Re: [PATCH v2 2/2] leds: add sgm3140 driver

Dan Murphy
2020-04-03T17:37:58Z

Luca

On 3/30/20 2:47 PM, Luca Weiss wrote:
> Add a driver for the SGMICRO SGM3140 Buck/Boost Charge Pump LED driver.
>
> This device is controlled by two GPIO pins, one for enabling and the
> second one for switching between torch and flash mode.
>
> Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
> ---
> Changes since v1:
> - Add vin-supply (keep track of 'enabled' state for that)
> - Wrap lines
> - static const -ify some structs and methods
> - use strscpy instead of strlcpy
> - remove u32 cast by adding 'U' suffix to constants
> - rebase on linux-next
>
> drivers/leds/Kconfig | 9 +
> drivers/leds/Makefile | 1 +
> drivers/leds/leds-sgm3140.c | 317 ++++++++++++++++++++++++++++++++++++
> 3 files changed, 327 insertions(+)
> create mode 100644 drivers/leds/leds-sgm3140.c
>
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index 7599dbee8de1..f5beeff16bdd 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -871,6 +871,15 @@ config LEDS_IP30
> To compile this driver as a module, choose M here: the module
> will be called leds-ip30.
>
> +config LEDS_SGM3140
> + tristate "LED support for the SGM3140"
> + depends on LEDS_CLASS_FLASH
> + depends on V4L2_FLASH_LED_CLASS || !V4L2_FLASH_LED_CLASS
> + depends on OF
> + help
> + This option enables support for the SGM3140 500mA Buck/Boost Charge
> + Pump LED Driver.
> +
> comment "LED Triggers"
> source "drivers/leds/trigger/Kconfig"
>
> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> index fd61421f7d40..f60ed0c09d4c 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -77,6 +77,7 @@ obj-$(CONFIG_LEDS_PWM) += leds-pwm.o
> obj-$(CONFIG_LEDS_REGULATOR) += leds-regulator.o
> obj-$(CONFIG_LEDS_S3C24XX) += leds-s3c24xx.o
> obj-$(CONFIG_LEDS_SC27XX_BLTC) += leds-sc27xx-bltc.o
> +obj-$(CONFIG_LEDS_SGM3140) += leds-sgm3140.o
> obj-$(CONFIG_LEDS_SUNFIRE) += leds-sunfire.o
> obj-$(CONFIG_LEDS_SYSCON) += leds-syscon.o
> obj-$(CONFIG_LEDS_TCA6507) += leds-tca6507.o
> diff --git a/drivers/leds/leds-sgm3140.c b/drivers/leds/leds-sgm3140.c
> new file mode 100644
> index 000000000000..28fe5e34f931
> --- /dev/null
> +++ b/drivers/leds/leds-sgm3140.c
> @@ -0,0 +1,317 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (C) 2020 Luca Weiss <luca@z3ntu.xyz>
> +
> +#include <linux/gpio/consumer.h>
> +#include <linux/led-class-flash.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/platform_device.h>
> +
> +#include <media/v4l2-flash-led-class.h>
> +
> +#define FLASH_TIMEOUT_DEFAULT 250000U /* 250ms */
> +#define FLASH_MAX_TIMEOUT_DEFAULT 300000U /* 300ms */
> +
> +struct sgm3140 {
> + bool enabled;
> + struct gpio_desc *flash_gpio;
> + struct gpio_desc *enable_gpio;
> + struct regulator *vin_regulator;
> +
> + /* current timeout in us */
> + u32 timeout;
> + /* maximum timeout in us */
> + u32 max_timeout;
> +
> + struct led_classdev_flash fled_cdev;
> + struct v4l2_flash *v4l2_flash;
> +
> + struct timer_list powerdown_timer;
> +};
> +
> +static struct sgm3140 *flcdev_to_sgm3140(struct led_classdev_flash *flcdev)
> +{
> + return container_of(flcdev, struct sgm3140, fled_cdev);
> +}
> +
> +static int sgm3140_strobe_set(struct led_classdev_flash *fled_cdev, bool state)
> +{
> + struct sgm3140 *priv = flcdev_to_sgm3140(fled_cdev);
> + int ret;
> +
> + if (priv->enabled == state)
> + return 0;
> +
> + if (state) {
> + ret = regulator_enable(priv->vin_regulator);
> + if (ret) {
> + dev_err(fled_cdev->led_cdev.dev,
> + "failed to enable regulator: %d\n", ret);
> + return ret;
> + }
> + gpiod_set_value_cansleep(priv->flash_gpio, 1);
> + gpiod_set_value_cansleep(priv->enable_gpio, 1);
> + mod_timer(&priv->powerdown_timer,
> + jiffies + usecs_to_jiffies(priv->timeout));
> + } else {
> + del_timer_sync(&priv->powerdown_timer);
> + gpiod_set_value_cansleep(priv->enable_gpio, 0);
> + gpiod_set_value_cansleep(priv->flash_gpio, 0);
> + ret = regulator_disable(priv->vin_regulator);
> + if (ret) {
> + dev_err(fled_cdev->led_cdev.dev,
> + "failed to disable regulator: %d\n", ret);
> + return ret;
> + }
> + }
> +
> + priv->enabled = state;
> +
