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

/*
 * Backlight driver for Pandora handheld.
 * Pandora uses TWL4030 PWM0 -> TPS61161 combo for control backlight.
 * Based on pwm_bl.c
 *
 * Copyright 2009,2012 Gražvydas Ignotas <notasas@gmail.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/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/fb.h>
#include <linux/backlight.h>
#include <linux/i2c/twl.h>
#include <linux/err.h>

#define TWL_PWM0_ON		0x00
#define TWL_PWM0_OFF		0x01

#define TWL_INTBR_GPBR1		0x0c
#define TWL_INTBR_PMBR1		0x0d

#define TWL_PMBR1_PWM0_MUXMASK	0x0c
#define TWL_PMBR1_PWM0		0x04
#define PWM0_CLK_ENABLE		BIT(0)
#define PWM0_ENABLE		BIT(2)

/* range accepted by hardware */
#define MIN_VALUE 9
#define MAX_VALUE 63
#define MAX_USER_VALUE (MAX_VALUE - MIN_VALUE)

#define PANDORABL_WAS_OFF BL_CORE_DRIVER1

static int pandora_backlight_update_status(struct backlight_device *bl)
{
	int brightness = bl->props.brightness;
	u8 r;

	if (bl->props.power != FB_BLANK_UNBLANK)
		brightness = 0;
	if (bl->props.state & BL_CORE_FBBLANK)
		brightness = 0;
	if (bl->props.state & BL_CORE_SUSPENDED)
		brightness = 0;

	if ((unsigned int)brightness > MAX_USER_VALUE)
		brightness = MAX_USER_VALUE;

	if (brightness == 0) {
		if (bl->props.state & PANDORABL_WAS_OFF)
			goto done;

		/* first disable PWM0 output, then clock */
		twl_i2c_read_u8(TWL4030_MODULE_INTBR, &r, TWL_INTBR_GPBR1);
		r &= ~PWM0_ENABLE;
		twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1);
		r &= ~PWM0_CLK_ENABLE;
		twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1);

		goto done;
	}

	if (bl->props.state & PANDORABL_WAS_OFF) {
		/*
		 * set PWM duty cycle to max. TPS61161 seems to use this
		 * to calibrate it's PWM sensitivity when it starts.
		 */
		twl_i2c_write_u8(TWL4030_MODULE_PWM0, MAX_VALUE,
					TWL_PWM0_OFF);

		/* first enable clock, then PWM0 out */
		twl_i2c_read_u8(TWL4030_MODULE_INTBR, &r, TWL_INTBR_GPBR1);
		r &= ~PWM0_ENABLE;
		r |= PWM0_CLK_ENABLE;
		twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1);
		r |= PWM0_ENABLE;
		twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1);

		/*
		 * TI made it very easy to enable digital control, so easy that
		 * it often triggers unintentionally and disabes PWM control,
		 * so wait until 1 wire mode detection window ends.
		 */
		usleep_range(2000, 10000);
	}

	twl_i2c_write_u8(TWL4030_MODULE_PWM0, MIN_VALUE + brightness,
				TWL_PWM0_OFF);

done:
	if (brightness != 0)
		bl->props.state &= ~PANDORABL_WAS_OFF;
	else
		bl->props.state |= PANDORABL_WAS_OFF;

	return 0;
}

static int pandora_backlight_get_brightness(struct backlight_device *bl)
{
	return bl->props.brightness;
}

static const struct backlight_ops pandora_backlight_ops = {
	.options	= BL_CORE_SUSPENDRESUME,
	.update_status	= pandora_backlight_update_status,
	.get_brightness	= pandora_backlight_get_brightness,
};

static int pandora_backlight_probe(struct platform_device *pdev)
{
	struct backlight_properties props;
	struct backlight_device *bl;
	u8 r;

	memset(&props, 0, sizeof(props));
	props.max_brightness = MAX_USER_VALUE;
	props.type = BACKLIGHT_RAW;
	bl = backlight_device_register(pdev->name, &pdev->dev,
			NULL, &pandora_backlight_ops, &props);
	if (IS_ERR(bl)) {
		dev_err(&pdev->dev, "failed to register backlight\n");
		return PTR_ERR(bl);
	}

	platform_set_drvdata(pdev, bl);

