Marek Vasut | 3857347 | 2020-08-09 12:59:38 +0200 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * Copyright (C) 2020 Marek Vasut <marex@denx.de> |
| 4 | * |
| 5 | * Based on rpi_touchscreen.c by Eric Anholt <eric@anholt.net> |
| 6 | */ |
| 7 | |
| 8 | #include <linux/backlight.h> |
| 9 | #include <linux/err.h> |
| 10 | #include <linux/gpio.h> |
| 11 | #include <linux/i2c.h> |
| 12 | #include <linux/init.h> |
| 13 | #include <linux/interrupt.h> |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/regmap.h> |
| 16 | #include <linux/regulator/driver.h> |
| 17 | #include <linux/regulator/machine.h> |
| 18 | #include <linux/regulator/of_regulator.h> |
| 19 | #include <linux/slab.h> |
| 20 | |
| 21 | /* I2C registers of the Atmel microcontroller. */ |
| 22 | #define REG_ID 0x80 |
| 23 | #define REG_PORTA 0x81 |
| 24 | #define REG_PORTA_HF BIT(2) |
| 25 | #define REG_PORTA_VF BIT(3) |
| 26 | #define REG_PORTB 0x82 |
| 27 | #define REG_POWERON 0x85 |
| 28 | #define REG_PWM 0x86 |
| 29 | |
| 30 | static const struct regmap_config attiny_regmap_config = { |
| 31 | .reg_bits = 8, |
| 32 | .val_bits = 8, |
| 33 | .max_register = REG_PWM, |
| 34 | .cache_type = REGCACHE_NONE, |
| 35 | }; |
| 36 | |
| 37 | static int attiny_lcd_power_enable(struct regulator_dev *rdev) |
| 38 | { |
| 39 | unsigned int data; |
| 40 | |
| 41 | regmap_write(rdev->regmap, REG_POWERON, 1); |
| 42 | /* Wait for nPWRDWN to go low to indicate poweron is done. */ |
| 43 | regmap_read_poll_timeout(rdev->regmap, REG_PORTB, data, |
| 44 | data & BIT(0), 10, 1000000); |
| 45 | |
| 46 | /* Default to the same orientation as the closed source |
| 47 | * firmware used for the panel. Runtime rotation |
| 48 | * configuration will be supported using VC4's plane |
| 49 | * orientation bits. |
| 50 | */ |
| 51 | regmap_write(rdev->regmap, REG_PORTA, BIT(2)); |
| 52 | |
| 53 | return 0; |
| 54 | } |
| 55 | |
| 56 | static int attiny_lcd_power_disable(struct regulator_dev *rdev) |
| 57 | { |
| 58 | regmap_write(rdev->regmap, REG_PWM, 0); |
| 59 | regmap_write(rdev->regmap, REG_POWERON, 0); |
| 60 | udelay(1); |
| 61 | return 0; |
| 62 | } |
| 63 | |
| 64 | static int attiny_lcd_power_is_enabled(struct regulator_dev *rdev) |
| 65 | { |
| 66 | unsigned int data; |
| 67 | int ret; |
| 68 | |
| 69 | ret = regmap_read(rdev->regmap, REG_POWERON, &data); |
| 70 | if (ret < 0) |
| 71 | return ret; |
| 72 | |
| 73 | if (!(data & BIT(0))) |
| 74 | return 0; |
| 75 | |
| 76 | ret = regmap_read(rdev->regmap, REG_PORTB, &data); |
| 77 | if (ret < 0) |
| 78 | return ret; |
| 79 | |
| 80 | return data & BIT(0); |
| 81 | } |
| 82 | |
| 83 | static const struct regulator_init_data attiny_regulator_default = { |
| 84 | .constraints = { |
| 85 | .valid_ops_mask = REGULATOR_CHANGE_STATUS, |
| 86 | }, |
| 87 | }; |
| 88 | |
| 89 | static const struct regulator_ops attiny_regulator_ops = { |
| 90 | .enable = attiny_lcd_power_enable, |
| 91 | .disable = attiny_lcd_power_disable, |
| 92 | .is_enabled = attiny_lcd_power_is_enabled, |
| 93 | }; |
| 94 | |
| 95 | static const struct regulator_desc attiny_regulator = { |
| 96 | .name = "tc358762-power", |
| 97 | .ops = &attiny_regulator_ops, |
| 98 | .type = REGULATOR_VOLTAGE, |
| 99 | .owner = THIS_MODULE, |
| 100 | }; |
| 101 | |
| 102 | static int attiny_update_status(struct backlight_device *bl) |
| 103 | { |
| 104 | struct regmap *regmap = bl_get_data(bl); |
| 105 | int brightness = bl->props.brightness; |
| 106 | |
| 107 | if (bl->props.power != FB_BLANK_UNBLANK || |
