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8aa41952ef
fwnode_get_next_available_child_node() bumps a reference counting of
a returned variable. We have to balance it whenever we return to
the caller.
Fixes: e1c6edcbea
("leds: rt8515: Add Richtek RT8515 LED driver")
Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
399 lines
10 KiB
C
399 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* LED driver for Richtek RT8515 flash/torch white LEDs
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* found on some Samsung mobile phones.
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*
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* This is a 1.5A Boost dual channel driver produced around 2011.
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*
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* The component lacks a datasheet, but in the schematic picture
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* from the LG P970 service manual you can see the connections
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* from the RT8515 to the LED, with two resistors connected
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* from the pins "RFS" and "RTS" to ground.
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*
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* On the LG P970:
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* RFS (resistance flash setting?) is 20 kOhm
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* RTS (resistance torch setting?) is 39 kOhm
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*
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* Some sleuthing finds us the RT9387A which we have a datasheet for:
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* https://static5.arrow.com/pdfs/2014/7/27/8/21/12/794/rtt_/manual/94download_ds.jspprt9387a.jspprt9387a.pdf
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* This apparently works the same way so in theory this driver
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* should cover RT9387A as well. This has not been tested, please
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* update the compatibles if you add RT9387A support.
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*
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* Linus Walleij <linus.walleij@linaro.org>
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*/
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/gpio/consumer.h>
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#include <linux/led-class-flash.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/property.h>
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#include <linux/regulator/consumer.h>
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#include <media/v4l2-flash-led-class.h>
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/* We can provide 15-700 mA out to the LED */
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#define RT8515_MIN_IOUT_MA 15
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#define RT8515_MAX_IOUT_MA 700
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/* The maximum intensity is 1-16 for flash and 1-100 for torch */
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#define RT8515_FLASH_MAX 16
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#define RT8515_TORCH_MAX 100
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#define RT8515_TIMEOUT_US 250000U
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#define RT8515_MAX_TIMEOUT_US 300000U
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struct rt8515 {
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struct led_classdev_flash fled;
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struct device *dev;
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struct v4l2_flash *v4l2_flash;
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struct mutex lock;
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struct regulator *reg;
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struct gpio_desc *enable_torch;
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struct gpio_desc *enable_flash;
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struct timer_list powerdown_timer;
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u32 max_timeout; /* Flash max timeout */
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int flash_max_intensity;
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int torch_max_intensity;
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};
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static struct rt8515 *to_rt8515(struct led_classdev_flash *fled)
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{
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return container_of(fled, struct rt8515, fled);
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}
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static void rt8515_gpio_led_off(struct rt8515 *rt)
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{
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gpiod_set_value(rt->enable_flash, 0);
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gpiod_set_value(rt->enable_torch, 0);
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}
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static void rt8515_gpio_brightness_commit(struct gpio_desc *gpiod,
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int brightness)
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{
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int i;
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/*
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* Toggling a GPIO line with a small delay increases the
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* brightness one step at a time.
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*/
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for (i = 0; i < brightness; i++) {
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gpiod_set_value(gpiod, 0);
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udelay(1);
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gpiod_set_value(gpiod, 1);
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udelay(1);
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}
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}
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/* This is setting the torch light level */
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static int rt8515_led_brightness_set(struct led_classdev *led,
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enum led_brightness brightness)
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{
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struct led_classdev_flash *fled = lcdev_to_flcdev(led);
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struct rt8515 *rt = to_rt8515(fled);
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mutex_lock(&rt->lock);
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if (brightness == LED_OFF) {
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/* Off */
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rt8515_gpio_led_off(rt);
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} else if (brightness < RT8515_TORCH_MAX) {
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/* Step it up to movie mode brightness using the flash pin */
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rt8515_gpio_brightness_commit(rt->enable_torch, brightness);
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} else {
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/* Max torch brightness requested */
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gpiod_set_value(rt->enable_torch, 1);
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}
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mutex_unlock(&rt->lock);
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return 0;
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}
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static int rt8515_led_flash_strobe_set(struct led_classdev_flash *fled,
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bool state)
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{
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struct rt8515 *rt = to_rt8515(fled);
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struct led_flash_setting *timeout = &fled->timeout;
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int brightness = rt->flash_max_intensity;
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mutex_lock(&rt->lock);
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if (state) {
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/* Enable LED flash mode and set brightness */
