Root/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
34static 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
40static 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
58static 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
95static int 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        return ret;
103
104    led->cdev = devm_kzalloc(&pdev->dev, sizeof(struct led_classdev),
105                GFP_KERNEL);
106    if (!led->cdev) {
107        ret = -ENOMEM;
108        goto out;
109    }
110
111    led->cdev->name = led->name;
112    led->cdev->flags = LED_CORE_SUSPENDRESUME;
113    led->cdev->brightness_set = brightness_set;
114    led->cdev->blink_set = blink_set;
115    led->cdev->default_trigger = led->default_trigger;
116
117    ret = led_classdev_register(&pdev->dev, led->cdev);
118    if (ret < 0)
119        goto out;
120
121    return 0;
122
123out:
124    (void) mfd_cell_disable(pdev);
125    return ret;
126}
127
128static int 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    return mfd_cell_disable(pdev);
135}
136
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
163static const struct dev_pm_ops asic3_led_pm_ops = {
164    .suspend = asic3_led_suspend,
165    .resume = asic3_led_resume,
166};
167
168static struct platform_driver asic3_led_driver = {
169    .probe = asic3_led_probe,
170    .remove = asic3_led_remove,
171    .driver = {
172        .name = "leds-asic3",
173        .owner = THIS_MODULE,
174        .pm = &asic3_led_pm_ops,
175    },
176};
177
178module_platform_driver(asic3_led_driver);
179
180MODULE_AUTHOR("Paul Parsons <lost.distance@yahoo.com>");
181MODULE_DESCRIPTION("HTC ASIC3 LED driver");
182MODULE_LICENSE("GPL");
183MODULE_ALIAS("platform:leds-asic3");
184

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