Re: [PATCH v8 2/2] leds: lm3601x: Introduce the lm3601x LED driver

From: Andy Shevchenko
Date: Tue May 22 2018 - 15:18:48 EST

On Tue, May 22, 2018 at 5:24 PM, Dan Murphy <dmurphy@xxxxxx> wrote:
> Introduce the family of LED devices that can
> drive a torch, strobe or IR LED.
>
> The LED driver can be configured with a strobe
> timer to execute a strobe flash. The IR LED
> brightness is controlled via the torch brightness
> register.
>
> The data sheet for each the LM36010 and LM36011
> LED drivers can be found here:
> http://www.ti.com/product/LM36010
> http://www.ti.com/product/LM36011
>
> Signed-off-by: Dan Murphy <dmurphy@xxxxxx>
> ---
>
> v8 - Removed OF Kconfig dependency, change strobe to flash, updated label generation,
> fixed brightness calculation, added mutex_destroy and flash_unregister - https://patchwork.kernel.org/patch/10416163/
>
> v7 - Numerous fixes to many to list. Highlights are moved from OF APIs to device_property
> APIs, updated LED registration, timeout to reg algorithim, and fixed label generation -
> https://patchwork.kernel.org/patch/10401437/
> v6 - This driver has been heavily modified from v5. There is no longer reading
> of individual child nodes. There are too many changes to list here see -
> https://patchwork.kernel.org/patch/10392123/
> v5 - Fixed magic numbers, change reg cache type, added of_put_node to release
> the dt node ref, and I did not change the remove function to leave the LED in its
> state on driver removal - https://patchwork.kernel.org/patch/10391741/
> v4 - Fixed Cocci issue using ARRAY_SIZE - https://patchwork.kernel.org/patch/10389259/
> v3 - removed wildcard dt compatible, fixed copyright, fixed struct doc, removed
> RO registers from default, added regmap volatile for FLAGS_REG, updated regmap cache type,
> fixed unlock and extra semi colon in strobe_set, removed unnecessary out label
> in led register and fixed checking of the ret in brightness_set - https://patchwork.kernel.org/patch/10386243/
> v2 - Fixed kbuild issue and removed unused cdev_strobe - https://patchwork.kernel.org/patch/10384585/
>
>
> drivers/leds/Kconfig | 9 +
> drivers/leds/Makefile | 1 +
> drivers/leds/leds-lm3601x.c | 492 ++++++++++++++++++++++++++++++++++++
> 3 files changed, 502 insertions(+)
> create mode 100644 drivers/leds/leds-lm3601x.c
>
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index 2c896c0e69e1..d95d436e6089 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -145,6 +145,15 @@ config LEDS_LM3692X
> This option enables support for the TI LM3692x family
> of white LED string drivers used for backlighting.
>
> +config LEDS_LM3601X
> + tristate "LED support for LM3601x Chips"
> + depends on LEDS_CLASS && I2C
> + depends on LEDS_CLASS_FLASH
> + select REGMAP_I2C
> + help
> + This option enables support for the TI LM3601x family
> + of flash, torch and indicator classes.
> +
> config LEDS_LOCOMO
> tristate "LED Support for Locomo device"
> depends on LEDS_CLASS
> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> index 91eca81cae82..b79807fe1b67 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -76,6 +76,7 @@ obj-$(CONFIG_LEDS_MLXREG) += leds-mlxreg.o
> obj-$(CONFIG_LEDS_NIC78BX) += leds-nic78bx.o
> obj-$(CONFIG_LEDS_MT6323) += leds-mt6323.o
> obj-$(CONFIG_LEDS_LM3692X) += leds-lm3692x.o
> +obj-$(CONFIG_LEDS_LM3601X) += leds-lm3601x.o
>
> # LED SPI Drivers
> obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o
> diff --git a/drivers/leds/leds-lm3601x.c b/drivers/leds/leds-lm3601x.c
> new file mode 100644
> index 000000000000..b1f0ede704c1
> --- /dev/null
> +++ b/drivers/leds/leds-lm3601x.c
> @@ -0,0 +1,492 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Flash and torch driver for Texas Instruments LM3601X LED
> +// Flash driver chip family
