summaryrefslogtreecommitdiff
path: root/drivers/regulator/rpi-panel-attiny-regulator.c
blob: e9719a378a0bc10d9333b8f9674b3496ce2250d5 (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
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
// 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/gpio/driver.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_PORTB	0x82
#define REG_PORTC	0x83
#define REG_POWERON	0x85
#define REG_PWM		0x86
#define REG_ADDR_L	0x8c
#define REG_ADDR_H	0x8d
#define REG_WRITE_DATA_H	0x90
#define REG_WRITE_DATA_L	0x91

#define PA_LCD_DITHB		BIT(0)
#define PA_LCD_MODE		BIT(1)
#define PA_LCD_LR		BIT(2)
#define PA_LCD_UD		BIT(3)

#define PB_BRIDGE_PWRDNX_N	BIT(0)
#define PB_LCD_VCC_N		BIT(1)
#define PB_LCD_MAIN		BIT(7)

#define PC_LED_EN		BIT(0)
#define PC_RST_TP_N		BIT(1)
#define PC_RST_LCD_N		BIT(2)
#define PC_RST_BRIDGE_N		BIT(3)

enum gpio_signals {
	RST_BRIDGE_N,	/* TC358762 bridge reset */
	RST_TP_N,	/* Touch controller reset */
	NUM_GPIO
};

struct gpio_signal_mappings {
	unsigned int reg;
	unsigned int mask;
};

static const struct gpio_signal_mappings mappings[NUM_GPIO] = {
	[RST_BRIDGE_N] = { REG_PORTC, PC_RST_BRIDGE_N | PC_RST_LCD_N  },
	[RST_TP_N] = { REG_PORTC, PC_RST_TP_N },
};

struct attiny_lcd {
	/* lock to serialise overall accesses to the Atmel */
	struct mutex	lock;
	struct regmap	*regmap;
	bool gpio_states[NUM_GPIO];
	u8 port_states[3];

	struct gpio_chip gc;
};

static const struct regmap_config attiny_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.disable_locking = 1,
	.max_register = REG_WRITE_DATA_L,
	.cache_type = REGCACHE_RBTREE,
};

static int attiny_set_port_state(struct attiny_lcd *state, int reg, u8 val)
{
	state->port_states[reg - REG_PORTA] = val;
	return regmap_write(state->regmap, reg, val);
};

static u8 attiny_get_port_state(struct attiny_lcd *state, int reg)
{
	return state->port_states[reg - REG_PORTA];
};

static int attiny_lcd_power_enable(struct regulator_dev *rdev)
{
	struct attiny_lcd *state = rdev_get_drvdata(rdev);

	mutex_lock(&state->lock);

	/* Ensure bridge, and tp stay in reset */
	attiny_set_port_state(state, REG_PORTC, 0);
	usleep_range(5000, 10000);

	/* 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.
	 */
	attiny_set_port_state(state, REG_PORTA, PA_LCD_LR);
	usleep_range(5000, 10000);
	/* Main regulator on, and power to the panel (LCD_VCC_N) */
	attiny_set_port_state(state, REG_PORTB, PB_LCD_MAIN);
	usleep_range(5000, 10000);
	/* Bring controllers out of reset */
	attiny_set_port_state(state, REG_PORTC, PC_LED_EN);

	msleep(80);

	mutex_unlock(&state->lock);

	return 0;
}

static int attiny_lcd_power_disable(struct regulator_dev *rdev)
{
	struct attiny_lcd *state = rdev_get_drvdata(rdev);

	mutex_lock(&state->lock);

	regmap_write(rdev->regmap, REG_PWM, 0);
	usleep_range(5000, 10000);

	attiny_set_port_state(state, REG_PORTA, 0);
	usleep_range(5000, 10000);
	attiny_set_port_state(state, REG_PORTB, PB_LCD_VCC_N);
	usleep_range(5000, 10000);
	attiny_set_port_state(state, REG_PORTC, 0);
	msleep(30);

	mutex_unlock(&state->lock);

	return 0;
}

static int attiny_lcd_power_is_enabled(struct regulator_dev *rdev)
{
	struct attiny_lcd *state = rdev_get_drvdata(rdev);
	unsigned int data;
	int ret, i;

	mutex_lock(&state->lock);

	for (i = 0; i < 10; i++) {
		ret = regmap_read(rdev->regmap, REG_PORTC, &data);
		if (!ret)
			break;
		usleep_range(10000, 12000);
	}

	mutex_unlock(&state->lock);

	if (ret < 0)
		return ret;

