summaryrefslogtreecommitdiffstats
path: root/drivers/regulator/rpi-panel-attiny-regulator.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/regulator/rpi-panel-attiny-regulator.c')
-rw-r--r--drivers/regulator/rpi-panel-attiny-regulator.c409
1 files changed, 409 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 0000000000..f52c3d47ec
--- /dev/null
+++ b/drivers/regulator/rpi-panel-attiny-regulator.c
@@ -0,0 +1,409 @@
+// 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/driver.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_PORTB 0x82
+#define REG_PORTC 0x83
+#define REG_POWERON 0x85
+#define REG_PWM 0x86
+#define REG_ADDR_L 0x8c
+#define REG_ADDR_H 0x8d
+#define REG_WRITE_DATA_H 0x90
+#define REG_WRITE_DATA_L 0x91
+
+#define PA_LCD_DITHB BIT(0)
+#define PA_LCD_MODE BIT(1)
+#define PA_LCD_LR BIT(2)
+#define PA_LCD_UD BIT(3)
+
+#define PB_BRIDGE_PWRDNX_N BIT(0)
+#define PB_LCD_VCC_N BIT(1)
+#define PB_LCD_MAIN BIT(7)
+
+#define PC_LED_EN BIT(0)
+#define PC_RST_TP_N BIT(1)
+#define PC_RST_LCD_N BIT(2)
+#define PC_RST_BRIDGE_N BIT(3)
+
+enum gpio_signals {
+ RST_BRIDGE_N, /* TC358762 bridge reset */
+ RST_TP_N, /* Touch controller reset */
+ NUM_GPIO
+};
+
+struct gpio_signal_mappings {
+ unsigned int reg;
+ unsigned int mask;
+};
+
+static const struct gpio_signal_mappings mappings[NUM_GPIO] = {
+ [RST_BRIDGE_N] = { REG_PORTC, PC_RST_BRIDGE_N | PC_RST_LCD_N },
+ [RST_TP_N] = { REG_PORTC, PC_RST_TP_N },
+};
+
+struct attiny_lcd {
+ /* lock to serialise overall accesses to the Atmel */
+ struct mutex lock;
+ struct regmap *regmap;
+ bool gpio_states[NUM_GPIO];
+ u8 port_states[3];
+
+ struct gpio_chip gc;
+};
+
+static const struct regmap_config attiny_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .disable_locking = 1,
+ .max_register = REG_WRITE_DATA_L,
+ .cache_type = REGCACHE_RBTREE,
+};
+
+static int attiny_set_port_state(struct attiny_lcd *state, int reg, u8 val)
+{
+ state->port_states[reg - REG_PORTA] = val;
+ return regmap_write(state->regmap, reg, val);
+};
+
+static u8 attiny_get_port_state(struct attiny_lcd *state, int reg)
+{
+ return state->port_states[reg - REG_PORTA];
+};
+
+static int attiny_lcd_power_enable(struct regulator_dev *rdev)
+{
+ struct attiny_lcd *state = rdev_get_drvdata(rdev);
+
+ mutex_lock(&state->lock);
+
+ /* Ensure bridge, and tp stay in reset */
+ attiny_set_port_state(state, REG_PORTC, 0);
+ usleep_range(5000, 10000);
+
+ /* 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.
