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Date: Sat, 4 Aug 2018 14:14:19 +0200
From: Jacek Anaszewski <jacek.anaszewski@...il.com>
To: Dan Murphy <dmurphy@...com>, robh+dt@...nel.org
Cc: devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-leds@...r.kernel.org
Subject: Re: [PATCH 2/2] leds: lm3697: Introduce the lm3697 driver
Hi Dan,
Thank you for the patch. Please find my comments below.
On 08/03/2018 05:02 PM, Dan Murphy wrote:
> Introduce the lm3697 LED driver for
> backlighting and display.
>
> Datasheet location:
> http://www.ti.com/lit/ds/symlink/lm3697.pdf
>
> Signed-off-by: Dan Murphy <dmurphy@...com>
> ---
> drivers/leds/Kconfig | 9 +
> drivers/leds/Makefile | 1 +
> drivers/leds/leds-lm3697.c | 375 +++++++++++++++++++++++++++++++++++++
> 3 files changed, 385 insertions(+)
> create mode 100644 drivers/leds/leds-lm3697.c
>
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index 6e3a998f3370..efa8be180934 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -150,6 +150,15 @@ config LEDS_LM3642
> converter plus 1.5A constant current driver for a high-current
> white LED.
>
> +config LEDS_LM3697
> + tristate "LED support for LM3697 Chip"
> + depends on LEDS_CLASS && I2C
> + select REGMAP_I2C
> + help
> + This option enables support for LEDs connected to LM3697.
> + The LM3697 is an 11 bit high performance backlight driver for
> + keypad and display lighting.
> +
> config LEDS_LM3692X
> tristate "LED support for LM3692x Chips"
> depends on LEDS_CLASS && I2C && OF
> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> index 420b5d2cfa62..2813f089f3db 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -19,6 +19,7 @@ obj-$(CONFIG_LEDS_LOCOMO) += leds-locomo.o
> obj-$(CONFIG_LEDS_LM3530) += leds-lm3530.o
> obj-$(CONFIG_LEDS_LM3533) += leds-lm3533.o
> obj-$(CONFIG_LEDS_LM3642) += leds-lm3642.o
> +obj-$(CONFIG_LEDS_LM3697) += leds-lm3697.o
> obj-$(CONFIG_LEDS_MIKROTIK_RB532) += leds-rb532.o
> obj-$(CONFIG_LEDS_S3C24XX) += leds-s3c24xx.o
> obj-$(CONFIG_LEDS_NET48XX) += leds-net48xx.o
> diff --git a/drivers/leds/leds-lm3697.c b/drivers/leds/leds-lm3697.c
> new file mode 100644
> index 000000000000..332bde4af01a
> --- /dev/null
> +++ b/drivers/leds/leds-lm3697.c
> @@ -0,0 +1,375 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// TI LM3697 LED chip family driver
> +// Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
> +
> +#include <linux/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/init.h>
> +#include <linux/leds.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/of.h>
> +#include <linux/of_gpio.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/slab.h>
> +#include <uapi/linux/uleds.h>
> +
> +#define LM3697_REV 0x0
> +#define LM3697_RESET 0x1
> +#define LM3697_OUTPUT_CONFIG 0x10
> +#define LM3697_CTRL_A_RAMP 0x11
> +#define LM3697_CTRL_B_RAMP 0x12
> +#define LM3697_CTRL_A_B_RT_RAMP 0x13
> +#define LM3697_CTRL_A_B_RAMP_CFG 0x14
> +#define LM3697_CTRL_A_B_BRT_CFG 0x16
> +#define LM3697_CTRL_A_FS_CURR_CFG 0x17
> +#define LM3697_CTRL_B_FS_CURR_CFG 0x18
> +#define LM3697_PWM_CFG 0x1c
> +#define LM3697_CTRL_A_BRT_LSB 0x20
> +#define LM3697_CTRL_A_BRT_MSB 0x21
> +#define LM3697_CTRL_B_BRT_LSB 0x22
> +#define LM3697_CTRL_B_BRT_MSB 0x23
> +#define LM3697_CTRL_ENABLE 0x24
> +
> +#define LM3697_SW_RESET BIT(0)
> +
> +#define LM3697_CTRL_A_EN BIT(0)
> +#define LM3697_CTRL_B_EN BIT(1)
> +#define LM3697_CTRL_A_B_EN (LM3697_CTRL_A_EN | LM3697_CTRL_B_EN)
> +
> +#define LM3697_CONTROL_A 0
> +#define LM3697_CONTROL_B 1
> +
> +#define LM3697_HVLED1_2_3_A 0
> +#define LM3697_HVLED1_B_HVLED2_3_A 1
> +#define LM3697_HVLED2_B_HVLED1_3_A 2
> +#define LM3697_HVLED1_2_B_HVLED3_A 3
> +#define LM3697_HVLED3_B_HVLED1_2_A 4
> +#define LM3697_HVLED1_3_B_HVLED2_A 5
> +#define LM3697_HVLED1_A_HVLED2_3_B 6
> +#define LM3697_HVLED1_2_3_B 7
> +
> +/**
> + * struct lm3697_led -
> + * @led_dev - LED class device pointer
This is not a pointer but static struct property,
i.e. it should be "LED class device".
