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.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, command: 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(usecs: 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, command: reg, value: 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(client: a500_ec_client_pm_off, |
110 | command: 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(client: a500_ec_client_pm_off, |
120 | command: REG_WARM_REBOOT, CMD_WARM_REBOOT); |
121 | else |
122 | i2c_smbus_write_word_data(client: a500_ec_client_pm_off, |
123 | command: 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(ptr: regmap)) |
148 | return PTR_ERR(ptr: regmap); |
149 | |
150 | err = devm_mfd_add_devices(dev: &client->dev, PLATFORM_DEVID_AUTO, |
151 | cells: a500_ec_cells, ARRAY_SIZE(a500_ec_cells), |
152 | NULL, irq_base: 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(np: 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(np: 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 | |