[linux-2.6-block.git] / drivers / video / backlight / ot200_bl.c

/*
 * Copyright (C) 2012 Bachmann electronic GmbH
 *	Christian Gmeiner <christian.gmeiner@gmail.com>
 *
 * Backlight driver for ot200 visualisation device from
 * Bachmann electronic GmbH.
 *
 * 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/module.h>
#include <linux/fb.h>
#include <linux/backlight.h>
#include <linux/gpio.h>
#include <linux/platform_device.h>
#include <linux/cs5535.h>

static struct cs5535_mfgpt_timer *pwm_timer;

/* this array defines the mapping of brightness in % to pwm frequency */
static const u8 dim_table[101] = {0, 0, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2,
				  2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4,
				  4, 5, 5, 5, 5, 6, 6, 6, 7, 7, 7, 8, 8, 9, 9,
				  10, 10, 11, 11, 12, 12, 13, 14, 15, 15, 16,
				  17, 18, 19, 20, 21, 22, 23, 24, 26, 27, 28,
				  30, 31, 33, 35, 37, 39, 41, 43, 45, 47, 50,
				  53, 55, 58, 61, 65, 68, 72, 75, 79, 84, 88,
				  93, 97, 103, 108, 114, 120, 126, 133, 140,
				  147, 155, 163};

struct ot200_backlight_data {
	int current_brightness;
};

#define GPIO_DIMM	27
#define SCALE		1
#define CMP1MODE	0x2	/* compare on GE; output high on compare
				 * greater than or equal */
#define PWM_SETUP	(SCALE | CMP1MODE << 6 | MFGPT_SETUP_CNTEN)
#define MAX_COMP2	163

static int ot200_backlight_update_status(struct backlight_device *bl)
{
	struct ot200_backlight_data *data = bl_get_data(bl);
	int brightness = bl->props.brightness;

	if (bl->props.state & BL_CORE_FBBLANK)
		brightness = 0;

	/* enable or disable PWM timer */
	if (brightness == 0)
		cs5535_mfgpt_write(pwm_timer, MFGPT_REG_SETUP, 0);
	else if (data->current_brightness == 0) {
		cs5535_mfgpt_write(pwm_timer, MFGPT_REG_COUNTER, 0);
		cs5535_mfgpt_write(pwm_timer, MFGPT_REG_SETUP,
			MFGPT_SETUP_CNTEN);
	}

	/* apply new brightness value */
	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_CMP1,
		MAX_COMP2 - dim_table[brightness]);
	data->current_brightness = brightness;

	return 0;
}

static int ot200_backlight_get_brightness(struct backlight_device *bl)
{
	struct ot200_backlight_data *data = bl_get_data(bl);
	return data->current_brightness;
}

static const struct backlight_ops ot200_backlight_ops = {
	.update_status	= ot200_backlight_update_status,
	.get_brightness	= ot200_backlight_get_brightness,
};

static int ot200_backlight_probe(struct platform_device *pdev)
{
	struct backlight_device *bl;
	struct ot200_backlight_data *data;
	struct backlight_properties props;
	int retval = 0;

	/* request gpio */
	if (devm_gpio_request(&pdev->dev, GPIO_DIMM,
				"ot200 backlight dimmer") < 0) {
		dev_err(&pdev->dev, "failed to request GPIO %d\n", GPIO_DIMM);
		return -ENODEV;
	}

	/* request timer */
	pwm_timer = cs5535_mfgpt_alloc_timer(7, MFGPT_DOMAIN_ANY);
	if (!pwm_timer) {
		dev_err(&pdev->dev, "MFGPT 7 not available\n");
		return -ENODEV;
	}

	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
	if (!data) {
		retval = -ENOMEM;
		goto error_devm_kzalloc;
	}

	/* setup gpio */
	cs5535_gpio_set(GPIO_DIMM, GPIO_OUTPUT_ENABLE);
	cs5535_gpio_set(GPIO_DIMM, GPIO_OUTPUT_AUX1);

