernel@...r.kernel.org,
linux-leds@...r.kernel.org
Subject: Re: [PATCH v2 2/2] leds: Add LED1202 I2C driver
On 2024-06-18 08:58:19+0000, Vicentiu Galanopulo wrote:
> 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@...ote-tech.co.uk>
> ---
>
> Changes in v2:
> - Fix build error for device_attribute modes
>
> drivers/leds/Kconfig | 10 +
> drivers/leds/Makefile | 1 +
> drivers/leds/leds-led1202.c | 617 ++++++++++++++++++++++++++++++++++++
> 3 files changed, 628 insertions(+)
> create mode 100644 drivers/leds/leds-led1202.c
>
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index 05e6af88b88c..c65f2b1bbe30 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -899,6 +899,16 @@ config LEDS_LM36274
> Say Y to enable the LM36274 LED driver for TI LMU devices.
> This supports the LED device LM36274.
>
> +config LEDS_LED1202
> + tristate "LED Support for LED1202 I2C chips"
> + depends on LEDS_CLASS
> + depends on I2C
> + depends on OF
> + 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 effdfc6f1e95..80423fa8818e 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -36,6 +36,7 @@ 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-$(CONFIG_LEDS_LED1202) += leds-led1202.o
> obj-$(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-led1202.c b/drivers/leds/leds-led1202.c
> new file mode 100644
> index 000000000000..4e82f0e66168
> --- /dev/null
> +++ b/drivers/leds/leds-led1202.c
> @@ -0,0 +1,617 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Simple LED driver for ST 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>
> +
> +#define DRIVER_NAME "led-driver-1202"
> +#define DRIVER_VERSION "0.0.1"
> +
> +#define LL1202_MAX_LEDS 12
> +
> +#define LL1202_DEVICE_ID 0x00
> +#define LL1202_DEV_ENABLE 0x01
> +#define LL1202_CHAN_ENABLE_LOW 0x02
> +#define LL1202_CHAN_ENABLE_HIGH 0x03
> +#define LL1202_CONFIG_REG 0x04
> +#define LL1202_ILED_REG0 0x09
> +#define LL1202_PATTERN_REP 0x15
> +#define LL1202_PATTERN_DUR 0x16
> +#define LL1202_PATTERN_PWM 0x1E
> +#define LL1202_CLOCK_REG 0xE0
> +
> +struct ll1202_led {
> + struct led_classdev led_cdev;
> + struct ll1202_chip *chip;
> + int led_num;
> + char name[32];
> + int is_active;
> +};
> +
> +struct ll1202_chip {
> + struct i2c_client *client;
> + struct mutex lock;
> + struct ll1202_led leds[LL1202_MAX_LEDS];
> +};
> +
> +static struct ll1202_led *cdev_to_ll1202_led(struct led_classdev *cdev)
> +{
> + return container_of(cdev, struct ll1202_led, led_cdev);
> +}
> +
> +static int ll1202_read_reg(struct ll1202_chip *chip, int reg, uint8_t *val)
> +{
> + int ret = i2c_smbus_read_byte_data(chip->client, reg);
> +
> + if (ret < 0)
> + return ret;
> +
> + *val = (uint8_t)ret;
> + return 0;
> +}
> +
> +static int ll1202_write_reg(struct ll1202_chip *chip, int reg, uint8_t val)
> +{
> + return i2c_smbus_write_byte_data(chip->client, reg, val);
> +}
> +
> +static int ll1202_get_channel(struct device *dev)
> +{
> + struct device_node *np = dev->parent->of_node, *child;
> + int err, ret = -1;
> +
> + for_each_child_of_node(np, child) {
> + if (strncmp(dev->kobj.name,
> + of_get_property(child, "label", NULL),
> + strnlen(dev->kobj.name, MAX_INPUT)) == 0) {
> + err = of_property_read_u32(child, "reg", &ret);
> + if (err) {
> + of_node_put(child);
> + pr_err(DRIVER_NAME
Use dev_err() where possible.
Also if you need to use pr_ APIs, use "#define pr_fmt(fmt) ..." for automatic
prefixes everywhere.
