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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> | |
dc0c386e | 12 | #include <linux/of.h> |
92eba680 DO |
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 | ||
ed5c2f5f | 172 | static void a500_ec_remove(struct i2c_client *client) |
92eba680 DO |
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 | } | |
92eba680 DO |
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 | }, | |
9816d859 | 193 | .probe = a500_ec_probe, |
92eba680 DO |
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"); |