	/* setup timer */
	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_CMP1, 0);
	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_CMP2, MAX_COMP2);
	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_SETUP, PWM_SETUP);

	data->current_brightness = 100;
	props.max_brightness = 100;
	props.brightness = 100;
	props.type = BACKLIGHT_RAW;

	bl = devm_backlight_device_register(&pdev->dev, dev_name(&pdev->dev),
					&pdev->dev, data, &ot200_backlight_ops,
					&props);
	if (IS_ERR(bl)) {
		dev_err(&pdev->dev, "failed to register backlight\n");
		retval = PTR_ERR(bl);
		goto error_devm_kzalloc;
	}

	platform_set_drvdata(pdev, bl);

	return 0;

error_devm_kzalloc:
	cs5535_mfgpt_free_timer(pwm_timer);
	return retval;
}

static int ot200_backlight_remove(struct platform_device *pdev)
{
	/* on module unload set brightness to 100% */
	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_COUNTER, 0);
	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_CMP1,
		MAX_COMP2 - dim_table[100]);

	cs5535_mfgpt_free_timer(pwm_timer);

	return 0;
}

static struct platform_driver ot200_backlight_driver = {
	.driver		= {
		.name	= "ot200-backlight",
	},
	.probe		= ot200_backlight_probe,
	.remove		= ot200_backlight_remove,
};

module_platform_driver(ot200_backlight_driver);