> + ": Failed to read property %s", child->name);
> + return ret;
> + }
> + break;
> + }
> + }
> + return ret;
> +}
> +
> +static ssize_t ll1202_show_all_registers(struct device *dev,
> + struct device_attribute *devattr,
> + char *buf)
> +{
> + struct ll1202_chip *chip = dev_get_drvdata(dev);
> + uint8_t reg_value = 0;
> + int ret, i;
> + char *bufp = buf;
> +
> + mutex_lock(&chip->lock);
> +
> + for (i = LL1202_DEVICE_ID; i <= LL1202_CLOCK_REG; i++) {
> + ret = ll1202_read_reg(chip, i, ®_value);
> + if (ret != 0)
> + dev_err(&chip->client->dev,
> + "Reading register [0x%x] failed.\n", i);
Also log the error value.
> +
> + bufp += snprintf(bufp, PAGE_SIZE, "Addr[0x%x] = 0x%x\n", i,
> + reg_value);
> + }
> +
> + mutex_unlock(&chip->lock);
> + return strlen(buf);
> +}
> +
> +static ssize_t
> +ll1202_show_patt_sequence_repetition(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct ll1202_chip *chip = dev_get_drvdata(dev);
> + unsigned int ret;
> + uint8_t reg_value;
> + char *bufp = buf;
> +
> + mutex_lock(&chip->lock);
> + ret = ll1202_read_reg(chip, LL1202_PATTERN_REP, ®_value);
> + if (ret != 0)
> + dev_err(&chip->client->dev, "Reading register [0x%x] failed\n", LL1202_PATTERN_REP);
> + mutex_unlock(&chip->lock);
> + bufp += snprintf(bufp, PAGE_SIZE,
> + "Pattern sequence register, repetition value = %d (times)\n",
> + reg_value);
> + return strlen(buf);
> +}
> +
> +static ssize_t
> +ll1202_store_patt_sequence_repetition(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct ll1202_chip *chip = dev_get_drvdata(dev);
> + unsigned int ret;
> + unsigned long duration;
> +
> + if (!count)
> + return -EINVAL;
> +
> + ret = kstrtoul(buf, 10, &duration);
> + if (ret) {
> + dev_err(&chip->client->dev, "sscanf failed with error :%d\n",
sscanf? looks like kstrtoul.
Also this is reachable directly from userspace, so it shouldn't log at
this high level.
Normally just returning the error code is enough.
> + ret);
> + return ret;
> + }
> +
> + mutex_lock(&chip->lock);
> + ret = ll1202_write_reg(chip, LL1202_PATTERN_REP, duration);
> + if (ret != 0)
> + dev_err(&chip->client->dev, "Writing register [0x%x] failed\n",
> + LL1202_PATTERN_REP);
> + mutex_unlock(&chip->lock);
> + return count;
> +}
> +
> +static int ll1202_prescalar_to_miliamps(uint8_t reg_value)
> +{
> + return reg_value * 20 / 255;
> +}
> +
> +static int ll1202_prescalar_to_miliseconds(uint8_t reg_value)
> +{
> + return reg_value * 5660 / 255;
> +}
> +
> +static ssize_t ll1202_show_channel_mA_current(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct ll1202_chip *chip = dev_get_drvdata(dev->parent);
> + unsigned int ret;
> + uint8_t reg_value;
> + char *bufp = buf;
> + int led_num = ll1202_get_channel(dev);
> +
> + if (led_num < 0 || led_num >= LL1202_MAX_LEDS) {
> + dev_err(&chip->client->dev,
> + "Invalid register [0x%x] (out of range)\n",
> + led_num);
> + }
> + mutex_lock(&chip->lock);
> + ret = ll1202_read_reg(chip, LL1202_ILED_REG0 + led_num, ®_value);
> + if (ret != 0)
> + dev_err(&chip->client->dev, "Reading analog dimming register [0x%x] failed\n",
> + led_num);
> + mutex_unlock(&chip->lock);
> + bufp += snprintf(bufp, PAGE_SIZE, "Channel[%d] = %d mA\n", led_num,
> + ll1202_prescalar_to_miliamps(reg_value));
Use sysfs_emit() and sysfs_emit_at() for sysfs output.
