410 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (C) 2020 Marek Vasut <marex@denx.de>4 *5 * Based on rpi_touchscreen.c by Eric Anholt <eric@anholt.net>6 */7 8#include <linux/backlight.h>9#include <linux/err.h>10#include <linux/gpio/driver.h>11#include <linux/i2c.h>12#include <linux/init.h>13#include <linux/interrupt.h>14#include <linux/module.h>15#include <linux/regmap.h>16#include <linux/regulator/driver.h>17#include <linux/regulator/machine.h>18#include <linux/regulator/of_regulator.h>19#include <linux/slab.h>20 21/* I2C registers of the Atmel microcontroller. */22#define REG_ID 0x8023#define REG_PORTA 0x8124#define REG_PORTB 0x8225#define REG_PORTC 0x8326#define REG_POWERON 0x8527#define REG_PWM 0x8628#define REG_ADDR_L 0x8c29#define REG_ADDR_H 0x8d30#define REG_WRITE_DATA_H 0x9031#define REG_WRITE_DATA_L 0x9132 33#define PA_LCD_DITHB BIT(0)34#define PA_LCD_MODE BIT(1)35#define PA_LCD_LR BIT(2)36#define PA_LCD_UD BIT(3)37 38#define PB_BRIDGE_PWRDNX_N BIT(0)39#define PB_LCD_VCC_N BIT(1)40#define PB_LCD_MAIN BIT(7)41 42#define PC_LED_EN BIT(0)43#define PC_RST_TP_N BIT(1)44#define PC_RST_LCD_N BIT(2)45#define PC_RST_BRIDGE_N BIT(3)46 47enum gpio_signals {48 RST_BRIDGE_N, /* TC358762 bridge reset */49 RST_TP_N, /* Touch controller reset */50 NUM_GPIO51};52 53struct gpio_signal_mappings {54 unsigned int reg;55 unsigned int mask;56};57 58static const struct gpio_signal_mappings mappings[NUM_GPIO] = {59 [RST_BRIDGE_N] = { REG_PORTC, PC_RST_BRIDGE_N | PC_RST_LCD_N },60 [RST_TP_N] = { REG_PORTC, PC_RST_TP_N },61};62 63struct attiny_lcd {64 /* lock to serialise overall accesses to the Atmel */65 struct mutex lock;66 struct regmap *regmap;67 bool gpio_states[NUM_GPIO];68 u8 port_states[3];69 70 struct gpio_chip gc;71};72 73static const struct regmap_config attiny_regmap_config = {74 .reg_bits = 8,75 .val_bits = 8,76 .disable_locking = 1,77 .max_register = REG_WRITE_DATA_L,78 .cache_type = REGCACHE_MAPLE,79};80 81static int attiny_set_port_state(struct attiny_lcd *state, int reg, u8 val)82{83 state->port_states[reg - REG_PORTA] = val;84 return regmap_write(state->regmap, reg, val);85};86 87static u8 attiny_get_port_state(struct attiny_lcd *state, int reg)88{89 return state->port_states[reg - REG_PORTA];90};91 92static int attiny_lcd_power_enable(struct regulator_dev *rdev)93{94 struct attiny_lcd *state = rdev_get_drvdata(rdev);95 96 mutex_lock(&state->lock);97 98 /* Ensure bridge, and tp stay in reset */99 attiny_set_port_state(state, REG_PORTC, 0);100 usleep_range(5000, 10000);101 102 /* Default to the same orientation as the closed source103 * firmware used for the panel. Runtime rotation104 * configuration will be supported using VC4's plane105 * orientation bits.106 */107 attiny_set_port_state(state, REG_PORTA, PA_LCD_LR);108 usleep_range(5000, 10000);109 /* Main regulator on, and power to the panel (LCD_VCC_N) */110 attiny_set_port_state(state, REG_PORTB, PB_LCD_MAIN);111 usleep_range(5000, 10000);112 /* Bring controllers out of reset */113 attiny_set_port_state(state, REG_PORTC, PC_LED_EN);114 115 msleep(80);116 117 mutex_unlock(&state->lock);118 119 return 0;120}121 122static int attiny_lcd_power_disable(struct regulator_dev *rdev)123{124 struct attiny_lcd *state = rdev_get_drvdata(rdev);125 126 mutex_lock(&state->lock);127 128 regmap_write(rdev->regmap, REG_PWM, 0);129 usleep_range(5000, 10000);130 131 attiny_set_port_state(state, REG_PORTA, 