[PATCH v2 05/11] leds: Add driver for AAT1290 flash LED controller

Jacek Anaszewski
2015-03-27T13:49:39Z

This patch adds a driver for the 1.5A Step-Up Current Regulator
for Flash LEDs. The device is programmed through a Skyworks proprietary
AS2Cwire serial digital interface.

Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Bryan Wu <cooloney@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
---
drivers/leds/Kconfig | 8 +
drivers/leds/Makefile | 1 +
drivers/leds/leds-aat1290.c | 372 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 381 insertions(+)
create mode 100644 drivers/leds/leds-aat1290.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index f9fbeb5..c3b5b027 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -42,6 +42,14 @@ config LEDS_88PM860X
This option enables support for on-chip LED drivers found on Marvell
Semiconductor 88PM8606 PMIC.

+config LEDS_AAT1290
+ tristate "LED support for the AAT1290"
+ depends on LEDS_CLASS_FLASH
+ depends on GPIOLIB
+ depends on OF
+ help
+ This option enables support for the LEDs on the AAT1290.
+
config LEDS_LM3530
tristate "LCD Backlight driver for LM3530"
depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 9413fdb..0b3fd0e 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_LEDS_TRIGGERS) += led-triggers.o

# LED Platform Drivers
obj-$(CONFIG_LEDS_88PM860X) += leds-88pm860x.o
+obj-$(CONFIG_LEDS_AAT1290) += leds-aat1290.o
obj-$(CONFIG_LEDS_BD2802) += leds-bd2802.o
obj-$(CONFIG_LEDS_LOCOMO) += leds-locomo.o
obj-$(CONFIG_LEDS_LM3530) += leds-lm3530.o
diff --git a/drivers/leds/leds-aat1290.c b/drivers/leds/leds-aat1290.c
new file mode 100644
index 0000000..acfae35
--- /dev/null
+++ b/drivers/leds/leds-aat1290.c
@@ -0,0 +1,372 @@
+/*
+ * LED Flash class driver for the AAT1290
+ * 1.5A Step-Up Current Regulator for Flash LEDs
+ *
+ * Copyright (C) 2015, Samsung Electronics Co., Ltd.
+ * Author: Jacek Anaszewski <j.anaszewski@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/led-class-flash.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+#define AAT1290_MOVIE_MODE_CURRENT_ADDR 17
+#define AAT1290_MAX_MM_CURR_PERCENT_0 16
+#define AAT1290_MAX_MM_CURR_PERCENT_100 1
+
+#define AAT1290_FLASH_SAFETY_TIMER_ADDR 18
+
+#define AAT1290_MOVIE_MODE_CONFIG_ADDR 19
+#define AAT1290_MOVIE_MODE_OFF 1
+#define AAT1290_MOVIE_MODE_ON 3
+
+#define AAT1290_MM_CURRENT_RATIO_ADDR 20
+#define AAT1290_MM_TO_FL_1_92 1
+
+#define AAT1290_MM_TO_FL_RATIO 1000 / 1920
+#define AAT1290_MAX_MM_CURRENT(fl_max) (fl_max * AAT1290_MM_TO_FL_RATIO)
+
+#define AAT1290_LATCH_TIME_MIN_US 500
+#define AAT1290_LATCH_TIME_MAX_US 1000
+#define AAT1290_EN_SET_TICK_TIME_US 1
+#define AAT1290_FLEN_OFF_DELAY_TIME_US 10
+#define AAT1290_FLASH_TM_NUM_LEVELS 16
+#define AAT1290_MM_CURRENT_SCALE_SIZE 15
+
+
+struct aat1290_led {
+ /* platform device data */
+ struct platform_device *pdev;
+ /* secures access to the device */
+ struct mutex lock;
+
+ /* corresponding LED Flash class device */
+ struct led_classdev_flash fled_cdev;
+
+ /* FLEN pin */
+ struct gpio_desc *gpio_fl_en;
+ /* EN|SET pin */
+ struct gpio_desc *gpio_en_set;
+
+ /* maximum flash timeout */
+ u32 max_flash_tm;
+ /* maximum LED current in flash mode */
+ u32 max_flash_current;
+ /* device mode */
+ bool movie_mode;
+
+ /* brightness cache */
+ unsigned int torch_brightness;
+ /* assures led-triggers compatibility */
+ struct work_struct work_brightness_set;
+};
+
+static struct aat1290_led *fled_cdev_to_led(
+ struct led_classdev_flash *fled_cdev)
+{
+ return container_of(fled_cdev, struct aat1290_led, fled_cdev);
+}
+
+static void aat1290_as2cwire_write(struct aat1290_led *led, int addr, int value)
+{
+ int i;
+
+ gpiod_direction_output(led->gpio_fl_en, 0);
+ gpiod_direction_output(led->gpio_en_set, 0);
+
+ udelay(AAT1290_FLEN_OFF_DELAY_TIME_US);
