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1// SPDX-License-Identifier: GPL-2.02/*3 * MMIO register bitfield-controlled multiplexer driver4 *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 18static 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 25static const struct mux_control_ops mux_mmio_ops = {26 .set = mux_mmio_set,27};28 29static const struct of_device_id mux_mmio_dt_ids[] = {30 { .compatible = "mmio-mux", },31 { .compatible = "reg-mux", },32 { /* sentinel */ }33};34MODULE_DEVICE_TABLE(of, mux_mmio_dt_ids);35 36static 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(np, "mmio-mux")) {48 regmap = syscon_node_to_regmap(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(regmap) && regmap != ERR_PTR(-EPROBE_DEFER)) {53 regmap = dev_get_regmap(dev->parent, NULL);54 if (!regmap)55 regmap = ERR_PTR(-ENODEV);56 }57 }58 if (IS_ERR(regmap))59 return dev_err_probe(dev, PTR_ERR(regmap),60 "failed to get regmap\n");61 62 ret = of_property_count_u32_elems(np, "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, num_fields, num_fields *73 sizeof(*fields));74 if (IS_ERR(mux_chip))75 return PTR_ERR(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, "mux-reg-masks",87 2 * i, ®);88 if (!ret)89 ret = of_property_read_u32_index(np, "mux-reg-masks",90 2 * i + 1, &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(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, field);108 if (IS_ERR(fields[i])) {109 ret = PTR_ERR(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, "idle-states", i,119 (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 136static 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};143module_platform_driver(mux_mmio_driver);144 145MODULE_DESCRIPTION("MMIO register bitfield-controlled multiplexer driver");146MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");147MODULE_LICENSE("GPL v2");148