> +// Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
> +
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/leds.h>
> +#include <linux/led-class-flash.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +#include <uapi/linux/uleds.h>
> +
> +#define LM3601X_LED_IR 0x0
> +#define LM3601X_LED_TORCH 0x1
> +
> +/* Registers */
> +#define LM3601X_ENABLE_REG 0x01
> +#define LM3601X_CFG_REG 0x02
> +#define LM3601X_LED_FLASH_REG 0x03
> +#define LM3601X_LED_TORCH_REG 0x04
> +#define LM3601X_FLAGS_REG 0x05
> +#define LM3601X_DEV_ID_REG 0x06
> +
> +#define LM3601X_SW_RESET BIT(7)
> +
> +/* Enable Mode bits */
> +#define LM3601X_MODE_STANDBY 0x00
> +#define LM3601X_MODE_IR_DRV BIT(0)
> +#define LM3601X_MODE_TORCH BIT(1)
> +#define LM3601X_MODE_STROBE (BIT(0) | BIT(1))
> +#define LM3601X_STRB_EN BIT(2)
> +#define LM3601X_STRB_EDGE_TRIG BIT(3)
> +#define LM3601X_IVFM_EN BIT(4)
> +
> +#define LM36010_BOOST_LIMIT_28 BIT(5)
> +#define LM36010_BOOST_FREQ_4MHZ BIT(6)
> +#define LM36010_BOOST_MODE_PASS BIT(7)
> +
> +/* Flag Mask */
> +#define LM3601X_FLASH_TIME_OUT BIT(0)
> +#define LM3601X_UVLO_FAULT BIT(1)
> +#define LM3601X_THERM_SHUTDOWN BIT(2)
> +#define LM3601X_THERM_CURR BIT(3)
> +#define LM36010_CURR_LIMIT BIT(4)
> +#define LM3601X_SHORT_FAULT BIT(5)
> +#define LM3601X_IVFM_TRIP BIT(6)
> +#define LM36010_OVP_FAULT BIT(7)
> +
> +#define LM3601X_MAX_TORCH_I_UA 376000
> +#define LM3601X_MIN_TORCH_I_UA 2400
> +#define LM3601X_TORCH_REG_DIV 2965
> +
> +#define LM3601X_MAX_STROBE_I_UA 1500000
> +#define LM3601X_MIN_STROBE_I_UA 11000
> +#define LM3601X_STROBE_REG_DIV 11800
> +
> +#define LM3601X_TIMEOUT_MASK 0x1e
> +#define LM3601X_ENABLE_MASK (LM3601X_MODE_IR_DRV | LM3601X_MODE_TORCH)
> +
> +#define LM3601X_LOWER_STEP_US 40000
> +#define LM3601X_UPPER_STEP_US 200000
> +#define LM3601X_MIN_TIMEOUT_US 40000
> +#define LM3601X_MAX_TIMEOUT_US 1600000
> +#define LM3601X_TIMEOUT_XOVER_US 400000
> +
> +enum lm3601x_type {
> + CHIP_LM36010 = 0,
> + CHIP_LM36011,
> +};
> +
> +/**
> + * struct lm3601x_led -
> + * @fled_cdev: flash LED class device pointer
> + * @client: Pointer to the I2C client
> + * @regmap: Devices register map
> + * @lock: Lock for reading/writing the device
> + * @led_name: LED label for the Torch or IR LED
> + * @flash_timeout: the timeout for the flash
> + * @last_flag: last known flags register value
> + * @torch_current_max: maximum current for the torch
> + * @flash_current_max: maximum current for the flash
> + * @max_flash_timeout: maximum timeout for the flash
> + * @led_mode: The mode to enable either IR or Torch
> + */
> +struct lm3601x_led {
> + struct led_classdev_flash fled_cdev;
> + struct i2c_client *client;
> + struct regmap *regmap;
> + struct mutex lock;
> +
> + char led_name[LED_MAX_NAME_SIZE];
> +
> + unsigned int flash_timeout;
> + unsigned int last_flag;
> +
> + u32 torch_current_max;
> + u32 flash_current_max;
> + u32 max_flash_timeout;
> +
> + u32 led_mode;
> +};
> +
> +static const struct reg_default lm3601x_regmap_defs[] = {
> + { LM3601X_ENABLE_REG, 0x20 },
> + { LM3601X_CFG_REG, 0x15 },
> + { LM3601X_LED_FLASH_REG, 0x00 },
> + { LM3601X_LED_TORCH_REG, 0x00 },
> +};
> +
> +static bool lm3601x_volatile_reg(struct device *dev, unsigned int reg)
> +{
> + switch (reg) {
> + case LM3601X_FLAGS_REG:
> + return true;
> + default:
> + return false;
> + }
> +}
> +
> +static const struct regmap_config lm3601x_regmap = {
> + .reg_bits = 8,
> + .val_bits = 8,
> +
> + .max_register = LM3601X_DEV_ID_REG,
> + .reg_defaults = lm3601x_regmap_defs,
> + .num_reg_defaults = ARRAY_SIZE(lm3601x_regmap_defs),
> + .cache_type = REGCACHE_RBTREE,
> + .volatile_reg = lm3601x_volatile_reg,
> +};
> +

> +static struct lm3601x_led *fled_cdev_to_led(
> + struct led_classdev_flash *fled_cdev)

Didn't notice before. This will look much better in one line.