> + * @priv - Pointer to the device struct
> + * @control_bank - Control bank the LED is associated to. 0 is control bank A
> + * 1 is control bank B.
> + * @label - LED label
> + */
> +struct lm3697_led {
> + struct led_classdev led_dev;
> + struct lm3697 *priv;
> + int control_bank;
> + char label[LED_MAX_NAME_SIZE];
> +};
> +
> +/**
> + * struct lm3697 -
> + * @lock - Lock for reading/writing the device
> + * @client - Pointer to the I2C client
> + * @dev - Pointer to the devices device struct
> + * @regmap - Devices register map
> + * @enable_gpio - Hardware enable gpio
> + * @regulator - LED supply regulator pointer
> + * @control_bank_config - Control bank configuration
> + * @leds - Array of LED strings.
> + */
> +struct lm3697 {
> + struct mutex lock;
> + struct i2c_client *client;
> + struct device *dev;
> + struct regmap *regmap;
> + struct gpio_desc *enable_gpio;
> + struct regulator *regulator;
> + int control_bank_config;
> + struct lm3697_led leds[];
> +};
> +
> +static const struct reg_default lm3697_reg_defs[] = {
> + {LM3697_OUTPUT_CONFIG, 0x6},
> + {LM3697_CTRL_A_RAMP, 0x0},
> + {LM3697_CTRL_B_RAMP, 0x0},
> + {LM3697_CTRL_A_B_RT_RAMP, 0x0},
> + {LM3697_CTRL_A_B_RAMP_CFG, 0x0},
> + {LM3697_CTRL_A_B_BRT_CFG, 0x0},
> + {LM3697_CTRL_A_FS_CURR_CFG, 0x13},
> + {LM3697_CTRL_B_FS_CURR_CFG, 0x13},
> + {LM3697_PWM_CFG, 0xc},
> + {LM3697_CTRL_A_BRT_LSB, 0x0},
> + {LM3697_CTRL_A_BRT_MSB, 0x0},
> + {LM3697_CTRL_B_BRT_LSB, 0x0},
> + {LM3697_CTRL_B_BRT_MSB, 0x0},
> + {LM3697_CTRL_ENABLE, 0x0},
> +};
> +
> +static const struct regmap_config lm3697_regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 8,
> +
> + .max_register = LM3697_CTRL_ENABLE,
> + .reg_defaults = lm3697_reg_defs,
> + .num_reg_defaults = ARRAY_SIZE(lm3697_reg_defs),
> + .cache_type = REGCACHE_RBTREE,
> +};
> +
> +static int lm3697_brightness_set(struct led_classdev *led_cdev,
> + enum led_brightness brt_val)
> +{
> + struct lm3697_led *led = container_of(led_cdev, struct lm3697_led,
> + led_dev);
> + int brt_msb_reg, brt_lsb_reg, ctrl_en_val;
> + int led_brightness_lsb = (brt_val >> 5);
> + int ret;
> +
> + mutex_lock(&led->priv->lock);
> +
> + if (led->control_bank == LM3697_CONTROL_A) {
> + brt_msb_reg = LM3697_CTRL_A_BRT_MSB;
> + brt_lsb_reg = LM3697_CTRL_A_BRT_LSB;
> + ctrl_en_val = LM3697_CTRL_A_EN;
> + } else {
> + brt_msb_reg = LM3697_CTRL_B_BRT_MSB;
> + brt_lsb_reg = LM3697_CTRL_B_BRT_LSB;
> + ctrl_en_val = LM3697_CTRL_B_EN;
> + }
> +
> + if (brt_val == LED_OFF)
> + ret = regmap_update_bits(led->priv->regmap, LM3697_CTRL_ENABLE,
> + ctrl_en_val, ~ctrl_en_val);
> + else
> + ret = regmap_update_bits(led->priv->regmap, LM3697_CTRL_ENABLE,
> + ctrl_en_val, ctrl_en_val);
> +
checkpatch.pl reports trailing whitespace here.
