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0edff03d | 1 | // SPDX-License-Identifier: GPL-2.0 |
2c089f08 PR |
2 | /* |
3 | * GPIO-controlled multiplexer driver | |
4 | * | |
5 | * Copyright (C) 2017 Axentia Technologies AB | |
6 | * | |
7 | * Author: Peter Rosin <peda@axentia.se> | |
2c089f08 PR |
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 | ||
18 | struct mux_gpio { | |
19 | struct gpio_descs *gpios; | |
2c089f08 PR |
20 | }; |
21 | ||
22 | static int mux_gpio_set(struct mux_control *mux, int state) | |
23 | { | |
24 | struct mux_gpio *mux_gpio = mux_chip_priv(mux->chip); | |
b9762beb | 25 | DECLARE_BITMAP(values, BITS_PER_TYPE(state)); |
2c089f08 | 26 | |
b9762beb | 27 | values[0] = state; |
2c089f08 PR |
28 | |
29 | gpiod_set_array_value_cansleep(mux_gpio->gpios->ndescs, | |
77588c14 JK |
30 | mux_gpio->gpios->desc, |
31 | mux_gpio->gpios->info, values); | |
2c089f08 PR |
32 | |
33 | return 0; | |
34 | } | |
35 | ||
36 | static const struct mux_control_ops mux_gpio_ops = { | |
37 | .set = mux_gpio_set, | |
38 | }; | |
39 | ||
40 | static const struct of_device_id mux_gpio_dt_ids[] = { | |
41 | { .compatible = "gpio-mux", }, | |
42 | { /* sentinel */ } | |
43 | }; | |
44 | MODULE_DEVICE_TABLE(of, mux_gpio_dt_ids); | |
45 | ||
46 | static int mux_gpio_probe(struct platform_device *pdev) | |
47 | { | |
48 | struct device *dev = &pdev->dev; | |
49 | struct mux_chip *mux_chip; | |
50 | struct mux_gpio *mux_gpio; | |
51 | int pins; | |
52 | s32 idle_state; | |
53 | int ret; | |
54 | ||
55 | pins = gpiod_count(dev, "mux"); | |
56 | if (pins < 0) | |
57 | return pins; | |
58 | ||
b9762beb | 59 | mux_chip = devm_mux_chip_alloc(dev, 1, sizeof(*mux_gpio)); |
2c089f08 PR |
60 | if (IS_ERR(mux_chip)) |
61 | return PTR_ERR(mux_chip); | |
62 | ||
63 | mux_gpio = mux_chip_priv(mux_chip); | |
2c089f08 PR |
64 | mux_chip->ops = &mux_gpio_ops; |
65 | ||
66 | mux_gpio->gpios = devm_gpiod_get_array(dev, "mux", GPIOD_OUT_LOW); | |
67 | if (IS_ERR(mux_gpio->gpios)) { | |
68 | ret = PTR_ERR(mux_gpio->gpios); | |
69 | if (ret != -EPROBE_DEFER) | |
70 | dev_err(dev, "failed to get gpios\n"); | |
71 | return ret; | |
72 | } | |
73 | WARN_ON(pins != mux_gpio->gpios->ndescs); | |
74 | mux_chip->mux->states = 1 << pins; | |
75 | ||
76 | ret = device_property_read_u32(dev, "idle-state", (u32 *)&idle_state); | |
77 | if (ret >= 0 && idle_state != MUX_IDLE_AS_IS) { | |
78 | if (idle_state < 0 || idle_state >= mux_chip->mux->states) { | |
79 | dev_err(dev, "invalid idle-state %u\n", idle_state); | |
80 | return -EINVAL; | |
81 | } | |
82 | ||
83 | mux_chip->mux->idle_state = idle_state; | |
84 | } | |
85 | ||
86 | ret = devm_mux_chip_register(dev, mux_chip); | |
87 | if (ret < 0) | |
88 | return ret; | |
89 | ||
90 | dev_info(dev, "%u-way mux-controller registered\n", | |
91 | mux_chip->mux->states); | |
92 | ||
93 | return 0; | |
94 | } | |
95 | ||
96 | static struct platform_driver mux_gpio_driver = { | |
97 | .driver = { | |
98 | .name = "gpio-mux", | |
99 | .of_match_table = of_match_ptr(mux_gpio_dt_ids), | |
100 | }, | |
101 | .probe = mux_gpio_probe, | |
102 | }; | |
103 | module_platform_driver(mux_gpio_driver); | |
104 | ||
105 | MODULE_DESCRIPTION("GPIO-controlled multiplexer driver"); | |
106 | MODULE_AUTHOR("Peter Rosin <peda@axentia.se>"); | |
107 | MODULE_LICENSE("GPL v2"); |