[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / video / backlight / atmel-pwm-bl.c

/*
 * Copyright (C) 2008 Atmel Corporation
 *
 * Backlight driver using Atmel PWM peripheral.
 *
 * 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/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/fb.h>
#include <linux/clk.h>
#include <linux/gpio.h>
#include <linux/backlight.h>
#include <linux/atmel_pwm.h>
#include <linux/atmel-pwm-bl.h>

struct atmel_pwm_bl {
	const struct atmel_pwm_bl_platform_data	*pdata;
	struct backlight_device			*bldev;
	struct platform_device			*pdev;
	struct pwm_channel			pwmc;
	int					gpio_on;
};

static int atmel_pwm_bl_set_intensity(struct backlight_device *bd)
{
	struct atmel_pwm_bl *pwmbl = bl_get_data(bd);
	int intensity = bd->props.brightness;
	int pwm_duty;

	if (bd->props.power != FB_BLANK_UNBLANK)
		intensity = 0;
	if (bd->props.fb_blank != FB_BLANK_UNBLANK)
		intensity = 0;

	if (pwmbl->pdata->pwm_active_low)
		pwm_duty = pwmbl->pdata->pwm_duty_min + intensity;
	else
		pwm_duty = pwmbl->pdata->pwm_duty_max - intensity;

	if (pwm_duty > pwmbl->pdata->pwm_duty_max)
		pwm_duty = pwmbl->pdata->pwm_duty_max;
	if (pwm_duty < pwmbl->pdata->pwm_duty_min)
		pwm_duty = pwmbl->pdata->pwm_duty_min;

	if (!intensity) {
		if (pwmbl->gpio_on != -1) {
			gpio_set_value(pwmbl->gpio_on,
					0 ^ pwmbl->pdata->on_active_low);
		}
		pwm_channel_writel(&pwmbl->pwmc, PWM_CUPD, pwm_duty);
		pwm_channel_disable(&pwmbl->pwmc);
	} else {
		pwm_channel_enable(&pwmbl->pwmc);
		pwm_channel_writel(&pwmbl->pwmc, PWM_CUPD, pwm_duty);
		if (pwmbl->gpio_on != -1) {
			gpio_set_value(pwmbl->gpio_on,
					1 ^ pwmbl->pdata->on_active_low);
		}
	}

	return 0;
}

static int atmel_pwm_bl_get_intensity(struct backlight_device *bd)
{
	struct atmel_pwm_bl *pwmbl = bl_get_data(bd);
	u8 intensity;

	if (pwmbl->pdata->pwm_active_low) {
		intensity = pwm_channel_readl(&pwmbl->pwmc, PWM_CDTY) -
			pwmbl->pdata->pwm_duty_min;
	} else {
		intensity = pwmbl->pdata->pwm_duty_max -
			pwm_channel_readl(&pwmbl->pwmc, PWM_CDTY);
	}

	return intensity;
}

static int atmel_pwm_bl_init_pwm(struct atmel_pwm_bl *pwmbl)
{
	unsigned long pwm_rate = pwmbl->pwmc.mck;
	unsigned long prescale = DIV_ROUND_UP(pwm_rate,
			(pwmbl->pdata->pwm_frequency *
			 pwmbl->pdata->pwm_compare_max)) - 1;

	/*
	 * Prescale must be power of two and maximum 0xf in size because of
	 * hardware limit. PWM speed will be:
	 *	PWM module clock speed / (2 ^ prescale).
	 */
	prescale = fls(prescale);
	if (prescale > 0xf)
		prescale = 0xf;

	pwm_channel_writel(&pwmbl->pwmc, PWM_CMR, prescale);
	pwm_channel_writel(&pwmbl->pwmc, PWM_CDTY,
			pwmbl->pdata->pwm_duty_min +
			pwmbl->bldev->props.brightness);
	pwm_channel_writel(&pwmbl->pwmc, PWM_CPRD,
			pwmbl->pdata->pwm_compare_max);

	dev_info(&pwmbl->pdev->dev, "Atmel PWM backlight driver "
			"(%lu Hz)\n", pwmbl->pwmc.mck /
			pwmbl->pdata->pwm_compare_max /
			(1 << prescale));

	return pwm_channel_enable(&pwmbl->pwmc);
}

static const struct backlight_ops atmel_pwm_bl_ops = {
	.get_brightness = atmel_pwm_bl_get_intensity,
	.update_status  = atmel_pwm_bl_set_intensity,
};

static int atmel_pwm_bl_probe(struct platform_device *pdev)
{
	const struct atmel_pwm_bl_platform_data *pdata;
	struct backlight_device *bldev;
	struct atmel_pwm_bl *pwmbl;
	int retval;

