drivers/platform/mellanox/mlxreg-io.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Mellanox register access driver
   4  *
   5  * Copyright (C) 2018 Mellanox Technologies
   6  * Copyright (C) 2018 Vadim Pasternak <vadimp@mellanox.com>
   7  */
   8
   9 #include <linux/bitops.h>
  10 #include <linux/device.h>
  11 #include <linux/hwmon.h>
  12 #include <linux/hwmon-sysfs.h>
  13 #include <linux/module.h>
  14 #include <linux/platform_data/mlxreg.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/regmap.h>
  17
  18 /* Attribute parameters. */
  19 #define MLXREG_IO_ATT_SIZE      10
  20 #define MLXREG_IO_ATT_NUM       96
  21
  22 /**
  23  * struct mlxreg_io_priv_data - driver's private data:
  24  *
  25  * @pdev: platform device;
  26  * @pdata: platform data;
  27  * @hwmon: hwmon device;
  28  * @mlxreg_io_attr: sysfs attributes array;
  29  * @mlxreg_io_dev_attr: sysfs sensor device attribute array;
  30  * @group: sysfs attribute group;
  31  * @groups: list of sysfs attribute group for hwmon registration;
  32  * @regsize: size of a register value;
  33  * @io_lock: user access locking;
  34  */
  35 struct mlxreg_io_priv_data {
  36         struct platform_device *pdev;
  37         struct mlxreg_core_platform_data *pdata;
  38         struct device *hwmon;
  39         struct attribute *mlxreg_io_attr[MLXREG_IO_ATT_NUM + 1];
  40         struct sensor_device_attribute mlxreg_io_dev_attr[MLXREG_IO_ATT_NUM];
  41         struct attribute_group group;
  42         const struct attribute_group *groups[2];
  43         int regsize;
  44         struct mutex io_lock; /* Protects user access. */
  45 };
  46
  47 static int
  48 mlxreg_io_get_reg(void *regmap, struct mlxreg_core_data *data, u32 in_val,
  49                   bool rw_flag, int regsize, u32 *regval)
  50 {
  51         int i, val, ret;
  52
  53         ret = regmap_read(regmap, data->reg, regval);
  54         if (ret)
  55                 goto access_error;
  56
  57         /*
  58          * There are four kinds of attributes: single bit, full register's
  59          * bits, bit sequence, bits in few registers For the first kind field
  60          * mask indicates which bits are not related and field bit is set zero.
  61          * For the second kind field mask is set to zero and field bit is set
  62          * with all bits one. No special handling for such kind of attributes -
  63          * pass value as is. For the third kind, the field mask indicates which
  64          * bits are related and the field bit is set to the first bit number
  65          * (from 1 to 32) is the bit sequence. For the fourth kind - the number
  66          * of registers which should be read for getting an attribute are
  67          * specified through 'data->regnum' field.
  68          */
  69         if (!data->bit) {
  70                 /* Single bit. */
  71                 if (rw_flag) {
  72                         /* For show: expose effective bit value as 0 or 1. */
  73                         *regval = !!(*regval & ~data->mask);
  74                 } else {
  75                         /* For store: set effective bit value. */
  76                         *regval &= data->mask;
  77                         if (in_val)
  78                                 *regval |= ~data->mask;
  79                 }
  80         } else if (data->mask) {
  81                 /* Bit sequence. */
  82                 if (rw_flag) {
  83                         /* For show: mask and shift right. */
  84                         *regval = ror32(*regval & data->mask, (data->bit - 1));
  85                 } else {
  86                         /* For store: shift to the position and mask. */
  87                         in_val = rol32(in_val, data->bit - 1) & data->mask;
  88                         /* Clear relevant bits and set them to new value. */
  89                         *regval = (*regval & ~data->mask) | in_val;
  90                 }
  91         } else {
  92                 /*
  93                  * Some attributes could occupied few registers in case regmap
  94                  * bit size is 8 or 16. Compose such attributes from 'regnum'
  95                  * registers. Such attributes contain read-only data.