	/* 64 cycle period, ON position 0 */
	twl_i2c_write_u8(TWL4030_MODULE_PWM0, 0x80, TWL_PWM0_ON);

	bl->props.state |= PANDORABL_WAS_OFF;
	bl->props.brightness = MAX_USER_VALUE;
	backlight_update_status(bl);

	/* enable PWM function in pin mux */
	twl_i2c_read_u8(TWL4030_MODULE_INTBR, &r, TWL_INTBR_PMBR1);
	r &= ~TWL_PMBR1_PWM0_MUXMASK;
	r |= TWL_PMBR1_PWM0;
	twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_PMBR1);

	return 0;
}

static int pandora_backlight_remove(struct platform_device *pdev)
{
	struct backlight_device *bl = platform_get_drvdata(pdev);
	backlight_device_unregister(bl);
	return 0;
}

static struct platform_driver pandora_backlight_driver = {
	.driver		= {
		.name	= "pandora-backlight",
		.owner	= THIS_MODULE,
	},
	.probe		= pandora_backlight_probe,
	.remove		= pandora_backlight_remove,
};

module_platform_driver(pandora_backlight_driver);

MODULE_AUTHOR("Gražvydas Ignotas <notasas@gmail.com>");
MODULE_DESCRIPTION("Pandora Backlight Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pandora-backlight");
Commit	Line	Data
35c1682c GI	1	/*
	2	* Backlight driver for Pandora handheld.
	3	* Pandora uses TWL4030 PWM0 -> TPS61161 combo for control backlight.
	4	* Based on pwm_bl.c
	5	*
	6	* Copyright 2009,2012 Gražvydas Ignotas <notasas@gmail.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*/
	12
	13	#include <linux/module.h>
	14	#include <linux/kernel.h>
	15	#include <linux/platform_device.h>
	16	#include <linux/delay.h>
	17	#include <linux/fb.h>
	18	#include <linux/backlight.h>
	19	#include <linux/i2c/twl.h>
	20	#include <linux/err.h>
	21
	22	#define TWL_PWM0_ON 0x00
	23	#define TWL_PWM0_OFF 0x01
	24
	25	#define TWL_INTBR_GPBR1 0x0c
	26	#define TWL_INTBR_PMBR1 0x0d
	27
	28	#define TWL_PMBR1_PWM0_MUXMASK 0x0c
	29	#define TWL_PMBR1_PWM0 0x04
	30	#define PWM0_CLK_ENABLE BIT(0)
	31	#define PWM0_ENABLE BIT(2)
	32
	33	/* range accepted by hardware */
	34	#define MIN_VALUE 9
	35	#define MAX_VALUE 63
	36	#define MAX_USER_VALUE (MAX_VALUE - MIN_VALUE)
	37
	38	#define PANDORABL_WAS_OFF BL_CORE_DRIVER1
	39
	40	static int pandora_backlight_update_status(struct backlight_device *bl)
	41	{
	42	int brightness = bl->props.brightness;
	43	u8 r;
	44
	45	if (bl->props.power != FB_BLANK_UNBLANK)
	46	brightness = 0;
	47	if (bl->props.state & BL_CORE_FBBLANK)
	48	brightness = 0;
	49	if (bl->props.state & BL_CORE_SUSPENDED)
	50	brightness = 0;
	51
	52	if ((unsigned int)brightness > MAX_USER_VALUE)
	53	brightness = MAX_USER_VALUE;
	54
	55	if (brightness == 0) {
	56	if (bl->props.state & PANDORABL_WAS_OFF)
	57	goto done;
	58
	59	/* first disable PWM0 output, then clock */
	60	twl_i2c_read_u8(TWL4030_MODULE_INTBR, &r, TWL_INTBR_GPBR1);
	61	r &= ~PWM0_ENABLE;
	62	twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1);
	63	r &= ~PWM0_CLK_ENABLE;
	64	twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1);
65
66	goto done;
67	}
68
69	if (bl->props.state & PANDORABL_WAS_OFF) {
70	/*
71	* set PWM duty cycle to max. TPS61161 seems to use this
