--- /dev/null
+// 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;
+
+ regmap_write(rdev->regmap, REG_POWERON, 1);
+ /* Wait for nPWRDWN to go low to indicate poweron is done. */
+ regmap_read_poll_timeout(rdev->regmap, REG_PORTB, data,
+ data & BIT(0), 10, 1000000);
+
+ /* 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);
+ udelay(1);
+ return 0;
+}
+
+static int attiny_lcd_power_is_enabled(struct regulator_dev *rdev)
+{
+ unsigned int data;
+ int ret;
+
+ ret = regmap_read(rdev->regmap, REG_POWERON, &data);
+ if (ret < 0)
+ return ret;
+
+ if (!(data & BIT(0)))
+ return 0;
+
+ ret = regmap_read(rdev->regmap, REG_PORTB, &data);
+ 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;
+
+ if (bl->props.power != FB_BLANK_UNBLANK ||
+ bl->props.fb_blank != FB_BLANK_UNBLANK)
+ brightness = 0;
+
+ return regmap_write(regmap, REG_PWM, brightness);
+}
+
+static int attiny_get_brightness(struct backlight_device *bl)
+{
+ struct regmap *regmap = bl_get_data(bl);
+ int ret, brightness;
+
+ ret = regmap_read(regmap, REG_PWM, &brightness);
+ 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);
+ mdelay(1);
+
+ 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");
projects / thirdparty / kernel / linux.git / commitdiff
