diff options
Diffstat (limited to 'drivers/regulator/rpi-panel-attiny-regulator.c')
| -rw-r--r-- | drivers/regulator/rpi-panel-attiny-regulator.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/drivers/regulator/rpi-panel-attiny-regulator.c b/drivers/regulator/rpi-panel-attiny-regulator.c new file mode 100644 index 000000000..991b4730d --- /dev/null +++ b/drivers/regulator/rpi-panel-attiny-regulator.c @@ -0,0 +1,250 @@ +// 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"); |