lkml.org 
[lkml]   [2020]   [Mar]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [RFC PATCH] leds: add sgm3140 driver
    From
    Date
    Hi Luca,

    Thank you for the patch.

    On 2/27/20 7:50 PM, Luca Weiss wrote:
    > Add a driver for the SGMICRO SGM3140 Buck/Boost Charge Pump LED driver.
    >
    > This device is controller by two GPIO lines, one for enabling the LED
    > and the second one for switching between torch and flash mode.
    >
    > The device will automatically switch to torch mode after being in flash
    > mode for about 250-300ms, so after that time the driver will turn the
    > LED off again automatically.
    >
    > Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
    > ---
    > Hi, this driver is controllable via sysfs and v4l2 APIs (as documented
    > in Documentation/leds/leds-class-flash.rst).
    >
    > The following is possible:
    >
    > # Torch on
    > echo 1 > /sys/class/leds/white\:flash/brightness
    > # Torch off
    > echo 0 > /sys/class/leds/white\:flash/brightness
    > # Activate flash
    > echo 1 > /sys/class/leds/white\:flash/flash_strobe
    >
    > # Torch on
    > v4l2-ctl -d /dev/video1 -c led_mode=2
    > # Torch off
    > v4l2-ctl -d /dev/video1 -c led_mode=0
    > # Activate flash
    > v4l2-ctl -d /dev/video1 -c strobe=1

    What is /dev/video1 ? Did you register vl42 flash subdev
    in some v4l2 media controller device?

    >
    > Unfortunately the last command (enabling the 'flash' via v4l2 results in
    > the following being printed and nothing happening:
    >
    > VIDIOC_S_EXT_CTRLS: failed: Resource busy
    > strobe: Resource busy
    >
    > Unfortunately I couldn't figure out the reason so I'm hoping to get some
    > guidance for this. iirc it worked at some point but then stopped.

    You have to be in flash mode to strobe i.e. led_mode=1.

    > I will also write dt bindings for the driver once I have "strobe"
    > working.
    >
    > Regards,
    > Luca
    >
    > drivers/leds/Kconfig | 9 ++
    > drivers/leds/Makefile | 1 +
    > drivers/leds/leds-sgm3140.c | 210 ++++++++++++++++++++++++++++++++++++
    > 3 files changed, 220 insertions(+)
    > create mode 100644 drivers/leds/leds-sgm3140.c
    >
    > diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
    > index 4b68520ac251..7c391af8b380 100644
    > --- a/drivers/leds/Kconfig
    > +++ b/drivers/leds/Kconfig
    > @@ -836,6 +836,15 @@ config LEDS_LM36274
    > Say Y to enable the LM36274 LED driver for TI LMU devices.
    > This supports the LED device LM36274.
    >
    > +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. It has supports flash and torch mode.
    > +
    > comment "LED Triggers"
    > source "drivers/leds/trigger/Kconfig"
    >
    > diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
    > index 2da39e896ce8..38d57dd53e4b 100644
    > --- a/drivers/leds/Makefile
    > +++ b/drivers/leds/Makefile
    > @@ -85,6 +85,7 @@ obj-$(CONFIG_LEDS_LM3601X) += leds-lm3601x.o
    > obj-$(CONFIG_LEDS_TI_LMU_COMMON) += leds-ti-lmu-common.o
    > obj-$(CONFIG_LEDS_LM3697) += leds-lm3697.o
    > obj-$(CONFIG_LEDS_LM36274) += leds-lm36274.o
    > +obj-$(CONFIG_LEDS_SGM3140) += leds-sgm3140.o
    >
    > # LED SPI Drivers
    > obj-$(CONFIG_LEDS_CR0014114) += leds-cr0014114.o
    > diff --git a/drivers/leds/leds-sgm3140.c b/drivers/leds/leds-sgm3140.c
    > new file mode 100644
    > index 000000000000..9e91392f0343
    > --- /dev/null
    > +++ b/drivers/leds/leds-sgm3140.c
    > @@ -0,0 +1,210 @@
    > +// 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/platform_device.h>
    > +
    > +#include <media/v4l2-flash-led-class.h>
    > +
    > +#define SGM3140_NAME "sgm3140"
    > +
    > +struct sgm3140 {
    > + struct gpio_desc *flash_gpio;
    > + struct gpio_desc *enable_gpio;
    > +
    > + 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);
    > +}
    > +
    > +int sgm3140_strobe_set(struct led_classdev_flash *fled_cdev, bool state)
    > +{
    > + struct sgm3140 *priv = flcdev_to_sgm3140(fled_cdev);
    > +
    > + if (state) {
    > + gpiod_set_value_cansleep(priv->flash_gpio, 1);
    > + gpiod_set_value_cansleep(priv->enable_gpio, 1);
    > + mod_timer(&priv->powerdown_timer,
    > + jiffies + msecs_to_jiffies(250));
    > + } else {
    > + gpiod_set_value_cansleep(priv->enable_gpio, 0);
    > + gpiod_set_value_cansleep(priv->flash_gpio, 0);
    > + del_timer_sync(&priv->powerdown_timer);
    > + }
    > +
    > + return 0;
    > +}
    > +
    > +struct led_flash_ops sgm3140_flash_ops = {
    > + .strobe_set = sgm3140_strobe_set,
    > +};
    > +
    > +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);
    > +
    > + if (brightness == LED_OFF)
    > + gpiod_set_value_cansleep(priv->enable_gpio, 0);
    > + else
    > + gpiod_set_value_cansleep(priv->enable_gpio, 1);
    > +
    > + return 0;
    > +}
    > +
    > +static void sgm3140_powerdown_timer(struct timer_list *t)
    > +{
    > + struct sgm3140 *priv = from_timer(priv, t, powerdown_timer);
    > +
    > + gpiod_set_value_cansleep(priv->enable_gpio, 0);
    > + gpiod_set_value_cansleep(priv->flash_gpio, 0);

