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