> + return strlen(buf);
> +}
> +
> +static int ll1202_channel_activate(struct ll1202_led *led)
> +{
> + struct ll1202_chip *chip;
> + uint8_t reg_chan_low, reg_chan_high;
> + int ret = 0;
> +
> + chip = led->chip;
> + if (led->is_active) {
> + mutex_lock(&chip->lock);
> +
> + ret = ll1202_read_reg(chip, LL1202_CHAN_ENABLE_LOW,
> + ®_chan_low);
> + if (ret < 0) {
> + dev_err(&chip->client->dev,
> + "Failed reading register [0x%x]\n", LL1202_CHAN_ENABLE_LOW);
> + }
These error cases are logged but then the logic continues.
That seems wrong.
> +
> + ret = ll1202_read_reg(chip, LL1202_CHAN_ENABLE_HIGH,
> + ®_chan_high);
> + if (ret < 0) {
> + dev_err(&chip->client->dev,
> + "Failed reading register [0x%x]\n", LL1202_CHAN_ENABLE_HIGH);
> + }
> +
> + reg_chan_low = reg_chan_low | BIT(led->led_num);
> + ret = ll1202_write_reg(chip, LL1202_CHAN_ENABLE_LOW,
> + reg_chan_low);
> + if (ret < 0) {
> + dev_err(&chip->client->dev,
> + "Failed writing to register [0x%x]\n", LL1202_CHAN_ENABLE_LOW);
> + }
> + reg_chan_high = reg_chan_high | (BIT(led->led_num) >> 7);
> + ret = ll1202_write_reg(chip, LL1202_CHAN_ENABLE_HIGH,
> + reg_chan_high);
> + if (ret < 0) {
> + dev_err(&chip->client->dev,
> + "Failed writing to register [0x%x]\n", LL1202_CHAN_ENABLE_HIGH);
> + }
> + mutex_unlock(&chip->lock);
> + }
> + return ret;
> +}
> +
> +#define LL1202_PWM_PATTERN_ATTR(pattern) \
> + static ssize_t ll1202_show_pwm_pattern##pattern( \
> + struct device *dev, struct device_attribute *attr, char *buf) \
Instead of all of the macro-mess you can use 'struct device_attribute *attr'
to figure out for which attribute the function is called.
Define your attributes as
struct ll1202_pattern_attribute {
struct device_attribute dev_attr;
u8 led_num;
};
Now in your callbacks you can use container_of() on attr to get the
enclosing ll1202_attribute and read ->led_num from there.
So a single callback function is enough for all attributes.
And no string comparisions are necessary.
> + { \
> + struct ll1202_chip *chip = dev_get_drvdata(dev->parent); \
> + uint8_t duration = 0; \
Use u8 in the kernel.
> + uint8_t reg_value_l = 0; \
> + uint8_t reg_value_h = 0; \
> + uint16_t reg_value = 0; \
> + int ret; \
> + char *bufp = buf; \
> + int led_num = ll1202_get_channel(dev); \
> + if (led_num < 0 || led_num >= LL1202_MAX_LEDS) { \
> + dev_err(&chip->client->dev, \
> + "Invalid register [0x%x] (out of range)\n", \
> + led_num); \
> + } \
> + mutex_lock(&chip->lock); \
> + ret = ll1202_read_reg( \
> + chip, \
> + (LL1202_PATTERN_PWM + (led_num * 2) + 0x18 * pattern), \
> + ®_value_l); \
> + if (ret != 0) \
> + dev_err(&chip->client->dev, \
> + "Reading pattern PWM register [0x%x] failed\n", led_num); \
> + ret = ll1202_read_reg(chip, \
> + (LL1202_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\n", led_num); \
> + reg_value = (uint16_t)reg_value_h << 8 | reg_value_l; \
> + ret = ll1202_read_reg(chip, (LL1202_PATTERN_DUR + pattern), \
> + &duration); \
> + if (ret != 0) \
> + dev_err(&chip->client->dev, \
> + "Reading pattern durating register [0x%x] failed\n", led_num); \
> + bufp += snprintf( \
> + bufp, PAGE_SIZE, \
> + "Pattern[%d][cs%d]: PWM = 0x%03X; DURATION = %d ms\n", \
> + pattern, led_num, reg_value, \
> + ll1202_prescalar_to_miliseconds(duration)); \
> + mutex_unlock(&chip->lock); \
> + return strlen(buf); \
