aboutsummaryrefslogtreecommitdiff
path: root/drivers/mfd/ene-kb3930.c
blob: 83243e668e3f9ba5801b2fa8f051582d5d0b5c90 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
// SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0-or-later
/*
 * ENE KB3930 Embedded Controller Driver
 *
 * Copyright (C) 2020 Lubomir Rintel
 */

#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/mfd/core.h>
#include <linux/module.h>
#include <linux/reboot.h>
#include <linux/regmap.h>

/* I2C registers that are multiplexing access to the EC RAM. */
enum {
	EC_DATA_IN	= 0x00,
	EC_RAM_OUT	= 0x80,
	EC_RAM_IN	= 0x81,
};

/* EC RAM registers. */
enum {
	EC_MODEL	= 0x30,
	EC_VERSION_MAJ	= 0x31,
	EC_VERSION_MIN	= 0x32,
};

struct kb3930 {
	struct i2c_client *client;
	struct regmap *ram_regmap;
	struct gpio_descs *off_gpios;
};

struct kb3930 *kb3930_power_off;

#define EC_GPIO_WAVE		0
#define EC_GPIO_OFF_MODE	1

#define EC_OFF_MODE_REBOOT	0
#define EC_OFF_MODE_POWER	1

static void kb3930_off(struct kb3930 *ddata, int off_mode)
{
	gpiod_direction_output(ddata->off_gpios->desc[EC_GPIO_OFF_MODE],
			       off_mode);

	/*
	 * This creates a 10 Hz wave on EC_GPIO_WAVE that signals a
	 * shutdown request to the EC. Once the EC detects it, it will
	 * proceed to turn the power off or reset the board depending on
	 * the value of EC_GPIO_OFF_MODE.
	 */
	while (1) {
		mdelay(50);
		gpiod_direction_output(ddata->off_gpios->desc[EC_GPIO_WAVE], 0);
		mdelay(50);
		gpiod_direction_output(ddata->off_gpios->desc[EC_GPIO_WAVE], 1);
	}
}

static int kb3930_restart(struct notifier_block *this,
			  unsigned long mode, void *cmd)
{
	kb3930_off(kb3930_power_off, EC_OFF_MODE_REBOOT);
	return NOTIFY_DONE;
}

static void kb3930_pm_power_off(void)
{
	kb3930_off(kb3930_power_off, EC_OFF_MODE_POWER);
}

static struct notifier_block kb3930_restart_nb = {
	.notifier_call = kb3930_restart,
};

static const struct mfd_cell ariel_ec_cells[] = {
	{ .name = "dell-wyse-ariel-led", },
	{ .name = "dell-wyse-ariel-power", },
};

static int kb3930_ec_ram_reg_write(void *context, unsigned int reg,
				   unsigned int val)
{
	struct kb3930 *ddata = context;

	return i2c_smbus_write_word_data(ddata->client, EC_RAM_OUT,
					 (val << 8) | reg);
}

static int kb3930_ec_ram_reg_read(void *context, unsigned int reg,
				  unsigned int *val)
{
	struct kb3930 *ddata = context;
	int ret;

	ret = i2c_smbus_write_word_data(ddata->client, EC_RAM_IN, reg);
	if (ret < 0)
		return ret;

	ret = i2c_smbus_read_word_data(ddata->client, EC_DATA_IN);
	if (ret < 0)
		return ret;

	*val = ret >> 8;
	return 0;
}

static const struct regmap_config kb3930_ram_regmap_config = {
	.name = "ec_ram",
	.reg_bits = 8,
	.val_bits = 8,
	.reg_stride = 1,
	.max_register = 0xff,
	.reg_write = kb3930_ec_ram_reg_write,
	.reg_read = kb3930_ec_ram_reg_read,
	.fast_io = false,
};

static int kb3930_probe(struct i2c_client *client)
{
	struct device *dev = &client->dev;
	struct device_node *np = dev->of_node;
	struct kb3930 *ddata;
	unsigned int model;
	int ret;

	ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
	if (!ddata)
		return -ENOMEM;

	kb3930_power_off = ddata;
	ddata->client = client;
	i2c_set_clientdata(client, ddata);

	ddata->ram_regmap = devm_regmap_init(dev, NULL, ddata,
					     &kb3930_ram_regmap_config);
	if (IS_ERR(ddata->ram_regmap))
		return PTR_ERR(ddata->ram_regmap);

	ret = regmap_read(ddata->ram_regmap, EC_MODEL, &model);
	if (ret < 0)
		return ret;

	/* Currently we only support the cells present on Dell Ariel model. */
	if (model != 'J') {
		dev_err(dev, "unknown board model: %02x\n", model);
		return -ENODEV;
	}

	ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_AUTO,
				   ariel_ec_cells,
				   ARRAY_SIZE(ariel_ec_cells),
				   NULL, 0, NULL);
	if (ret)
		return ret;

	if (of_property_read_bool(np, "system-power-controller")) {
		ddata->off_gpios =
			devm_gpiod_get_array_optional(dev, "off", GPIOD_IN);
		if (IS_ERR(ddata->off_gpios))
			return PTR_ERR(ddata->off_gpios);
		if (ddata->off_gpios->ndescs < 2) {
			dev_err(dev, "invalid off-gpios property\n");
			return -EINVAL;
		}
	}

	if (ddata->off_gpios) {
		register_restart_handler(&kb3930_restart_nb);
		if (!pm_power_off)
			pm_power_off = kb3930_pm_power_off;
	}

	return 0;
}

static int kb3930_remove(struct i2c_client *client)
{
	struct kb3930 *ddata = i2c_get_clientdata(client);

	if (ddata->off_gpios) {
		if (pm_power_off == kb3930_pm_power_off)
			pm_power_off = NULL;
		unregister_restart_handler(&kb3930_restart_nb);
	}
	kb3930_power_off = NULL;

	return 0;
}

static const struct of_device_id kb3930_dt_ids[] = {
	{ .compatible = "ene,kb3930" },
	{ }
};
MODULE_DEVICE_TABLE(of, kb3930_dt_ids);

static struct i2c_driver kb3930_driver = {
	.probe_new = kb3930_probe,
	.remove = kb3930_remove,
	.driver = {
		.name = "ene-kb3930",
		.of_match_table = kb3930_dt_ids,
	},
};
module_i2c_driver(kb3930_driver);

MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
MODULE_DESCRIPTION("ENE KB3930 Embedded Controller Driver");
MODULE_LICENSE("Dual BSD/GPL");