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12#include <linux/gpio/consumer.h>
13#include <linux/gpio/driver.h>
14#include <linux/i2c-mux.h>
15#include <linux/i2c.h>
16#include <linux/module.h>
17#include <linux/of.h>
18#include <linux/of_device.h>
19#include <linux/property.h>
20#include <linux/regmap.h>
21#include <linux/slab.h>
22
23#define LTC4305_MAX_NCHANS 2
24#define LTC4306_MAX_NCHANS 4
25
26#define LTC_REG_STATUS 0x0
27#define LTC_REG_CONFIG 0x1
28#define LTC_REG_MODE 0x2
29#define LTC_REG_SWITCH 0x3
30
31#define LTC_DOWNSTREAM_ACCL_EN BIT(6)
32#define LTC_UPSTREAM_ACCL_EN BIT(7)
33
34#define LTC_GPIO_ALL_INPUT 0xC0
35#define LTC_SWITCH_MASK 0xF0
36
37enum ltc_type {
38 ltc_4305,
39 ltc_4306,
40};
41
42struct chip_desc {
43 u8 nchans;
44 u8 num_gpios;
45};
46
47struct ltc4306 {
48 struct regmap *regmap;
49 struct gpio_chip gpiochip;
50 const struct chip_desc *chip;
51};
52
53static const struct chip_desc chips[] = {
54 [ltc_4305] = {
55 .nchans = LTC4305_MAX_NCHANS,
56 },
57 [ltc_4306] = {
58 .nchans = LTC4306_MAX_NCHANS,
59 .num_gpios = 2,
60 },
61};
62
63static bool ltc4306_is_volatile_reg(struct device *dev, unsigned int reg)
64{
65 return (reg == LTC_REG_CONFIG) ? true : false;
66}
67
68static const struct regmap_config ltc4306_regmap_config = {
69 .reg_bits = 8,
70 .val_bits = 8,
71 .max_register = LTC_REG_SWITCH,
72 .volatile_reg = ltc4306_is_volatile_reg,
73 .cache_type = REGCACHE_FLAT,
74};
75
76static int ltc4306_gpio_get(struct gpio_chip *chip, unsigned int offset)
77{
78 struct ltc4306 *data = gpiochip_get_data(chip);
79 unsigned int val;
80 int ret;
81
82 ret = regmap_read(data->regmap, LTC_REG_CONFIG, &val);
83 if (ret < 0)
84 return ret;
85
86 return !!(val & BIT(1 - offset));
87}
88
89static void ltc4306_gpio_set(struct gpio_chip *chip, unsigned int offset,
90 int value)
91{
92 struct ltc4306 *data = gpiochip_get_data(chip);
93
94 regmap_update_bits(data->regmap, LTC_REG_CONFIG, BIT(5 - offset),
95 value ? BIT(5 - offset) : 0);
96}
97
98static int ltc4306_gpio_get_direction(struct gpio_chip *chip,
99 unsigned int offset)
100{
101 struct ltc4306 *data = gpiochip_get_data(chip);
102 unsigned int val;
103 int ret;
104
105 ret = regmap_read(data->regmap, LTC_REG_MODE, &val);
106 if (ret < 0)
107 return ret;
108
109 return !!(val & BIT(7 - offset));
110}
111
112static int ltc4306_gpio_direction_input(struct gpio_chip *chip,
113 unsigned int offset)
114{
115 struct ltc4306 *data = gpiochip_get_data(chip);
116
117 return regmap_update_bits(data->regmap, LTC_REG_MODE,
118 BIT(7 - offset), BIT(7 - offset));
119}
120
121static int ltc4306_gpio_direction_output(struct gpio_chip *chip,
122 unsigned int offset, int value)
123{
124 struct ltc4306 *data = gpiochip_get_data(chip);
125
126 ltc4306_gpio_set(chip, offset, value);
127 return regmap_update_bits(data->regmap, LTC_REG_MODE,
128 BIT(7 - offset), 0);
129}
130
131static int ltc4306_gpio_set_config(struct gpio_chip *chip,
132 unsigned int offset, unsigned long config)
133{
134 struct ltc4306 *data = gpiochip_get_data(chip);
135 unsigned int val;
136
137 switch (pinconf_to_config_param(config)) {
138 case PIN_CONFIG_DRIVE_OPEN_DRAIN:
139 val = 0;
140 break;
141 case PIN_CONFIG_DRIVE_PUSH_PULL:
142 val = BIT(4 - offset);
143 break;
144 default:
145 return -ENOTSUPP;
146 }
147
148 return regmap_update_bits(data->regmap, LTC_REG_MODE,
149 BIT(4 - offset), val);
150}
151
152static int ltc4306_gpio_init(struct ltc4306 *data)
153{
154 struct device *dev = regmap_get_device(data->regmap);
155
156 if (!data->chip->num_gpios)
157 return 0;
158
159 data->gpiochip.label = dev_name(dev);
160 data->gpiochip.base = -1;
161 data->gpiochip.ngpio = data->chip->num_gpios;
162 data->gpiochip.parent = dev;
163 data->gpiochip.can_sleep = true;
164 data->gpiochip.get_direction = ltc4306_gpio_get_direction;
165 data->gpiochip.direction_input = ltc4306_gpio_direction_input;
166 data->gpiochip.direction_output = ltc4306_gpio_direction_output;
167 data->gpiochip.get = ltc4306_gpio_get;
