linux/drivers/leds/leds-lp8788.c
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   1/*
   2 * TI LP8788 MFD - keyled driver
   3 *
   4 * Copyright 2012 Texas Instruments
   5 *
   6 * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License version 2 as
  10 * published by the Free Software Foundation.
  11 *
  12 */
  13
  14#include <linux/module.h>
  15#include <linux/slab.h>
  16#include <linux/err.h>
  17#include <linux/platform_device.h>
  18#include <linux/leds.h>
  19#include <linux/mutex.h>
  20#include <linux/mfd/lp8788.h>
  21#include <linux/mfd/lp8788-isink.h>
  22
  23#define MAX_BRIGHTNESS                  LP8788_ISINK_MAX_PWM
  24#define DEFAULT_LED_NAME                "keyboard-backlight"
  25
  26struct lp8788_led {
  27        struct lp8788 *lp;
  28        struct mutex lock;
  29        struct work_struct work;
  30        struct led_classdev led_dev;
  31        enum lp8788_isink_number isink_num;
  32        enum led_brightness brightness;
  33        int on;
  34};
  35
  36struct lp8788_led_config {
  37        enum lp8788_isink_scale scale;
  38        enum lp8788_isink_number num;
  39        int iout;
  40};
  41
  42static struct lp8788_led_config default_led_config = {
  43        .scale = LP8788_ISINK_SCALE_100mA,
  44        .num   = LP8788_ISINK_3,
  45        .iout  = 0,
  46};
  47
  48static int lp8788_led_init_device(struct lp8788_led *led,
  49                                struct lp8788_led_platform_data *pdata)
  50{
  51        struct lp8788_led_config *cfg = &default_led_config;
  52        u8 addr, mask, val;
  53        int ret;
  54
  55        if (pdata) {
  56                cfg->scale = pdata->scale;
  57                cfg->num = pdata->num;
  58                cfg->iout = pdata->iout_code;
  59        }
  60
  61        led->isink_num = cfg->num;
  62
  63        /* scale configuration */
  64        addr = LP8788_ISINK_CTRL;
  65        mask = 1 << (cfg->num + LP8788_ISINK_SCALE_OFFSET);
  66        val = cfg->scale << (cfg->num + LP8788_ISINK_SCALE_OFFSET);
  67        ret = lp8788_update_bits(led->lp, addr, mask, val);
  68        if (ret)
  69                return ret;
  70
  71        /* current configuration */
  72        addr = lp8788_iout_addr[cfg->num];
  73        mask = lp8788_iout_mask[cfg->num];
  74        val = cfg->iout;
  75
  76        return lp8788_update_bits(led->lp, addr, mask, val);
  77}
  78
  79static void lp8788_led_enable(struct lp8788_led *led,
  80                        enum lp8788_isink_number num, int on)
  81{
  82        u8 mask = 1 << num;
  83        u8 val = on << num;
  84
  85        if (lp8788_update_bits(led->lp, LP8788_ISINK_CTRL, mask, val))
  86                return;
  87
  88        led->on = on;
  89}
  90
  91static void lp8788_led_work(struct work_struct *work)
  92{
  93        struct lp8788_led *led = container_of(work, struct lp8788_led, work);
  94        enum lp8788_isink_number num = led->isink_num;
  95        int enable;
  96        u8 val = led->brightness;
  97
  98        mutex_lock(&led->lock);
  99
 100        switch (num) {
 101        case LP8788_ISINK_1:
 102        case LP8788_ISINK_2:
 103        case LP8788_ISINK_3:
 104                lp8788_write_byte(led->lp, lp8788_pwm_addr[num], val);
 105                break;
 106        default:
 107                mutex_unlock(&led->lock);
 108                return;
 109        }
 110
 111        enable = (val > 0) ? 1 : 0;
 112        if (enable != led->on)
 113                lp8788_led_enable(led, num, enable);
 114
 115        mutex_unlock(&led->lock);
 116}
 117
 118static void lp8788_brightness_set(struct led_classdev *led_cdev,
 119                                enum led_brightness brt_val)
 120{
 121        struct lp8788_led *led =
 122                        container_of(led_cdev, struct lp8788_led, led_dev);
 123
 124        led->brightness = brt_val;
 125        schedule_work(&led->work);
 126}
 127
 128static int lp8788_led_probe(struct platform_device *pdev)
 129{
 130        struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
 131        struct lp8788_led_platform_data *led_pdata;
 132        struct lp8788_led *led;
 133        int ret;
 134
 135        led = devm_kzalloc(lp->dev, sizeof(struct lp8788_led), GFP_KERNEL);
 136        if (!led)
 137                return -ENOMEM;
 138
 139        led->lp = lp;
 140        led->led_dev.max_brightness = MAX_BRIGHTNESS;
 141        led->led_dev.brightness_set = lp8788_brightness_set;
 142
 143        led_pdata = lp->pdata ? lp->pdata->led_pdata : NULL;
 144
 145        if (!led_pdata || !led_pdata->name)
 146                led->led_dev.name = DEFAULT_LED_NAME;
 147        else
 148                led->led_dev.name = led_pdata->name;
 149
 150        mutex_init(&led->lock);
 151        INIT_WORK(&led->work, lp8788_led_work);
 152
 153        platform_set_drvdata(pdev, led);
 154
 155        ret = lp8788_led_init_device(led, led_pdata);
 156        if (ret) {
 157                dev_err(lp->dev, "led init device err: %d\n", ret);
 158                return ret;
 159        }
 160
 161        ret = led_classdev_register(lp->dev, &led->led_dev);
 162        if (ret) {
 163                dev_err(lp->dev, "led register err: %d\n", ret);
 164                return ret;
 165        }
 166
 167        return 0;
 168}
 169
 170static int lp8788_led_remove(struct platform_device *pdev)
 171{
 172        struct lp8788_led *led = platform_get_drvdata(pdev);
 173
 174        led_classdev_unregister(&led->led_dev);
 175        flush_work(&led->work);
 176
 177        return 0;
 178}
 179
 180static struct platform_driver lp8788_led_driver = {
 181        .probe = lp8788_led_probe,
 182        .remove = lp8788_led_remove,
 183        .driver = {
 184                .name = LP8788_DEV_KEYLED,
 185                .owner = THIS_MODULE,
 186        },
 187};
 188module_platform_driver(lp8788_led_driver);
 189
 190MODULE_DESCRIPTION("Texas Instruments LP8788 Keyboard LED Driver");
 191MODULE_AUTHOR("Milo Kim");
 192MODULE_LICENSE("GPL");
 193MODULE_ALIAS("platform:lp8788-keyled");
 194
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