> +{
> + return container_of(fled_cdev, struct lm3601x_led, fled_cdev);
> +}
> +
> +static int lm3601x_read_faults(struct lm3601x_led *led)
> +{
> + int flags_val;
> + int ret;
> +
> + ret = regmap_read(led->regmap, LM3601X_FLAGS_REG, &flags_val);
> + if (ret < 0)
> + return -EIO;
> +
> + led->last_flag = 0;
> +
> + if (flags_val & LM36010_OVP_FAULT)
> + led->last_flag |= LED_FAULT_OVER_VOLTAGE;
> +
> + if (flags_val & (LM3601X_THERM_SHUTDOWN | LM3601X_THERM_CURR))
> + led->last_flag |= LED_FAULT_OVER_TEMPERATURE;
> +
> + if (flags_val & LM3601X_SHORT_FAULT)
> + led->last_flag |= LED_FAULT_SHORT_CIRCUIT;
> +
> + if (flags_val & LM36010_CURR_LIMIT)
> + led->last_flag |= LED_FAULT_OVER_CURRENT;
> +
> + if (flags_val & LM3601X_UVLO_FAULT)
> + led->last_flag |= LED_FAULT_UNDER_VOLTAGE;
> +
> + if (flags_val & LM3601X_IVFM_TRIP)
> + led->last_flag |= LED_FAULT_INPUT_VOLTAGE;
> +
> + if (flags_val & LM3601X_THERM_SHUTDOWN)
> + led->last_flag |= LED_FAULT_LED_OVER_TEMPERATURE;
> +
> + return led->last_flag;
> +}
> +
> +static int lm3601x_brightness_set(struct led_classdev *cdev,
> + enum led_brightness brightness)
> +{
> + struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(cdev);
> + struct lm3601x_led *led = fled_cdev_to_led(fled_cdev);
> + int ret, led_mode_val;
> +
> + mutex_lock(&led->lock);
> +
> + ret = lm3601x_read_faults(led);
> + if (ret < 0)
> + goto out;
> +
> + if (led->led_mode == LM3601X_LED_TORCH)
> + led_mode_val = LM3601X_MODE_TORCH;
> + else
> + led_mode_val = LM3601X_MODE_IR_DRV;
> +
> + if (brightness == LED_OFF) {
> + ret = regmap_update_bits(led->regmap, LM3601X_ENABLE_REG,
> + led_mode_val, LED_OFF);
> + goto out;
> + }
> +
> + ret = regmap_write(led->regmap, LM3601X_LED_TORCH_REG, brightness);
> + if (ret < 0)
> + goto out;
> +
> + ret = regmap_update_bits(led->regmap, LM3601X_ENABLE_REG,
> + LM3601X_MODE_TORCH | LM3601X_MODE_IR_DRV,
> + led_mode_val);
> +out:
> + mutex_unlock(&led->lock);
> + return ret;
> +}
> +
> +static int lm3601x_flash_set(struct led_classdev_flash *fled_cdev,
> + bool state)
> +{
> + struct lm3601x_led *led = fled_cdev_to_led(fled_cdev);

> + int timeout_reg_val = 0;

Redundant assignment.

> + int current_timeout;
> + int ret;
> +
> + mutex_lock(&led->lock);
> +
> + ret = regmap_read(led->regmap, LM3601X_CFG_REG, &current_timeout);
> + if (ret < 0)
> + goto out;
> +
> + if (led->flash_timeout >= LM3601X_TIMEOUT_XOVER_US)
> + timeout_reg_val = led->flash_timeout / LM3601X_UPPER_STEP_US + 0x07;
> + else
> + timeout_reg_val = led->flash_timeout / LM3601X_LOWER_STEP_US - 0x01;
> +
> + if (led->flash_timeout != current_timeout)
> + ret = regmap_update_bits(led->regmap, LM3601X_CFG_REG,
> + LM3601X_TIMEOUT_MASK, timeout_reg_val);
> +
> + if (state)
> + ret = regmap_update_bits(led->regmap, LM3601X_ENABLE_REG,
> + LM3601X_MODE_TORCH | LM3601X_MODE_IR_DRV,
> + LM3601X_MODE_STROBE);
> + else
> + ret = regmap_update_bits(led->regmap, LM3601X_ENABLE_REG,
> + LM3601X_MODE_STROBE, LED_OFF);
> +
> + ret = lm3601x_read_faults(led);
> +out:
> + mutex_unlock(&led->lock);
> + return ret;
> +}
> +
> +static int lm3601x_flash_brightness_set(struct led_classdev_flash *fled_cdev,
> + u32 brightness)
> +{
> + struct lm3601x_led *led = fled_cdev_to_led(fled_cdev);

> + int ret;
> + u8 brightness_val;

Better to read reversed xmas tree order.

