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0edff03d | 1 | // SPDX-License-Identifier: GPL-2.0 |
73726380 PZ |
2 | /* |
3 | * MMIO register bitfield-controlled multiplexer driver | |
4 | * | |
5 | * Copyright (C) 2017 Pengutronix, Philipp Zabel <kernel@pengutronix.de> | |
73726380 PZ |
6 | */ |
7 | ||
8 | #include <linux/bitops.h> | |
9 | #include <linux/err.h> | |
10 | #include <linux/mfd/syscon.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/mux/driver.h> | |
13 | #include <linux/of_platform.h> | |
14 | #include <linux/platform_device.h> | |
15 | #include <linux/property.h> | |
16 | #include <linux/regmap.h> | |
17 | ||
18 | static int mux_mmio_set(struct mux_control *mux, int state) | |
19 | { | |
20 | struct regmap_field **fields = mux_chip_priv(mux->chip); | |
21 | ||
22 | return regmap_field_write(fields[mux_control_get_index(mux)], state); | |
23 | } | |
24 | ||
25 | static const struct mux_control_ops mux_mmio_ops = { | |
26 | .set = mux_mmio_set, | |
27 | }; | |
28 | ||
29 | static const struct of_device_id mux_mmio_dt_ids[] = { | |
30 | { .compatible = "mmio-mux", }, | |
31 | { /* sentinel */ } | |
32 | }; | |
33 | MODULE_DEVICE_TABLE(of, mux_mmio_dt_ids); | |
34 | ||
35 | static int mux_mmio_probe(struct platform_device *pdev) | |
36 | { | |
37 | struct device *dev = &pdev->dev; | |
38 | struct device_node *np = dev->of_node; | |
39 | struct regmap_field **fields; | |
40 | struct mux_chip *mux_chip; | |
41 | struct regmap *regmap; | |
42 | int num_fields; | |
43 | int ret; | |
44 | int i; | |
45 | ||
46 | regmap = syscon_node_to_regmap(np->parent); | |
47 | if (IS_ERR(regmap)) { | |
48 | ret = PTR_ERR(regmap); | |
49 | dev_err(dev, "failed to get regmap: %d\n", ret); | |
50 | return ret; | |
51 | } | |
52 | ||
53 | ret = of_property_count_u32_elems(np, "mux-reg-masks"); | |
54 | if (ret == 0 || ret % 2) | |
55 | ret = -EINVAL; | |
56 | if (ret < 0) { | |
57 | dev_err(dev, "mux-reg-masks property missing or invalid: %d\n", | |
58 | ret); | |
59 | return ret; | |
60 | } | |
61 | num_fields = ret / 2; | |
62 | ||
63 | mux_chip = devm_mux_chip_alloc(dev, num_fields, num_fields * | |
64 | sizeof(*fields)); | |
65 | if (IS_ERR(mux_chip)) | |
66 | return PTR_ERR(mux_chip); | |
67 | ||
68 | fields = mux_chip_priv(mux_chip); | |
69 | ||
70 | for (i = 0; i < num_fields; i++) { | |
71 | struct mux_control *mux = &mux_chip->mux[i]; | |
72 | struct reg_field field; | |
73 | s32 idle_state = MUX_IDLE_AS_IS; | |
74 | u32 reg, mask; | |
75 | int bits; | |
76 | ||
77 | ret = of_property_read_u32_index(np, "mux-reg-masks", | |
78 | 2 * i, ®); | |
79 | if (!ret) | |
80 | ret = of_property_read_u32_index(np, "mux-reg-masks", | |
81 | 2 * i + 1, &mask); | |
82 | if (ret < 0) { | |
83 | dev_err(dev, "bitfield %d: failed to read mux-reg-masks property: %d\n", | |
84 | i, ret); | |
85 | return ret; | |
86 | } | |
87 | ||
88 | field.reg = reg; | |
89 | field.msb = fls(mask) - 1; | |
90 | field.lsb = ffs(mask) - 1; | |
91 | ||
92 | if (mask != GENMASK(field.msb, field.lsb)) { | |
93 | dev_err(dev, "bitfield %d: invalid mask 0x%x\n", | |
94 | i, mask); | |
95 | return -EINVAL; | |
96 | } | |
97 | ||
98 | fields[i] = devm_regmap_field_alloc(dev, regmap, field); | |
99 | if (IS_ERR(fields[i])) { | |
100 | ret = PTR_ERR(fields[i]); | |
101 | dev_err(dev, "bitfield %d: failed allocate: %d\n", | |
102 | i, ret); | |
103 | return ret; | |
104 | } | |
105 | ||
106 | bits = 1 + field.msb - field.lsb; | |
107 | mux->states = 1 << bits; | |
108 | ||
109 | of_property_read_u32_index(np, "idle-states", i, | |
110 | (u32 *)&idle_state); | |
111 | if (idle_state != MUX_IDLE_AS_IS) { | |
112 | if (idle_state < 0 || idle_state >= mux->states) { | |
113 | dev_err(dev, "bitfield: %d: out of range idle state %d\n", | |
114 | i, idle_state); | |
115 | return -EINVAL; | |
116 | } | |
117 | ||
118 | mux->idle_state = idle_state; | |
119 | } | |
120 | } | |
121 | ||
122 | mux_chip->ops = &mux_mmio_ops; | |
123 | ||
124 | return devm_mux_chip_register(dev, mux_chip); | |
125 | } | |
126 | ||
127 | static struct platform_driver mux_mmio_driver = { | |
128 | .driver = { | |
129 | .name = "mmio-mux", | |
130 | .of_match_table = of_match_ptr(mux_mmio_dt_ids), | |
131 | }, | |
132 | .probe = mux_mmio_probe, | |
133 | }; | |
134 | module_platform_driver(mux_mmio_driver); | |
135 | ||
136 | MODULE_DESCRIPTION("MMIO register bitfield-controlled multiplexer driver"); | |
137 | MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>"); | |
138 | MODULE_LICENSE("GPL v2"); |