	pwmbl = kzalloc(sizeof(struct atmel_pwm_bl), GFP_KERNEL);
	if (!pwmbl)
		return -ENOMEM;

	pwmbl->pdev = pdev;

	pdata = pdev->dev.platform_data;
	if (!pdata) {
		retval = -ENODEV;
		goto err_free_mem;
	}

	if (pdata->pwm_compare_max < pdata->pwm_duty_max ||
			pdata->pwm_duty_min > pdata->pwm_duty_max ||
			pdata->pwm_frequency == 0) {
		retval = -EINVAL;
		goto err_free_mem;
	}

	pwmbl->pdata = pdata;
	pwmbl->gpio_on = pdata->gpio_on;

	retval = pwm_channel_alloc(pdata->pwm_channel, &pwmbl->pwmc);
	if (retval)
		goto err_free_mem;

	if (pwmbl->gpio_on != -1) {
		retval = gpio_request(pwmbl->gpio_on, "gpio_atmel_pwm_bl");
		if (retval) {
			pwmbl->gpio_on = -1;
			goto err_free_pwm;
		}

		/* Turn display off by default. */
		retval = gpio_direction_output(pwmbl->gpio_on,
				0 ^ pdata->on_active_low);
		if (retval)
			goto err_free_gpio;
	}

	bldev = backlight_device_register("atmel-pwm-bl",
			&pdev->dev, pwmbl, &atmel_pwm_bl_ops);
	if (IS_ERR(bldev)) {
		retval = PTR_ERR(bldev);
		goto err_free_gpio;
	}

	pwmbl->bldev = bldev;

	platform_set_drvdata(pdev, pwmbl);

	/* Power up the backlight by default at middle intesity. */
	bldev->props.power = FB_BLANK_UNBLANK;
	bldev->props.max_brightness = pdata->pwm_duty_max - pdata->pwm_duty_min;
	bldev->props.brightness = bldev->props.max_brightness / 2;

	retval = atmel_pwm_bl_init_pwm(pwmbl);
	if (retval)
		goto err_free_bl_dev;

	atmel_pwm_bl_set_intensity(bldev);

	return 0;

err_free_bl_dev:
	platform_set_drvdata(pdev, NULL);
	backlight_device_unregister(bldev);
err_free_gpio:
	if (pwmbl->gpio_on != -1)
		gpio_free(pwmbl->gpio_on);
err_free_pwm:
	pwm_channel_free(&pwmbl->pwmc);
err_free_mem:
	kfree(pwmbl);
	return retval;
}

static int __exit atmel_pwm_bl_remove(struct platform_device *pdev)
{
	struct atmel_pwm_bl *pwmbl = platform_get_drvdata(pdev);

	if (pwmbl->gpio_on != -1) {
		gpio_set_value(pwmbl->gpio_on, 0);
		gpio_free(pwmbl->gpio_on);
	}
	pwm_channel_disable(&pwmbl->pwmc);
	pwm_channel_free(&pwmbl->pwmc);
	backlight_device_unregister(pwmbl->bldev);
	platform_set_drvdata(pdev, NULL);
	kfree(pwmbl);

	return 0;
}

static struct platform_driver atmel_pwm_bl_driver = {
	.driver = {
		.name = "atmel-pwm-bl",
	},
	/* REVISIT add suspend() and resume() */
	.remove = __exit_p(atmel_pwm_bl_remove),
};

static int __init atmel_pwm_bl_init(void)
{
	return platform_driver_probe(&atmel_pwm_bl_driver, atmel_pwm_bl_probe);
}
module_init(atmel_pwm_bl_init);

static void __exit atmel_pwm_bl_exit(void)
{
	platform_driver_unregister(&atmel_pwm_bl_driver);
}
module_exit(atmel_pwm_bl_exit);

