leds-asic3.c
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/*
* Copyright (C) 2011 Paul Parsons <lost.distance@yahoo.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/leds.h>
#include <linux/slab.h>
#include <linux/mfd/asic3.h>
#include <linux/mfd/core.h>
#include <linux/module.h>
/*
* The HTC ASIC3 LED GPIOs are inputs, not outputs.
* Hence we turn the LEDs on/off via the TimeBase register.
*/
/*
* When TimeBase is 4 the clock resolution is about 32Hz.
* This driver supports hardware blinking with an on+off
* period from 62ms (2 clocks) to 125s (4000 clocks).
*/
#define MS_TO_CLK(ms) DIV_ROUND_CLOSEST(((ms)*1024), 32000)
#define CLK_TO_MS(clk) (((clk)*32000)/1024)
#define MAX_CLK 4000 /* Fits into 12-bit Time registers */
#define MAX_MS CLK_TO_MS(MAX_CLK)
static const unsigned int led_n_base[ASIC3_NUM_LEDS] = {
[0] = ASIC3_LED_0_Base,
[1] = ASIC3_LED_1_Base,
[2] = ASIC3_LED_2_Base,
};
static void brightness_set(struct led_classdev *cdev,
enum led_brightness value)
{
struct platform_device *pdev = to_platform_device(cdev->dev->parent);
const struct mfd_cell *cell = mfd_get_cell(pdev);
struct asic3 *asic = dev_get_drvdata(pdev->dev.parent);
u32 timebase;
unsigned int base;
timebase = (value == LED_OFF) ? 0 : (LED_EN|0x4);
base = led_n_base[cell->id];
asic3_write_register(asic, (base + ASIC3_LED_PeriodTime), 32);
asic3_write_register(asic, (base + ASIC3_LED_DutyTime), 32);
asic3_write_register(asic, (base + ASIC3_LED_AutoStopCount), 0);
asic3_write_register(asic, (base + ASIC3_LED_TimeBase), timebase);
}
static int blink_set(struct led_classdev *cdev,
unsigned long *delay_on,
unsigned long *delay_off)
{
struct platform_device *pdev = to_platform_device(cdev->dev->parent);
const struct mfd_cell *cell = mfd_get_cell(pdev);
struct asic3 *asic = dev_get_drvdata(pdev->dev.parent);
u32 on;
u32 off;
unsigned int base;
if (*delay_on > MAX_MS || *delay_off > MAX_MS)
return -EINVAL;
if (*delay_on == 0 && *delay_off == 0) {
/* If both are zero then a sensible default should be chosen */
on = MS_TO_CLK(500);
off = MS_TO_CLK(500);
} else {
on = MS_TO_CLK(*delay_on);
off = MS_TO_CLK(*delay_off);
if ((on + off) > MAX_CLK)
return -EINVAL;
}
base = led_n_base[cell->id];
asic3_write_register(asic, (base + ASIC3_LED_PeriodTime), (on + off));
asic3_write_register(asic, (base + ASIC3_LED_DutyTime), on);
asic3_write_register(asic, (base + ASIC3_LED_AutoStopCount), 0);
asic3_write_register(asic, (base + ASIC3_LED_TimeBase), (LED_EN|0x4));
*delay_on = CLK_TO_MS(on);
*delay_off = CLK_TO_MS(off);
return 0;
}
static int asic3_led_probe(struct platform_device *pdev)
{
struct asic3_led *led = dev_get_platdata(&pdev->dev);
int ret;
ret = mfd_cell_enable(pdev);
if (ret < 0)
return ret;
led->cdev = devm_kzalloc(&pdev->dev, sizeof(struct led_classdev),
GFP_KERNEL);
if (!led->cdev) {
ret = -ENOMEM;
goto out;
}
led->cdev->name = led->name;
led->cdev->flags = LED_CORE_SUSPENDRESUME;
led->cdev->brightness_set = brightness_set;
led->cdev->blink_set = blink_set;
led->cdev->default_trigger = led->default_trigger;
ret = led_classdev_register(&pdev->dev, led->cdev);
if (ret < 0)
goto out;
return 0;
out:
(void) mfd_cell_disable(pdev);
return ret;
}
static int asic3_led_remove(struct platform_device *pdev)
{
struct asic3_led *led = dev_get_platdata(&pdev->dev);
led_classdev_unregister(led->cdev);
return mfd_cell_disable(pdev);
}
#ifdef CONFIG_PM_SLEEP
static int asic3_led_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
const struct mfd_cell *cell = mfd_get_cell(pdev);
int ret;
ret = 0;
if (cell->suspend)
ret = (*cell->suspend)(pdev);
return ret;
}
static int asic3_led_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
const struct mfd_cell *cell = mfd_get_cell(pdev);
int ret;
ret = 0;
if (cell->resume)
ret = (*cell->resume)(pdev);
return ret;
}
#endif
static SIMPLE_DEV_PM_OPS(asic3_led_pm_ops, asic3_led_suspend, asic3_led_resume);
static struct platform_driver asic3_led_driver = {
.probe = asic3_led_probe,
.remove = asic3_led_remove,
.driver = {
.name = "leds-asic3",
.pm = &asic3_led_pm_ops,
},
};
module_platform_driver(asic3_led_driver);
MODULE_AUTHOR("Paul Parsons <lost.distance@yahoo.com>");
MODULE_DESCRIPTION("HTC ASIC3 LED driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:leds-asic3");