> +
> + mutex_lock(&led->lock);
> + ret = lm3601x_read_faults(led);
> + if (ret < 0)
> + goto out;
> +
> + if (brightness == LED_OFF) {
> + ret = regmap_update_bits(led->regmap, LM3601X_ENABLE_REG,
> + LM3601X_MODE_STROBE, LED_OFF);
> + goto out;
> + }
> +
> + brightness_val = brightness / LM3601X_STROBE_REG_DIV;
> +
> + ret = regmap_write(led->regmap, LM3601X_LED_FLASH_REG, brightness_val);
> +out:
> + mutex_unlock(&led->lock);
> + return ret;
> +}
> +
> +static int lm3601x_flash_timeout_set(struct led_classdev_flash *fled_cdev,
> + u32 timeout)
> +{
> + struct lm3601x_led *led = fled_cdev_to_led(fled_cdev);

> + int ret = 0;

Redundant variable.

> +
> + mutex_lock(&led->lock);
> +
> + led->flash_timeout = timeout;
> +
> + mutex_unlock(&led->lock);
> +
> + return ret;
> +}
> +
> +static int lm3601x_flash_get(struct led_classdev_flash *fled_cdev,
> + bool *state)
> +{
> + struct lm3601x_led *led = fled_cdev_to_led(fled_cdev);
> + int ret;
> + int flash_state;
> +
> + mutex_lock(&led->lock);
> +
> + ret = regmap_read(led->regmap, LM3601X_ENABLE_REG, &flash_state);
> + if (ret < 0)
> + goto out;
> +
> + *state = flash_state & LM3601X_MODE_STROBE;
> +
> +out:
> + mutex_unlock(&led->lock);
> + return ret;
> +}
> +
> +static int lm3601x_flash_fault_get(struct led_classdev_flash *fled_cdev,
> + u32 *fault)
> +{
> + struct lm3601x_led *led = fled_cdev_to_led(fled_cdev);
> +
> + lm3601x_read_faults(led);
> +
> + *fault = led->last_flag;
> +
> + return 0;
> +}
> +
> +static const struct led_flash_ops flash_ops = {
> + .flash_brightness_set = lm3601x_flash_brightness_set,
> + .strobe_set = lm3601x_flash_set,
> + .strobe_get = lm3601x_flash_get,
> + .timeout_set = lm3601x_flash_timeout_set,
> + .fault_get = lm3601x_flash_fault_get,
> +};
> +
> +static int lm3601x_register_leds(struct lm3601x_led *led)
> +{
> + struct led_classdev *led_cdev;
> + struct led_flash_setting *setting;
> +
> + led->fled_cdev.ops = &flash_ops;
> +
> + setting = &led->fled_cdev.timeout;
> + setting->min = LM3601X_MIN_TIMEOUT_US;
> + setting->max = led->max_flash_timeout;
> + setting->step = LM3601X_LOWER_STEP_US;
> + setting->val = led->max_flash_timeout;
> +
> + setting = &led->fled_cdev.brightness;
> + setting->min = LM3601X_MIN_STROBE_I_UA;
> + setting->max = led->flash_current_max;
> + setting->step = LM3601X_TORCH_REG_DIV;
> + setting->val = led->flash_current_max;
> +
> + led_cdev = &led->fled_cdev.led_cdev;
> + led_cdev->name = led->led_name;
> + led_cdev->brightness_set_blocking = lm3601x_brightness_set;
> + led_cdev->max_brightness = DIV_ROUND_UP(led->torch_current_max,
> + LM3601X_TORCH_REG_DIV);
> + led_cdev->flags |= LED_DEV_CAP_FLASH;
> +
> + return led_classdev_flash_register(&led->client->dev, &led->fled_cdev);
> +}
> +
> +static int lm3601x_parse_node(struct lm3601x_led *led,

> + struct device_node *node)

I don't see how it's used.

