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0edff03d | 1 | // SPDX-License-Identifier: GPL-2.0 |
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2 | /* |
3 | * GPIO-controlled multiplexer driver | |
4 | * | |
5 | * Copyright (C) 2017 Axentia Technologies AB | |
6 | * | |
7 | * Author: Peter Rosin <peda@axentia.se> | |
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8 | */ |
9 | ||
5c777233 | 10 | #include <linux/bitmap.h> |
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11 | #include <linux/err.h> |
12 | #include <linux/gpio/consumer.h> | |
7fef54e2 | 13 | #include <linux/mod_devicetable.h> |
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14 | #include <linux/module.h> |
15 | #include <linux/mux/driver.h> | |
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16 | #include <linux/platform_device.h> |
17 | #include <linux/property.h> | |
18 | ||
19 | struct mux_gpio { | |
20 | struct gpio_descs *gpios; | |
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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); | |
b9762beb | 26 | DECLARE_BITMAP(values, BITS_PER_TYPE(state)); |
5c777233 | 27 | u32 value = state; |
2c089f08 | 28 | |
5c777233 | 29 | bitmap_from_arr32(values, &value, BITS_PER_TYPE(value)); |
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30 | |
31 | gpiod_set_array_value_cansleep(mux_gpio->gpios->ndescs, | |
77588c14 JK |
32 | mux_gpio->gpios->desc, |
33 | mux_gpio->gpios->info, values); | |
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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, "mux"); | |
58 | if (pins < 0) | |
59 | return pins; | |
60 | ||
b9762beb | 61 | mux_chip = devm_mux_chip_alloc(dev, 1, sizeof(*mux_gpio)); |
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62 | if (IS_ERR(mux_chip)) |
63 | return PTR_ERR(mux_chip); | |
64 | ||
65 | mux_gpio = mux_chip_priv(mux_chip); | |
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66 | mux_chip->ops = &mux_gpio_ops; |
67 | ||
68 | mux_gpio->gpios = devm_gpiod_get_array(dev, "mux", GPIOD_OUT_LOW); | |
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69 | if (IS_ERR(mux_gpio->gpios)) |
70 | return dev_err_probe(dev, PTR_ERR(mux_gpio->gpios), | |
71 | "failed to get gpios\n"); | |
2c089f08 | 72 | WARN_ON(pins != mux_gpio->gpios->ndescs); |
5c777233 | 73 | mux_chip->mux->states = BIT(pins); |
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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 | ||
95 | static struct platform_driver mux_gpio_driver = { | |
96 | .driver = { | |
97 | .name = "gpio-mux", | |
7fef54e2 | 98 | .of_match_table = mux_gpio_dt_ids, |
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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"); |