> + } \
> + static ssize_t ll1202_store_pwm_pattern##pattern( \
> + struct device *dev, struct device_attribute *attr, \
> + const char *buf, size_t count) \
> + { \
> + struct ll1202_chip *chip = dev_get_drvdata(dev->parent); \
> + unsigned int ret, reg_value; \
> + unsigned long duration; \
> + char buf_u8[16]; \
> + uint8_t reg_value_l = 0; \
> + uint8_t reg_value_h = 0; \
> + int led_num = ll1202_get_channel(dev); \
> + if (led_num < 0 || led_num >= LL1202_MAX_LEDS) { \
> + dev_err(&chip->client->dev, \
> + "Invalid register [0x%x] (out of range)\n", \
> + led_num); \
> + return count; \
> + } \
> + if (!count) \
> + return -EINVAL; \
> + ret = sscanf(buf, "%X %s", ®_value, buf_u8); \
> + if (ret == 0) { \
> + dev_err(&chip->client->dev, \
> + "sscanf failed with error :%d\n", ret); \
> + return ret; \
> + } \
> + ret = kstrtoul(buf_u8, 10, &duration); \
> + if (ret) \
> + return ret; \
> + reg_value_l = (uint8_t)reg_value; \
> + reg_value_h = (uint8_t)(reg_value >> 8); \
> + mutex_lock(&chip->lock); \
> + ret = ll1202_write_reg( \
> + chip, \
> + (LL1202_PATTERN_PWM + (led_num * 2) + 0x18 * pattern), \
> + (uint8_t)reg_value_l); \
> + if (ret != 0) \
> + dev_err(&chip->client->dev, \
> + "Writing to register [0x%x] failed, value %d\n", \
> + LL1202_PATTERN_PWM + (led_num * 2) + \
> + 0x18 * pattern, \
> + reg_value_l); \
> + ret = ll1202_write_reg(chip, \
> + (LL1202_PATTERN_PWM + 0x1 + \
> + (led_num * 2) + 0x18 * pattern), \
> + (uint8_t)reg_value_h); \
> + if (ret != 0) \
> + dev_err(&chip->client->dev, \
> + "Writing to register [0x%x] failed, value %d\n", \
> + (LL1202_PATTERN_PWM + 0x1 + (led_num * 2) + \
> + 0x18 * pattern), \
> + reg_value_h); \
> + ret = ll1202_write_reg(chip, (LL1202_PATTERN_DUR + pattern), \
> + (u8)duration); \
> + if (ret != 0) \
> + dev_err(&chip->client->dev, \
> + "Writing to register [0x%x] failed, value %d\n", \
> + (LL1202_PATTERN_DUR + pattern), (u8)duration); \
> + ret = ll1202_write_reg(chip, LL1202_CONFIG_REG, \
> + (0xC0 | pattern)); \
> + if (ret != 0) { \
> + dev_err(&chip->client->dev, \
> + "Failed writing to reg [0x%x]\n", LL1202_CONFIG_REG); \
> + } \
> + mutex_unlock(&chip->lock); \
> + ll1202_channel_activate(&chip->leds[led_num]); \
> + return count; \
> + } \
> + static struct device_attribute dev_attr_led_pwm_pattern##pattern = { \
> + .attr = { \
> + .name = __stringify(pwm_pattern##pattern), \
> + .mode = 00444 | 00200, \
> + }, \
> + .show = ll1202_show_pwm_pattern##pattern, \
> + .store = ll1202_store_pwm_pattern##pattern, \
This is custom sysfs ABI and should be documented.
> +}
> +
> +LL1202_PWM_PATTERN_ATTR(0);
> +LL1202_PWM_PATTERN_ATTR(1);
> +LL1202_PWM_PATTERN_ATTR(2);
> +LL1202_PWM_PATTERN_ATTR(3);
> +LL1202_PWM_PATTERN_ATTR(4);
> +LL1202_PWM_PATTERN_ATTR(5);
> +LL1202_PWM_PATTERN_ATTR(6);
> +LL1202_PWM_PATTERN_ATTR(7);
> +
> +static DEVICE_ATTR(led_device_regsdump, 00444, ll1202_show_all_registers,
DEVICE_ATTR_RO()
> + NULL);
> +static DEVICE_ATTR(patt_sequence_repetition, 00444 | 00200,
DEVICE_ATTR_RW()
> + ll1202_show_patt_sequence_repetition,
> + ll1202_store_patt_sequence_repetition);
> +static DEVICE_ATTR(current_mA, 00444, ll1202_show_channel_mA_current, NULL);
> +
> +static struct attribute *led_attrs[] = {
> + &dev_attr_led_device_regsdump.attr,
> + &dev_attr_patt_sequence_repetition.attr,
> + NULL,
No comma.