+ */
+ attiny_set_port_state(state, REG_PORTA, PA_LCD_LR);
+ usleep_range(5000, 10000);
+ /* Main regulator on, and power to the panel (LCD_VCC_N) */
+ attiny_set_port_state(state, REG_PORTB, PB_LCD_MAIN);
+ usleep_range(5000, 10000);
+ /* Bring controllers out of reset */
+ attiny_set_port_state(state, REG_PORTC, PC_LED_EN);
+
+ msleep(80);
+
+ mutex_unlock(&state->lock);
+
+ return 0;
+}
+
+static int attiny_lcd_power_disable(struct regulator_dev *rdev)
+{
+ struct attiny_lcd *state = rdev_get_drvdata(rdev);
+
+ mutex_lock(&state->lock);
+
+ regmap_write(rdev->regmap, REG_PWM, 0);
+ usleep_range(5000, 10000);
+
+ attiny_set_port_state(state, REG_PORTA, 0);
+ usleep_range(5000, 10000);
+ attiny_set_port_state(state, REG_PORTB, PB_LCD_VCC_N);
+ usleep_range(5000, 10000);
+ attiny_set_port_state(state, REG_PORTC, 0);
+ msleep(30);
+
+ mutex_unlock(&state->lock);
+
+ return 0;
+}
+
+static int attiny_lcd_power_is_enabled(struct regulator_dev *rdev)
+{
+ struct attiny_lcd *state = rdev_get_drvdata(rdev);
+ unsigned int data;
+ int ret, i;
+
+ mutex_lock(&state->lock);
+
+ for (i = 0; i < 10; i++) {
+ ret = regmap_read(rdev->regmap, REG_PORTC, &data);
+ if (!ret)
+ break;
+ usleep_range(10000, 12000);
+ }
+
+ mutex_unlock(&state->lock);
+
+ if (ret < 0)
+ return ret;
+
+ return data & PC_RST_BRIDGE_N;
+}
+
+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 attiny_lcd *state = bl_get_data(bl);
+ struct regmap *regmap = state->regmap;
+ int brightness = backlight_get_brightness(bl);
+ int ret, i;
+
+ mutex_lock(&state->lock);
+
+ for (i = 0; i < 10; i++) {
+ ret = regmap_write(regmap, REG_PWM, brightness);
+ if (!ret)
+ break;
+ }
+
+ mutex_unlock(&state->lock);
+
+ return ret;
+}
+
+static const struct backlight_ops attiny_bl = {
+ .update_status = attiny_update_status,
+};
+
+static int attiny_gpio_get_direction(struct gpio_chip *gc, unsigned int off)
+{
+ return GPIO_LINE_DIRECTION_OUT;
+}
+
+static void attiny_gpio_set(struct gpio_chip *gc, unsigned int off, int val)
+{
+ struct attiny_lcd *state = gpiochip_get_data(gc);
+ u8 last_val;
+
+ if (off >= NUM_GPIO)
+ return;
+
+ mutex_lock(&state->lock);
+
+ last_val = attiny_get_port_state(state, mappings[off].reg);
+ if (val)
+ last_val |= mappings[off].mask;
+ else
+ last_val &= ~mappings[off].mask;
+
+ attiny_set_port_state(state, mappings[off].reg, last_val);
+
+ if (off == RST_BRIDGE_N && val) {
+ usleep_range(5000, 8000);
+ regmap_write(state->regmap, REG_ADDR_H, 0x04);
+ usleep_range(5000, 8000);
+ regmap_write(state->regmap, REG_ADDR_L, 0x7c);
+ usleep_range(5000, 8000);
+ regmap_write(state->regmap, REG_WRITE_DATA_H, 0x00);
+ usleep_range(5000, 8000);
+ regmap_write(state->regmap, REG_WRITE_DATA_L, 0x00);
+
+ msleep(100);
+ }
+
+ mutex_unlock(&state->lock);
+}
+
+static int attiny_i2c_read(struct i2c_client *client, u8 reg, unsigned int *buf)
+{
+ struct i2c_msg msgs[1];
+ u8 addr_buf[1] = { reg };
+ u8 data_buf[1] = { 0, };
+ int ret;
+
+ /* Write register address */
+ msgs[0].addr = client->addr;
+ msgs[0].flags = 0;
+ msgs[0].len = ARRAY_SIZE(addr_buf);
