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, ®val); 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, ®val); 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 int 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 return 0; 273 } 274 275 static struct platform_driver mlxreg_io_driver = { 276 .driver = { 277 .name = "mlxreg-io", 278 }, 279 .probe = mlxreg_io_probe, 280 .remove = mlxreg_io_remove, 281 }; 282 283 module_platform_driver(mlxreg_io_driver); 284 285 MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>"); 286 MODULE_DESCRIPTION("Mellanox regmap I/O access driver"); 287 MODULE_LICENSE("GPL"); 288 MODULE_ALIAS("platform:mlxreg-io"); 289