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 96 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 * @io_lock: user access locking; 35 */ 36 struct mlxreg_io_priv_data { 37 struct platform_device *pdev; 38 struct mlxreg_core_platform_data *pdata; 39 struct device *hwmon; 40 struct attribute *mlxreg_io_attr[MLXREG_IO_ATT_NUM + 1]; 41 struct sensor_device_attribute mlxreg_io_dev_attr[MLXREG_IO_ATT_NUM]; 42 struct attribute_group group; 43 const struct attribute_group *groups[2]; 44 int regsize; 45 struct mutex io_lock; /* Protects user access. */ 46 }; 47 48 static int 49 mlxreg_io_get_reg(void *regmap, struct mlxreg_core_data *data, u32 in_val, 50 bool rw_flag, int regsize, u32 *regval) 51 { 52 int i, val, ret; 53 54 ret = regmap_read(regmap, data->reg, regval); 55 if (ret) 56 goto access_error; 57 58 /* 59 * There are four kinds of attributes: single bit, full register's 60 * bits, bit sequence, bits in few registers For the first kind field 61 * mask indicates which bits are not related and field bit is set zero. 62 * For the second kind field mask is set to zero and field bit is set 63 * with all bits one. No special handling for such kind of attributes - 64 * pass value as is. For the third kind, the field mask indicates which 65 * bits are related and the field bit is set to the first bit number 66 * (from 1 to 32) is the bit sequence. For the fourth kind - the number 67 * of registers which should be read for getting an attribute are 68 * specified through 'data->regnum' field. 69 */ 70 if (!data->bit) { 71 /* Single bit. */ 72 if (rw_flag) { 73 /* For show: expose effective bit value as 0 or 1. */ 74 *regval = !!(*regval & ~data->mask); 75 } else { 76 /* For store: set effective bit value. */ 77 *regval &= data->mask; 78 if (in_val) 79 *regval |= ~data->mask; 80 } 81 } else if (data->mask) { 82 /* Bit sequence. */ 83 if (rw_flag) { 84 /* For show: mask and shift right. */ 85 *regval = ror32(*regval & data->mask, (data->bit - 1)); 86 } else { 87 /* For store: shift to the position and mask. */ 88 in_val = rol32(in_val, data->bit - 1) & data->mask; 89 /* Clear relevant bits and set them to new value. */ 90 *regval = (*regval & ~data->mask) | in_val; 91 } 92 } else { 93 /* 94 * Some attributes could occupied few registers in case regmap 95 * bit size is 8 or 16. Compose such attributes from 'regnum' 96 * registers. Such attributes contain read-only data. 97 */ 98 for (i = 1; i < data->regnum; i++) { 99 ret = regmap_read(regmap, data->reg + i, &val); 100 if (ret) 101 goto access_error; 102 103 *regval |= rol32(val, regsize * i * 8); 104 } 105 } 106 107 access_error: 108 return ret; 109 } 110 111 static ssize_t 112 mlxreg_io_attr_show(struct device *dev, struct device_attribute *attr, 113 char *buf) 114 { 115 struct mlxreg_io_priv_data *priv = dev_get_drvdata(dev); 116 int index = to_sensor_dev_attr(attr)->index; 117 struct mlxreg_core_data *data = priv->pdata->data + index; 118 u32 regval = 0; 119 int ret; 120 121 mutex_lock(&priv->io_lock); 122 123 ret = mlxreg_io_get_reg(priv->pdata->regmap, data, 0, true, 124 priv->regsize, ®val); 125 if (ret) 126 goto access_error; 127 128 mutex_unlock(&priv->io_lock); 129 130 return sprintf(buf, "%u\n", regval); 131 132 access_error: 133 mutex_unlock(&priv->io_lock); 134 return ret; 135 } 136 137 static ssize_t 138 mlxreg_io_attr_store(struct device *dev, struct device_attribute *attr, 139 const char *buf, size_t len) 140 { 141 struct mlxreg_io_priv_data *priv = dev_get_drvdata(dev); 142 int index = to_sensor_dev_attr(attr)->index; 143 struct mlxreg_core_data *data = priv->pdata->data + index; 144 u32 input_val, regval; 145 int ret; 146 147 if (len > MLXREG_IO_ATT_SIZE) 148 