Linux 4.19.133
[linux/fpc-iii.git] / drivers / i2c / muxes / i2c-mux-ltc4306.c
bloba9af93259b19df97c4a60da563ffb2174125b42c
1 /*
2 * Linear Technology LTC4306 and LTC4305 I2C multiplexer/switch
4 * Copyright (C) 2017 Analog Devices Inc.
6 * Licensed under the GPL-2.
8 * Based on: i2c-mux-pca954x.c
10 * Datasheet: http://cds.linear.com/docs/en/datasheet/4306.pdf
13 #include <linux/gpio/consumer.h>
14 #include <linux/gpio/driver.h>
15 #include <linux/i2c-mux.h>
16 #include <linux/i2c.h>
17 #include <linux/module.h>
18 #include <linux/of.h>
19 #include <linux/of_device.h>
20 #include <linux/property.h>
21 #include <linux/regmap.h>
22 #include <linux/slab.h>
24 #define LTC4305_MAX_NCHANS 2
25 #define LTC4306_MAX_NCHANS 4
27 #define LTC_REG_STATUS 0x0
28 #define LTC_REG_CONFIG 0x1
29 #define LTC_REG_MODE 0x2
30 #define LTC_REG_SWITCH 0x3
32 #define LTC_DOWNSTREAM_ACCL_EN BIT(6)
33 #define LTC_UPSTREAM_ACCL_EN BIT(7)
35 #define LTC_GPIO_ALL_INPUT 0xC0
36 #define LTC_SWITCH_MASK 0xF0
38 enum ltc_type {
39 ltc_4305,
40 ltc_4306,
43 struct chip_desc {
44 u8 nchans;
45 u8 num_gpios;
48 struct ltc4306 {
49 struct regmap *regmap;
50 struct gpio_chip gpiochip;
51 const struct chip_desc *chip;
54 static const struct chip_desc chips[] = {
55 [ltc_4305] = {
56 .nchans = LTC4305_MAX_NCHANS,
58 [ltc_4306] = {
59 .nchans = LTC4306_MAX_NCHANS,
60 .num_gpios = 2,
64 static bool ltc4306_is_volatile_reg(struct device *dev, unsigned int reg)
66 return (reg == LTC_REG_CONFIG) ? true : false;
69 static const struct regmap_config ltc4306_regmap_config = {
70 .reg_bits = 8,
71 .val_bits = 8,
72 .max_register = LTC_REG_SWITCH,
73 .volatile_reg = ltc4306_is_volatile_reg,
74 .cache_type = REGCACHE_FLAT,
77 static int ltc4306_gpio_get(struct gpio_chip *chip, unsigned int offset)
79 struct ltc4306 *data = gpiochip_get_data(chip);
80 unsigned int val;
81 int ret;
83 ret = regmap_read(data->regmap, LTC_REG_CONFIG, &val);
84 if (ret < 0)
85 return ret;
87 return !!(val & BIT(1 - offset));
90 static void ltc4306_gpio_set(struct gpio_chip *chip, unsigned int offset,
91 int value)
93 struct ltc4306 *data = gpiochip_get_data(chip);
95 regmap_update_bits(data->regmap, LTC_REG_CONFIG, BIT(5 - offset),
96 value ? BIT(5 - offset) : 0);
99 static int ltc4306_gpio_get_direction(struct gpio_chip *chip,
100 unsigned int offset)
102 struct ltc4306 *data = gpiochip_get_data(chip);
103 unsigned int val;
104 int ret;
106 ret = regmap_read(data->regmap, LTC_REG_MODE, &val);
107 if (ret < 0)
108 return ret;
110 return !!(val & BIT(7 - offset));
113 static int ltc4306_gpio_direction_input(struct gpio_chip *chip,
114 unsigned int offset)
116 struct ltc4306 *data = gpiochip_get_data(chip);
118 return regmap_update_bits(data->regmap, LTC_REG_MODE,
119 BIT(7 - offset), BIT(7 - offset));
122 static int ltc4306_gpio_direction_output(struct gpio_chip *chip,
123 unsigned int offset, int value)
125 struct ltc4306 *data = gpiochip_get_data(chip);
127 ltc4306_gpio_set(chip, offset, value);
128 return regmap_update_bits(data->regmap, LTC_REG_MODE,
129 BIT(7 - offset), 0);
132 static int ltc4306_gpio_set_config(struct gpio_chip *chip,
133 unsigned int offset, unsigned long config)
135 struct ltc4306 *data = gpiochip_get_data(chip);
136 unsigned int val;
138 switch (pinconf_to_config_param(config)) {
139 case PIN_CONFIG_DRIVE_OPEN_DRAIN:
140 val = 0;
141 break;
142 case PIN_CONFIG_DRIVE_PUSH_PULL:
143 val = BIT(4 - offset);
144 break;
145 default:
146 return -ENOTSUPP;
149 return regmap_update_bits(data->regmap, LTC_REG_MODE,
150 BIT(4 - offset), val);
153 static int ltc4306_gpio_init(struct ltc4306 *data)
155 struct device *dev = regmap_get_device(data->regmap);
157 if (!data->chip->num_gpios)
158 return 0;
160 data->gpiochip.label = dev_name(dev);
161 data->gpiochip.base = -1;
162 data->gpiochip.ngpio = data->chip->num_gpios;
163 data->gpiochip.parent = dev;
164 data->gpiochip.can_sleep = true;
165 data->gpiochip.get_direction = ltc4306_gpio_get_direction;
166 data->gpiochip.direction_input = ltc4306_gpio_direction_input;
167 data->gpiochip.direction_output = ltc4306_gpio_direction_output;
