/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
 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");