MODULE_DESCRIPTION("backlight driver for ot200 visualisation device");
MODULE_AUTHOR("Christian Gmeiner <christian.gmeiner@gmail.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ot200-backlight");
Commit	Line	Data
c8df7428 CG	1	/*
	2	* Copyright (C) 2012 Bachmann electronic GmbH
	3	* Christian Gmeiner <christian.gmeiner@gmail.com>
	4	*
	5	* Backlight driver for ot200 visualisation device from
	6	* Bachmann electronic GmbH.
	7	*
	8	* This program is free software; you can redistribute it and/or modify it
	9	* under the terms of the GNU General Public License version 2 as published by
	10	* the Free Software Foundation.
	11	*/
	12
	13	#include <linux/module.h>
	14	#include <linux/fb.h>
	15	#include <linux/backlight.h>
	16	#include <linux/gpio.h>
16559ae4	17	#include <linux/platform_device.h>
c8df7428 CG	18	#include <linux/cs5535.h>
	19
	20	static struct cs5535_mfgpt_timer *pwm_timer;
	21
	22	/* this array defines the mapping of brightness in % to pwm frequency */
	23	static const u8 dim_table[101] = {0, 0, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2,
	24	2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4,
	25	4, 5, 5, 5, 5, 6, 6, 6, 7, 7, 7, 8, 8, 9, 9,
	26	10, 10, 11, 11, 12, 12, 13, 14, 15, 15, 16,
	27	17, 18, 19, 20, 21, 22, 23, 24, 26, 27, 28,
	28	30, 31, 33, 35, 37, 39, 41, 43, 45, 47, 50,
	29	53, 55, 58, 61, 65, 68, 72, 75, 79, 84, 88,
	30	93, 97, 103, 108, 114, 120, 126, 133, 140,
	31	147, 155, 163};
	32
	33	struct ot200_backlight_data {
	34	int current_brightness;
	35	};
	36
	37	#define GPIO_DIMM 27
	38	#define SCALE 1
	39	#define CMP1MODE 0x2 /* compare on GE; output high on compare
	40	* greater than or equal */
	41	#define PWM_SETUP (SCALE \| CMP1MODE << 6 \| MFGPT_SETUP_CNTEN)
	42	#define MAX_COMP2 163
	43
	44	static int ot200_backlight_update_status(struct backlight_device *bl)
	45	{
	46	struct ot200_backlight_data *data = bl_get_data(bl);
	47	int brightness = bl->props.brightness;
	48
	49	if (bl->props.state & BL_CORE_FBBLANK)
	50	brightness = 0;
	51
	52	/* enable or disable PWM timer */
	53	if (brightness == 0)
	54	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_SETUP, 0);
	55	else if (data->current_brightness == 0) {
	56	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_COUNTER, 0);
	57	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_SETUP,
	58	MFGPT_SETUP_CNTEN);
	59	}
	60
	61	/* apply new brightness value */
	62	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_CMP1,
	63	MAX_COMP2 - dim_table[brightness]);
	64	data->current_brightness = brightness;
	65
	66	return 0;
	67	}
	68
	69	static int ot200_backlight_get_brightness(struct backlight_device *bl)
	70	{
	71	struct ot200_backlight_data *data = bl_get_data(bl);
	72	return data->current_brightness;
	73	}
	74
	75	static const struct backlight_ops ot200_backlight_ops = {
	76	.update_status = ot200_backlight_update_status,
	77	.get_brightness = ot200_backlight_get_brightness,
	78	};
	79
	80	static int ot200_backlight_probe(struct platform_device *pdev)
	81	{
82	struct backlight_device *bl;
83	struct ot200_backlight_data *data;
84	struct backlight_properties props;
85	int retval = 0;
86
87	/* request gpio */
f673934c JH	88	if (devm_gpio_request(&pdev->dev, GPIO_DIMM,
f673934c JH	89	"ot200 backlight dimmer") < 0) {
c8df7428 CG	90	dev_err(&pdev->dev, "failed to request GPIO %d\n", GPIO_DIMM);
	91	return -ENODEV;
	92	}
	93
	94	/* request timer */
	95	pwm_timer = cs5535_mfgpt_alloc_timer(7, MFGPT_DOMAIN_ANY);
	96	if (!pwm_timer) {
	97	dev_err(&pdev->dev, "MFGPT 7 not available\n");
f673934c	98	return -ENODEV;
c8df7428 CG	99	}
c8df7428 CG	100
f1b60d46	101	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
c8df7428 CG	102	if (!data) {
c8df7428 CG	103	retval = -ENOMEM;
f1b60d46	104	goto error_devm_kzalloc;
c8df7428 CG	105	}
	106
	107	/* setup gpio */
	108	cs5535_gpio_set(GPIO_DIMM, GPIO_OUTPUT_ENABLE);
	109	cs5535_gpio_set(GPIO_DIMM, GPIO_OUTPUT_AUX1);
	110
	111	/* setup timer */
	112	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_CMP1, 0);
	113	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_CMP2, MAX_COMP2);
	114	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_SETUP, PWM_SETUP);
	115
	116	data->current_brightness = 100;
	117	props.max_brightness = 100;
	118	props.brightness = 100;
	119	props.type = BACKLIGHT_RAW;
	120
443956fd JH	121	bl = devm_backlight_device_register(&pdev->dev, dev_name(&pdev->dev),
	122	&pdev->dev, data, &ot200_backlight_ops,
	123	&props);
c8df7428 CG	124	if (IS_ERR(bl)) {
	125	dev_err(&pdev->dev, "failed to register backlight\n");
	126	retval = PTR_ERR(bl);
f1b60d46	127	goto error_devm_kzalloc;
c8df7428 CG	128	}
	129
	130	platform_set_drvdata(pdev, bl);
	131
	132	return 0;
	133
f1b60d46	134	error_devm_kzalloc:
c8df7428	135	cs5535_mfgpt_free_timer(pwm_timer);
c8df7428 CG	136	return retval;
	137	}
	138
	139	static int ot200_backlight_remove(struct platform_device *pdev)
	140	{
c8df7428 CG	141	/* on module unload set brightness to 100% */
	142	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_COUNTER, 0);
	143	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
	144	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_CMP1,
	145	MAX_COMP2 - dim_table[100]);
	146
	147	cs5535_mfgpt_free_timer(pwm_timer);
c8df7428	148
c8df7428 CG	149	return 0;
	150	}
	151
	152	static struct platform_driver ot200_backlight_driver = {
	153	.driver = {
	154	.name = "ot200-backlight",
c8df7428 CG	155	},
	156	.probe = ot200_backlight_probe,
	157	.remove = ot200_backlight_remove,
	158	};
	159
	160	module_platform_driver(ot200_backlight_driver);
	161
	162	MODULE_DESCRIPTION("backlight driver for ot200 visualisation device");
	163	MODULE_AUTHOR("Christian Gmeiner <christian.gmeiner@gmail.com>");
	164	MODULE_LICENSE("GPL");
	165	MODULE_ALIAS("platform:ot200-backlight");