0);132 usleep_range(5000, 10000);133 attiny_set_port_state(state, REG_PORTB, PB_LCD_VCC_N);134 usleep_range(5000, 10000);135 attiny_set_port_state(state, REG_PORTC, 0);136 msleep(30);137 138 mutex_unlock(&state->lock);139 140 return 0;141}142 143static int attiny_lcd_power_is_enabled(struct regulator_dev *rdev)144{145 struct attiny_lcd *state = rdev_get_drvdata(rdev);146 unsigned int data;147 int ret, i;148 149 mutex_lock(&state->lock);150 151 for (i = 0; i < 10; i++) {152 ret = regmap_read(rdev->regmap, REG_PORTC, &data);153 if (!ret)154 break;155 usleep_range(10000, 12000);156 }157 158 mutex_unlock(&state->lock);159 160 if (ret < 0)161 return ret;162 163 return data & PC_RST_BRIDGE_N;164}165 166static const struct regulator_init_data attiny_regulator_default = {167 .constraints = {168 .valid_ops_mask = REGULATOR_CHANGE_STATUS,169 },170};171 172static const struct regulator_ops attiny_regulator_ops = {173 .enable = attiny_lcd_power_enable,174 .disable = attiny_lcd_power_disable,175 .is_enabled = attiny_lcd_power_is_enabled,176};177 178static const struct regulator_desc attiny_regulator = {179 .name = "tc358762-power",180 .ops = &attiny_regulator_ops,181 .type = REGULATOR_VOLTAGE,182 .owner = THIS_MODULE,183};184 185static int attiny_update_status(struct backlight_device *bl)186{187 struct attiny_lcd *state = bl_get_data(bl);188 struct regmap *regmap = state->regmap;189 int brightness = backlight_get_brightness(bl);190 int ret, i;191 192 mutex_lock(&state->lock);193 194 for (i = 0; i < 10; i++) {195 ret = regmap_write(regmap, REG_PWM, brightness);196 if (!ret)197 break;198 }199 200 mutex_unlock(&state->lock);201 202 return ret;203}204 205static const struct backlight_ops attiny_bl = {206 .update_status = attiny_update_status,207};208 209static int attiny_gpio_get_direction(struct gpio_chip *gc, unsigned int off)210{211 return GPIO_LINE_DIRECTION_OUT;212}213 214static void attiny_gpio_set(struct gpio_chip *gc, unsigned int off, int val)215{216 struct attiny_lcd *state = gpiochip_get_data(gc);217 u8 last_val;218 219 if (off >= NUM_GPIO)220 return;221 222 mutex_lock(&state->lock);223 224 last_val = attiny_get_port_state(state, mappings[off].reg);225 if (val)226 last_val |= mappings[off].mask;227 else228 last_val &= ~mappings[off].mask;229 230 attiny_set_port_state(state, mappings[off].reg, last_val);231 232 if (off == RST_BRIDGE_N && val) {233 usleep_range(5000, 8000);234 regmap_write(state->regmap, REG_ADDR_H, 0x04);235 usleep_range(5000, 8000);236 regmap_write(state->regmap, REG_ADDR_L, 0x7c);237 usleep_range(5000, 8000);238 regmap_write(state->regmap, REG_WRITE_DATA_H, 0x00);239 usleep_range(5000, 8000);240 regmap_write(state->regmap, REG_WRITE_DATA_L, 0x00);241 242 msleep(100);243 }244 245 mutex_unlock(&state->lock);246}247 248static int attiny_i2c_read(struct i2c_client *client, u8 reg, unsigned int *buf)249{250 struct i2c_msg msgs[1];251 u8 addr_buf[1] = { reg };252 u8 data_buf[1] = { 0, };253 int ret;254 255 /* Write register address */256 msgs[0].addr = client->addr;257 msgs[0].flags = 0;258 msgs[0].len = ARRAY_SIZE(addr_buf);259 msgs[0].buf = addr_buf;260 261 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));262 if (ret != ARRAY_SIZE(msgs))263 return -EIO;264 265 usleep_range(5000, 10000);266 267 /* Read data from register */268 msgs[0].addr = client->addr;269 msgs[0].flags = I2C_M_RD;270 msgs[0].len = 1;271 msgs[0].buf = data_buf;272 