  96                  */
  97                 for (i = 1; i < data->regnum; i++) {
  98                         ret = regmap_read(regmap, data->reg + i, &val);
  99                         if (ret)
 100                                 goto access_error;
 101
 102                         *regval |= rol32(val, regsize * i * 8);
 103                 }
 104         }
 105
 106 access_error:
 107         return ret;
 108 }
 109
 110 static ssize_t
 111 mlxreg_io_attr_show(struct device *dev, struct device_attribute *attr,
 112                     char *buf)
 113 {
 114         struct mlxreg_io_priv_data *priv = dev_get_drvdata(dev);
 115         int index = to_sensor_dev_attr(attr)->index;
 116         struct mlxreg_core_data *data = priv->pdata->data + index;
 117         u32 regval = 0;
 118         int ret;
 119
 120         mutex_lock(&priv->io_lock);
 121
 122         ret = mlxreg_io_get_reg(priv->pdata->regmap, data, 0, true,
 123                                 priv->regsize, &regval);
 124         if (ret)
 125                 goto access_error;
 126
 127         mutex_unlock(&priv->io_lock);
 128
 129         return sprintf(buf, "%u\n", regval);
 130
 131 access_error:
 132         mutex_unlock(&priv->io_lock);
 133         return ret;
 134 }
 135
 136 static ssize_t
 137 mlxreg_io_attr_store(struct device *dev, struct device_attribute *attr,
 138                      const char *buf, size_t len)
 139 {
 140         struct mlxreg_io_priv_data *priv = dev_get_drvdata(dev);
 141         int index = to_sensor_dev_attr(attr)->index;
 142         struct mlxreg_core_data *data = priv->pdata->data + index;
 143         u32 input_val, regval;
 144         int ret;
 145
 146         if (len > MLXREG_IO_ATT_SIZE)
 147                 return -EINVAL;
 148
 149         /* Convert buffer to input value. */
 150         ret = kstrtou32(buf, 0, &input_val);
 151         if (ret)
 152                 return ret;
 153
 154         mutex_lock(&priv->io_lock);
 155
 156         ret = mlxreg_io_get_reg(priv->pdata->regmap, data, input_val, false,
 157                                 priv->regsize, &regval);
 158         if (ret)
 159                 goto access_error;
 160
 161         ret = regmap_write(priv->pdata->regmap, data->reg, regval);
 162         if (ret)
 163                 goto access_error;
 164
 165         mutex_unlock(&priv->io_lock);
 166
 167         return len;
 168
 169 access_error:
 170         mutex_unlock(&priv->io_lock);
 171         dev_err(&priv->pdev->dev, "Bus access error\n");
 172         return ret;
 173 }
 174
 175 static struct device_attribute mlxreg_io_devattr_rw = {
 176         .show   = mlxreg_io_attr_show,
 177         .store  = mlxreg_io_attr_store,
 178 };
 179
 180 static int mlxreg_io_attr_init(struct mlxreg_io_priv_data *priv)
 181 {
 182         int i;
 183
 184         priv->group.attrs = devm_kcalloc(&priv->pdev->dev,
 185                                          priv->pdata->counter,
 186                                          sizeof(struct attribute *),
 187                                          GFP_KERNEL);
 188         if (!priv->group.attrs)
 189                 return -ENOMEM;
 190
 191         for (i = 0; i < priv->pdata->counter; i++) {
 192                 priv->mlxreg_io_attr[i] =
 193                                 &priv->mlxreg_io_dev_attr[i].dev_attr.attr;
 194                 memcpy(&priv->mlxreg_io_dev_attr[i].dev_attr,
 195                        &mlxreg_io_devattr_rw, sizeof(struct device_attribute));
 196
 197                 /* Set attribute name as a label. */
 198                 priv->mlxreg_io_attr[i]->name =
 199                                 devm_kasprintf(&priv->pdev->dev, GFP_KERNEL,
 200                                                priv->pdata->data[i].label);
 201
 202                 if (!priv->mlxreg_io_attr[i]->name) {
 203                         dev_err(&priv->pdev->dev, "Memory allocation failed for sysfs attribute %d.\n",
 204                                 i + 1);
 205                         return -ENOMEM;
 206                 }
 207
 208                 priv->mlxreg_io_dev_attr[i].dev_attr.attr.mode =
 209                                                 priv->pdata->data[i].mode;
 210                 priv->mlxreg_io_dev_attr[i].dev_attr.attr.name =
 211                                         priv->mlxreg_io_attr[i]->name;
 212                 priv->mlxreg_io_dev_attr[i].index = i;
 213                 sysfs_attr_init(&priv->mlxreg_io_dev_attr[i].dev_attr.attr);
 214         }
 215
 216         priv->group.attrs = priv->mlxreg_io_attr;
 217         priv->groups[0] = &priv->group;
 218         priv->groups[1] = NULL;
 219
 220         return 0;
 221 }
 222
 223 static int mlxreg_io_probe(struct platform_device *pdev)
 224 {
 225         struct mlxreg_io_priv_data *priv;
 226         int err;
 227
 228         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 229         if (!priv)
 230                 return -ENOMEM;
 231
 232         priv->pdata = dev_get_platdata(&pdev->dev);
 233         if (!priv->pdata) {
 234                 dev_err(&pdev->dev, "Failed to get platform data.\n");
 235                 return -EINVAL;
 236         }
 237
 238         priv->pdev = pdev;
 239         priv->regsize = regmap_get_val_bytes(priv->pdata->regmap);
 240         if (priv->regsize < 0)
 241                 return priv->regsize;
 242
 243         err = mlxreg_io_attr_init(priv);
 244         if (err) {
 245                 dev_err(&priv->pdev->dev, "Failed to allocate attributes: %d\n",
 246                         err);
 247                 return err;
 248         }
 249
 250         priv->hwmon = devm_hwmon_device_register_with_groups(&pdev->dev,
 251                                                              "mlxreg_io",
 252                                                               priv,
 253                                                               priv->groups);
 254         if (IS_ERR(priv->hwmon)) {
 255                 dev_err(&pdev->dev, "Failed to register hwmon device %ld\n",
 256                         PTR_ERR(priv->hwmon));
 257                 return PTR_ERR(priv->hwmon);
 258         }
 259
 260         mutex_init(&priv->io_lock);
 261         dev_set_drvdata(&pdev->dev, priv);
 262
 263         return 0;
 264 }
 265
 266 static void mlxreg_io_remove(struct platform_device *pdev)
 267 {
 268         struct mlxreg_io_priv_data *priv = dev_get_drvdata(&pdev->dev);
 269
 270         mutex_destroy(&priv->io_lock);
 271 }
 272
 273 static struct platform_driver mlxreg_io_driver = {
 274         .driver = {
 275             .name = "mlxreg-io",
 276         },
 277         .probe = mlxreg_io_probe,
 278         .remove = mlxreg_io_remove,
 279 };
 280
 281 module_platform_driver(mlxreg_io_driver);
 282
 283 MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>");
 284 MODULE_DESCRIPTION("Mellanox regmap I/O access driver");
 285 MODULE_LICENSE("GPL");
 286 MODULE_ALIAS("platform:mlxreg-io");