1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * MMIO register bitfield-controlled multiplexer driver |
4 | * |
5 | * Copyright (C) 2017 Pengutronix, Philipp Zabel <kernel@pengutronix.de> |
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.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: mux->chip); |
21 | |
22 | return regmap_field_write(field: fields[mux_control_get_index(mux)], val: 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 | { .compatible = "reg-mux" , }, |
32 | { /* sentinel */ } |
33 | }; |
34 | MODULE_DEVICE_TABLE(of, mux_mmio_dt_ids); |
35 | |
36 | static int mux_mmio_probe(struct platform_device *pdev) |
37 | { |
38 | struct device *dev = &pdev->dev; |
39 | struct device_node *np = dev->of_node; |
40 | struct regmap_field **fields; |
41 | struct mux_chip *mux_chip; |
42 | struct regmap *regmap; |
43 | int num_fields; |
44 | int ret; |
45 | int i; |
46 | |
47 | if (of_device_is_compatible(device: np, "mmio-mux" )) { |
48 | regmap = syscon_node_to_regmap(np: np->parent); |
49 | } else { |
50 | regmap = device_node_to_regmap(np); |
51 | /* Fallback to checking the parent node on "real" errors. */ |
52 | if (IS_ERR(ptr: regmap) && regmap != ERR_PTR(error: -EPROBE_DEFER)) { |
53 | regmap = dev_get_regmap(dev: dev->parent, NULL); |
54 | if (!regmap) |
55 | regmap = ERR_PTR(error: -ENODEV); |
56 | } |
57 | } |
58 | if (IS_ERR(ptr: regmap)) |
59 | return dev_err_probe(dev, err: PTR_ERR(ptr: regmap), |
60 | fmt: "failed to get regmap\n" ); |
61 | |
62 | ret = of_property_count_u32_elems(np, propname: "mux-reg-masks" ); |
63 | if (ret == 0 || ret % 2) |
64 | ret = -EINVAL; |
65 | if (ret < 0) { |
66 | dev_err(dev, "mux-reg-masks property missing or invalid: %d\n" , |
67 | ret); |
68 | return ret; |
69 | } |
70 | num_fields = ret / 2; |
71 | |
72 | mux_chip = devm_mux_chip_alloc(dev, controllers: num_fields, sizeof_priv: num_fields * |
73 | sizeof(*fields)); |
74 | if (IS_ERR(ptr: mux_chip)) |
75 | return PTR_ERR(ptr: mux_chip); |
76 | |
77 | fields = mux_chip_priv(mux_chip); |
78 | |
79 | for (i = 0; i < num_fields; i++) { |
80 | struct mux_control *mux = &mux_chip->mux[i]; |
81 | struct reg_field field; |
82 | s32 idle_state = MUX_IDLE_AS_IS; |
83 | u32 reg, mask; |
84 | int bits; |
85 | |
86 | ret = of_property_read_u32_index(np, propname: "mux-reg-masks" , |
87 | index: 2 * i, out_value: ®); |
88 | if (!ret) |
89 | ret = of_property_read_u32_index(np, propname: "mux-reg-masks" , |
90 | index: 2 * i + 1, out_value: &mask); |
91 | if (ret < 0) { |
92 | dev_err(dev, "bitfield %d: failed to read mux-reg-masks property: %d\n" , |
93 | i, ret); |
94 | return ret; |
95 | } |
96 | |
97 | field.reg = reg; |
98 | field.msb = fls(x: mask) - 1; |
99 | field.lsb = ffs(mask) - 1; |
100 | |
101 | if (mask != GENMASK(field.msb, field.lsb)) { |
102 | dev_err(dev, "bitfield %d: invalid mask 0x%x\n" , |
103 | i, mask); |
104 | return -EINVAL; |
105 | } |
106 | |
107 | fields[i] = devm_regmap_field_alloc(dev, regmap, reg_field: field); |
108 | if (IS_ERR(ptr: fields[i])) { |
109 | ret = PTR_ERR(ptr: fields[i]); |
110 | dev_err(dev, "bitfield %d: failed allocate: %d\n" , |
111 | i, ret); |
112 | return ret; |
113 | } |
114 | |
115 | bits = 1 + field.msb - field.lsb; |
116 | mux->states = 1 << bits; |
117 | |
118 | of_property_read_u32_index(np, propname: "idle-states" , index: i, |
119 | out_value: (u32 *)&idle_state); |
120 | if (idle_state != MUX_IDLE_AS_IS) { |
121 | if (idle_state < 0 || idle_state >= mux->states) { |
122 | dev_err(dev, "bitfield: %d: out of range idle state %d\n" , |
123 | i, idle_state); |
124 | return -EINVAL; |
125 | } |
126 | |
127 | mux->idle_state = idle_state; |
128 | } |
129 | } |
130 | |
131 | mux_chip->ops = &mux_mmio_ops; |
132 | |
133 | return devm_mux_chip_register(dev, mux_chip); |
134 | } |
135 | |
136 | static struct platform_driver mux_mmio_driver = { |
137 | .driver = { |
138 | .name = "mmio-mux" , |
139 | .of_match_table = mux_mmio_dt_ids, |
140 | }, |
141 | .probe = mux_mmio_probe, |
142 | }; |
143 | module_platform_driver(mux_mmio_driver); |
144 | |
145 | MODULE_DESCRIPTION("MMIO register bitfield-controlled multiplexer driver" ); |
146 | MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>" ); |
147 | MODULE_LICENSE("GPL v2" ); |
148 | |