drivers/mux/mmio.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * MMIO register bitfield-controlled multiplexer driver
   4  * Based on the linux mmio multiplexer driver
   5  *
   6  * Copyright (C) 2017 Pengutronix, Philipp Zabel <kernel@pengutronix.de>
   7  * Copyright (C) 2019 Texas Instrument, Jean-jacques Hiblot <jjhiblot@ti.com>
   8  */
   9 #include <common.h>
  10 #include <dm.h>
  11 #include <mux-internal.h>
  12 #include <regmap.h>
  13 #include <syscon.h>
  14 #include <dm/device.h>
  15 #include <dm/device-internal.h>
  16 #include <dm/device_compat.h>
  17 #include <dm/read.h>
  18 #include <dm/devres.h>
  19 #include <dt-bindings/mux/mux.h>
  20 #include <linux/bitops.h>
  21
  22 static int mux_mmio_set(struct mux_control *mux, int state)
  23 {
  24         struct regmap_field **fields = dev_get_priv(mux->dev);
  25
  26         return regmap_field_write(fields[mux_control_get_index(mux)], state);
  27 }
  28
  29 static const struct mux_control_ops mux_mmio_ops = {
  30         .set = mux_mmio_set,
  31 };
  32
  33 static const struct udevice_id mmio_mux_of_match[] = {
  34         { .compatible = "mmio-mux" },
  35         { /* sentinel */ },
  36 };
  37
  38 static int mmio_mux_probe(struct udevice *dev)
  39 {
  40         struct regmap_field **fields;
  41         struct mux_chip *mux_chip = dev_get_uclass_priv(dev);
  42         struct regmap *regmap;
  43         u32 *mux_reg_masks;
  44         u32 *idle_states;
  45         int num_fields;
  46         int ret;
  47         int i;
  48
  49         regmap = syscon_node_to_regmap(dev_ofnode(dev->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         num_fields = dev_read_size(dev, "mux-reg-masks");
  57         if (num_fields < 0)
  58                 return log_msg_ret("mux-reg-masks missing", -EINVAL);
  59
  60         num_fields /= sizeof(u32);
  61         if (num_fields == 0 || num_fields % 2)
  62                 ret = -EINVAL;
  63         num_fields = num_fields / 2;
  64
  65         ret = mux_alloc_controllers(dev, num_fields);
  66         if (ret < 0)
  67                 return log_msg_ret("mux_alloc_controllers", ret);
  68
  69         fields = devm_kmalloc(dev, num_fields * sizeof(*fields), __GFP_ZERO);
  70         if (!fields)
  71                 return -ENOMEM;
  72         dev_set_priv(dev, fields);
  73
  74         mux_reg_masks = devm_kmalloc(dev, num_fields * 2 * sizeof(u32),
  75                                      __GFP_ZERO);
  76         if (!mux_reg_masks)
  77                 return -ENOMEM;
  78
  79         ret = dev_read_u32_array(dev, "mux-reg-masks", mux_reg_masks,
  80                                  num_fields * 2);
  81         if (ret < 0)
  82                 return log_msg_ret("mux-reg-masks read", ret);
  83
  84         idle_states = devm_kmalloc(dev, num_fields * sizeof(u32), __GFP_ZERO);
  85         if (!idle_states)
  86                 return -ENOMEM;
  87
  88         ret = dev_read_u32_array(dev, "idle-states", idle_states, num_fields);
  89         if (ret < 0) {
  90                 log_err("idle-states");
  91                 devm_kfree(dev, idle_states);
  92                 idle_states = NULL;
  93         }
  94
  95         for (i = 0; i < num_fields; i++) {
  96                 struct mux_control *mux = &mux_chip->mux[i];
  97                 struct reg_field field;
  98                 u32 reg, mask;
  99                 int bits;
 100
 101                 reg = mux_reg_masks[2 * i];
 102                 mask = mux_reg_masks[2 * i + 1];
 103
 104                 field.reg = reg;
 105                 field.msb = fls(mask) - 1;
 106                 field.lsb = ffs(mask) - 1;
 107
 108                 if (mask != GENMASK(field.msb, field.lsb))
 109                         return log_msg_ret("invalid mask", -EINVAL);
 110
 111                 fields[i] = devm_regmap_field_alloc(dev, regmap, field);
 112                 if (IS_ERR(fields[i])) {
 113                         ret = PTR_ERR(fields[i]);
 114                         return log_msg_ret("regmap_field_alloc", ret);
 115                 }
 116
 117                 bits = 1 + field.msb - field.lsb;
 118                 mux->states = 1 << bits;
 119
 120                 if (!idle_states)
 121                         continue;
 122
 123                 if (idle_states[i] != MUX_IDLE_AS_IS &&
 124                     idle_states[i] >= mux->states)
 125                         return log_msg_ret("idle-states range", -EINVAL);
 126
 127                 mux->idle_state = idle_states[i];
 128         }
 129
 130         devm_kfree(dev, mux_reg_masks);
 131         if (idle_states)
 132                 devm_kfree(dev, idle_states);
 133
 134         return 0;
 135 }
 136
 137 U_BOOT_DRIVER(mmio_mux) = {
 138         .name = "mmio-mux",
 139         .id = UCLASS_MUX,
 140         .of_match = mmio_mux_of_match,
 141         .probe = mmio_mux_probe,
 142         .ops = &mux_mmio_ops,
 143 };