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- // 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;
- int ret, i;
- regmap_write(rdev->regmap, REG_POWERON, 1);
- msleep(80);
- /* Wait for nPWRDWN to go low to indicate poweron is done. */
- for (i = 0; i < 20; i++) {
- ret = regmap_read(rdev->regmap, REG_PORTB, &data);
- if (!ret) {
- if (data & BIT(0))
- break;
- }
- usleep_range(10000, 12000);
- }
- usleep_range(10000, 12000);
- if (ret)
- pr_err("%s: regmap_read_poll_timeout failed %d\n", __func__, ret);
- /* 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);
- msleep(30);
- return 0;
- }
- static int attiny_lcd_power_is_enabled(struct regulator_dev *rdev)
- {
- unsigned int data;
- int ret, i;
- for (i = 0; i < 10; i++) {
- ret = regmap_read(rdev->regmap, REG_POWERON, &data);
- if (!ret)
- break;
- usleep_range(10000, 12000);
- }
- if (ret < 0)
- return ret;
- if (!(data & BIT(0)))
- return 0;
- for (i = 0; i < 10; i++) {
- ret = regmap_read(rdev->regmap, REG_PORTB, &data);
- if (!ret)
- break;
- usleep_range(10000, 12000);
- }
- 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;
- int ret, i;
- if (bl->props.power != FB_BLANK_UNBLANK ||
- bl->props.fb_blank != FB_BLANK_UNBLANK)
- brightness = 0;
- for (i = 0; i < 10; i++) {
- ret = regmap_write(regmap, REG_PWM, brightness);
- if (!ret)
- break;
- }
- return ret;
- }
- static int attiny_get_brightness(struct backlight_device *bl)
- {
- struct regmap *regmap = bl_get_data(bl);
- int ret, brightness, i;
- for (i = 0; i < 10; i++) {
- ret = regmap_read(regmap, REG_PWM, &brightness);
- if (!ret)
- break;
- }
- 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);
- msleep(30);
- 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");
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