> +};
> +
> +static struct attribute *led_group_attrs[] = {
> + &dev_attr_led_pwm_pattern0.attr, &dev_attr_led_pwm_pattern1.attr,
> + &dev_attr_led_pwm_pattern2.attr, &dev_attr_led_pwm_pattern3.attr,
> + &dev_attr_led_pwm_pattern4.attr, &dev_attr_led_pwm_pattern5.attr,
> + &dev_attr_led_pwm_pattern6.attr, &dev_attr_led_pwm_pattern7.attr,
> + &dev_attr_current_mA.attr, NULL,
No comma.
> +};
> +
> +static struct attribute_group attr_group = {
> + .attrs = led_attrs,
> +};
> +
> +static struct attribute_group attr_pat_group = {
> + .attrs = led_group_attrs,
> +};
> +
> +static const struct attribute_group *ll1202_groups[] = { &attr_pat_group,
> + NULL };
> +
> +static void ll1202_brightness_set(struct led_classdev *led_cdev,
> + enum led_brightness value)
> +{
> + struct ll1202_led *led = cdev_to_ll1202_led(led_cdev);
> + struct ll1202_chip *chip = led->chip;
> + int ret;
> +
> + mutex_lock(&chip->lock);
> + ret = ll1202_write_reg(chip, LL1202_ILED_REG0 + led->led_num, value);
> + if (ret != 0)
> + dev_err(&chip->client->dev, "Reading register [0x%x] failed\n",
> + LL1202_ILED_REG0 + led->led_num);
> + mutex_unlock(&chip->lock);
> +}
> +
> +static enum led_brightness ll1202_brightness_get(struct led_classdev *led_cdev)
> +{
> + struct ll1202_led *led = cdev_to_ll1202_led(led_cdev);
> + struct ll1202_chip *chip = led->chip;
> + uint8_t reg_value;
> + int ret;
> +
> + mutex_lock(&chip->lock);
> + ret = ll1202_read_reg(chip, LL1202_ILED_REG0 + led->led_num,
> + ®_value);
> + if (ret != 0)
> + dev_err(&chip->client->dev, "Reading register [0x%x] failed\n",
> + LL1202_ILED_REG0 + led->led_num);
> +
> + mutex_unlock(&chip->lock);
> + return reg_value;
> +}
> +
> +static int ll1202_dt_init(struct ll1202_chip *chip)
> +{
> + struct device_node *np = chip->client->dev.of_node, *child;
dev_of_node()
> + struct ll1202_led *led;
> + int err, reg;
> +
> + for_each_child_of_node(np, child) {
> + err = of_property_read_u32(child, "reg", ®);
> + if (err) {
> + of_node_put(child);
> + pr_err(DRIVER_NAME ": Failed to get child node");
> + return err;
> + }
> + if (reg < 0 || reg >= LL1202_MAX_LEDS) {
> + of_node_put(child);
> + pr_err(DRIVER_NAME ": Invalid register value [0x%x] (out of range)", 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 (err) {
> + of_node_put(child);
> + pr_err(DRIVER_NAME ": Failed to get child node");
> + return err;
> + }
> +
> + led->led_cdev.brightness_set = ll1202_brightness_set;
> + led->led_cdev.brightness_get = ll1202_brightness_get;
> + led->led_cdev.groups = ll1202_groups;
> + }
> + return 0;
> +}
> +
> +static int ll1202_setup(struct ll1202_chip *chip)
> +{
> + int ret;
> +
> + mutex_lock(&chip->lock);
> + ret = ll1202_write_reg(chip, LL1202_DEV_ENABLE, 0x1);
> + if (ret < 0) {
> + dev_err(&chip->client->dev, "Failed writing to register [0x%x]\n",
> + LL1202_DEV_ENABLE);
> + }
> + mutex_unlock(&chip->lock);
> + usleep_range(6500, 10000);
> + mutex_lock(&chip->lock);
> + ret = ll1202_write_reg(chip, LL1202_DEV_ENABLE, 0x80);
> + if (ret < 0) {
> + dev_err(&chip->client->dev, "Failed writing to register [0x%x]\n",
> + LL1202_DEV_ENABLE);
> + }
> + mutex_unlock(&chip->lock);
