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
  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
  33 static 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
  39 static 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
  57 static 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
  94 static int __devinit asic3_led_probe(struct platform_device *pdev)
  95 {
  96         struct asic3_led *led = pdev->dev.platform_data;
  97         int ret;
  98
  99         ret = mfd_cell_enable(pdev);
 100         if (ret < 0)
 101                 goto ret0;
 102
 103         led->cdev = kzalloc(sizeof(struct led_classdev), GFP_KERNEL);
 104         if (!led->cdev) {
 105                 ret = -ENOMEM;
 106                 goto ret1;
 107         }
 108
 109         led->cdev->name = led->name;
 110         led->cdev->default_trigger = led->default_trigger;
 111         led->cdev->brightness_set = brightness_set;
 112         led->cdev->blink_set = blink_set;
 113
 114         ret = led_classdev_register(&pdev->dev, led->cdev);
 115         if (ret < 0)
 116                 goto ret2;
 117
 118         return 0;
 119
 120 ret2:
 121         kfree(led->cdev);
 122 ret1:
 123         (void) mfd_cell_disable(pdev);
 124 ret0:
 125         return ret;
 126 }
 127
 128 static int __devexit asic3_led_remove(struct platform_device *pdev)
 129 {
 130         struct asic3_led *led = pdev->dev.platform_data;
 131
 132         led_classdev_unregister(led->cdev);
 133
 134         kfree(led->cdev);
 135
 136         return mfd_cell_disable(pdev);
 137 }
 138
 139 static struct platform_driver asic3_led_driver = {
 140         .probe          = asic3_led_probe,
 141         .remove         = __devexit_p(asic3_led_remove),
 142         .driver         = {
 143                 .name   = "leds-asic3",
 144                 .owner  = THIS_MODULE,
 145         },
 146 };
 147
 148 MODULE_ALIAS("platform:leds-asic3");
 149
 150 static int __init asic3_led_init(void)
 151 {
 152         return platform_driver_register(&asic3_led_driver);
 153 }
 154
 155 static void __exit asic3_led_exit(void)
 156 {
 157         platform_driver_unregister(&asic3_led_driver);
 158 }
 159
 160 module_init(asic3_led_init);
 161 module_exit(asic3_led_exit);
 162
 163 MODULE_AUTHOR("Paul Parsons <lost.distance@yahoo.com>");
 164 MODULE_DESCRIPTION("HTC ASIC3 LED driver");
 165 MODULE_LICENSE("GPL");