> + return 0;
> +}
> +
> +static int sgm3140_strobe_get(struct led_classdev_flash *fled_cdev, bool *state)
> +{
> + struct sgm3140 *priv = flcdev_to_sgm3140(fled_cdev);
> +
> + *state = timer_pending(&priv->powerdown_timer);
> +
> + return 0;
> +}
> +
> +static int sgm3140_timeout_set(struct led_classdev_flash *fled_cdev,
> + u32 timeout)
> +{
> + struct sgm3140 *priv = flcdev_to_sgm3140(fled_cdev);
> +
> + priv->timeout = timeout;
> +
> + return 0;
> +}
> +
> +static const struct led_flash_ops sgm3140_flash_ops = {
> + .strobe_set = sgm3140_strobe_set,
> + .strobe_get = sgm3140_strobe_get,
> + .timeout_set = sgm3140_timeout_set,
> +};
> +
> +static int sgm3140_brightness_set(struct led_classdev *led_cdev,
> + enum led_brightness brightness)
> +{
> + struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
> + struct sgm3140 *priv = flcdev_to_sgm3140(fled_cdev);
> + bool enable = brightness == LED_ON;
> + int ret;
> +
> + if (priv->enabled == enable)
> + return 0;
> +
> + if (enable) {
> + ret = regulator_enable(priv->vin_regulator);
> + if (ret) {
> + dev_err(led_cdev->dev,
> + "failed to enable regulator: %d\n", ret);
> + return ret;
> + }
> + gpiod_set_value_cansleep(priv->enable_gpio, 1);
> + } else {
> + gpiod_set_value_cansleep(priv->enable_gpio, 0);
> + ret = regulator_disable(priv->vin_regulator);
> + if (ret) {
> + dev_err(led_cdev->dev,
> + "failed to disable regulator: %d\n", ret);
> + return ret;
> + }
> + }
> +
> + priv->enabled = enable;
> +
> + return 0;
> +}
> +
> +static void sgm3140_powerdown_timer(struct timer_list *t)
> +{
> + struct sgm3140 *priv = from_timer(priv, t, powerdown_timer);
> +
> + gpiod_set_value(priv->enable_gpio, 0);
> + gpiod_set_value(priv->flash_gpio, 0);
> + regulator_disable(priv->vin_regulator);
> +
> + priv->enabled = false;
> +}
> +
> +static void sgm3140_init_flash_timeout(struct sgm3140 *priv)
> +{
> + struct led_classdev_flash *fled_cdev = &priv->fled_cdev;
> + struct led_flash_setting *s;
> +
> + /* Init flash timeout setting */
> + s = &fled_cdev->timeout;
> + s->min = 1;
> + s->max = priv->max_timeout;
> + s->step = 1;
> + s->val = FLASH_TIMEOUT_DEFAULT;
> +}
> +
> +#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
> +static void sgm3140_init_v4l2_flash_config(struct sgm3140 *priv,
> + struct v4l2_flash_config *v4l2_sd_cfg)
> +{
> + struct led_classdev *led_cdev = &priv->fled_cdev.led_cdev;
> + struct led_flash_setting *s;
> +
> + strscpy(v4l2_sd_cfg->dev_name, led_cdev->dev->kobj.name,
> + sizeof(v4l2_sd_cfg->dev_name));
> +
> + /* Init flash intensity setting */
> + s = &v4l2_sd_cfg->intensity;
> + s->min = 0;
> + s->max = 1;
> + s->step = 1;
> + s->val = 1;
> +}
> +
> +#else
> +static void sgm3140_init_v4l2_flash_config(struct sgm3140 *priv,
> + struct v4l2_flash_config *v4l2_sd_cfg)
> +{
> +}
> +#endif
> +
> +static int sgm3140_probe(struct platform_device *pdev)
> +{
> + struct sgm3140 *priv;
> + struct led_classdev *led_cdev;
> + struct led_classdev_flash *fled_cdev;
> + struct led_init_data init_data = {};
> + struct device_node *child_node;
> + struct v4l2_flash_config v4l2_sd_cfg = {};
> + int ret;
> +
> + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->flash_gpio = devm_gpiod_get(&pdev->dev, "flash", GPIOD_OUT_LOW);
> + ret = PTR_ERR_OR_ZERO(priv->flash_gpio);
> + if (ret) {
> + if (ret != -EPROBE_DEFER)
> + dev_err(&pdev->dev,
> + "Failed to request flash gpio: %d\n", ret);
> + return ret;
> + }
> +
> + priv->enable_gpio = devm_gpiod_get(&pdev->dev, "enable", GPIOD_OUT_LOW);
> + ret = PTR_ERR_OR_ZERO(priv->enable_gpio);
> + if (ret) {
> + if (ret != -EPROBE_DEFER)
> + dev_err(&pdev->dev,
> + "Failed to request enable gpio: %d\n", ret);
> + return ret;
> + }
> +
> + priv->vin_regulator = devm_regulator_get(&pdev->dev, "vin");
> + ret = PTR_ERR_OR_ZERO(priv->vin_regulator);
> + if (ret) {
> + if (ret != -EPROBE_DEFER)
> + dev_err(&pdev->dev,
> + "Failed to request regulator: %d\n", ret);
> + return ret;
This regulator is optional so why would you return here?  You should
only return if -EPROBE_DEFER.
> + }
> +
> + child_node = of_get_next_available_child(pdev->dev.of_node, NULL);