> + usleep_range(6500, 10000);
> + mutex_lock(&chip->lock);
> + ret = ll1202_write_reg(chip, LL1202_PATTERN_REP, 0xFF);
> + if (ret < 0) {
> + dev_err(&chip->client->dev, "Failed writing to register [0x%x]\n",
> + LL1202_PATTERN_REP);
> + return ret;
> + }
> + mutex_unlock(&chip->lock);
> + return ret;
> +}
> +
> +static int ll1202_probe(struct i2c_client *client)
> +{
> + struct ll1202_chip *chip;
> + struct ll1202_led *led;
> + int ret, err;
> + int i;
> +
> + pr_info(DRIVER_NAME ": (I2C) " DRIVER_VERSION "\n");
> +
> + 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);
> +
> + mutex_init(&chip->lock);
devm_mutex_init()
> + chip->client = client;
> +
> + /* Device tree setup */
> + ret = ll1202_dt_init(chip);
> + if (ret < 0)
> + goto exit;
> +
> + /* Configuration setup */
> + ret = ll1202_setup(chip);
> + if (ret < 0)
> + goto exit;
> +
> + for (i = 0; i < LL1202_MAX_LEDS; i++) {
> + led = &chip->leds[i];
> + led->chip = chip;
> + led->led_num = i;
> + if (led->is_active) {
> + err = led_classdev_register(&client->dev,
> + &led->led_cdev);
devm_led_classdev_register()
> + if (err < 0) {
> + pr_err(DRIVER_NAME
dev_err?
> + ": Failed to register LED class dev");
> + goto exit;
> + }
> + }
> + }
> +
> + ret = sysfs_create_group(&client->dev.kobj, &attr_group);
This is racy.
Assign .driver.dev_groups directly in the i2c_driver struct.
> + if (ret) {
> + dev_err(&client->dev,
> + "Failed to create sysfs group for ll1202\n");
> + goto err_setup;
> + }
> +
> + return 0;
> +
> +err_setup:
> + for (i = 0; i < LL1202_MAX_LEDS; i++)
> + led_classdev_unregister(&chip->leds[i].led_cdev);
> +exit:
> + mutex_destroy(&chip->lock);
> + devm_kfree(&client->dev, chip);
If probing fails all device-managed resources are automatically cleaned
up. The more resources are device-managed the less you need to clean up
the or in _remove.
> + return ret;
> +}
> +
> +static void ll1202_remove(struct i2c_client *client)
> +{
> + struct ll1202_chip *dev = i2c_get_clientdata(client);
> + int i;
> +
> + for (i = 0; i < LL1202_MAX_LEDS; i++)
> + led_classdev_unregister(&dev->leds[i].led_cdev);
> +
> + sysfs_remove_group(&client->dev.kobj, &attr_group);
> +
> + mutex_destroy(&dev->lock);
> + devm_kfree(&client->dev, dev->leds);
> + devm_kfree(&client->dev, dev);
No need to free device-managed resource in the remove callback.
> +}
> +
> +static const struct i2c_device_id ll1202_id[] = {
> + { DRIVER_NAME "-i2c", 0 },
> + {}
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, ll1202_id);
> +
> +static const struct of_device_id ll1202_dt_ids[] = {
> + {
> + .compatible = "st,led1202",
> + },
Needs a sentinel element.
> +};
> +
> +MODULE_DEVICE_TABLE(of, ll1202_dt_ids);
> +
> +static struct i2c_driver ll1202_driver = {
> + .driver = {
> + .name = "ll1202",
> + .of_match_table = of_match_ptr(ll1202_dt_ids),
> + },
> + .probe = ll1202_probe,
> + .remove = ll1202_remove,
> + .id_table = ll1202_id,
> +};
> +
> +module_i2c_driver(ll1202_driver);
> +
> +MODULE_AUTHOR("Remote Tech LTD");
> +MODULE_DESCRIPTION("LED1202 : 12-channel constant current LED driver");
> +MODULE_LICENSE("GPL");
> --
> 2.25.1
>
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