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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * GPIO-controlled multiplexer driver
4 *
5 * Copyright (C) 2017 Axentia Technologies AB
6 *
7 * Author: Peter Rosin <peda@axentia.se>
8 */
9
10#include <linux/bitmap.h>
11#include <linux/err.h>
12#include <linux/gpio/consumer.h>
13#include <linux/mod_devicetable.h>
14#include <linux/module.h>
15#include <linux/mux/driver.h>
16#include <linux/platform_device.h>
17#include <linux/property.h>
18
19struct mux_gpio {
20 struct gpio_descs *gpios;
21};
22
23static int mux_gpio_set(struct mux_control *mux, int state)
24{
25 struct mux_gpio *mux_gpio = mux_chip_priv(mux->chip);
26 DECLARE_BITMAP(values, BITS_PER_TYPE(state));
27 u32 value = state;
28
29 bitmap_from_arr32(values, &value, BITS_PER_TYPE(value));
30
31 gpiod_set_array_value_cansleep(mux_gpio->gpios->ndescs,
32 mux_gpio->gpios->desc,
33 mux_gpio->gpios->info, values);
34
35 return 0;
36}
37
38static const struct mux_control_ops mux_gpio_ops = {
39 .set = mux_gpio_set,
40};
41
42static const struct of_device_id mux_gpio_dt_ids[] = {
43 { .compatible = "gpio-mux", },
44 { /* sentinel */ }
45};
46MODULE_DEVICE_TABLE(of, mux_gpio_dt_ids);
47
48static int mux_gpio_probe(struct platform_device *pdev)
49{
50 struct device *dev = &pdev->dev;
51 struct mux_chip *mux_chip;
52 struct mux_gpio *mux_gpio;
53 int pins;
54 s32 idle_state;
55 int ret;
56
57 pins = gpiod_count(dev, "mux");
58 if (pins < 0)
59 return pins;
60
61 mux_chip = devm_mux_chip_alloc(dev, 1, sizeof(*mux_gpio));
62 if (IS_ERR(mux_chip))
63 return PTR_ERR(mux_chip);
64
65 mux_gpio = mux_chip_priv(mux_chip);
66 mux_chip->ops = &mux_gpio_ops;
67
68 mux_gpio->gpios = devm_gpiod_get_array(dev, "mux", GPIOD_OUT_LOW);
69 if (IS_ERR(mux_gpio->gpios))
70 return dev_err_probe(dev, PTR_ERR(mux_gpio->gpios),
71 "failed to get gpios\n");
72 WARN_ON(pins != mux_gpio->gpios->ndescs);
73 mux_chip->mux->states = BIT(pins);
74
75 ret = device_property_read_u32(dev, "idle-state", (u32 *)&idle_state);
76 if (ret >= 0 && idle_state != MUX_IDLE_AS_IS) {
77 if (idle_state < 0 || idle_state >= mux_chip->mux->states) {
78 dev_err(dev, "invalid idle-state %u\n", idle_state);
79 return -EINVAL;
80 }
81
82 mux_chip->mux->idle_state = idle_state;
83 }
84
85 ret = devm_mux_chip_register(dev, mux_chip);
86 if (ret < 0)
87 return ret;
88
89 dev_info(dev, "%u-way mux-controller registered\n",
90 mux_chip->mux->states);
91
92 return 0;
93}
94
95static struct platform_driver mux_gpio_driver = {
96 .driver = {
97 .name = "gpio-mux",
98 .of_match_table = mux_gpio_dt_ids,
99 },
100 .probe = mux_gpio_probe,
101};
102module_platform_driver(mux_gpio_driver);
103
104MODULE_DESCRIPTION("GPIO-controlled multiplexer driver");
105MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
106MODULE_LICENSE("GPL v2");
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * GPIO-controlled multiplexer driver
4 *
5 * Copyright (C) 2017 Axentia Technologies AB
6 *
7 * Author: Peter Rosin <peda@axentia.se>
8 */
9
10#include <linux/err.h>
11#include <linux/gpio/consumer.h>
12#include <linux/module.h>
13#include <linux/mux/driver.h>
14#include <linux/of_platform.h>
15#include <linux/platform_device.h>
16#include <linux/property.h>
17
18struct mux_gpio {
19 struct gpio_descs *gpios;
20 int *val;
21};
22
23static int mux_gpio_set(struct mux_control *mux, int state)
24{
25 struct mux_gpio *mux_gpio = mux_chip_priv(mux->chip);
26 int i;
27
28 for (i = 0; i < mux_gpio->gpios->ndescs; i++)
29 mux_gpio->val[i] = (state >> i) & 1;
30
31 gpiod_set_array_value_cansleep(mux_gpio->gpios->ndescs,
32 mux_gpio->gpios->desc,
33 mux_gpio->val);
34
35 return 0;
36}
37
38static const struct mux_control_ops mux_gpio_ops = {
39 .set = mux_gpio_set,
40};
41
42static const struct of_device_id mux_gpio_dt_ids[] = {
43 { .compatible = "gpio-mux", },
44 { /* sentinel */ }
45};
46MODULE_DEVICE_TABLE(of, mux_gpio_dt_ids);
47
48static int mux_gpio_probe(struct platform_device *pdev)
49{
50 struct device *dev = &pdev->dev;
51 struct mux_chip *mux_chip;
52 struct mux_gpio *mux_gpio;
53 int pins;
54 s32 idle_state;
55 int ret;
56
57 pins = gpiod_count(dev, "mux");
58 if (pins < 0)
59 return pins;
60
61 mux_chip = devm_mux_chip_alloc(dev, 1, sizeof(*mux_gpio) +
62 pins * sizeof(*mux_gpio->val));
63 if (IS_ERR(mux_chip))
64 return PTR_ERR(mux_chip);
65
66 mux_gpio = mux_chip_priv(mux_chip);
67 mux_gpio->val = (int *)(mux_gpio + 1);
68 mux_chip->ops = &mux_gpio_ops;
69
70 mux_gpio->gpios = devm_gpiod_get_array(dev, "mux", GPIOD_OUT_LOW);
71 if (IS_ERR(mux_gpio->gpios)) {
72 ret = PTR_ERR(mux_gpio->gpios);
73 if (ret != -EPROBE_DEFER)
74 dev_err(dev, "failed to get gpios\n");
75 return ret;
76 }
77 WARN_ON(pins != mux_gpio->gpios->ndescs);
78 mux_chip->mux->states = 1 << pins;
79
80 ret = device_property_read_u32(dev, "idle-state", (u32 *)&idle_state);
81 if (ret >= 0 && idle_state != MUX_IDLE_AS_IS) {
82 if (idle_state < 0 || idle_state >= mux_chip->mux->states) {
83 dev_err(dev, "invalid idle-state %u\n", idle_state);
84 return -EINVAL;
85 }
86
87 mux_chip->mux->idle_state = idle_state;
88 }
89
90 ret = devm_mux_chip_register(dev, mux_chip);
91 if (ret < 0)
92 return ret;
93
94 dev_info(dev, "%u-way mux-controller registered\n",
95 mux_chip->mux->states);
96
97 return 0;
98}
99
100static struct platform_driver mux_gpio_driver = {
101 .driver = {
102 .name = "gpio-mux",
103 .of_match_table = of_match_ptr(mux_gpio_dt_ids),
104 },
105 .probe = mux_gpio_probe,
106};
107module_platform_driver(mux_gpio_driver);
108
109MODULE_DESCRIPTION("GPIO-controlled multiplexer driver");
110MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
111MODULE_LICENSE("GPL v2");