72	* to calibrate it's PWM sensitivity when it starts.
73	*/
74	twl_i2c_write_u8(TWL4030_MODULE_PWM0, MAX_VALUE,
75	TWL_PWM0_OFF);
76
77	/* first enable clock, then PWM0 out */
78	twl_i2c_read_u8(TWL4030_MODULE_INTBR, &r, TWL_INTBR_GPBR1);
79	r &= ~PWM0_ENABLE;
80	r \|= PWM0_CLK_ENABLE;
81	twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1);
82	r \|= PWM0_ENABLE;
83	twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1);
84
85	/*
86	* TI made it very easy to enable digital control, so easy that
87	* it often triggers unintentionally and disabes PWM control,
88	* so wait until 1 wire mode detection window ends.
89	*/
90	usleep_range(2000, 10000);
91	}
92
93	twl_i2c_write_u8(TWL4030_MODULE_PWM0, MIN_VALUE + brightness,
94	TWL_PWM0_OFF);
95
96	done:
97	if (brightness != 0)
98	bl->props.state &= ~PANDORABL_WAS_OFF;
99	else
100	bl->props.state \|= PANDORABL_WAS_OFF;
101
102	return 0;
103	}
104
105	static int pandora_backlight_get_brightness(struct backlight_device *bl)
106	{
107	return bl->props.brightness;
108	}
109
110	static const struct backlight_ops pandora_backlight_ops = {
111	.options = BL_CORE_SUSPENDRESUME,
112	.update_status = pandora_backlight_update_status,
113	.get_brightness = pandora_backlight_get_brightness,
114	};
115
116	static int pandora_backlight_probe(struct platform_device *pdev)
117	{
118	struct backlight_properties props;
119	struct backlight_device *bl;
120	u8 r;
121
122	memset(&props, 0, sizeof(props));
123	props.max_brightness = MAX_USER_VALUE;
124	props.type = BACKLIGHT_RAW;
125	bl = backlight_device_register(pdev->name, &pdev->dev,
126	NULL, &pandora_backlight_ops, &props);
127	if (IS_ERR(bl)) {
128	dev_err(&pdev->dev, "failed to register backlight\n");
129	return PTR_ERR(bl);
130	}
131
132	platform_set_drvdata(pdev, bl);
133
134	/* 64 cycle period, ON position 0 */
135	twl_i2c_write_u8(TWL4030_MODULE_PWM0, 0x80, TWL_PWM0_ON);
136
137	bl->props.state \|= PANDORABL_WAS_OFF;
138	bl->props.brightness = MAX_USER_VALUE;
139	backlight_update_status(bl);
140
141	/* enable PWM function in pin mux */
142	twl_i2c_read_u8(TWL4030_MODULE_INTBR, &r, TWL_INTBR_PMBR1);
143	r &= ~TWL_PMBR1_PWM0_MUXMASK;
144	r \|= TWL_PMBR1_PWM0;
145	twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_PMBR1);
146
147	return 0;
148	}
149
150	static int pandora_backlight_remove(struct platform_device *pdev)
151	{
152	struct backlight_device *bl = platform_get_drvdata(pdev);
153	backlight_device_unregister(bl);
154	return 0;
155	}
156
157	static struct platform_driver pandora_backlight_driver = {
158	.driver = {
159	.name = "pandora-backlight",
160	.owner = THIS_MODULE,
161	},
162	.probe = pandora_backlight_probe,
163	.remove = pandora_backlight_remove,
164	};
165
166	module_platform_driver(pandora_backlight_driver);
167
168	MODULE_AUTHOR("Gražvydas Ignotas <notasas@gmail.com>");
169	MODULE_DESCRIPTION("Pandora Backlight Driver");
170	MODULE_LICENSE("GPL");
171	MODULE_ALIAS("platform:pandora-backlight");