MODULE_AUTHOR("Hans-Christian egtvedt <hans-christian.egtvedt@atmel.com>");
MODULE_DESCRIPTION("Atmel PWM backlight driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
3e074058 HCE	1	/*
	2	* Copyright (C) 2008 Atmel Corporation
	3	*
	4	* Backlight driver using Atmel PWM peripheral.
	5	*
	6	* This program is free software; you can redistribute it and/or modify it
	7	* under the terms of the GNU General Public License version 2 as published by
	8	* the Free Software Foundation.
	9	*/
	10	#include <linux/init.h>
	11	#include <linux/kernel.h>
	12	#include <linux/module.h>
	13	#include <linux/platform_device.h>
	14	#include <linux/fb.h>
	15	#include <linux/clk.h>
	16	#include <linux/gpio.h>
	17	#include <linux/backlight.h>
	18	#include <linux/atmel_pwm.h>
	19	#include <linux/atmel-pwm-bl.h>
	20
	21	struct atmel_pwm_bl {
	22	const struct atmel_pwm_bl_platform_data *pdata;
	23	struct backlight_device *bldev;
	24	struct platform_device *pdev;
	25	struct pwm_channel pwmc;
	26	int gpio_on;
	27	};
	28
	29	static int atmel_pwm_bl_set_intensity(struct backlight_device *bd)
	30	{
	31	struct atmel_pwm_bl *pwmbl = bl_get_data(bd);
	32	int intensity = bd->props.brightness;
	33	int pwm_duty;
	34
	35	if (bd->props.power != FB_BLANK_UNBLANK)
	36	intensity = 0;
	37	if (bd->props.fb_blank != FB_BLANK_UNBLANK)
	38	intensity = 0;
	39
	40	if (pwmbl->pdata->pwm_active_low)
	41	pwm_duty = pwmbl->pdata->pwm_duty_min + intensity;
	42	else
	43	pwm_duty = pwmbl->pdata->pwm_duty_max - intensity;
	44
	45	if (pwm_duty > pwmbl->pdata->pwm_duty_max)
	46	pwm_duty = pwmbl->pdata->pwm_duty_max;
	47	if (pwm_duty < pwmbl->pdata->pwm_duty_min)
	48	pwm_duty = pwmbl->pdata->pwm_duty_min;
	49
	50	if (!intensity) {
	51	if (pwmbl->gpio_on != -1) {
	52	gpio_set_value(pwmbl->gpio_on,
	53	0 ^ pwmbl->pdata->on_active_low);
	54	}
	55	pwm_channel_writel(&pwmbl->pwmc, PWM_CUPD, pwm_duty);
	56	pwm_channel_disable(&pwmbl->pwmc);
	57	} else {
	58	pwm_channel_enable(&pwmbl->pwmc);
	59	pwm_channel_writel(&pwmbl->pwmc, PWM_CUPD, pwm_duty);
	60	if (pwmbl->gpio_on != -1) {
	61	gpio_set_value(pwmbl->gpio_on,
	62	1 ^ pwmbl->pdata->on_active_low);
	63	}
	64	}
65
66	return 0;
67	}
68
69	static int atmel_pwm_bl_get_intensity(struct backlight_device *bd)
70	{
71	struct atmel_pwm_bl *pwmbl = bl_get_data(bd);
72	u8 intensity;
73
74	if (pwmbl->pdata->pwm_active_low) {
75	intensity = pwm_channel_readl(&pwmbl->pwmc, PWM_CDTY) -
76	pwmbl->pdata->pwm_duty_min;
77	} else {
78	intensity = pwmbl->pdata->pwm_duty_max -
79	pwm_channel_readl(&pwmbl->pwmc, PWM_CDTY);
80	}
81
82	return intensity;
83	}
84
85	static int atmel_pwm_bl_init_pwm(struct atmel_pwm_bl *pwmbl)
86	{
87	unsigned long pwm_rate = pwmbl->pwmc.mck;
88	unsigned long prescale = DIV_ROUND_UP(pwm_rate,
89	(pwmbl->pdata->pwm_frequency *
90	pwmbl->pdata->pwm_compare_max)) - 1;
91
92	/*
93	* Prescale must be power of two and maximum 0xf in size because of
94	* hardware limit. PWM speed will be:
95	* PWM module clock speed / (2 ^ prescale).
96	*/
97	prescale = fls(prescale);
98	if (prescale > 0xf)
99	prescale = 0xf;
100
101	pwm_channel_writel(&pwmbl->pwmc, PWM_CMR, prescale);
102	pwm_channel_writel(&pwmbl->pwmc, PWM_CDTY,
103	pwmbl->pdata->pwm_duty_min +
104	pwmbl->bldev->props.brightness);
105	pwm_channel_writel(&pwmbl->pwmc, PWM_CPRD,
106	pwmbl->pdata->pwm_compare_max);
107
108	dev_info(&pwmbl->pdev->dev, "Atmel PWM backlight driver "
109	"(%lu Hz)\n", pwmbl->pwmc.mck /
110	pwmbl->pdata->pwm_compare_max /
111	(1 << prescale));
112
113	return pwm_channel_enable(&pwmbl->pwmc);
114	}
115
