linux/drivers/leds/leds-asic3.c
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   1/*
   2 *  Copyright (C) 2011 Paul Parsons <lost.distance@yahoo.com>
   3 *
   4 *  This program is free software; you can redistribute it and/or modify
   5 *  it under the terms of the GNU General Public License version 2 as
   6 *  published by the Free Software Foundation.
   7 */
   8
   9#include <linux/kernel.h>
  10#include <linux/platform_device.h>
  11#include <linux/leds.h>
  12#include <linux/slab.h>
  13
  14#include <linux/mfd/asic3.h>
  15#include <linux/mfd/core.h>
  16#include <linux/module.h>
  17
  18/*
  19 *      The HTC ASIC3 LED GPIOs are inputs, not outputs.
  20 *      Hence we turn the LEDs on/off via the TimeBase register.
  21 */
  22
  23/*
  24 *      When TimeBase is 4 the clock resolution is about 32Hz.
  25 *      This driver supports hardware blinking with an on+off
  26 *      period from 62ms (2 clocks) to 125s (4000 clocks).
  27 */
  28#define MS_TO_CLK(ms)   DIV_ROUND_CLOSEST(((ms)*1024), 32000)
  29#define CLK_TO_MS(clk)  (((clk)*32000)/1024)
  30#define MAX_CLK         4000            /* Fits into 12-bit Time registers */
  31#define MAX_MS          CLK_TO_MS(MAX_CLK)
  32
  33static const unsigned int led_n_base[ASIC3_NUM_LEDS] = {
  34        [0] = ASIC3_LED_0_Base,
  35        [1] = ASIC3_LED_1_Base,
  36        [2] = ASIC3_LED_2_Base,
  37};
  38
  39static void brightness_set(struct led_classdev *cdev,
  40        enum led_brightness value)
  41{
  42        struct platform_device *pdev = to_platform_device(cdev->dev->parent);
  43        const struct mfd_cell *cell = mfd_get_cell(pdev);
  44        struct asic3 *asic = dev_get_drvdata(pdev->dev.parent);
  45        u32 timebase;
  46        unsigned int base;
  47
  48        timebase = (value == LED_OFF) ? 0 : (LED_EN|0x4);
  49
  50        base = led_n_base[cell->id];
  51        asic3_write_register(asic, (base + ASIC3_LED_PeriodTime), 32);
  52        asic3_write_register(asic, (base + ASIC3_LED_DutyTime), 32);
  53        asic3_write_register(asic, (base + ASIC3_LED_AutoStopCount), 0);
  54        asic3_write_register(asic, (base + ASIC3_LED_TimeBase), timebase);
  55}
  56
  57static int blink_set(struct led_classdev *cdev,
  58        unsigned long *delay_on,
  59        unsigned long *delay_off)
  60{
  61        struct platform_device *pdev = to_platform_device(cdev->dev->parent);
  62        const struct mfd_cell *cell = mfd_get_cell(pdev);
  63        struct asic3 *asic = dev_get_drvdata(pdev->dev.parent);
  64        u32 on;
  65        u32 off;
  66        unsigned int base;
  67
  68        if (*delay_on > MAX_MS || *delay_off > MAX_MS)
  69                return -EINVAL;
  70
  71        if (*delay_on == 0 && *delay_off == 0) {
  72                /* If both are zero then a sensible default should be chosen */
  73                on = MS_TO_CLK(500);
  74                off = MS_TO_CLK(500);
  75        } else {
  76                on = MS_TO_CLK(*delay_on);
  77                off = MS_TO_CLK(*delay_off);
  78                if ((on + off) > MAX_CLK)
  79                        return -EINVAL;
  80        }
  81
  82        base = led_n_base[cell->id];
  83        asic3_write_register(asic, (base + ASIC3_LED_PeriodTime), (on + off));
  84        asic3_write_register(asic, (base + ASIC3_LED_DutyTime), on);
  85        asic3_write_register(asic, (base + ASIC3_LED_AutoStopCount), 0);
  86        asic3_write_register(asic, (base + ASIC3_LED_TimeBase), (LED_EN|0x4));
  87
  88        *delay_on = CLK_TO_MS(on);
  89        *delay_off = CLK_TO_MS(off);
  90
  91        return 0;
  92}
  93
  94static int asic3_led_probe(struct platform_device *pdev)
  95{
  96        struct asic3_led *led = dev_get_platdata(&pdev->dev);
  97        int ret;
  98
  99        ret = mfd_cell_enable(pdev);
 100        if (ret < 0)
 101                return ret;
 102
 103        led->cdev = devm_kzalloc(&pdev->dev, sizeof(struct led_classdev),
 104                                GFP_KERNEL);
 105        if (!led->cdev) {
 106                ret = -ENOMEM;
 107                goto out;
 108        }
 109
 110        led->cdev->name = led->name;
 111        led->cdev->flags = LED_CORE_SUSPENDRESUME;
 112        led->cdev->brightness_set = brightness_set;
 113        led->cdev->blink_set = blink_set;
 114        led->cdev->default_trigger = led->default_trigger;
 115
 116        ret = led_classdev_register(&pdev->dev, led->cdev);
 117        if (ret < 0)
 118                goto out;
 119
 120        return 0;
 121
 122out:
 123        (void) mfd_cell_disable(pdev);
 124        return ret;
 125}
 126
 127static int asic3_led_remove(struct platform_device *pdev)
 128{
 129        struct asic3_led *led = dev_get_platdata(&pdev->dev);
 130
 131        led_classdev_unregister(led->cdev);
 132
 133        return mfd_cell_disable(pdev);
 134}
 135
 136#ifdef CONFIG_PM_SLEEP
 137static int asic3_led_suspend(struct device *dev)
 138{
 139        struct platform_device *pdev = to_platform_device(dev);
 140        const struct mfd_cell *cell = mfd_get_cell(pdev);
 141        int ret;
 142
 143        ret = 0;
 144        if (cell->suspend)
 145                ret = (*cell->suspend)(pdev);
 146
 147        return ret;
 148}
 149
 150static int asic3_led_resume(struct device *dev)
 151{
 152        struct platform_device *pdev = to_platform_device(dev);
 153        const struct mfd_cell *cell = mfd_get_cell(pdev);
 154        int ret;
 155
 156        ret = 0;
 157        if (cell->resume)
 158                ret = (*cell->resume)(pdev);
 159
 160        return ret;
 161}
 162#endif
 163
 164static SIMPLE_DEV_PM_OPS(asic3_led_pm_ops, asic3_led_suspend, asic3_led_resume);
 165
 166static struct platform_driver asic3_led_driver = {
 167        .probe          = asic3_led_probe,
 168        .remove         = asic3_led_remove,
 169        .driver         = {
 170                .name   = "leds-asic3",
 171                .pm     = &asic3_led_pm_ops,
 172        },
 173};
 174
 175module_platform_driver(asic3_led_driver);
 176
 177MODULE_AUTHOR("Paul Parsons <lost.distance@yahoo.com>");
 178MODULE_DESCRIPTION("HTC ASIC3 LED driver");
 179MODULE_LICENSE("GPL");
 180MODULE_ALIAS("platform:leds-asic3");
 181