> +{
> + struct fwnode_handle *child = NULL;
> + int ret = -ENODEV;
> + const char *name;
> +
> + child = device_get_next_child_node(&led->client->dev, child);
> + if (!child) {
> + dev_err(&led->client->dev, "No LED Child node\n");
> + return ret;
> + }
> +
> + ret = fwnode_property_read_u32(child, "reg", &led->led_mode);
> + if (ret) {
> + dev_err(&led->client->dev, "reg DT property missing\n");
> + goto out_err;
> + }
> +
> + if (led->led_mode > LM3601X_LED_TORCH ||
> + led->led_mode < LM3601X_LED_IR) {
> + dev_warn(&led->client->dev, "Invalid led mode requested\n");
> + ret = -EINVAL;
> + goto out_err;
> + }
> +
> + ret = fwnode_property_read_string(child, "label", &name);
> + if (ret) {
> + if (led->led_mode == LM3601X_LED_TORCH)
> + name = "torch";
> + else
> + name = "infrared";
> + }
> +
> + snprintf(led->led_name, sizeof(led->led_name),
> + "%s:%s", led->client->name, name);
> +
> + ret = fwnode_property_read_u32(child, "led-max-microamp",
> + &led->torch_current_max);

> + if (ret < 0) {

Be consistent with above or other way around.

> + dev_warn(&led->client->dev,
> + "led-max-microamp DT property missing\n");
> + goto out_err;
> + }
> +
> + ret = fwnode_property_read_u32(child, "flash-max-microamp",
> + &led->flash_current_max);
> + if (ret < 0) {
> + dev_warn(&led->client->dev,
> + "flash-max-microamp DT property missing\n");
> + goto out_err;
> + }
> +
> + ret = fwnode_property_read_u32(child, "flash-max-timeout-us",
> + &led->max_flash_timeout);
> + if (ret < 0) {
> + dev_warn(&led->client->dev,
> + "flash-max-timeout-us DT property missing\n");
> + goto out_err;
> + }
> +
> +out_err:
> + fwnode_handle_put(child);
> + return ret;
> +}
> +
> +static int lm3601x_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct lm3601x_led *led;

> + int err;

Be consistent, either err everywhere, or ret.

> +
> + led = devm_kzalloc(&client->dev, sizeof(*led), GFP_KERNEL);
> + if (!led)
> + return -ENOMEM;
> +
> + led->client = client;
> + i2c_set_clientdata(client, led);
> +

> + err = lm3601x_parse_node(led, client->dev.of_node);

Can't you use dev_fwnode() helper?
It seems it's even not used inside the function.

> + if (err < 0)
> + return -ENODEV;
> +
> + led->regmap = devm_regmap_init_i2c(client, &lm3601x_regmap);
> + if (IS_ERR(led->regmap)) {
> + err = PTR_ERR(led->regmap);
> + dev_err(&client->dev,
> + "Failed to allocate register map: %d\n", err);
> + return err;
> + }
> +
> + mutex_init(&led->lock);
> +
> + return lm3601x_register_leds(led);
> +}
> +
> +static int lm3601x_remove(struct i2c_client *client)
> +{
> + struct lm3601x_led *led = i2c_get_clientdata(client);
> +
> + led_classdev_flash_unregister(&led->fled_cdev);
> + mutex_destroy(&led->lock);
> +
> + return regmap_update_bits(led->regmap, LM3601X_ENABLE_REG,
> + LM3601X_ENABLE_MASK,
> + LM3601X_MODE_STANDBY);
> +}
> +

> +static const struct i2c_device_id lm3601x_id[] = {
> + { "LM36010", CHIP_LM36010 },
> + { "LM36011", CHIP_LM36011 },
> + { }
> +};
> +MODULE_DEVICE_TABLE(i2c, lm3601x_id);

Are you going to use it as a pure i2c driver? If yes, I would like to hear why.
Otherwise just switch to ->probe_new().

> +
> +static const struct of_device_id of_lm3601x_leds_match[] = {
> + { .compatible = "ti,lm36010", },
> + { .compatible = "ti,lm36011", },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, of_lm3601x_leds_match);
> +
> +static struct i2c_driver lm3601x_i2c_driver = {
> + .driver = {
> + .name = "lm3601x",
> + .of_match_table = of_lm3601x_leds_match,
> + },
> + .probe = lm3601x_probe,
> + .remove = lm3601x_remove,
> + .id_table = lm3601x_id,
> +};
> +module_i2c_driver(lm3601x_i2c_driver);
> +
> +MODULE_DESCRIPTION("Texas Instruments Flash Lighting driver for LM3601X");
> +MODULE_AUTHOR("Dan Murphy <dmurphy@xxxxxx>");
> +MODULE_LICENSE("GPL v2");
> --
> 2.17.0.582.gccdcbd54c
>



--
With Best Regards,
Andy Shevchenko