+ msgs[0].buf = addr_buf;
+
+ ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
+ if (ret != ARRAY_SIZE(msgs))
+ return -EIO;
+
+ usleep_range(5000, 10000);
+
+ /* Read data from register */
+ msgs[0].addr = client->addr;
+ msgs[0].flags = I2C_M_RD;
+ msgs[0].len = 1;
+ msgs[0].buf = data_buf;
+
+ ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
+ if (ret != ARRAY_SIZE(msgs))
+ return -EIO;
+
+ *buf = data_buf[0];
+ return 0;
+}
+
+/*
+ * I2C driver interface functions
+ */
+static int attiny_i2c_probe(struct i2c_client *i2c)
+{
+ struct backlight_properties props = { };
+ struct regulator_config config = { };
+ struct backlight_device *bl;
+ struct regulator_dev *rdev;
+ struct attiny_lcd *state;
+ struct regmap *regmap;
+ unsigned int data;
+ int ret;
+
+ state = devm_kzalloc(&i2c->dev, sizeof(*state), GFP_KERNEL);
+ if (!state)
+ return -ENOMEM;
+
+ mutex_init(&state->lock);
+ i2c_set_clientdata(i2c, state);
+
+ 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);
+ goto error;
+ }
+
+ ret = attiny_i2c_read(i2c, REG_ID, &data);
+ if (ret < 0) {
+ dev_err(&i2c->dev, "Failed to read REG_ID reg: %d\n", ret);
+ goto error;
+ }
+
+ switch (data) {
+ case 0xde: /* ver 1 */
+ case 0xc3: /* ver 2 */
+ break;
+ default:
+ dev_err(&i2c->dev, "Unknown Atmel firmware revision: 0x%02x\n", data);
+ ret = -ENODEV;
+ goto error;
+ }
+
+ regmap_write(regmap, REG_POWERON, 0);
+ msleep(30);
+ regmap_write(regmap, REG_PWM, 0);
+
+ config.dev = &i2c->dev;
+ config.regmap = regmap;
+ config.of_node = i2c->dev.of_node;
+ config.init_data = &attiny_regulator_default;
+ config.driver_data = state;
+
+ rdev = devm_regulator_register(&i2c->dev, &attiny_regulator, &config);
+ if (IS_ERR(rdev)) {
+ dev_err(&i2c->dev, "Failed to register ATTINY regulator\n");
+ ret = PTR_ERR(rdev);
+ goto error;
+ }
+
+ props.type = BACKLIGHT_RAW;
+ props.max_brightness = 0xff;
+
+ state->regmap = regmap;
+
+ bl = devm_backlight_device_register(&i2c->dev, dev_name(&i2c->dev),
+ &i2c->dev, state, &attiny_bl,
+ &props);
+ if (IS_ERR(bl)) {
+ ret = PTR_ERR(bl);
+ goto error;
+ }
+
+ bl->props.brightness = 0xff;
+
+ state->gc.parent = &i2c->dev;
+ state->gc.label = i2c->name;
+ state->gc.owner = THIS_MODULE;
+ state->gc.base = -1;
+ state->gc.ngpio = NUM_GPIO;
+
+ state->gc.set = attiny_gpio_set;
+ state->gc.get_direction = attiny_gpio_get_direction;
+ state->gc.can_sleep = true;
+
+ ret = devm_gpiochip_add_data(&i2c->dev, &state->gc, state);
+ if (ret) {
+ dev_err(&i2c->dev, "Failed to create gpiochip: %d\n", ret);
+ goto error;
+ }
+
+ return 0;
+
+error:
+ mutex_destroy(&state->lock);
+
+ return ret;
+}
+
+static void attiny_i2c_remove(struct i2c_client *client)
+{
+ struct attiny_lcd *state = i2c_get_clientdata(client);
+
+ mutex_destroy(&state->lock);
+}
+
+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",
+ .probe_type = PROBE_PREFER_ASYNCHRONOUS,
+ .of_match_table = attiny_dt_ids,
+ },
+ .probe = attiny_i2c_probe,
+ .remove = attiny_i2c_remove,
+};
+
+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");