1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Acer Iconia Tab A500 Embedded Controller Driver 4 * 5 * Copyright 2020 GRATE-driver project 6 */ 7 8 #include <linux/delay.h> 9 #include <linux/i2c.h> 10 #include <linux/mfd/core.h> 11 #include <linux/module.h> 12 #include <linux/of_device.h> 13 #include <linux/reboot.h> 14 #include <linux/regmap.h> 15 16 #define A500_EC_I2C_ERR_TIMEOUT 500 17 #define A500_EC_POWER_CMD_TIMEOUT 1000 18 19 /* 20 * Controller's firmware expects specific command opcodes to be used for the 21 * corresponding registers. Unsupported commands are skipped by the firmware. 22 */ 23 #define CMD_SHUTDOWN 0x0 24 #define CMD_WARM_REBOOT 0x0 25 #define CMD_COLD_REBOOT 0x1 26 27 enum { 28 REG_CURRENT_NOW = 0x03, 29 REG_SHUTDOWN = 0x52, 30 REG_WARM_REBOOT = 0x54, 31 REG_COLD_REBOOT = 0x55, 32 }; 33 34 static struct i2c_client *a500_ec_client_pm_off; 35 36 static int a500_ec_read(void *context, const void *reg_buf, size_t reg_size, 37 void *val_buf, size_t val_sizel) 38 { 39 struct i2c_client *client = context; 40 unsigned int reg, retries = 5; 41 u16 *ret_val = val_buf; 42 s32 ret = 0; 43 44 reg = *(u8 *)reg_buf; 45 46 while (retries-- > 0) { 47 ret = i2c_smbus_read_word_data(client, reg); 48 if (ret >= 0) 49 break; 50 51 msleep(A500_EC_I2C_ERR_TIMEOUT); 52 } 53 54 if (ret < 0) { 55 dev_err(&client->dev, "read 0x%x failed: %d\n", reg, ret); 56 return ret; 57 } 58 59 *ret_val = ret; 60 61 if (reg == REG_CURRENT_NOW) 62 fsleep(10000); 63 64 return 0; 65 } 66 67 static int a500_ec_write(void *context, const void *data, size_t count) 68 { 69 struct i2c_client *client = context; 70 unsigned int reg, val, retries = 5; 71 s32 ret = 0; 72 73 reg = *(u8 *)(data + 0); 74 val = *(u16 *)(data + 1); 75 76 while (retries-- > 0) { 77 ret = i2c_smbus_write_word_data(client, reg, val); 78 if (ret >= 0) 79 break; 80 81 msleep(A500_EC_I2C_ERR_TIMEOUT); 82 } 83 84 if (ret < 0) { 85 dev_err(&client->dev, "write 0x%x failed: %d\n", reg, ret); 86 return ret; 87 } 88 89 return 0; 90 } 91 92 static const struct regmap_config a500_ec_regmap_config = { 93 .name = "KB930", 94 .reg_bits = 8, 95 .val_bits = 16, 96 .max_register = 0xff, 97 }; 98 99 static const struct regmap_bus a500_ec_regmap_bus = { 100 .reg_format_endian_default = REGMAP_ENDIAN_NATIVE, 101 .val_format_endian_default = REGMAP_ENDIAN_LITTLE, 102 .write = a500_ec_write, 103 .read = a500_ec_read, 104 .max_raw_read = 2, 105 }; 106 107 static void a500_ec_poweroff(void) 108 { 109 i2c_smbus_write_word_data(a500_ec_client_pm_off, 110 REG_SHUTDOWN, CMD_SHUTDOWN); 111 112 mdelay(A500_EC_POWER_CMD_TIMEOUT); 113 } 114 115 static int a500_ec_restart_notify(struct notifier_block *this, 116 unsigned long reboot_mode, void *data) 117 { 118 if (reboot_mode == REBOOT_WARM) 119 i2c_smbus_write_word_data(a500_ec_client_pm_off, 120 REG_WARM_REBOOT, CMD_WARM_REBOOT); 121 else 122 i2c_smbus_write_word_data(a500_ec_client_pm_off, 123 REG_COLD_REBOOT, CMD_COLD_REBOOT); 124 125 mdelay(A500_EC_POWER_CMD_TIMEOUT); 126 127 return NOTIFY_DONE; 128 } 129 130 static struct notifier_block a500_ec_restart_handler = { 131 .notifier_call = a500_ec_restart_notify, 132 .priority = 200, 133 }; 134 135 static const struct mfd_cell a500_ec_cells[] = { 136 { .name = "acer-a500-iconia-battery", }, 137 { .name = "acer-a500-iconia-leds", }, 138 }; 139 140 static int a500_ec_probe(struct i2c_client *client) 141 { 142 struct regmap *regmap; 143 int err; 144 145 regmap = devm_regmap_init(&client->dev, &a500_ec_regmap_bus, 146 client, &a500_ec_regmap_config); 147 if (IS_ERR(regmap)) 148 return PTR_ERR(regmap); 149 150 err = devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_AUTO, 151 a500_ec_cells, ARRAY_SIZE(a500_ec_cells), 152 NULL, 0, NULL); 153 if (err) { 154 dev_err(&client->dev, "failed to add sub-devices: %d\n", err); 155 return err; 156 } 157 158 if (of_device_is_system_power_controller(client->dev.of_node)) { 159 a500_ec_client_pm_off = client; 160 161 err = register_restart_handler(&a500_ec_restart_handler); 162 if (err) 163 return err; 164 165 if (!pm_power_off) 166 pm_power_off = a500_ec_poweroff; 167 } 168 169 return 0; 170 } 171 172 static void a500_ec_remove(struct i2c_client *client) 173 { 174 if (of_device_is_system_power_controller(client->dev.of_node)) { 175 if (pm_power_off == a500_ec_poweroff) 176 pm_power_off = NULL; 177 178 unregister_restart_handler(&a500_ec_restart_handler); 179 } 180 } 181 182 static const struct of_device_id a500_ec_match[] = { 183 { .compatible = "acer,a500-iconia-ec" }, 184 { } 185 }; 186 MODULE_DEVICE_TABLE(of, a500_ec_match); 187 188 static struct i2c_driver a500_ec_driver = { 189 .driver = { 190 .name = "acer-a500-embedded-controller", 191 .of_match_table = a500_ec_match, 192 }, 193 .probe = a500_ec_probe, 194 .remove = a500_ec_remove, 195 }; 196 module_i2c_driver(a500_ec_driver); 197 198 MODULE_DESCRIPTION("Acer Iconia Tab A500 Embedded Controller driver"); 199 MODULE_AUTHOR("Dmitry Osipenko <digetx@gmail.com>"); 200 MODULE_LICENSE("GPL"); 201