/drivers/leds/leds-asic3.c
C | 165 lines | 117 code | 31 blank | 17 comment | 12 complexity | d05aa53f115fce921bc6ad6e364da7ca MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
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 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 __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 120ret2: 121 kfree(led->cdev); 122ret1: 123 (void) mfd_cell_disable(pdev); 124ret0: 125 return ret; 126} 127 128static 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 139static 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 148MODULE_ALIAS("platform:leds-asic3"); 149 150static int __init asic3_led_init(void) 151{ 152 return platform_driver_register(&asic3_led_driver); 153} 154 155static void __exit asic3_led_exit(void) 156{ 157 platform_driver_unregister(&asic3_led_driver); 158} 159 160module_init(asic3_led_init); 161module_exit(asic3_led_exit); 162 163MODULE_AUTHOR("Paul Parsons <lost.distance@yahoo.com>"); 164MODULE_DESCRIPTION("HTC ASIC3 LED driver"); 165MODULE_LICENSE("GPL");