2 * I2C multiplexer using GPIO API
4 * Peter Korsgaard <peter.korsgaard@barco.com>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
11 #include <linux/i2c.h>
12 #include <linux/i2c-mux.h>
13 #include <linux/platform_data/i2c-mux-gpio.h>
14 #include <linux/platform_device.h>
15 #include <linux/module.h>
16 #include <linux/slab.h>
17 #include <linux/gpio.h>
18 #include "../../gpio/gpiolib.h"
19 #include <linux/of_gpio.h>
22 struct i2c_mux_gpio_platform_data data
;
24 struct gpio_desc
**gpios
;
27 static void i2c_mux_gpio_set(const struct gpiomux
*mux
, unsigned val
)
29 DECLARE_BITMAP(values
, BITS_PER_TYPE(val
));
33 gpiod_set_array_value_cansleep(mux
->data
.n_gpios
, mux
->gpios
, NULL
,
37 static int i2c_mux_gpio_select(struct i2c_mux_core
*muxc
, u32 chan
)
39 struct gpiomux
*mux
= i2c_mux_priv(muxc
);
41 i2c_mux_gpio_set(mux
, chan
);
46 static int i2c_mux_gpio_deselect(struct i2c_mux_core
*muxc
, u32 chan
)
48 struct gpiomux
*mux
= i2c_mux_priv(muxc
);
50 i2c_mux_gpio_set(mux
, mux
->data
.idle
);
55 static int match_gpio_chip_by_label(struct gpio_chip
*chip
,
58 return !strcmp(chip
->label
, data
);
62 static int i2c_mux_gpio_probe_dt(struct gpiomux
*mux
,
63 struct platform_device
*pdev
)
65 struct device_node
*np
= pdev
->dev
.of_node
;
66 struct device_node
*adapter_np
, *child
;
67 struct i2c_adapter
*adapter
;
68 unsigned *values
, *gpios
;
74 adapter_np
= of_parse_phandle(np
, "i2c-parent", 0);
76 dev_err(&pdev
->dev
, "Cannot parse i2c-parent\n");
79 adapter
= of_find_i2c_adapter_by_node(adapter_np
);
80 of_node_put(adapter_np
);
84 mux
->data
.parent
= i2c_adapter_id(adapter
);
85 put_device(&adapter
->dev
);
87 mux
->data
.n_values
= of_get_child_count(np
);
89 values
= devm_kcalloc(&pdev
->dev
,
90 mux
->data
.n_values
, sizeof(*mux
->data
.values
),
93 dev_err(&pdev
->dev
, "Cannot allocate values array");
97 for_each_child_of_node(np
, child
) {
98 of_property_read_u32(child
, "reg", values
+ i
);
101 mux
->data
.values
= values
;
103 if (of_property_read_u32(np
, "idle-state", &mux
->data
.idle
))
104 mux
->data
.idle
= I2C_MUX_GPIO_NO_IDLE
;
106 mux
->data
.n_gpios
= of_gpio_named_count(np
, "mux-gpios");
107 if (mux
->data
.n_gpios
< 0) {
108 dev_err(&pdev
->dev
, "Missing mux-gpios property in the DT.\n");
112 gpios
= devm_kcalloc(&pdev
->dev
,
113 mux
->data
.n_gpios
, sizeof(*mux
->data
.gpios
),
116 dev_err(&pdev
->dev
, "Cannot allocate gpios array");
120 for (i
= 0; i
< mux
->data
.n_gpios
; i
++) {
121 ret
= of_get_named_gpio(np
, "mux-gpios", i
);
127 mux
->data
.gpios
= gpios
;
132 static int i2c_mux_gpio_probe_dt(struct gpiomux
*mux
,
133 struct platform_device
*pdev
)
139 static int i2c_mux_gpio_probe(struct platform_device
*pdev
)
141 struct i2c_mux_core
*muxc
;
143 struct i2c_adapter
*parent
;
144 struct i2c_adapter
*root
;
145 unsigned initial_state
, gpio_base
;
148 mux
= devm_kzalloc(&pdev
->dev
, sizeof(*mux
), GFP_KERNEL
);
152 if (!dev_get_platdata(&pdev
->dev
)) {
153 ret
= i2c_mux_gpio_probe_dt(mux
, pdev
);
157 memcpy(&mux
->data
, dev_get_platdata(&pdev
->dev
),
162 * If a GPIO chip name is provided, the GPIO pin numbers provided are
163 * relative to its base GPIO number. Otherwise they are absolute.