    You could also implement strobe_get op and return from it a flag
    indicating if LED is strobing.

    > +}
    > +
    > +#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;
    > +
    > + strlcpy(v4l2_sd_cfg->dev_name, led_cdev->dev->kobj.name,
    > + sizeof(v4l2_sd_cfg->dev_name));
    > +
    > + 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;

    s/v4l2_sd_cfg;/v4l2_sd_cfg = {};/

    Otherwise it is possible that some controls would be initialized
    to random values.

    > + 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;
    > + }
    > +
    > + child_node = of_get_next_available_child(pdev->dev.of_node, NULL);
    > + if (!child_node) {
    > + dev_err(&pdev->dev, "No DT child node found for connected LED.\n");
    > + return -EINVAL;
    > + }
    > +
    > + 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;
    > +
    > + init_data.fwnode = of_fwnode_handle(child_node);
    > + init_data.devicename = SGM3140_NAME;

    devicename should be skipped in new drivers.

    > +
    > + platform_set_drvdata(pdev, priv);
    > +
    > + /* Register in the LED subsystem */
    > + ret = led_classdev_flash_register_ext(&pdev->dev, fled_cdev, &init_data);

    We already have devm_* prefixed version thereof.

    > + if (ret < 0) {
    > + dev_err(&pdev->dev, "Failed to register flash device: %d\n",
    > + ret);
    > + goto err_flash_register;
    > + }
    > +
    > + 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_v4l2_flash_init;
    > + }
    > +
    > + return 0;
    > +
    > +err_v4l2_flash_init:
    > + led_classdev_flash_unregister(fled_cdev);
    > +err_flash_register:
    > + of_node_put(child_node);

    You need to relase of_node also in case of success.

    > + return ret;
    > +}
    > +
    > +static int sgm3140_remove(struct platform_device *pdev)
    > +{
    > + struct sgm3140 *priv = platform_get_drvdata(pdev);
    > +
    > + del_timer_sync(&priv->powerdown_timer);
    > +
    > + v4l2_flash_release(priv->v4l2_flash);
    > + led_classdev_flash_unregister(&priv->fled_cdev);
    > +
    > + return 0;
    > +}
    > +
    > +static const struct of_device_id sgm3140_dt_match[] = {
    > + { .compatible = "sgmicro,sgm3140" },
    > + { /* sentinel */ }
    > +};
    > +MODULE_DEVICE_TABLE(of, sgm3140_dt_match);
    > +
    > +static struct platform_driver sgm3140_driver = {
    > + .probe = sgm3140_probe,
    > + .remove = sgm3140_remove,
    > + .driver = {
    > + .name = "sgm3140",
    > + .of_match_table = sgm3140_dt_match,
    > + },
    > +};
    > +
    > +module_platform_driver(sgm3140_driver);
    > +
    > +MODULE_AUTHOR("Luca Weiss <luca@z3ntu.xyz>");
    > +MODULE_DESCRIPTION("SG Micro SGM3140 charge pump led driver");
    > +MODULE_LICENSE("GPL v2");
    >

    --
    Best regards,
    Jacek Anaszewski

    \
     
     \ /
      Last update: 2020-03-05 22:09    [W:3.076 / U:0.600 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site