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 | |
19 | struct mux_gpio { |
20 | struct gpio_descs *gpios; |
21 | }; |
22 | |
23 | static int mux_gpio_set(struct mux_control *mux, int state) |
24 | { |
25 | struct mux_gpio *mux_gpio = mux_chip_priv(mux_chip: mux->chip); |
26 | DECLARE_BITMAP(values, BITS_PER_TYPE(state)); |
27 | u32 value = state; |
28 | |
29 | bitmap_from_arr32(bitmap: values, buf: &value, BITS_PER_TYPE(value)); |
30 | |
31 | gpiod_set_array_value_cansleep(array_size: mux_gpio->gpios->ndescs, |
32 | desc_array: mux_gpio->gpios->desc, |
33 | array_info: mux_gpio->gpios->info, value_bitmap: values); |
34 | |
35 | return 0; |
36 | } |
37 | |
38 | static const struct mux_control_ops mux_gpio_ops = { |
39 | .set = mux_gpio_set, |
40 | }; |
41 | |
42 | static const struct of_device_id mux_gpio_dt_ids[] = { |
43 | { .compatible = "gpio-mux" , }, |
44 | { /* sentinel */ } |
45 | }; |
46 | MODULE_DEVICE_TABLE(of, mux_gpio_dt_ids); |
47 | |
48 | static 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, con_id: "mux" ); |
58 | if (pins < 0) |
59 | return pins; |
60 | |
61 | mux_chip = devm_mux_chip_alloc(dev, controllers: 1, sizeof_priv: sizeof(*mux_gpio)); |
62 | if (IS_ERR(ptr: mux_chip)) |
63 | return PTR_ERR(ptr: 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, con_id: "mux" , flags: GPIOD_OUT_LOW); |
69 | if (IS_ERR(ptr: mux_gpio->gpios)) |
70 | return dev_err_probe(dev, err: PTR_ERR(ptr: mux_gpio->gpios), |
71 | fmt: "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, propname: "idle-state" , val: (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 | |
95 | static 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 | }; |
102 | module_platform_driver(mux_gpio_driver); |
103 | |
104 | MODULE_DESCRIPTION("GPIO-controlled multiplexer driver" ); |
105 | MODULE_AUTHOR("Peter Rosin <peda@axentia.se>" ); |
106 | MODULE_LICENSE("GPL v2" ); |
107 | |