	return data & PC_RST_BRIDGE_N;
}

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 attiny_lcd *state = bl_get_data(bl);
	struct regmap *regmap = state->regmap;
	int brightness = backlight_get_brightness(bl);
	int ret, i;

	mutex_lock(&state->lock);

	for (i = 0; i < 10; i++) {
		ret = regmap_write(regmap, REG_PWM, brightness);
		if (!ret)
			break;
	}

	mutex_unlock(&state->lock);

	return ret;
}

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

static int attiny_gpio_get_direction(struct gpio_chip *gc, unsigned int off)
{
	return GPIO_LINE_DIRECTION_OUT;
}

static void attiny_gpio_set(struct gpio_chip *gc, unsigned int off, int val)
{
	struct attiny_lcd *state = gpiochip_get_data(gc);
	u8 last_val;

	if (off >= NUM_GPIO)
		return;

	mutex_lock(&state->lock);

	last_val = attiny_get_port_state(state, mappings[off].reg);
	if (val)
		last_val |= mappings[off].mask;
	else
		last_val &= ~mappings[off].mask;

	attiny_set_port_state(state, mappings[off].reg, last_val);

	if (off == RST_BRIDGE_N && val) {
		usleep_range(5000, 8000);
		regmap_write(state->regmap, REG_ADDR_H, 0x04);
		usleep_range(5000, 8000);
		regmap_write(state->regmap, REG_ADDR_L, 0x7c);
		usleep_range(5000, 8000);
		regmap_write(state->regmap, REG_WRITE_DATA_H, 0x00);
		usleep_range(5000, 8000);
		regmap_write(state->regmap, REG_WRITE_DATA_L, 0x00);

		msleep(100);
	}

	mutex_unlock(&state->lock);
}

static int attiny_i2c_read(struct i2c_client *client, u8 reg, unsigned int *buf)
{
	struct i2c_msg msgs[1];
	u8 addr_buf[1] = { reg };
	u8 data_buf[1] = { 0, };
	int ret;

	/* Write register address */
	msgs[0].addr = client->addr;
	msgs[0].flags = 0;
	msgs[0].len = ARRAY_SIZE(addr_buf);
	msgs[0].buf = addr_buf;

	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
	if (ret != ARRAY_SIZE(msgs))
		return -EIO;

	usleep_range(5000, 10000);

	/* Read data from register */
	msgs[0].addr = client->addr;
	msgs[0].flags = I2C_M_RD;
	msgs[0].len = 1;
	msgs[0].buf = data_buf;

	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
	if (ret != ARRAY_SIZE(msgs))
		return -EIO;

	*buf = data_buf[0];
	return 0;
}

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

	state = devm_kzalloc(&i2c->dev, sizeof(*state), GFP_KERNEL);
	if (!state)
		return -ENOMEM;

	mutex_init(&state->lock);
	i2c_set_clientdata(i2c, state);

	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);
		goto error;
	}

	ret = attiny_i2c_read(i2c, REG_ID, &data);
	if (ret < 0) {
		dev_err(&i2c->dev, "Failed to read REG_ID reg: %d\n", ret);
		goto error;
	}

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

	regmap_write(regmap, REG_POWERON, 0);
	msleep(30);
	regmap_write(regmap, REG_PWM, 0);

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

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

	props.type = BACKLIGHT_RAW;
	props.max_brightness = 0xff;

	state->regmap = regmap;

	bl = devm_backlight_device_register(&i2c->dev, dev_name(&i2c->dev),
					    &i2c->dev, state, &attiny_bl,
					    &props);
	if (IS_ERR(bl)) {
		ret = PTR_ERR(bl);
		goto error;
	}

	bl->props.brightness = 0xff;

	state->gc.parent = &i2c->dev;
	state->gc.label = i2c->name;
	state->gc.owner = THIS_MODULE;
	state->gc.base = -1;
	state->gc.ngpio = NUM_GPIO;

	state->gc.set = attiny_gpio_set;
	state->gc.get_direction = attiny_gpio_get_direction;
	state->gc.can_sleep = true;

	ret = devm_gpiochip_add_data(&i2c->dev, &state->gc, state);
	if (ret) {
		dev_err(&i2c->dev, "Failed to create gpiochip: %d\n", ret);
		goto error;
	}

	return 0;

error:
	mutex_destroy(&state->lock);

	return ret;
}

static void attiny_i2c_remove(struct i2c_client *client)
{
	struct attiny_lcd *state = i2c_get_clientdata(client);

	mutex_destroy(&state->lock);
}

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",
		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
		.of_match_table = of_match_ptr(attiny_dt_ids),
	},
	.probe = attiny_i2c_probe,
	.remove	= attiny_i2c_remove,
};

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");