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); 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 { .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(np, "mmio-mux")) 48 regmap = syscon_node_to_regmap(np->parent); 49 else 50 regmap = dev_get_regmap(dev->parent, NULL) ?: ERR_PTR(-ENODEV); 51 if (IS_ERR(regmap)) { 52 ret = PTR_ERR(regmap); 53 dev_err(dev, "failed to get regmap: %d\n", ret); 54 return ret; 55 } 56 57 ret = of_property_count_u32_elems(np, "mux-reg-masks"); 58 if (ret == 0 || ret % 2) 59 ret = -EINVAL; 60 if (ret < 0) { 61 dev_err(dev, "mux-reg-masks property missing or invalid: %d\n", 62 ret); 63 return ret; 64 } 65 num_fields = ret / 2; 66 67 mux_chip = devm_mux_chip_alloc(dev, num_fields, num_fields * 68 sizeof(*fields)); 69 if (IS_ERR(mux_chip)) 70 return PTR_ERR(mux_chip); 71 72 fields = mux_chip_priv(mux_chip); 73 74 for (i = 0; i < num_fields; i++) { 75 struct mux_control *mux = &mux_chip->mux[i]; 76 struct reg_field field; 77 s32 idle_state = MUX_IDLE_AS_IS; 78 u32 reg, mask; 79 int bits; 80 81 ret = of_property_read_u32_index(np, "mux-reg-masks", 82 2 * i, ®); 83 if (!ret) 84 ret = of_property_read_u32_index(np, "mux-reg-masks", 85 2 * i + 1, &mask); 86 if (ret < 0) { 87 dev_err(dev, "bitfield %d: failed to read mux-reg-masks property: %d\n", 88 i, ret); 89 return ret; 90 } 91 92 field.reg = reg; 93 field.msb = fls(mask) - 1; 94 field.lsb = ffs(mask) - 1; 95 96 if (mask != GENMASK(field.msb, field.lsb)) { 97 dev_err(dev, "bitfield %d: invalid mask 0x%x\n", 98 i, mask); 99 return -EINVAL; 100 } 101 102 fields[i] = devm_regmap_field_alloc(dev, regmap, field); 103 if (IS_ERR(fields[i])) { 104 ret = PTR_ERR(fields[i]); 105 dev_err(dev, "bitfield %d: failed allocate: %d\n", 106 i, ret); 107 return ret; 108 } 109 110 bits = 1 + field.msb - field.lsb; 111 mux->states = 1 << bits; 112 113 of_property_read_u32_index(np, "idle-states", i, 114 (u32 *)&idle_state); 115 if (idle_state != MUX_IDLE_AS_IS) { 116 if (idle_state < 0 || idle_state >= mux->states) { 117 dev_err(dev, "bitfield: %d: out of range idle state %d\n", 118 i, idle_state); 119 return -EINVAL; 120 } 121 122 mux->idle_state = idle_state; 123 } 124 } 125 126 mux_chip->ops = &mux_mmio_ops; 127 128 return devm_mux_chip_register(dev, mux_chip); 129 } 130 131 static struct platform_driver mux_mmio_driver = { 132 .driver = { 133 .name = "mmio-mux", 134 .of_match_table = mux_mmio_dt_ids, 135 }, 136 .probe = mux_mmio_probe, 137 }; 138 module_platform_driver(mux_mmio_driver); 139 140 MODULE_DESCRIPTION("MMIO register bitfield-controlled multiplexer driver"); 141 MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>"); 142 MODULE_LICENSE("GPL v2"); 143