leds: Add driver for AAT1290 flash LED controller
authorJacek Anaszewski <j.anaszewski@samsung.com>
Thu, 30 Apr 2015 10:34:57 +0000 (03:34 -0700)
committerBryan Wu <cooloney@gmail.com>
Mon, 4 May 2015 18:21:16 +0000 (11:21 -0700)
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>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
drivers/leds/Kconfig
drivers/leds/Makefile
drivers/leds/leds-aat1290.c [new file with mode: 0644]

index 62be033100b6ef0f19c063142d35da434c87851c..dd7834c32608093a107cfcb258714c604ea9cb9c 100644 (file)
@@ -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
index 8bddae6b8ac203b90dd01ca3c305df2123087062..71f7c9accb9424a23dd3e7b118dbf06fbe600106 100644 (file)
@@ -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 (file)
index 0000000..6ea1d54
--- /dev/null
@@ -0,0 +1,451 @@
+/*
+ *     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_config_data {
+       /* maximum LED current in movie mode */
+       u32 max_mm_current;
+       /* maximum LED current in flash mode */
+       u32 max_flash_current;
+       /* maximum flash timeout */
+       u32 max_flash_tm;
+       /* max LED brightness level */
+       enum led_brightness max_brightness;
+};
+
+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;
+       /* movie mode current scale */
+       int *mm_current_scale;
+       /* 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;
+       } else {
+               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);
+       }
+
+       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) {
+               aat1290_set_flash_safety_timer(led, timeout->val);
+               gpiod_direction_output(led->gpio_fl_en, 1);
+       } else {
+               gpiod_direction_output(led->gpio_fl_en, 0);
+               gpiod_direction_output(led->gpio_en_set, 0);
+       }
+
+       /*
+        * 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 aat1290_led_config_data *cfg)
+{
+       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, "led-max-microamp",
+                               &cfg->max_mm_current);
+       /*
+        * led-max-microamp will default to 1/20 of flash-max-microamp
+        * in case it is missing.
+        */
+       if (ret < 0)
+               dev_warn(dev,
+                       "led-max-microamp DT property missing\n");
+
+       ret = of_property_read_u32(child_node, "flash-max-microamp",
+                               &cfg->max_flash_current);
+       if (ret < 0) {
+               dev_err(dev,
+                       "flash-max-microamp DT property missing\n");
+               return ret;
+       }
+
+       ret = of_property_read_u32(child_node, "flash-max-timeout-us",
+                               &cfg->max_flash_tm);
+       if (ret < 0) {
+               dev_err(dev,
+                       "flash-max-timeout-us DT property missing\n");
+               return ret;
+       }
+
+       of_node_put(child_node);
+
+       return ret;
+}
+
+static void aat1290_led_validate_mm_current(struct aat1290_led *led,
+                                       struct aat1290_led_config_data *cfg)
+{
+       int i, b = 0, e = AAT1290_MM_CURRENT_SCALE_SIZE;
+
+       while (e - b > 1) {
+               i = b + (e - b) / 2;
+               if (cfg->max_mm_current < led->mm_current_scale[i])
+                       e = i;
+               else
+                       b = i;
+       }
+
+       cfg->max_mm_current = led->mm_current_scale[b];
+       cfg->max_brightness = b + 1;
+}
+
+int init_mm_current_scale(struct aat1290_led *led,
+                       struct aat1290_led_config_data *cfg)
+{
+       int max_mm_current_percent[] = { 20, 22, 25, 28, 32, 36, 40, 45, 50, 56,
+                                               63, 71, 79, 89, 100 };
+       int i, max_mm_current =
+                       AAT1290_MAX_MM_CURRENT(cfg->max_flash_current);
+
+       led->mm_current_scale = kzalloc(sizeof(max_mm_current_percent),
+                                       GFP_KERNEL);
+       if (!led->mm_current_scale)
+               return -ENOMEM;
+
+       for (i = 0; i < AAT1290_MM_CURRENT_SCALE_SIZE; ++i)
+               led->mm_current_scale[i] = max_mm_current *
+                                         max_mm_current_percent[i] / 100;
+
+       return 0;
+}
+
+static int aat1290_led_get_configuration(struct aat1290_led *led,
+                                       struct aat1290_led_config_data *cfg)
+{
+       int ret;
+
+       ret = aat1290_led_parse_dt(led, cfg);
+       if (ret < 0)
+               return ret;
+       /*
+        * Init non-linear movie mode current scale basing
+        * on the max flash current from led configuration.
+        */
+       ret = init_mm_current_scale(led, cfg);
+       if (ret < 0)
+               return ret;
+
+       aat1290_led_validate_mm_current(led, cfg);
+
+       kfree(led->mm_current_scale);
+
+       return 0;
+}
+
+static void aat1290_init_flash_timeout(struct aat1290_led *led,
+                               struct aat1290_led_config_data *cfg)
+{
+       struct led_classdev_flash *fled_cdev = &led->fled_cdev;
+       struct led_flash_setting *setting;
+
+       /* Init flash timeout setting */
+       setting = &fled_cdev->timeout;
+       setting->min = cfg->max_flash_tm / AAT1290_FLASH_TM_NUM_LEVELS;
+       setting->max = cfg->max_flash_tm;
+       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;
+       struct aat1290_led_config_data led_cfg = {};
+       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_get_configuration(led, &led_cfg);
+       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 = led_cfg.max_brightness;
+       led_cdev->flags |= LED_DEV_CAP_FLASH;
+       INIT_WORK(&led->work_brightness_set, aat1290_brightness_set_work);
+
+       aat1290_init_flash_timeout(led, &led_cfg);
+
+       /* 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",
+               .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");