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This regulator/backlight driver handles the ATTINY88 present on the RPi 7" touchscreen panel and exposes the power/backlight interfaces. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Eric Anholt <eric@anholt.net> Cc: Mark Brown <broonie@kernel.org> Cc: Sam Ravnborg <sam@ravnborg.org> To: dri-devel@lists.freedesktop.org Link: https://lore.kernel.org/r/20200809105938.6388-2-marex@denx.de Signed-off-by: Mark Brown <broonie@kernel.org>
214 lines
5 KiB
C
214 lines
5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2020 Marek Vasut <marex@denx.de>
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*
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* Based on rpi_touchscreen.c by Eric Anholt <eric@anholt.net>
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*/
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#include <linux/backlight.h>
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#include <linux/err.h>
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#include <linux/gpio.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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#include <linux/regmap.h>
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#include <linux/regulator/driver.h>
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#include <linux/regulator/machine.h>
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#include <linux/regulator/of_regulator.h>
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#include <linux/slab.h>
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/* I2C registers of the Atmel microcontroller. */
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#define REG_ID 0x80
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#define REG_PORTA 0x81
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#define REG_PORTA_HF BIT(2)
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#define REG_PORTA_VF BIT(3)
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#define REG_PORTB 0x82
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#define REG_POWERON 0x85
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#define REG_PWM 0x86
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static const struct regmap_config attiny_regmap_config = {
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.reg_bits = 8,
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.val_bits = 8,
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.max_register = REG_PWM,
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.cache_type = REGCACHE_NONE,
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};
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static int attiny_lcd_power_enable(struct regulator_dev *rdev)
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{
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unsigned int data;
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regmap_write(rdev->regmap, REG_POWERON, 1);
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/* Wait for nPWRDWN to go low to indicate poweron is done. */
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regmap_read_poll_timeout(rdev->regmap, REG_PORTB, data,
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data & BIT(0), 10, 1000000);
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/* Default to the same orientation as the closed source
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* firmware used for the panel. Runtime rotation
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* configuration will be supported using VC4's plane
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* orientation bits.
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*/
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regmap_write(rdev->regmap, REG_PORTA, BIT(2));
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return 0;
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}
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static int attiny_lcd_power_disable(struct regulator_dev *rdev)
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{
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regmap_write(rdev->regmap, REG_PWM, 0);
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regmap_write(rdev->regmap, REG_POWERON, 0);
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udelay(1);
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return 0;
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}
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static int attiny_lcd_power_is_enabled(struct regulator_dev *rdev)
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{
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unsigned int data;
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int ret;
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ret = regmap_read(rdev->regmap, REG_POWERON, &data);
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if (ret < 0)
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return ret;
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if (!(data & BIT(0)))
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return 0;
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ret = regmap_read(rdev->regmap, REG_PORTB, &data);
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if (ret < 0)
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return ret;
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return data & BIT(0);
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}
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static const struct regulator_init_data attiny_regulator_default = {
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.constraints = {
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.valid_ops_mask = REGULATOR_CHANGE_STATUS,
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},
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};
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static const struct regulator_ops attiny_regulator_ops = {
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.enable = attiny_lcd_power_enable,
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.disable = attiny_lcd_power_disable,
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.is_enabled = attiny_lcd_power_is_enabled,
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};
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static const struct regulator_desc attiny_regulator = {
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.name = "tc358762-power",
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.ops = &attiny_regulator_ops,
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.type = REGULATOR_VOLTAGE,
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.owner = THIS_MODULE,
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};
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static int attiny_update_status(struct backlight_device *bl)
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{
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struct regmap *regmap = bl_get_data(bl);
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int brightness = bl->props.brightness;
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if (bl->props.power != FB_BLANK_UNBLANK ||
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bl->props.fb_blank != FB_BLANK_UNBLANK)
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brightness = 0;
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return regmap_write(regmap, REG_PWM, brightness);
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}
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static int attiny_get_brightness(struct backlight_device *bl)
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{
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struct regmap *regmap = bl_get_data(bl);
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int ret, brightness;
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ret = regmap_read(regmap, REG_PWM, &brightness);
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if (ret)
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return ret;
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return brightness;
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}
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static const struct backlight_ops attiny_bl = {
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.update_status = attiny_update_status,
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.get_brightness = attiny_get_brightness,
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};
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/*
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* I2C driver interface functions
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*/
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static int attiny_i2c_probe(struct i2c_client *i2c,
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const struct i2c_device_id *id)
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{
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struct backlight_properties props = { };
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struct regulator_config config = { };
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struct backlight_device *bl;
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struct regulator_dev *rdev;
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struct regmap *regmap;
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unsigned int data;
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int ret;
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regmap = devm_regmap_init_i2c(i2c, &attiny_regmap_config);
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if (IS_ERR(regmap)) {
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ret = PTR_ERR(regmap);
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dev_err(&i2c->dev, "Failed to allocate register map: %d\n",
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ret);
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return ret;
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}
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ret = regmap_read(regmap, REG_ID, &data);
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if (ret < 0) {
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dev_err(&i2c->dev, "Failed to read REG_ID reg: %d\n", ret);
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return ret;
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}
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switch (data) {
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case 0xde: /* ver 1 */
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case 0xc3: /* ver 2 */
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break;
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default:
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dev_err(&i2c->dev, "Unknown Atmel firmware revision: 0x%02x\n", data);
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return -ENODEV;
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}
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regmap_write(regmap, REG_POWERON, 0);
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mdelay(1);
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config.dev = &i2c->dev;
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config.regmap = regmap;
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config.of_node = i2c->dev.of_node;
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config.init_data = &attiny_regulator_default;
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rdev = devm_regulator_register(&i2c->dev, &attiny_regulator, &config);
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if (IS_ERR(rdev)) {
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dev_err(&i2c->dev, "Failed to register ATTINY regulator\n");
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return PTR_ERR(rdev);
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}
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props.type = BACKLIGHT_RAW;
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props.max_brightness = 0xff;
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bl = devm_backlight_device_register(&i2c->dev,
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"7inch-touchscreen-panel-bl",
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&i2c->dev, regmap, &attiny_bl,
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&props);
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if (IS_ERR(bl))
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return PTR_ERR(bl);
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bl->props.brightness = 0xff;
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return 0;
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}
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static const struct of_device_id attiny_dt_ids[] = {
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{ .compatible = "raspberrypi,7inch-touchscreen-panel-regulator" },
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{},
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};
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MODULE_DEVICE_TABLE(of, attiny_dt_ids);
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static struct i2c_driver attiny_regulator_driver = {
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.driver = {
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.name = "rpi_touchscreen_attiny",
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.of_match_table = of_match_ptr(attiny_dt_ids),
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},
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.probe = attiny_i2c_probe,
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};
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module_i2c_driver(attiny_regulator_driver);
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MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
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MODULE_DESCRIPTION("Regulator device driver for Raspberry Pi 7-inch touchscreen");
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MODULE_LICENSE("GPL v2");
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