drivers/leds/leds-asic3.c

   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/init.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/leds.h>
  13 #include <linux/slab.h>
  14
  15 #include <linux/mfd/asic3.h>
  16 #include <linux/mfd/core.h>
  17 #include <linux/module.h>
  18
  19 /*
  20  *      The HTC ASIC3 LED GPIOs are inputs, not outputs.
  21  *      Hence we turn the LEDs on/off via the TimeBase register.
  22  */
  23
  24 /*
  25  *      When TimeBase is 4 the clock resolution is about 32Hz.
  26  *      This driver supports hardware blinking with an on+off
  27  *      period from 62ms (2 clocks) to 125s (4000 clocks).
  28  */
  29 #define MS_TO_CLK(ms)   DIV_ROUND_CLOSEST(((ms)*1024), 32000)
  30 #define CLK_TO_MS(clk)  (((clk)*32000)/1024)
  31 #define MAX_CLK         4000            /* Fits into 12-bit Time registers */
  32 #define MAX_MS          CLK_TO_MS(MAX_CLK)
  33
  34 static const unsigned int led_n_base[ASIC3_NUM_LEDS] = {
  35         [0] = ASIC3_LED_0_Base,
  36         [1] = ASIC3_LED_1_Base,
  37         [2] = ASIC3_LED_2_Base,
  38 };
  39
  40 static void brightness_set(struct led_classdev *cdev,
  41         enum led_brightness value)
  42 {
  43         struct platform_device *pdev = to_platform_device(cdev->dev->parent);
  44         const struct mfd_cell *cell = mfd_get_cell(pdev);
  45         struct asic3 *asic = dev_get_drvdata(pdev->dev.parent);
  46         u32 timebase;
  47         unsigned int base;
  48
  49         timebase = (value == LED_OFF) ? 0 : (LED_EN|0x4);
  50
  51         base = led_n_base[cell->id];
  52         asic3_write_register(asic, (base + ASIC3_LED_PeriodTime), 32);
  53         asic3_write_register(asic, (base + ASIC3_LED_DutyTime), 32);
  54         asic3_write_register(asic, (base + ASIC3_LED_AutoStopCount), 0);
  55         asic3_write_register(asic, (base + ASIC3_LED_TimeBase), timebase);
  56 }
  57
  58 static int blink_set(struct led_classdev *cdev,
  59         unsigned long *delay_on,
  60         unsigned long *delay_off)
  61 {
  62         struct platform_device *pdev = to_platform_device(cdev->dev->parent);
  63         const struct mfd_cell *cell = mfd_get_cell(pdev);
  64         struct asic3 *asic = dev_get_drvdata(pdev->dev.parent);
  65         u32 on;
  66         u32 off;
  67         unsigned int base;
  68
  69         if (*delay_on > MAX_MS || *delay_off > MAX_MS)
  70                 return -EINVAL;
  71
  72         if (*delay_on == 0 && *delay_off == 0) {
  73                 /* If both are zero then a sensible default should be chosen */
  74                 on = MS_TO_CLK(500);
  75                 off = MS_TO_CLK(500);
  76         } else {
  77                 on = MS_TO_CLK(*delay_on);
  78                 off = MS_TO_CLK(*delay_off);
  79                 if ((on + off) > MAX_CLK)
  80                         return -EINVAL;
  81         }
  82
  83         base = led_n_base[cell->id];
  84         asic3_write_register(asic, (base + ASIC3_LED_PeriodTime), (on + off));
  85         asic3_write_register(asic, (base + ASIC3_LED_DutyTime), on);
  86         asic3_write_register(asic, (base + ASIC3_LED_AutoStopCount), 0);
  87         asic3_write_register(asic, (base + ASIC3_LED_TimeBase), (LED_EN|0x4));
  88
  89         *delay_on = CLK_TO_MS(on);
  90         *delay_off = CLK_TO_MS(off);
  91
  92         return 0;
  93 }
  94
  95 static int __devinit asic3_led_probe(struct platform_device *pdev)
  96 {
  97         struct asic3_led *led = pdev->dev.platform_data;
  98         int ret;
  99
 100         ret = mfd_cell_enable(pdev);
 101         if (ret < 0)
 102                 goto ret0;
 103
 104         led->cdev = kzalloc(sizeof(struct led_classdev), GFP_KERNEL);
 105         if (!led->cdev) {
 106                 ret = -ENOMEM;
 107                 goto ret1;
 108         }
 109
 110         led->cdev->name = led->name;
 111         led->cdev->default_trigger = led->default_trigger;
 112         led->cdev->brightness_set = brightness_set;
 113         led->cdev->blink_set = blink_set;
 114
 115         ret = led_classdev_register(&pdev->dev, led->cdev);
 116         if (ret < 0)
 117                 goto ret2;
 118
 119         return 0;
 120
 121 ret2:
 122         kfree(led->cdev);
 123 ret1:
 124         (void) mfd_cell_disable(pdev);
 125 ret0:
 126         return ret;
 127 }
 128
 129 static int __devexit asic3_led_remove(struct platform_device *pdev)
 130 {
 131         struct asic3_led *led = pdev->dev.platform_data;
 132
 133         led_classdev_unregister(led->cdev);
 134
 135         kfree(led->cdev);
 136
 137         return mfd_cell_disable(pdev);
 138 }
 139
 140 static struct platform_driver asic3_led_driver = {
 141         .probe          = asic3_led_probe,
 142         .remove         = __devexit_p(asic3_led_remove),
 143         .driver         = {
 144                 .name   = "leds-asic3",
 145                 .owner  = THIS_MODULE,
 146         },
 147 };
 148
 149 MODULE_ALIAS("platform:leds-asic3");
 150
 151 static int __init asic3_led_init(void)
 152 {
 153         return platform_driver_register(&asic3_led_driver);
 154 }
 155
 156 static void __exit asic3_led_exit(void)
 157 {
 158         platform_driver_unregister(&asic3_led_driver);
 159 }
 160
 161 module_init(asic3_led_init);
 162 module_exit(asic3_led_exit);
 163
 164 MODULE_AUTHOR("Paul Parsons <lost.distance@yahoo.com>");
 165 MODULE_DESCRIPTION("HTC ASIC3 LED driver");
 166 MODULE_LICENSE("GPL");