return -EINVAL; 149 150 /* Convert buffer to input value. */ 151 ret = kstrtou32(buf, 0, &input_val); 152 if (ret) 153 return ret; 154 155 mutex_lock(&priv->io_lock); 156 157 ret = mlxreg_io_get_reg(priv->pdata->regmap, data, input_val, false, 158 priv->regsize, ®val); 159 if (ret) 160 goto access_error; 161 162 ret = regmap_write(priv->pdata->regmap, data->reg, regval); 163 if (ret) 164 goto access_error; 165 166 mutex_unlock(&priv->io_lock); 167 168 return len; 169 170 access_error: 171 mutex_unlock(&priv->io_lock); 172 dev_err(&priv->pdev->dev, "Bus access error\n"); 173 return ret; 174 } 175 176 static struct device_attribute mlxreg_io_devattr_rw = { 177 .show = mlxreg_io_attr_show, 178 .store = mlxreg_io_attr_store, 179 }; 180 181 static int mlxreg_io_attr_init(struct mlxreg_io_priv_data *priv) 182 { 183 int i; 184 185 priv->group.attrs = devm_kcalloc(&priv->pdev->dev, 186 priv->pdata->counter, 187 sizeof(struct attribute *), 188 GFP_KERNEL); 189 if (!priv->group.attrs) 190 return -ENOMEM; 191 192 for (i = 0; i < priv->pdata->counter; i++) { 193 priv->mlxreg_io_attr[i] = 194 &priv->mlxreg_io_dev_attr[i].dev_attr.attr; 195 memcpy(&priv->mlxreg_io_dev_attr[i].dev_attr, 196 &mlxreg_io_devattr_rw, sizeof(struct device_attribute)); 197 198 /* Set attribute name as a label. */ 199 priv->mlxreg_io_attr[i]->name = 200 devm_kasprintf(&priv->pdev->dev, GFP_KERNEL, 201 priv->pdata->data[i].label); 202 203 if (!priv->mlxreg_io_attr[i]->name) { 204 dev_err(&priv->pdev->dev, "Memory allocation failed for sysfs attribute %d.\n", 205 i + 1); 206 return -ENOMEM; 207 } 208 209 priv->mlxreg_io_dev_attr[i].dev_attr.attr.mode = 210 priv->pdata->data[i].mode; 211 priv->mlxreg_io_dev_attr[i].dev_attr.attr.name = 212 priv->mlxreg_io_attr[i]->name; 213 priv->mlxreg_io_dev_attr[i].index = i; 214 sysfs_attr_init(&priv->mlxreg_io_dev_attr[i].dev_attr.attr); 215 } 216 217 priv->group.attrs = priv->mlxreg_io_attr; 218 priv->groups[0] = &priv->group; 219 priv->groups[1] = NULL; 220 221 return 0; 222 } 223 224 static int mlxreg_io_probe(struct platform_device *pdev) 225 { 226 struct mlxreg_io_priv_data *priv; 227 int err; 228 229 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 230 if (!priv) 231 return -ENOMEM; 232 233 priv->pdata = dev_get_platdata(&pdev->dev); 234 if (!priv->pdata) { 235 dev_err(&pdev->dev, "Failed to get platform data.\n"); 236 return -EINVAL; 237 } 238 239 priv->pdev = pdev; 240 priv->regsize = regmap_get_val_bytes(priv->pdata->regmap); 241 if (priv->regsize < 0) 242 return priv->regsize; 243 244 err = mlxreg_io_attr_init(priv); 245 if (err) { 246 dev_err(&priv->pdev->dev, "Failed to allocate attributes: %d\n", 247 err); 248 return err; 249 } 250 251 priv->hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, 252 "mlxreg_io", 253 priv, 254 priv->groups); 255 if (IS_ERR(priv->hwmon)) { 256 dev_err(&pdev->dev, "Failed to register hwmon device %ld\n", 257 PTR_ERR(priv->hwmon)); 258 return PTR_ERR(priv->hwmon); 259 } 260 261 mutex_init(&priv->io_lock); 262 dev_set_drvdata(&pdev->dev, priv); 263 264 return 0; 265 } 266 267 static int mlxreg_io_remove(struct platform_device *pdev) 268 { 269 struct mlxreg_io_priv_data *priv = dev_get_drvdata(&pdev->dev); 270 271 mutex_destroy(&priv->io_lock); 272 273 return 0; 274 } 275 276 static struct platform_driver mlxreg_io_driver = { 277 .driver = { 278 .name = "mlxreg-io", 279 }, 280 .probe = mlxreg_io_probe, 281 .remove = mlxreg_io_remove, 282 }; 283 284 module_platform_driver(mlxreg_io_driver); 285 286 MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>"); 287 MODULE_DESCRIPTION("Mellanox regmap I/O access driver"); 288 MODULE_LICENSE("GPL"); 289 MODULE_ALIAS("platform:mlxreg-io"); 290