[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>
#include <linux/slab.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)
{
	struct backlight_properties props;
	const struct atmel_pwm_bl_platform_data *pdata;
	struct backlight_device *bldev;
	struct atmel_pwm_bl *pwmbl;
	int retval;

	pwmbl = devm_kzalloc(&pdev->dev, 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 = devm_gpio_request(&pdev->dev, 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_pwm;
	}

	memset(&props, 0, sizeof(struct backlight_properties));
	props.type = BACKLIGHT_RAW;
	props.max_brightness = pdata->pwm_duty_max - pdata->pwm_duty_min;
	bldev = backlight_device_register("atmel-pwm-bl", &pdev->dev, pwmbl,
					  &atmel_pwm_bl_ops, &props);
	if (IS_ERR(bldev)) {
		retval = PTR_ERR(bldev);
		goto err_free_pwm;
	}

	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.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_pwm:
	pwm_channel_free(&pwmbl->pwmc);
err_free_mem:
	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);
	pwm_channel_disable(&pwmbl->pwmc);
	pwm_channel_free(&pwmbl->pwmc);
	backlight_device_unregister(pwmbl->bldev);
	platform_set_drvdata(pdev, NULL);

	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>
5a0e3ad6	20	#include <linux/slab.h>
3e074058 HCE	21
	22	struct atmel_pwm_bl {
	23	const struct atmel_pwm_bl_platform_data *pdata;
	24	struct backlight_device *bldev;
	25	struct platform_device *pdev;
	26	struct pwm_channel pwmc;
	27	int gpio_on;
	28	};
	29
	30	static int atmel_pwm_bl_set_intensity(struct backlight_device *bd)
	31	{
	32	struct atmel_pwm_bl *pwmbl = bl_get_data(bd);
	33	int intensity = bd->props.brightness;
	34	int pwm_duty;
	35
	36	if (bd->props.power != FB_BLANK_UNBLANK)
	37	intensity = 0;
	38	if (bd->props.fb_blank != FB_BLANK_UNBLANK)
	39	intensity = 0;
	40
	41	if (pwmbl->pdata->pwm_active_low)
	42	pwm_duty = pwmbl->pdata->pwm_duty_min + intensity;
	43	else
	44	pwm_duty = pwmbl->pdata->pwm_duty_max - intensity;
	45
	46	if (pwm_duty > pwmbl->pdata->pwm_duty_max)
	47	pwm_duty = pwmbl->pdata->pwm_duty_max;
	48	if (pwm_duty < pwmbl->pdata->pwm_duty_min)
	49	pwm_duty = pwmbl->pdata->pwm_duty_min;
	50
	51	if (!intensity) {
	52	if (pwmbl->gpio_on != -1) {
	53	gpio_set_value(pwmbl->gpio_on,
	54	0 ^ pwmbl->pdata->on_active_low);
	55	}
	56	pwm_channel_writel(&pwmbl->pwmc, PWM_CUPD, pwm_duty);
	57	pwm_channel_disable(&pwmbl->pwmc);
	58	} else {
	59	pwm_channel_enable(&pwmbl->pwmc);
	60	pwm_channel_writel(&pwmbl->pwmc, PWM_CUPD, pwm_duty);
	61	if (pwmbl->gpio_on != -1) {
	62	gpio_set_value(pwmbl->gpio_on,
	63	1 ^ pwmbl->pdata->on_active_low);
	64	}
	65	}
	66
	67	return 0;
	68	}
	69
	70	static int atmel_pwm_bl_get_intensity(struct backlight_device *bd)
	71	{
	72	struct atmel_pwm_bl *pwmbl = bl_get_data(bd);
	73	u8 intensity;
	74
	75	if (pwmbl->pdata->pwm_active_low) {
	76	intensity = pwm_channel_readl(&pwmbl->pwmc, PWM_CDTY) -
	77	pwmbl->pdata->pwm_duty_min;
	78	} else {
	79	intensity = pwmbl->pdata->pwm_duty_max -
	80	pwm_channel_readl(&pwmbl->pwmc, PWM_CDTY);
	81	}
	82
	83	return intensity;
	84	}
85
86	static int atmel_pwm_bl_init_pwm(struct atmel_pwm_bl *pwmbl)
87	{
88	unsigned long pwm_rate = pwmbl->pwmc.mck;
89	unsigned long prescale = DIV_ROUND_UP(pwm_rate,
90	(pwmbl->pdata->pwm_frequency *
91	pwmbl->pdata->pwm_compare_max)) - 1;
92
93	/*
94	* Prescale must be power of two and maximum 0xf in size because of
95	* hardware limit. PWM speed will be:
96	* PWM module clock speed / (2 ^ prescale).
97	*/
98	prescale = fls(prescale);
99	if (prescale > 0xf)
100	prescale = 0xf;
101
102	pwm_channel_writel(&pwmbl->pwmc, PWM_CMR, prescale);
103	pwm_channel_writel(&pwmbl->pwmc, PWM_CDTY,
104	pwmbl->pdata->pwm_duty_min +
105	pwmbl->bldev->props.brightness);
106	pwm_channel_writel(&pwmbl->pwmc, PWM_CPRD,
107	pwmbl->pdata->pwm_compare_max);
108