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rt8515_gpio_brightness_commit(rt->enable_flash, brightness);
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/* Set timeout */
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mod_timer(&rt->powerdown_timer,
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jiffies + usecs_to_jiffies(timeout->val));
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} else {
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del_timer_sync(&rt->powerdown_timer);
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/* Turn the LED off */
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rt8515_gpio_led_off(rt);
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}
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fled->led_cdev.brightness = LED_OFF;
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/* After this the torch LED will be disabled */
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mutex_unlock(&rt->lock);
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return 0;
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}
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static int rt8515_led_flash_strobe_get(struct led_classdev_flash *fled,
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bool *state)
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{
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struct rt8515 *rt = to_rt8515(fled);
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*state = timer_pending(&rt->powerdown_timer);
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return 0;
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}
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static int rt8515_led_flash_timeout_set(struct led_classdev_flash *fled,
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u32 timeout)
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{
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/* The timeout is stored in the led-class-flash core */
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return 0;
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}
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static const struct led_flash_ops rt8515_flash_ops = {
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.strobe_set = rt8515_led_flash_strobe_set,
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.strobe_get = rt8515_led_flash_strobe_get,
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.timeout_set = rt8515_led_flash_timeout_set,
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};
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static void rt8515_powerdown_timer(struct timer_list *t)
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{
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struct rt8515 *rt = from_timer(rt, t, powerdown_timer);
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/* Turn the LED off */
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rt8515_gpio_led_off(rt);
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}
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static void rt8515_init_flash_timeout(struct rt8515 *rt)
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{
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struct led_classdev_flash *fled = &rt->fled;
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struct led_flash_setting *s;
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/* Init flash timeout setting */
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s = &fled->timeout;
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s->min = 1;
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s->max = rt->max_timeout;
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s->step = 1;
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/*
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* Set default timeout to RT8515_TIMEOUT_US except if
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* max_timeout from DT is lower.
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*/
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s->val = min(rt->max_timeout, RT8515_TIMEOUT_US);
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}
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#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
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/* Configure the V2L2 flash subdevice */
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static void rt8515_init_v4l2_flash_config(struct rt8515 *rt,
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struct v4l2_flash_config *v4l2_sd_cfg)
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{
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struct led_classdev *led = &rt->fled.led_cdev;
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struct led_flash_setting *s;
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strscpy(v4l2_sd_cfg->dev_name, led->dev->kobj.name,
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sizeof(v4l2_sd_cfg->dev_name));
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/*
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* Init flash intensity setting: this is a linear scale
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* capped from the device tree max intensity setting
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* 1..flash_max_intensity
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*/
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s = &v4l2_sd_cfg->intensity;
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s->min = 1;
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s->max = rt->flash_max_intensity;
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s->step = 1;
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s->val = s->max;
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}
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static void rt8515_v4l2_flash_release(struct rt8515 *rt)
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{
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v4l2_flash_release(rt->v4l2_flash);
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}
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#else
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static void rt8515_init_v4l2_flash_config(struct rt8515 *rt,
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struct v4l2_flash_config *v4l2_sd_cfg)
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{
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}
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static void rt8515_v4l2_flash_release(struct rt8515 *rt)
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{
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}
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#endif
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static void rt8515_determine_max_intensity(struct rt8515 *rt,
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struct fwnode_handle *led,
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const char *resistance,
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const char *max_ua_prop, int hw_max,
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int *max_intensity_setting)
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{
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u32 res = 0; /* Can't be 0 so 0 is undefined */
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u32 ua;
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u32 max_ma;
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int max_intensity;
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int ret;
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fwnode_property_read_u32(rt->dev->fwnode, resistance, &res);
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ret = fwnode_property_read_u32(led, max_ua_prop, &ua);
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/* Missing info in DT, OK go with hardware maxima */
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if (ret || res == 0) {
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dev_err(rt->dev,
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"either %s or %s missing from DT, using HW max\n",
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resistance, max_ua_prop);
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max_ma = RT8515_MAX_IOUT_MA;
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max_intensity = hw_max;
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goto out_assign_max;
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}
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/*
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* Formula from the datasheet, this is the maximum current
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* defined by the hardware.
