summaryrefslogtreecommitdiffstats
path: root/drivers/regulator/rpi-panel-attiny-regulator.c
blob: ee46bfbf5eee7e25380208372c5ac0a47ae8293f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2020 Marek Vasut <marex@denx.de>
 *
 * Based on rpi_touchscreen.c by Eric Anholt <eric@anholt.net>
 */

#include <linux/backlight.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/of_regulator.h>
#include <linux/slab.h>

/* I2C registers of the Atmel microcontroller. */
#define REG_ID		0x80
#define REG_PORTA	0x81
#define REG_PORTA_HF	BIT(2)
#define REG_PORTA_VF	BIT(3)
#define REG_PORTB	0x82
#define REG_POWERON	0x85
#define REG_PWM		0x86

static const struct regmap_config attiny_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = REG_PWM,
	.cache_type = REGCACHE_NONE,
};

static int attiny_lcd_power_enable(struct regulator_dev *rdev)
{
	unsigned int data;

	regmap_write(rdev->regmap, REG_POWERON, 1);
	/* Wait for nPWRDWN to go low to indicate poweron is done. */
	regmap_read_poll_timeout(rdev->regmap, REG_PORTB, data,
					data & BIT(0), 10, 1000000);

	/* Default to the same orientation as the closed source
	 * firmware used for the panel.  Runtime rotation
	 * configuration will be supported using VC4's plane
	 * orientation bits.
	 */
	regmap_write(rdev->regmap, REG_PORTA, BIT(2));

	return 0;
}

static int attiny_lcd_power_disable(struct regulator_dev *rdev)
{
	regmap_write(rdev->regmap, REG_PWM, 0);
	regmap_write(rdev->regmap, REG_POWERON, 0);
	udelay(1);
	return 0;
}

static int attiny_lcd_power_is_enabled(struct regulator_dev *rdev)
{
	unsigned int data;
	int ret;

	ret = regmap_read(rdev->regmap, REG_POWERON, &data);
	if (ret < 0)
		return ret;

	if (!(data & BIT(0)))
		return 0;

	ret = regmap_read(rdev->regmap, REG_PORTB, &data);
	if (ret < 0)
		return ret;

	return data & BIT(0);
}

static const struct regulator_init_data attiny_regulator_default = {
	.constraints = {
		.valid_ops_mask = REGULATOR_CHANGE_STATUS,
	},
};

static const struct regulator_ops attiny_regulator_ops = {
	.enable = attiny_lcd_power_enable,
	.disable = attiny_lcd_power_disable,
	.is_enabled = attiny_lcd_power_is_enabled,
};

static const struct regulator_desc attiny_regulator = {
	.name	= "tc358762-power",
	.ops	= &attiny_regulator_ops,
	.type	= REGULATOR_VOLTAGE,
	.owner	= THIS_MODULE,
};

static int attiny_update_status(struct backlight_device *bl)
{
	struct regmap *regmap = bl_get_data(bl);
	int brightness = bl->props.brightness;

	if (bl->props.power != FB_BLANK_UNBLANK ||
	    bl->props.fb_blank != FB_BLANK_UNBLANK)
		brightness = 0;

	return regmap_write(regmap, REG_PWM, brightness);
}

static int attiny_get_brightness(struct backlight_device *bl)
{
	struct regmap *regmap = bl_get_data(bl);
	int ret, brightness;

	ret = regmap_read(regmap, REG_PWM, &brightness);
	if (ret)
		return ret;

	return brightness;
}

static const struct backlight_ops attiny_bl = {
	.update_status	= attiny_update_status,
	.get_brightness	= attiny_get_brightness,
};

/*
 * I2C driver interface functions
 */
static int attiny_i2c_probe(struct i2c_client *i2c,
		const struct i2c_device_id *id)
{
	struct backlight_properties props = { };
	struct regulator_config config = { };
	struct backlight_device *bl;
	struct regulator_dev *rdev;
	struct regmap *regmap;
	unsigned int data;
	int ret;

	regmap = devm_regmap_init_i2c(i2c, &attiny_regmap_config);
	if (IS_ERR(regmap)) {
		ret = PTR_ERR(regmap);
		dev_err(&i2c->dev, "Failed to allocate register map: %d\n",
			ret);
		return ret;
	}

	ret = regmap_read(regmap, REG_ID, &data);
	if (ret < 0) {
		dev_err(&i2c->dev, "Failed to read REG_ID reg: %d\n", ret);
		return ret;
	}

	switch (data) {
	case 0xde: /* ver 1 */
	case 0xc3: /* ver 2 */
		break;
	default:
		dev_err(&i2c->dev, "Unknown Atmel firmware revision: 0x%02x\n", data);
		return -ENODEV;
	}

	regmap_write(regmap, REG_POWERON, 0);
	mdelay(1);

	config.dev = &i2c->dev;
	config.regmap = regmap;
	config.of_node = i2c->dev.of_node;
	config.init_data = &attiny_regulator_default;

	rdev = devm_regulator_register(&i2c->dev, &attiny_regulator, &config);
	if (IS_ERR(rdev)) {
		dev_err(&i2c->dev, "Failed to register ATTINY regulator\n");
		return PTR_ERR(rdev);
	}

	props.type = BACKLIGHT_RAW;
	props.max_brightness = 0xff;
	bl = devm_backlight_device_register(&i2c->dev,
					    "7inch-touchscreen-panel-bl",
					    &i2c->dev, regmap, &attiny_bl,
					    &props);
	if (IS_ERR(bl))
		return PTR_ERR(bl);

	bl->props.brightness = 0xff;

	return 0;
}

static const struct of_device_id attiny_dt_ids[] = {
	{ .compatible = "raspberrypi,7inch-touchscreen-panel-regulator" },
	{},
};
MODULE_DEVICE_TABLE(of, attiny_dt_ids);

static struct i2c_driver attiny_regulator_driver = {
	.driver = {
		.name = "rpi_touchscreen_attiny",
		.of_match_table = of_match_ptr(attiny_dt_ids),
	},
	.probe = attiny_i2c_probe,
};

module_i2c_driver(attiny_regulator_driver);

MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
MODULE_DESCRIPTION("Regulator device driver for Raspberry Pi 7-inch touchscreen");
MODULE_LICENSE("GPL v2");