+
+ /* write address */
+ for (i = 0; i < addr; ++i) {
+ udelay(AAT1290_EN_SET_TICK_TIME_US);
+ gpiod_direction_output(led->gpio_en_set, 0);
+ udelay(AAT1290_EN_SET_TICK_TIME_US);
+ gpiod_direction_output(led->gpio_en_set, 1);
+ }
+
+ usleep_range(AAT1290_LATCH_TIME_MIN_US, AAT1290_LATCH_TIME_MAX_US);
+
+ /* write data */
+ for (i = 0; i < value; ++i) {
+ udelay(AAT1290_EN_SET_TICK_TIME_US);
+ gpiod_direction_output(led->gpio_en_set, 0);
+ udelay(AAT1290_EN_SET_TICK_TIME_US);
+ gpiod_direction_output(led->gpio_en_set, 1);
+ }
+
+ usleep_range(AAT1290_LATCH_TIME_MIN_US, AAT1290_LATCH_TIME_MAX_US);
+}
+
+static void aat1290_set_flash_safety_timer(struct aat1290_led *led,
+ unsigned int micro_sec)
+{
+ struct led_classdev_flash *fled_cdev = &led->fled_cdev;
+ struct led_flash_setting *flash_tm = &fled_cdev->timeout;
+ int flash_tm_reg = AAT1290_FLASH_TM_NUM_LEVELS -
+ (micro_sec / flash_tm->step) + 1;
+
+ aat1290_as2cwire_write(led, AAT1290_FLASH_SAFETY_TIMER_ADDR,
+ flash_tm_reg);
+}
+
+static void aat1290_brightness_set(struct aat1290_led *led,
+ enum led_brightness brightness)
+{
+ mutex_lock(&led->lock);
+
+ if (brightness == 0) {
+ gpiod_direction_output(led->gpio_fl_en, 0);
+ gpiod_direction_output(led->gpio_en_set, 0);
+ led->movie_mode = false;
+ goto unlock;
+ }
+
+ if (!led->movie_mode) {
+ aat1290_as2cwire_write(led, AAT1290_MM_CURRENT_RATIO_ADDR,
+ AAT1290_MM_TO_FL_1_92);
+ led->movie_mode = true;
+ }
+
+ aat1290_as2cwire_write(led, AAT1290_MOVIE_MODE_CURRENT_ADDR,
+ AAT1290_MAX_MM_CURR_PERCENT_0 - brightness);
+ aat1290_as2cwire_write(led, AAT1290_MOVIE_MODE_CONFIG_ADDR,
+ AAT1290_MOVIE_MODE_ON);
+unlock:
+ mutex_unlock(&led->lock);
+}
+
+/* LED subsystem callbacks */
+
+static void aat1290_brightness_set_work(struct work_struct *work)
+{
+ struct aat1290_led *led =
+ container_of(work, struct aat1290_led, work_brightness_set);
+
+ aat1290_brightness_set(led, led->torch_brightness);
+}
+
+static void aat1290_led_brightness_set(struct led_classdev *led_cdev,
+ enum led_brightness brightness)
+{
+ struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
+ struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
+
+ led->torch_brightness = brightness;
+ schedule_work(&led->work_brightness_set);
+}
+
+static int aat1290_led_brightness_set_sync(struct led_classdev *led_cdev,
+ enum led_brightness brightness)
+{
+ struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
+ struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
+
+ aat1290_brightness_set(led, brightness);
+
+ return 0;
+}
+
+static int aat1290_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
+ bool state)
+
+{
+ struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
+ struct led_classdev *led_cdev = &fled_cdev->led_cdev;
+ struct led_flash_setting *timeout = &fled_cdev->timeout;
+
+ mutex_lock(&led->lock);
+
+ if (state == 0) {
+ gpiod_direction_output(led->gpio_fl_en, 0);
+ gpiod_direction_output(led->gpio_en_set, 0);
+ goto done;
+ }
+
+ aat1290_set_flash_safety_timer(led, timeout->val);
+
+ gpiod_direction_output(led->gpio_fl_en, 1);
+
+done:
+ /*
+ * To reenter movie mode after a flash event the part must be cycled
+ * off and back on to reset the movie mode and reprogrammed via the
+ * AS2Cwire. Therefore the brightness and movie_mode properties needs
+ * to be updated here to reflect the actual state.
+ */
+ led_cdev->brightness = 0;
+ led->movie_mode = false;
+
+ mutex_unlock(&led->lock);
+
+ return 0;
+}
+
+static int aat1290_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
+ u32 timeout)
+{
+ /*
+ * Don't do anything - flash timeout is cached in the led-class-flash
+ * core and will be applied in the strobe_set op, as writing the
+ * safety timer register spuriously turns the torch mode on.
+ */
+
+ return 0;