273 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));274 if (ret != ARRAY_SIZE(msgs))275 return -EIO;276 277 *buf = data_buf[0];278 return 0;279}280 281/*282 * I2C driver interface functions283 */284static int attiny_i2c_probe(struct i2c_client *i2c)285{286 struct backlight_properties props = { };287 struct regulator_config config = { };288 struct backlight_device *bl;289 struct regulator_dev *rdev;290 struct attiny_lcd *state;291 struct regmap *regmap;292 unsigned int data;293 int ret;294 295 state = devm_kzalloc(&i2c->dev, sizeof(*state), GFP_KERNEL);296 if (!state)297 return -ENOMEM;298 299 mutex_init(&state->lock);300 i2c_set_clientdata(i2c, state);301 302 regmap = devm_regmap_init_i2c(i2c, &attiny_regmap_config);303 if (IS_ERR(regmap)) {304 ret = PTR_ERR(regmap);305 dev_err(&i2c->dev, "Failed to allocate register map: %d\n",306 ret);307 goto error;308 }309 310 ret = attiny_i2c_read(i2c, REG_ID, &data);311 if (ret < 0) {312 dev_err(&i2c->dev, "Failed to read REG_ID reg: %d\n", ret);313 goto error;314 }315 316 switch (data) {317 case 0xde: /* ver 1 */318 case 0xc3: /* ver 2 */319 break;320 default:321 dev_err(&i2c->dev, "Unknown Atmel firmware revision: 0x%02x\n", data);322 ret = -ENODEV;323 goto error;324 }325 326 regmap_write(regmap, REG_POWERON, 0);327 msleep(30);328 regmap_write(regmap, REG_PWM, 0);329 330 config.dev = &i2c->dev;331 config.regmap = regmap;332 config.of_node = i2c->dev.of_node;333 config.init_data = &attiny_regulator_default;334 config.driver_data = state;335 336 rdev = devm_regulator_register(&i2c->dev, &attiny_regulator, &config);337 if (IS_ERR(rdev)) {338 dev_err(&i2c->dev, "Failed to register ATTINY regulator\n");339 ret = PTR_ERR(rdev);340 goto error;341 }342 343 props.type = BACKLIGHT_RAW;344 props.max_brightness = 0xff;345 346 state->regmap = regmap;347 348 bl = devm_backlight_device_register(&i2c->dev, dev_name(&i2c->dev),349 &i2c->dev, state, &attiny_bl,350 &props);351 if (IS_ERR(bl)) {352 ret = PTR_ERR(bl);353 goto error;354 }355 356 bl->props.brightness = 0xff;357 358 state->gc.parent = &i2c->dev;359 state->gc.label = i2c->name;360 state->gc.owner = THIS_MODULE;361 state->gc.base = -1;362 state->gc.ngpio = NUM_GPIO;363 364 state->gc.set = attiny_gpio_set;365 state->gc.get_direction = attiny_gpio_get_direction;366 state->gc.can_sleep = true;367 368 ret = devm_gpiochip_add_data(&i2c->dev, &state->gc, state);369 if (ret) {370 dev_err(&i2c->dev, "Failed to create gpiochip: %d\n", ret);371 goto error;372 }373 374 return 0;375 376error:377 mutex_destroy(&state->lock);378 379 return ret;380}381 382static void attiny_i2c_remove(struct i2c_client *client)383{384 struct attiny_lcd *state = i2c_get_clientdata(client);385 386 mutex_destroy(&state->lock);387}388 389static const struct of_device_id attiny_dt_ids[] = {390 { .compatible = "raspberrypi,7inch-touchscreen-panel-regulator" },391 {},392};393MODULE_DEVICE_TABLE(of, attiny_dt_ids);394 395static struct i2c_driver attiny_regulator_driver = {396 .driver = {397 .name = "rpi_touchscreen_attiny",398 .probe_type = PROBE_PREFER_ASYNCHRONOUS,399 .of_match_table = attiny_dt_ids,400 },401 .probe = attiny_i2c_probe,402 .remove = attiny_i2c_remove,403};404 405module_i2c_driver(attiny_regulator_driver);406 407MODULE_AUTHOR("Marek Vasut <marex@denx.de>");408MODULE_DESCRIPTION("Regulator device driver for Raspberry Pi 7-inch touchscreen");409MODULE_LICENSE("GPL v2");410