| 108 | bl->props.fb_blank != FB_BLANK_UNBLANK) |
| 109 | brightness = 0; |
| 110 | |
| 111 | return regmap_write(regmap, REG_PWM, brightness); |
| 112 | } |
| 113 | |
| 114 | static int attiny_get_brightness(struct backlight_device *bl) |
| 115 | { |
| 116 | struct regmap *regmap = bl_get_data(bl); |
| 117 | int ret, brightness; |
| 118 | |
| 119 | ret = regmap_read(regmap, REG_PWM, &brightness); |
| 120 | if (ret) |
| 121 | return ret; |
| 122 | |
| 123 | return brightness; |
| 124 | } |
| 125 | |
| 126 | static const struct backlight_ops attiny_bl = { |
| 127 | .update_status = attiny_update_status, |
| 128 | .get_brightness = attiny_get_brightness, |
| 129 | }; |
| 130 | |
| 131 | /* |
| 132 | * I2C driver interface functions |
| 133 | */ |
| 134 | static int attiny_i2c_probe(struct i2c_client *i2c, |
| 135 | const struct i2c_device_id *id) |
| 136 | { |
| 137 | struct backlight_properties props = { }; |
| 138 | struct regulator_config config = { }; |
| 139 | struct backlight_device *bl; |
| 140 | struct regulator_dev *rdev; |
| 141 | struct regmap *regmap; |
| 142 | unsigned int data; |
| 143 | int ret; |
| 144 | |
| 145 | regmap = devm_regmap_init_i2c(i2c, &attiny_regmap_config); |
| 146 | if (IS_ERR(regmap)) { |
| 147 | ret = PTR_ERR(regmap); |
| 148 | dev_err(&i2c->dev, "Failed to allocate register map: %d\n", |
| 149 | ret); |
| 150 | return ret; |
| 151 | } |
| 152 | |
| 153 | ret = regmap_read(regmap, REG_ID, &data); |
| 154 | if (ret < 0) { |
| 155 | dev_err(&i2c->dev, "Failed to read REG_ID reg: %d\n", ret); |
| 156 | return ret; |
| 157 | } |
| 158 | |
| 159 | switch (data) { |
| 160 | case 0xde: /* ver 1 */ |
| 161 | case 0xc3: /* ver 2 */ |
| 162 | break; |
| 163 | default: |
| 164 | dev_err(&i2c->dev, "Unknown Atmel firmware revision: 0x%02x\n", data); |
| 165 | return -ENODEV; |
| 166 | } |
| 167 | |
| 168 | regmap_write(regmap, REG_POWERON, 0); |
| 169 | mdelay(1); |
| 170 | |
| 171 | config.dev = &i2c->dev; |
| 172 | config.regmap = regmap; |
| 173 | config.of_node = i2c->dev.of_node; |
| 174 | config.init_data = &attiny_regulator_default; |
| 175 | |
| 176 | rdev = devm_regulator_register(&i2c->dev, &attiny_regulator, &config); |
| 177 | if (IS_ERR(rdev)) { |
| 178 | dev_err(&i2c->dev, "Failed to register ATTINY regulator\n"); |
| 179 | return PTR_ERR(rdev); |
| 180 | } |
| 181 | |
| 182 | props.type = BACKLIGHT_RAW; |
| 183 | props.max_brightness = 0xff; |
| 184 | bl = devm_backlight_device_register(&i2c->dev, |
| 185 | "7inch-touchscreen-panel-bl", |
| 186 | &i2c->dev, regmap, &attiny_bl, |
| 187 | &props); |
| 188 | if (IS_ERR(bl)) |
| 189 | return PTR_ERR(bl); |
| 190 | |
| 191 | bl->props.brightness = 0xff; |
| 192 | |
| 193 | return 0; |
| 194 | } |
| 195 | |
| 196 | static const struct of_device_id attiny_dt_ids[] = { |
| 197 | { .compatible = "raspberrypi,7inch-touchscreen-panel-regulator" }, |
| 198 | {}, |
| 199 | }; |
| 200 | MODULE_DEVICE_TABLE(of, attiny_dt_ids); |
| 201 | |
| 202 | static struct i2c_driver attiny_regulator_driver = { |
| 203 | .driver = { |
| 204 | .name = "rpi_touchscreen_attiny", |
| 205 | .of_match_table = of_match_ptr(attiny_dt_ids), |
| 206 | }, |
| 207 | .probe = attiny_i2c_probe, |
| 208 | }; |
| 209 | |
| 210 | module_i2c_driver(attiny_regulator_driver); |
| 211 | |
| 212 | MODULE_AUTHOR("Marek Vasut <marex@denx.de>"); |
| 213 | MODULE_DESCRIPTION("Regulator device driver for Raspberry Pi 7-inch touchscreen"); |
| 214 | MODULE_LICENSE("GPL v2"); |