168 data->gpiochip.set = ltc4306_gpio_set;
169 data->gpiochip.set_config = ltc4306_gpio_set_config;
170 data->gpiochip.owner = THIS_MODULE;
171
172
173 regmap_write(data->regmap, LTC_REG_MODE, LTC_GPIO_ALL_INPUT);
174
175 return devm_gpiochip_add_data(dev, &data->gpiochip, data);
176}
177
178static int ltc4306_select_mux(struct i2c_mux_core *muxc, u32 chan)
179{
180 struct ltc4306 *data = i2c_mux_priv(muxc);
181
182 return regmap_update_bits(data->regmap, LTC_REG_SWITCH,
183 LTC_SWITCH_MASK, BIT(7 - chan));
184}
185
186static int ltc4306_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
187{
188 struct ltc4306 *data = i2c_mux_priv(muxc);
189
190 return regmap_update_bits(data->regmap, LTC_REG_SWITCH,
191 LTC_SWITCH_MASK, 0);
192}
193
194static const struct i2c_device_id ltc4306_id[] = {
195 { "ltc4305", ltc_4305 },
196 { "ltc4306", ltc_4306 },
197 { }
198};
199MODULE_DEVICE_TABLE(i2c, ltc4306_id);
200
201static const struct of_device_id ltc4306_of_match[] = {
202 { .compatible = "lltc,ltc4305", .data = &chips[ltc_4305] },
203 { .compatible = "lltc,ltc4306", .data = &chips[ltc_4306] },
204 { }
205};
206MODULE_DEVICE_TABLE(of, ltc4306_of_match);
207
208static int ltc4306_probe(struct i2c_client *client)
209{
210 struct i2c_adapter *adap = client->adapter;
211 const struct chip_desc *chip;
212 struct i2c_mux_core *muxc;
213 struct ltc4306 *data;
214 struct gpio_desc *gpio;
215 bool idle_disc;
216 unsigned int val = 0;
217 int num, ret;
218
219 chip = of_device_get_match_data(&client->dev);
220
221 if (!chip)
222 chip = &chips[i2c_match_id(ltc4306_id, client)->driver_data];
223
224 idle_disc = device_property_read_bool(&client->dev,
225 "i2c-mux-idle-disconnect");
226
227 muxc = i2c_mux_alloc(adap, &client->dev,
228 chip->nchans, sizeof(*data),
229 I2C_MUX_LOCKED, ltc4306_select_mux,
230 idle_disc ? ltc4306_deselect_mux : NULL);
231 if (!muxc)
232 return -ENOMEM;
233 data = i2c_mux_priv(muxc);
234 data->chip = chip;
235
236 i2c_set_clientdata(client, muxc);
237
238 data->regmap = devm_regmap_init_i2c(client, <c4306_regmap_config);
239 if (IS_ERR(data->regmap)) {
240 ret = PTR_ERR(data->regmap);
241 dev_err(&client->dev, "Failed to allocate register map: %d\n",
242 ret);
243 return ret;
244 }
245
246
247 gpio = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_LOW);
248 if (IS_ERR(gpio))
249 return PTR_ERR(gpio);
250
251 if (gpio) {
252 udelay(1);
253 gpiod_set_value(gpio, 1);
254 }
255
256
257
258
259
260
261 if (regmap_write(data->regmap, LTC_REG_SWITCH, 0) < 0) {
262 dev_warn(&client->dev, "probe failed\n");
263 return -ENODEV;
264 }
265
266 if (device_property_read_bool(&client->dev,
267 "ltc,downstream-accelerators-enable"))
268 val |= LTC_DOWNSTREAM_ACCL_EN;
269
270 if (device_property_read_bool(&client->dev,
271 "ltc,upstream-accelerators-enable"))
272 val |= LTC_UPSTREAM_ACCL_EN;
273
274 if (regmap_write(data->regmap, LTC_REG_CONFIG, val) < 0)
275 return -ENODEV;
276
277 ret = ltc4306_gpio_init(data);
278 if (ret < 0)
279 return ret;
280
281
282 for (num = 0; num < chip->nchans; num++) {
283 ret = i2c_mux_add_adapter(muxc, 0, num, 0);
284 if (ret) {
285 i2c_mux_del_adapters(muxc);
286 return ret;
287 }
288 }
289
290 dev_info(&client->dev,
291 "registered %d multiplexed busses for I2C switch %s\n",
292 num, client->name);
293
294 return 0;
295}
296
297static int ltc4306_remove(struct i2c_client *client)
298{
299 struct i2c_mux_core *muxc = i2c_get_clientdata(client);
300
301 i2c_mux_del_adapters(muxc);
302
303 return 0;
304}
305
306static struct i2c_driver ltc4306_driver = {
307 .driver = {
308 .name = "ltc4306",
309 .of_match_table = of_match_ptr(ltc4306_of_match),
310 },
311 .probe_new = ltc4306_probe,
312 .remove = ltc4306_remove,
313 .id_table = ltc4306_id,
314};
315
316module_i2c_driver(ltc4306_driver);
317
318MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
319MODULE_DESCRIPTION("Linear Technology LTC4306, LTC4305 I2C mux/switch driver");
320MODULE_LICENSE("GPL v2");
321