168 data->gpiochip.get = ltc4306_gpio_get;
169 data->gpiochip.set = ltc4306_gpio_set;
170 data->gpiochip.set_config = ltc4306_gpio_set_config;
171 data->gpiochip.owner = THIS_MODULE;
173 /* gpiolib assumes all GPIOs default input */
174 regmap_write(data->regmap, LTC_REG_MODE, LTC_GPIO_ALL_INPUT);
176 return devm_gpiochip_add_data(dev, &data->gpiochip, data);
179 static int ltc4306_select_mux(struct i2c_mux_core *muxc, u32 chan)
181 struct ltc4306 *data = i2c_mux_priv(muxc);
183 return regmap_update_bits(data->regmap, LTC_REG_SWITCH,
184 LTC_SWITCH_MASK, BIT(7 - chan));
187 static int ltc4306_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
189 struct ltc4306 *data = i2c_mux_priv(muxc);
191 return regmap_update_bits(data->regmap, LTC_REG_SWITCH,
192 LTC_SWITCH_MASK, 0);
195 static const struct i2c_device_id ltc4306_id[] = {
196 { "ltc4305", ltc_4305 },
197 { "ltc4306", ltc_4306 },
200 MODULE_DEVICE_TABLE(i2c, ltc4306_id);
202 static const struct of_device_id ltc4306_of_match[] = {
203 { .compatible = "lltc,ltc4305", .data = &chips[ltc_4305] },
204 { .compatible = "lltc,ltc4306", .data = &chips[ltc_4306] },
207 MODULE_DEVICE_TABLE(of, ltc4306_of_match);
209 static int ltc4306_probe(struct i2c_client *client)
211 struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
212 const struct chip_desc *chip;
213 struct i2c_mux_core *muxc;
214 struct ltc4306 *data;
215 struct gpio_desc *gpio;
216 bool idle_disc;
217 unsigned int val = 0;
218 int num, ret;
220 chip = of_device_get_match_data(&client->dev);
222 if (!chip)
223 chip = &chips[i2c_match_id(ltc4306_id, client)->driver_data];
225 idle_disc = device_property_read_bool(&client->dev,
226 "i2c-mux-idle-disconnect");
228 muxc = i2c_mux_alloc(adap, &client->dev,
229 chip->nchans, sizeof(*data),
230 I2C_MUX_LOCKED, ltc4306_select_mux,
231 idle_disc ? ltc4306_deselect_mux : NULL);
232 if (!muxc)
233 return -ENOMEM;
234 data = i2c_mux_priv(muxc);
235 data->chip = chip;
237 i2c_set_clientdata(client, muxc);
239 data->regmap = devm_regmap_init_i2c(client, &ltc4306_regmap_config);
240 if (IS_ERR(data->regmap)) {
241 ret = PTR_ERR(data->regmap);
242 dev_err(&client->dev, "Failed to allocate register map: %d\n",
243 ret);
244 return ret;
247 /* Reset and enable the mux if an enable GPIO is specified. */
248 gpio = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_LOW);
249 if (IS_ERR(gpio))
250 return PTR_ERR(gpio);
252 if (gpio) {
253 udelay(1);
254 gpiod_set_value(gpio, 1);
258 * Write the mux register at addr to verify
259 * that the mux is in fact present. This also
260 * initializes the mux to disconnected state.
262 if (regmap_write(data->regmap, LTC_REG_SWITCH, 0) < 0) {
263 dev_warn(&client->dev, "probe failed\n");
264 return -ENODEV;
267 if (device_property_read_bool(&client->dev,
268 "ltc,downstream-accelerators-enable"))
269 val |= LTC_DOWNSTREAM_ACCL_EN;
271 if (device_property_read_bool(&client->dev,
272 "ltc,upstream-accelerators-enable"))
273 val |= LTC_UPSTREAM_ACCL_EN;
275 if (regmap_write(data->regmap, LTC_REG_CONFIG, val) < 0)
276 return -ENODEV;
278 ret = ltc4306_gpio_init(data);
279 if (ret < 0)
280 return ret;
282 /* Now create an adapter for each channel */
283 for (num = 0; num < chip->nchans; num++) {
284 ret = i2c_mux_add_adapter(muxc, 0, num, 0);
285 if (ret) {
286 i2c_mux_del_adapters(muxc);
287 return ret;
291 dev_info(&client->dev,
292 "registered %d multiplexed busses for I2C switch %s\n",
293 num, client->name);
295 return 0;
298 static int ltc4306_remove(struct i2c_client *client)
300 struct i2c_mux_core *muxc = i2c_get_clientdata(client);
302 i2c_mux_del_adapters(muxc);
304 return 0;
307 static struct i2c_driver ltc4306_driver = {
308 .driver = {
309 .name = "ltc4306",
310 .of_match_table = of_match_ptr(ltc4306_of_match),
312 .probe_new = ltc4306_probe,
313 .remove = ltc4306_remove,
314 .id_table = ltc4306_id,
317 module_i2c_driver(ltc4306_driver);
319 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
320 MODULE_DESCRIPTION("Linear Technology LTC4306, LTC4305 I2C mux/switch driver");
321 MODULE_LICENSE("GPL v2");