> + if (ret) {
> + dev_err(&led->priv->client->dev, "Cannot write CTRL enable\n");
> + goto out;
> + }
> +> + ret = regmap_write(led->priv->regmap, brt_lsb_reg, led_brightness_lsb);
> + if (ret) {
> + dev_err(&led->priv->client->dev, "Cannot write LSB\n");
> + goto out;
> + }
> +
> + ret = regmap_write(led->priv->regmap, brt_msb_reg, brt_val);
> + if (ret) {
> + dev_err(&led->priv->client->dev, "Cannot write MSB\n");
> + goto out;
> + }
> +out:
> + mutex_unlock(&led->priv->lock);
> + return ret;
> +}
> +
> +static int lm3697_init(struct lm3697 *priv)
> +{
> + int ret;
> +
> + if (priv->enable_gpio)
> + gpiod_direction_output(priv->enable_gpio, 1);
> + else
> + regmap_write(priv->regmap, LM3697_RESET, LM3697_SW_RESET);
> +
> + ret = regmap_write(priv->regmap, LM3697_OUTPUT_CONFIG,
> + priv->control_bank_config);
> + if (ret) {
> + dev_err(&priv->client->dev, "Cannot write MSB\n");
> + goto out;
> + }
> +
> + ret = regmap_write(priv->regmap, LM3697_CTRL_ENABLE, 0x0);
> + if (ret) {
> + dev_err(&priv->client->dev, "Cannot write LSB\n");
> + goto out;
> + }
> +
> +out:
> + return ret;
> +}
> +
> +static int lm3697_probe_dt(struct lm3697 *priv)
> +{
> + struct fwnode_handle *child = NULL;
> + struct fwnode_handle *fwnode;
> + struct device_node *np;
> + struct lm3697_led *led;
> + const char *name;
> + size_t i = 0;
> + int ret;
> +
> + priv->enable_gpio = devm_gpiod_get_optional(&priv->client->dev,
> + "enable", GPIOD_OUT_LOW);
> + if (IS_ERR(priv->enable_gpio)) {
> + ret = PTR_ERR(priv->enable_gpio);
> + dev_err(&priv->client->dev, "Failed to get enable gpio: %d\n",
> + ret);
> + return ret;
> + }
> +
> + priv->regulator = devm_regulator_get(&priv->client->dev, "vled");
> + if (IS_ERR(priv->regulator))
> + priv->regulator = NULL;
> +
> + fwnode = of_fwnode_handle(priv->client->dev.of_node);
To remain OF agnostic here, you could use
dev_fwnode(&priv->client->dev) here.
> + ret = fwnode_property_read_u32(fwnode, "control-bank-cfg",
> + &priv->control_bank_config);
> + if (ret) {
> + dev_err(&priv->client->dev, "reg DT property missing\n");
> + goto out;
> + }
> +
> + if (priv->control_bank_config < LM3697_HVLED1_2_3_A ||
> + priv->control_bank_config > LM3697_HVLED1_2_3_B) {
> + dev_err(&priv->client->dev, "Control bank configuration is \
> + out of range\n");
> + ret = -EINVAL;
> + goto out;
> + }
> +
Please remove one empty line here.
> +
> + device_for_each_child_node(priv->dev, child) {
> + np = to_of_node(child);
This is not needed really.