+}
+
+static int aat1290_led_parse_dt(struct aat1290_led *led)
+{
+ struct led_classdev *led_cdev = &led->fled_cdev.led_cdev;
+ struct device *dev = &led->pdev->dev;
+ struct device_node *child_node;
+ int ret = 0;
+
+ led->gpio_fl_en = devm_gpiod_get(dev, "flen");
+ if (IS_ERR(led->gpio_fl_en)) {
+ ret = PTR_ERR(led->gpio_fl_en);
+ dev_err(dev, "Unable to claim gpio \"flen\".\n");
+ return ret;
+ }
+
+ led->gpio_en_set = devm_gpiod_get(dev, "enset");
+ if (IS_ERR(led->gpio_en_set)) {
+ ret = PTR_ERR(led->gpio_en_set);
+ dev_err(dev, "Unable to claim gpio \"enset\".\n");
+ return ret;
+ }
+
+ child_node = of_get_next_available_child(dev->of_node, NULL);
+ if (!child_node) {
+ dev_err(dev, "No DT child node found for connected LED.\n");
+ return -EINVAL;
+ }
+
+ led_cdev->name = of_get_property(child_node, "label", NULL) ? :
+ child_node->name;
+
+ ret = of_property_read_u32(child_node, "flash-max-microamp",
+ &led->max_flash_current);
+ if (ret < 0) {
+ dev_err(dev,
+ "Error reading \"flash-max-microamp\" DT property\n");
+ return ret;
+ }
+
+ ret = of_property_read_u32(child_node, "flash-timeout-us",
+ &led->max_flash_tm);
+ if (ret < 0) {
+ dev_err(dev,
+ "Error reading \"flash-timeout-us\" DT property\n");
+ return ret;
+ }
+
+ return ret;
+}
+
+static void aat1290_init_flash_timeout(struct aat1290_led *led)
+{
+ struct led_classdev_flash *fled_cdev = &led->fled_cdev;
+ struct led_flash_setting *setting;
+
+ /* Init flash timeout setting */
+ setting = &fled_cdev->timeout;
+ setting->min = led->max_flash_tm / AAT1290_FLASH_TM_NUM_LEVELS;
+ setting->max = setting->min * AAT1290_FLASH_TM_NUM_LEVELS;
+ setting->step = setting->min;
+ setting->val = setting->max;
+}
+
+static const struct led_flash_ops flash_ops = {
+ .strobe_set = aat1290_led_flash_strobe_set,
+ .timeout_set = aat1290_led_flash_timeout_set,
+};
+
+static int aat1290_led_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct aat1290_led *led;
+ struct led_classdev *led_cdev;
+ struct led_classdev_flash *fled_cdev;
+ int ret;
+
+ led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
+ if (!led)
+ return -ENOMEM;
+
+ led->pdev = pdev;
+ platform_set_drvdata(pdev, led);
+
+ fled_cdev = &led->fled_cdev;
+ fled_cdev->ops = &flash_ops;
+ led_cdev = &fled_cdev->led_cdev;
+
+ ret = aat1290_led_parse_dt(led);
+ if (ret < 0)
+ return ret;
+
+ mutex_init(&led->lock);
+
+ /* Initialize LED Flash class device */
+ led_cdev->brightness_set = aat1290_led_brightness_set;
+ led_cdev->brightness_set_sync = aat1290_led_brightness_set_sync;
+ led_cdev->max_brightness = AAT1290_MM_CURRENT_SCALE_SIZE;
+ led_cdev->flags |= LED_DEV_CAP_FLASH;
+ INIT_WORK(&led->work_brightness_set, aat1290_brightness_set_work);
+
+ aat1290_init_flash_timeout(led);
+
+ /* Register LED Flash class device */
+ ret = led_classdev_flash_register(&pdev->dev, fled_cdev);
+ if (ret < 0)
+ goto err_flash_register;
+
+ return 0;
+
+err_flash_register:
+ mutex_destroy(&led->lock);
+
+ return ret;
+}
+
+static int aat1290_led_remove(struct platform_device *pdev)
+{
+ struct aat1290_led *led = platform_get_drvdata(pdev);
+
+ led_classdev_flash_unregister(&led->fled_cdev);
+ cancel_work_sync(&led->work_brightness_set);
+
+ mutex_destroy(&led->lock);
+
+ return 0;
+}
+
+static const struct of_device_id aat1290_led_dt_match[] = {
+ { .compatible = "skyworks,aat1290" },
+ {},
+};
+
+static struct platform_driver aat1290_led_driver = {
+ .probe = aat1290_led_probe,
+ .remove = aat1290_led_remove,
+ .driver = {
+ .name = "aat1290",
+ .owner = THIS_MODULE,
+ .of_match_table = aat1290_led_dt_match,
+ },
+};
+
+module_platform_driver(aat1290_led_driver);
+
+MODULE_AUTHOR("Jacek Anaszewski <j.anaszewski@samsung.com>");
+MODULE_DESCRIPTION("Skyworks Current Regulator for Flash LEDs");
+MODULE_LICENSE("GPL v2");
--
1.7.9.5