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gerrit-public.fairphone.software / kernel / msm-4.19 / 6af1de2e4ec49635905aaed31d073a0d92c8d3bf / . / drivers / mux / mmio.c
blob: 37c1de359a7055afa6179b49b4827a94fdeeb45d [file] [log] [blame]
Philipp Zabel73726382017-05-14 21:51:16 +0200[diff] [blame]1/*
2 * MMIO register bitfield-controlled multiplexer driver
3 *
4 * Copyright (C) 2017 Pengutronix, Philipp Zabel <kernel@pengutronix.de>
5 *
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.
9 */
10
11#include <linux/bitops.h>
12#include <linux/err.h>
13#include <linux/mfd/syscon.h>
14#include <linux/module.h>
15#include <linux/mux/driver.h>
16#include <linux/of_platform.h>
17#include <linux/platform_device.h>
18#include <linux/property.h>
19#include <linux/regmap.h>
20
21static int mux_mmio_set(struct mux_control *mux, int state)
22{
23 struct regmap_field **fields = mux_chip_priv(mux->chip);
24
25 return regmap_field_write(fields[mux_control_get_index(mux)], state);
26}
27
28static const struct mux_control_ops mux_mmio_ops = {
29 .set = mux_mmio_set,
30};
31
32static const struct of_device_id mux_mmio_dt_ids[] = {
33 { .compatible = "mmio-mux", },
34 { /* sentinel */ }
35};
36MODULE_DEVICE_TABLE(of, mux_mmio_dt_ids);
37
38static int mux_mmio_probe(struct platform_device *pdev)
39{
40 struct device *dev = &pdev->dev;
41 struct device_node *np = dev->of_node;
42 struct regmap_field **fields;
43 struct mux_chip *mux_chip;
44 struct regmap *regmap;
45 int num_fields;
46 int ret;
47 int i;
48
49 regmap = syscon_node_to_regmap(np->parent);
50 if (IS_ERR(regmap)) {
51 ret = PTR_ERR(regmap);
52 dev_err(dev, "failed to get regmap: %d\n", ret);
53 return ret;
54 }
55
56 ret = of_property_count_u32_elems(np, "mux-reg-masks");
57 if (ret == 0 || ret % 2)
58 ret = -EINVAL;
59 if (ret < 0) {
60 dev_err(dev, "mux-reg-masks property missing or invalid: %d\n",
61 ret);
62 return ret;
63 }
64 num_fields = ret / 2;
65
66 mux_chip = devm_mux_chip_alloc(dev, num_fields, num_fields *
67 sizeof(*fields));
68 if (IS_ERR(mux_chip))
69 return PTR_ERR(mux_chip);
70
71 fields = mux_chip_priv(mux_chip);
72
73 for (i = 0; i < num_fields; i++) {
74 struct mux_control *mux = &mux_chip->mux[i];
75 struct reg_field field;
76 s32 idle_state = MUX_IDLE_AS_IS;
77 u32 reg, mask;
78 int bits;
79
80 ret = of_property_read_u32_index(np, "mux-reg-masks",
81 2 * i, &reg);
82 if (!ret)
83 ret = of_property_read_u32_index(np, "mux-reg-masks",
84 2 * i + 1, &mask);
85 if (ret < 0) {
86 dev_err(dev, "bitfield %d: failed to read mux-reg-masks property: %d\n",
87 i, ret);
88 return ret;
89 }
90
91 field.reg = reg;
92 field.msb = fls(mask) - 1;
93 field.lsb = ffs(mask) - 1;
94
95 if (mask != GENMASK(field.msb, field.lsb)) {
96 dev_err(dev, "bitfield %d: invalid mask 0x%x\n",
97 i, mask);
98 return -EINVAL;
99 }
100
101 fields[i] = devm_regmap_field_alloc(dev, regmap, field);
102 if (IS_ERR(fields[i])) {
103 ret = PTR_ERR(fields[i]);
104 dev_err(dev, "bitfield %d: failed allocate: %d\n",
105 i, ret);
106 return ret;
107 }
108
109 bits = 1 + field.msb - field.lsb;
110 mux->states = 1 << bits;
111
112 of_property_read_u32_index(np, "idle-states", i,
113 (u32 *)&idle_state);
114 if (idle_state != MUX_IDLE_AS_IS) {
115 if (idle_state < 0 || idle_state >= mux->states) {
116 dev_err(dev, "bitfield: %d: out of range idle state %d\n",
117 i, idle_state);
118 return -EINVAL;
119 }
120
121 mux->idle_state = idle_state;
122 }
123 }
124
125 mux_chip->ops = &mux_mmio_ops;
126
127 return devm_mux_chip_register(dev, mux_chip);
128}
129
130static struct platform_driver mux_mmio_driver = {
131 .driver = {
132 .name = "mmio-mux",
133 .of_match_table = of_match_ptr(mux_mmio_dt_ids),
134 },
135 .probe = mux_mmio_probe,
136};
137module_platform_driver(mux_mmio_driver);
138
139MODULE_DESCRIPTION("MMIO register bitfield-controlled multiplexer driver");
140MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");
141MODULE_LICENSE("GPL v2");