9905a43b	116	static const struct backlight_ops atmel_pwm_bl_ops = {
3e074058 HCE	117	.get_brightness = atmel_pwm_bl_get_intensity,
	118	.update_status = atmel_pwm_bl_set_intensity,
	119	};
	120
	121	static int atmel_pwm_bl_probe(struct platform_device *pdev)
	122	{
	123	const struct atmel_pwm_bl_platform_data *pdata;
	124	struct backlight_device *bldev;
	125	struct atmel_pwm_bl *pwmbl;
	126	int retval;
	127
	128	pwmbl = kzalloc(sizeof(struct atmel_pwm_bl), GFP_KERNEL);
	129	if (!pwmbl)
	130	return -ENOMEM;
	131
	132	pwmbl->pdev = pdev;
	133
	134	pdata = pdev->dev.platform_data;
	135	if (!pdata) {
	136	retval = -ENODEV;
	137	goto err_free_mem;
	138	}
	139
	140	if (pdata->pwm_compare_max < pdata->pwm_duty_max \|\|
	141	pdata->pwm_duty_min > pdata->pwm_duty_max \|\|
	142	pdata->pwm_frequency == 0) {
	143	retval = -EINVAL;
	144	goto err_free_mem;
	145	}
	146
	147	pwmbl->pdata = pdata;
	148	pwmbl->gpio_on = pdata->gpio_on;
	149
	150	retval = pwm_channel_alloc(pdata->pwm_channel, &pwmbl->pwmc);
	151	if (retval)
	152	goto err_free_mem;
	153
	154	if (pwmbl->gpio_on != -1) {
	155	retval = gpio_request(pwmbl->gpio_on, "gpio_atmel_pwm_bl");
	156	if (retval) {
	157	pwmbl->gpio_on = -1;
	158	goto err_free_pwm;
	159	}
	160
af901ca1	161	/* Turn display off by default. */
3e074058 HCE	162	retval = gpio_direction_output(pwmbl->gpio_on,
	163	0 ^ pdata->on_active_low);
	164	if (retval)
	165	goto err_free_gpio;
	166	}
	167
	168	bldev = backlight_device_register("atmel-pwm-bl",
	169	&pdev->dev, pwmbl, &atmel_pwm_bl_ops);
	170	if (IS_ERR(bldev)) {
	171	retval = PTR_ERR(bldev);
	172	goto err_free_gpio;
	173	}
	174
	175	pwmbl->bldev = bldev;
	176
	177	platform_set_drvdata(pdev, pwmbl);
	178
	179	/* Power up the backlight by default at middle intesity. */
	180	bldev->props.power = FB_BLANK_UNBLANK;
	181	bldev->props.max_brightness = pdata->pwm_duty_max - pdata->pwm_duty_min;
	182	bldev->props.brightness = bldev->props.max_brightness / 2;
	183
	184	retval = atmel_pwm_bl_init_pwm(pwmbl);
	185	if (retval)
	186	goto err_free_bl_dev;
	187
	188	atmel_pwm_bl_set_intensity(bldev);
	189
	190	return 0;
	191
	192	err_free_bl_dev:
	193	platform_set_drvdata(pdev, NULL);
	194	backlight_device_unregister(bldev);
	195	err_free_gpio:
	196	if (pwmbl->gpio_on != -1)
	197	gpio_free(pwmbl->gpio_on);
	198	err_free_pwm:
	199	pwm_channel_free(&pwmbl->pwmc);
	200	err_free_mem:
	201	kfree(pwmbl);
	202	return retval;
	203	}
	204
	205	static int __exit atmel_pwm_bl_remove(struct platform_device *pdev)
	206	{
	207	struct atmel_pwm_bl *pwmbl = platform_get_drvdata(pdev);
	208
	209	if (pwmbl->gpio_on != -1) {
	210	gpio_set_value(pwmbl->gpio_on, 0);
	211	gpio_free(pwmbl->gpio_on);
	212	}
	213	pwm_channel_disable(&pwmbl->pwmc);
	214	pwm_channel_free(&pwmbl->pwmc);
	215	backlight_device_unregister(pwmbl->bldev);
	216	platform_set_drvdata(pdev, NULL);
	217	kfree(pwmbl);
	218
	219	return 0;
	220	}
	221
	222	static struct platform_driver atmel_pwm_bl_driver = {
	223	.driver = {
	224	.name = "atmel-pwm-bl",
	225	},
226	/* REVISIT add suspend() and resume() */
227	.remove = __exit_p(atmel_pwm_bl_remove),
228	};
229
230	static int __init atmel_pwm_bl_init(void)
231	{
232	return platform_driver_probe(&atmel_pwm_bl_driver, atmel_pwm_bl_probe);
233	}
234	module_init(atmel_pwm_bl_init);
235
236	static void __exit atmel_pwm_bl_exit(void)
237	{
238	platform_driver_unregister(&atmel_pwm_bl_driver);
239	}
240	module_exit(atmel_pwm_bl_exit);
241
242	MODULE_AUTHOR("Hans-Christian egtvedt <hans-christian.egtvedt@atmel.com>");
243	MODULE_DESCRIPTION("Atmel PWM backlight driver");
244	MODULE_LICENSE("GPL");