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*/
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max_ma = (5500 * 1000) / res;
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/*
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* Calculate max intensity (linear scaling)
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* Formula is ((ua / 1000) / max_ma) * 100, then simplified
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*/
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max_intensity = (ua / 10) / max_ma;
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dev_info(rt->dev,
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"current restricted from %u to %u mA, max intensity %d/100\n",
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max_ma, (ua / 1000), max_intensity);
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out_assign_max:
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dev_info(rt->dev, "max intensity %d/%d = %d mA\n",
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max_intensity, hw_max, max_ma);
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*max_intensity_setting = max_intensity;
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}
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static int rt8515_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct fwnode_handle *child;
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struct rt8515 *rt;
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struct led_classdev *led;
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struct led_classdev_flash *fled;
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struct led_init_data init_data = {};
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struct v4l2_flash_config v4l2_sd_cfg = {};
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int ret;
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rt = devm_kzalloc(dev, sizeof(*rt), GFP_KERNEL);
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if (!rt)
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return -ENOMEM;
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rt->dev = dev;
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fled = &rt->fled;
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led = &fled->led_cdev;
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/* ENF - Enable Flash line */
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rt->enable_flash = devm_gpiod_get(dev, "enf", GPIOD_OUT_LOW);
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if (IS_ERR(rt->enable_flash))
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return dev_err_probe(dev, PTR_ERR(rt->enable_flash),
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"cannot get ENF (enable flash) GPIO\n");
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/* ENT - Enable Torch line */
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rt->enable_torch = devm_gpiod_get(dev, "ent", GPIOD_OUT_LOW);
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if (IS_ERR(rt->enable_torch))
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return dev_err_probe(dev, PTR_ERR(rt->enable_torch),
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"cannot get ENT (enable torch) GPIO\n");
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child = fwnode_get_next_available_child_node(dev->fwnode, NULL);
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if (!child) {
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dev_err(dev,
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"No fwnode child node found for connected LED.\n");
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return -EINVAL;
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}
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init_data.fwnode = child;
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rt8515_determine_max_intensity(rt, child, "richtek,rfs-ohms",
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"flash-max-microamp",
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RT8515_FLASH_MAX,
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&rt->flash_max_intensity);
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rt8515_determine_max_intensity(rt, child, "richtek,rts-ohms",
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"led-max-microamp",
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RT8515_TORCH_MAX,
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&rt->torch_max_intensity);
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ret = fwnode_property_read_u32(child, "flash-max-timeout-us",
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&rt->max_timeout);
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if (ret) {
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rt->max_timeout = RT8515_MAX_TIMEOUT_US;
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dev_warn(dev,
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"flash-max-timeout-us property missing\n");
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}
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timer_setup(&rt->powerdown_timer, rt8515_powerdown_timer, 0);
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rt8515_init_flash_timeout(rt);
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fled->ops = &rt8515_flash_ops;
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led->max_brightness = rt->torch_max_intensity;
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led->brightness_set_blocking = rt8515_led_brightness_set;
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led->flags |= LED_CORE_SUSPENDRESUME | LED_DEV_CAP_FLASH;
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mutex_init(&rt->lock);
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platform_set_drvdata(pdev, rt);
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ret = devm_led_classdev_flash_register_ext(dev, fled, &init_data);
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if (ret) {
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fwnode_handle_put(child);
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mutex_destroy(&rt->lock);
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dev_err(dev, "can't register LED %s\n", led->name);
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return ret;
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}
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rt8515_init_v4l2_flash_config(rt, &v4l2_sd_cfg);
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/* Create a V4L2 Flash device if V4L2 flash is enabled */
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rt->v4l2_flash = v4l2_flash_init(dev, child, fled, NULL, &v4l2_sd_cfg);
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if (IS_ERR(rt->v4l2_flash)) {
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ret = PTR_ERR(rt->v4l2_flash);
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dev_err(dev, "failed to register V4L2 flash device (%d)\n",
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ret);
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/*
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* Continue without the V4L2 flash
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* (we still have the classdev)
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*/
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}
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fwnode_handle_put(child);
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return 0;
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}
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static int rt8515_remove(struct platform_device *pdev)
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{
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struct rt8515 *rt = platform_get_drvdata(pdev);
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rt8515_v4l2_flash_release(rt);
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del_timer_sync(&rt->powerdown_timer);
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mutex_destroy(&rt->lock);
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return 0;
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}
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static const struct of_device_id rt8515_match[] = {
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{ .compatible = "richtek,rt8515", },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, rt8515_match);
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static struct platform_driver rt8515_driver = {
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.driver = {
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.name = "rt8515",
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.of_match_table = rt8515_match,
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},
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.probe = rt8515_probe,
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.remove = rt8515_remove,
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};
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module_platform_driver(rt8515_driver);
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MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
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MODULE_DESCRIPTION("Richtek RT8515 LED driver");
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MODULE_LICENSE("GPL");
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