16a63149 JH	109	dev_info(&pwmbl->pdev->dev, "Atmel PWM backlight driver (%lu Hz)\n",
	110	pwmbl->pwmc.mck / pwmbl->pdata->pwm_compare_max /
	111	(1 << prescale));
3e074058 HCE	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	{
a19a6ee6	123	struct backlight_properties props;
3e074058 HCE	124	const struct atmel_pwm_bl_platform_data *pdata;
	125	struct backlight_device *bldev;
	126	struct atmel_pwm_bl *pwmbl;
	127	int retval;
	128
a4be29ac JH	129	pwmbl = devm_kzalloc(&pdev->dev, sizeof(struct atmel_pwm_bl),
a4be29ac JH	130	GFP_KERNEL);
3e074058 HCE	131	if (!pwmbl)
	132	return -ENOMEM;
	133
	134	pwmbl->pdev = pdev;
	135
	136	pdata = pdev->dev.platform_data;
	137	if (!pdata) {
	138	retval = -ENODEV;
	139	goto err_free_mem;
	140	}
	141
	142	if (pdata->pwm_compare_max < pdata->pwm_duty_max \|\|
	143	pdata->pwm_duty_min > pdata->pwm_duty_max \|\|
	144	pdata->pwm_frequency == 0) {
	145	retval = -EINVAL;
	146	goto err_free_mem;
	147	}
	148
	149	pwmbl->pdata = pdata;
	150	pwmbl->gpio_on = pdata->gpio_on;
	151
	152	retval = pwm_channel_alloc(pdata->pwm_channel, &pwmbl->pwmc);
	153	if (retval)
	154	goto err_free_mem;
	155
	156	if (pwmbl->gpio_on != -1) {
5f9dd5c9 JH	157	retval = devm_gpio_request(&pdev->dev, pwmbl->gpio_on,
5f9dd5c9 JH	158	"gpio_atmel_pwm_bl");
3e074058 HCE	159	if (retval) {
	160	pwmbl->gpio_on = -1;
	161	goto err_free_pwm;
	162	}
	163
af901ca1	164	/* Turn display off by default. */
3e074058 HCE	165	retval = gpio_direction_output(pwmbl->gpio_on,
	166	0 ^ pdata->on_active_low);
	167	if (retval)
5f9dd5c9	168	goto err_free_pwm;
3e074058 HCE	169	}
3e074058 HCE	170
a19a6ee6	171	memset(&props, 0, sizeof(struct backlight_properties));
bb7ca747	172	props.type = BACKLIGHT_RAW;
a19a6ee6 MG	173	props.max_brightness = pdata->pwm_duty_max - pdata->pwm_duty_min;
	174	bldev = backlight_device_register("atmel-pwm-bl", &pdev->dev, pwmbl,
	175	&atmel_pwm_bl_ops, &props);
3e074058 HCE	176	if (IS_ERR(bldev)) {
3e074058 HCE	177	retval = PTR_ERR(bldev);
5f9dd5c9	178	goto err_free_pwm;
3e074058 HCE	179	}
	180
	181	pwmbl->bldev = bldev;
	182
	183	platform_set_drvdata(pdev, pwmbl);
	184
	185	/* Power up the backlight by default at middle intesity. */
	186	bldev->props.power = FB_BLANK_UNBLANK;
3e074058 HCE	187	bldev->props.brightness = bldev->props.max_brightness / 2;
	188
	189	retval = atmel_pwm_bl_init_pwm(pwmbl);
	190	if (retval)
	191	goto err_free_bl_dev;
	192
	193	atmel_pwm_bl_set_intensity(bldev);
	194
	195	return 0;
	196
	197	err_free_bl_dev:
	198	platform_set_drvdata(pdev, NULL);
	199	backlight_device_unregister(bldev);
3e074058 HCE	200	err_free_pwm:
	201	pwm_channel_free(&pwmbl->pwmc);
	202	err_free_mem:
3e074058 HCE	203	return retval;
	204	}
	205
	206	static int __exit atmel_pwm_bl_remove(struct platform_device *pdev)
	207	{
	208	struct atmel_pwm_bl *pwmbl = platform_get_drvdata(pdev);
	209
5f9dd5c9	210	if (pwmbl->gpio_on != -1)
3e074058	211	gpio_set_value(pwmbl->gpio_on, 0);
3e074058 HCE	212	pwm_channel_disable(&pwmbl->pwmc);
	213	pwm_channel_free(&pwmbl->pwmc);
	214	backlight_device_unregister(pwmbl->bldev);
	215	platform_set_drvdata(pdev, NULL);
3e074058 HCE	216
	217	return 0;
	218	}
	219
	220	static struct platform_driver atmel_pwm_bl_driver = {
	221	.driver = {
	222	.name = "atmel-pwm-bl",
	223	},
	224	/* REVISIT add suspend() and resume() */
	225	.remove = __exit_p(atmel_pwm_bl_remove),
	226	};
	227
	228	static int __init atmel_pwm_bl_init(void)
	229	{
	230	return platform_driver_probe(&atmel_pwm_bl_driver, atmel_pwm_bl_probe);
	231	}
	232	module_init(atmel_pwm_bl_init);
	233
	234	static void __exit atmel_pwm_bl_exit(void)
	235	{
	236	platform_driver_unregister(&atmel_pwm_bl_driver);
	237	}
	238	module_exit(atmel_pwm_bl_exit);
	239
	240	MODULE_AUTHOR("Hans-Christian egtvedt <hans-christian.egtvedt@atmel.com>");
	241	MODULE_DESCRIPTION("Atmel PWM backlight driver");
	242	MODULE_LICENSE("GPL");