Maybe this should be the first check before doing all the processing to
make sure that the DT is not

malformed.

> + if (!child_node) {
> + dev_err(&pdev->dev,
> + "No DT child node found for connected LED.\n");
> + return -EINVAL;
> + }
> +
> + ret = of_property_read_u32(child_node, "flash-max-timeout-us",
> + &priv->max_timeout);
> + if (ret) {
> + priv->max_timeout = FLASH_MAX_TIMEOUT_DEFAULT;
> + dev_warn(&pdev->dev,
> + "flash-max-timeout-us DT property missing\n");
> + }
> +
> + /*
> + * Set default timeout to FLASH_DEFAULT_TIMEOUT except if max_timeout
> + * from DT is lower.
> + */
> + priv->timeout = min(priv->max_timeout, FLASH_TIMEOUT_DEFAULT);
> +
> + timer_setup(&priv->powerdown_timer, sgm3140_powerdown_timer, 0);
> +
> + fled_cdev = &priv->fled_cdev;
> + led_cdev = &fled_cdev->led_cdev;
> +
> + fled_cdev->ops = &sgm3140_flash_ops;
> +
> + led_cdev->brightness_set_blocking = sgm3140_brightness_set;
> + led_cdev->max_brightness = LED_ON;
> + led_cdev->flags |= LED_DEV_CAP_FLASH;
> +
> + sgm3140_init_flash_timeout(priv);
> +
> + init_data.fwnode = of_fwnode_handle(child_node);
> +
> + platform_set_drvdata(pdev, priv);
> +
> + /* Register in the LED subsystem */
> + ret = devm_led_classdev_flash_register_ext(&pdev->dev,
> + fled_cdev, &init_data);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to register flash device: %d\n",
> + ret);
> + goto err;
> + }
> +
> + sgm3140_init_v4l2_flash_config(priv, &v4l2_sd_cfg);
> +
> + /* Create V4L2 Flash subdev */
> + priv->v4l2_flash = v4l2_flash_init(&pdev->dev,
> + of_fwnode_handle(child_node),
> + fled_cdev, NULL,
> + &v4l2_sd_cfg);
> + if (IS_ERR(priv->v4l2_flash)) {
> + ret = PTR_ERR(priv->v4l2_flash);
> + goto err;
Not sure why this is here you are not in a for loop and this will fall
through anyway to the err label.
> + }
> +
> +err:
> + of_node_put(child_node);
> + return ret;
> +}
> +
Dan