165 if (mux
->data
.gpio_chip
) {
166 struct gpio_chip
*gpio
;
168 gpio
= gpiochip_find(mux
->data
.gpio_chip
,
169 match_gpio_chip_by_label
);
171 return -EPROBE_DEFER
;
173 gpio_base
= gpio
->base
;
178 parent
= i2c_get_adapter(mux
->data
.parent
);
180 return -EPROBE_DEFER
;
182 muxc
= i2c_mux_alloc(parent
, &pdev
->dev
, mux
->data
.n_values
,
183 mux
->data
.n_gpios
* sizeof(*mux
->gpios
), 0,
184 i2c_mux_gpio_select
, NULL
);
189 mux
->gpios
= muxc
->priv
;
192 platform_set_drvdata(pdev
, muxc
);
194 root
= i2c_root_adapter(&parent
->dev
);
196 muxc
->mux_locked
= true;
197 mux
->gpio_base
= gpio_base
;
199 if (mux
->data
.idle
!= I2C_MUX_GPIO_NO_IDLE
) {
200 initial_state
= mux
->data
.idle
;
201 muxc
->deselect
= i2c_mux_gpio_deselect
;
203 initial_state
= mux
->data
.values
[0];
206 for (i
= 0; i
< mux
->data
.n_gpios
; i
++) {
207 struct device
*gpio_dev
;
208 struct gpio_desc
*gpio_desc
;
210 ret
= gpio_request(gpio_base
+ mux
->data
.gpios
[i
], "i2c-mux-gpio");
212 dev_err(&pdev
->dev
, "Failed to request GPIO %d\n",
214 goto err_request_gpio
;
217 ret
= gpio_direction_output(gpio_base
+ mux
->data
.gpios
[i
],
218 initial_state
& (1 << i
));
221 "Failed to set direction of GPIO %d to output\n",
223 i
++; /* gpio_request above succeeded, so must free */
224 goto err_request_gpio
;
227 gpio_desc
= gpio_to_desc(gpio_base
+ mux
->data
.gpios
[i
]);
228 mux
->gpios
[i
] = gpio_desc
;
230 if (!muxc
->mux_locked
)
233 gpio_dev
= &gpio_desc
->gdev
->dev
;
234 muxc
->mux_locked
= i2c_root_adapter(gpio_dev
) == root
;
237 if (muxc
->mux_locked
)
238 dev_info(&pdev
->dev
, "mux-locked i2c mux\n");
240 for (i
= 0; i
< mux
->data
.n_values
; i
++) {
241 u32 nr
= mux
->data
.base_nr
? (mux
->data
.base_nr
+ i
) : 0;
242 unsigned int class = mux
->data
.classes
? mux
->data
.classes
[i
] : 0;
244 ret
= i2c_mux_add_adapter(muxc
, nr
, mux
->data
.values
[i
], class);
246 goto add_adapter_failed
;
249 dev_info(&pdev
->dev
, "%d port mux on %s adapter\n",
250 mux
->data
.n_values
, parent
->name
);
255 i2c_mux_del_adapters(muxc
);
256 i
= mux
->data
.n_gpios
;
259 gpio_free(gpio_base
+ mux
->data
.gpios
[i
- 1]);
261 i2c_put_adapter(parent
);
266 static int i2c_mux_gpio_remove(struct platform_device
*pdev
)
268 struct i2c_mux_core
*muxc
= platform_get_drvdata(pdev
);
269 struct gpiomux
*mux
= i2c_mux_priv(muxc
);
272 i2c_mux_del_adapters(muxc
);
274 for (i
= 0; i
< mux
->data
.n_gpios
; i
++)
275 gpio_free(mux
->gpio_base
+ mux
->data
.gpios
[i
]);
277 i2c_put_adapter(muxc
->parent
);
282 static const struct of_device_id i2c_mux_gpio_of_match
[] = {
283 { .compatible
= "i2c-mux-gpio", },
286 MODULE_DEVICE_TABLE(of
, i2c_mux_gpio_of_match
);
288 static struct platform_driver i2c_mux_gpio_driver
= {
289 .probe
= i2c_mux_gpio_probe
,
290 .remove
= i2c_mux_gpio_remove
,
292 .name
= "i2c-mux-gpio",
293 .of_match_table
= i2c_mux_gpio_of_match
,
297 module_platform_driver(i2c_mux_gpio_driver
);
299 MODULE_DESCRIPTION("GPIO-based I2C multiplexer driver");
300 MODULE_AUTHOR("Peter Korsgaard <peter.korsgaard@barco.com>");
301 MODULE_LICENSE("GPL");
302 MODULE_ALIAS("platform:i2c-mux-gpio");