> + led = &priv->leds[i];
> +
> + ret = fwnode_property_read_u32(child, "reg", &led->control_bank);
> + if (ret) {
> + dev_err(&priv->client->dev, "reg DT property missing\n");
> + goto child_out;
> + }
> +
> + fwnode_property_read_string(child, "linux,default-trigger",
> + &led->led_dev.default_trigger);
> +
> + ret = fwnode_property_read_string(child, "label", &name);
> + if (ret)
> + snprintf(led->label, sizeof(led->label),
> + "%s::", priv->client->name);
> + else
> + snprintf(led->label, sizeof(led->label),
> + "%s:%s", priv->client->name, name);
> +
> +
> + led->priv = priv;
> + led->led_dev.name = led->label;
> + led->led_dev.brightness_set_blocking = lm3697_brightness_set;
> +
> + ret = devm_of_led_classdev_register(priv->dev, np,
> + &led->led_dev);
Please use devm_led_classdev_register() wrapper.
devm_of_led_classdev_register() was introduced to enable parsing trigger
related DT properties, but the support hasn't been finalized.
> + if (ret) {
> + dev_err(&priv->client->dev, "led register err: %d\n", ret);
> + goto child_out;
> + }
> +
> + led->led_dev.dev->of_node = to_of_node(child);
of_led_classdev_register() does this assignment already, but you don't
need it either way.
> +
> + if (priv->control_bank_config == LM3697_HVLED1_2_3_A ||
> + priv->control_bank_config == LM3697_HVLED1_2_3_B)
> + goto child_out;
> +
> + i++;
> + fwnode_handle_put(child);
> + }
> +
> +child_out:
> + fwnode_handle_put(child);
> +out:
> + return ret;
> +}
> +
> +static int lm3697_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct lm3697 *led;
> + int count;
> + int ret;
> +
> + count = device_get_child_node_count(&client->dev);
> + if (!count) {
> + dev_err(&client->dev, "LEDs are not defined in device tree!");
> + return -ENODEV;
> + }
> +
> + led = devm_kzalloc(&client->dev, struct_size(led, leds, count), GFP_KERNEL);
> + if (!led)
> + return -ENOMEM;
> +
> + mutex_init(&led->lock);
> + i2c_set_clientdata(client, led);
> +
> + led->client = client;
> + led->dev = &client->dev;
> + led->regmap = devm_regmap_init_i2c(client, &lm3697_regmap_config);
> + if (IS_ERR(led->regmap)) {
> + ret = PTR_ERR(led->regmap);
> + dev_err(&client->dev, "Failed to allocate register map: %d\n",
> + ret);
> + return ret;
> + }
> +
> + ret = lm3697_probe_dt(led);
> + if (ret)
> + return ret;
> +
> + ret = lm3697_init(led);
> + if (ret)
> + return ret;
> +
> + return ret;
> +}
> +
> +static int lm3697_remove(struct i2c_client *client)
> +{
> + struct lm3697 *led = i2c_get_clientdata(client);
> + int ret;
> +
> + ret = regmap_update_bits(led->regmap, LM3697_CTRL_ENABLE,
> + LM3697_CTRL_A_B_EN, 0);
> + if (ret) {
> + dev_err(&led->client->dev, "Failed to disable regulator\n");
> + return ret;
> + }
> +
> + if (led->enable_gpio)
> + gpiod_direction_output(led->enable_gpio, 0);
> +
> + if (led->regulator) {
> + ret = regulator_disable(led->regulator);
> + if (ret)
> + dev_err(&led->client->dev,
> + "Failed to disable regulator\n");
> + }
> +
> + mutex_destroy(&led->lock);
> +
> + return 0;
> +}
> +
> +static const struct i2c_device_id lm3697_id[] = {
> + { "lm3697", 0 },
> + { }
> +};
> +MODULE_DEVICE_TABLE(i2c, lm3697_id);
> +
> +static const struct of_device_id of_lm3697_leds_match[] = {
> + { .compatible = "ti,lm3697", },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, of_lm3697_leds_match);
> +
> +static struct i2c_driver lm3697_driver = {
> + .driver = {
> + .name = "lm3697",
> + .of_match_table = of_lm3697_leds_match,
> + },
> + .probe = lm3697_probe,
> + .remove = lm3697_remove,
> + .id_table = lm3697_id,
> +};
> +module_i2c_driver(lm3697_driver);
> +
> +MODULE_DESCRIPTION("Texas Instruments LM3697 LED driver");
> +MODULE_AUTHOR("Dan Murphy <dmurphy@...com>");
> +MODULE_LICENSE("GPL v2");
>
--
Best regards,
Jacek Anaszewski
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