drivers/hwmon/max197.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Maxim MAX197 A/D Converter driver
   4  *
   5  * Copyright (c) 2012 Savoir-faire Linux Inc.
   6  *          Vivien Didelot <vivien.didelot@savoirfairelinux.com>
   7  *
   8  * For further information, see the Documentation/hwmon/max197.rst file.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/mod_devicetable.h>
  14 #include <linux/init.h>
  15 #include <linux/err.h>
  16 #include <linux/slab.h>
  17 #include <linux/mutex.h>
  18 #include <linux/device.h>
  19 #include <linux/sysfs.h>
  20 #include <linux/hwmon.h>
  21 #include <linux/hwmon-sysfs.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/platform_data/max197.h>
  24
  25 #define MAX199_LIMIT    4000            /* 4V */
  26 #define MAX197_LIMIT    10000           /* 10V */
  27
  28 #define MAX197_NUM_CH   8               /* 8 Analog Input Channels */
  29
  30 /* Control byte format */
  31 #define MAX197_BIP      (1 << 3)        /* Bipolarity */
  32 #define MAX197_RNG      (1 << 4)        /* Full range */
  33
  34 #define MAX197_SCALE    12207           /* Scale coefficient for raw data */
  35
  36 /* List of supported chips */
  37 enum max197_chips { max197, max199 };
  38
  39 /**
  40  * struct max197_data - device instance specific data
  41  * @pdata:              Platform data.
  42  * @hwmon_dev:          The hwmon device.
  43  * @lock:               Read/Write mutex.
  44  * @limit:              Max range value (10V for MAX197, 4V for MAX199).
  45  * @scale:              Need to scale.
  46  * @ctrl_bytes:         Channels control byte.
  47  */
  48 struct max197_data {
  49         struct max197_platform_data *pdata;
  50         struct device *hwmon_dev;
  51         struct mutex lock;
  52         int limit;
  53         bool scale;
  54         u8 ctrl_bytes[MAX197_NUM_CH];
  55 };
  56
  57 static inline void max197_set_unipolarity(struct max197_data *data, int channel)
  58 {
  59         data->ctrl_bytes[channel] &= ~MAX197_BIP;
  60 }
  61
  62 static inline void max197_set_bipolarity(struct max197_data *data, int channel)
  63 {
  64         data->ctrl_bytes[channel] |= MAX197_BIP;
  65 }
  66
  67 static inline void max197_set_half_range(struct max197_data *data, int channel)
  68 {
  69         data->ctrl_bytes[channel] &= ~MAX197_RNG;
  70 }
  71
  72 static inline void max197_set_full_range(struct max197_data *data, int channel)
  73 {
  74         data->ctrl_bytes[channel] |= MAX197_RNG;
  75 }
  76
  77 static inline bool max197_is_bipolar(struct max197_data *data, int channel)
  78 {
  79         return data->ctrl_bytes[channel] & MAX197_BIP;
  80 }
  81
  82 static inline bool max197_is_full_range(struct max197_data *data, int channel)
  83 {
  84         return data->ctrl_bytes[channel] & MAX197_RNG;
  85 }
  86
  87 /* Function called on read access on in{0,1,2,3,4,5,6,7}_{min,max} */
  88 static ssize_t max197_show_range(struct device *dev,
  89                                  struct device_attribute *devattr, char *buf)
  90 {
  91         struct max197_data *data = dev_get_drvdata(dev);
  92         struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
  93         int channel = attr->index;
  94         bool is_min = attr->nr;
  95         int range;
  96
  97         if (mutex_lock_interruptible(&data->lock))
  98                 return -ERESTARTSYS;
  99
 100         range = max197_is_full_range(data, channel) ?
 101                 data->limit : data->limit / 2;
 102         if (is_min) {
 103                 if (max197_is_bipolar(data, channel))
 104                         range = -range;
 105                 else
 106                         range = 0;
 107         }
 108
 109         mutex_unlock(&data->lock);
 110
 111         return sprintf(buf, "%d\n", range);
 112 }
 113
 114 /* Function called on write access on in{0,1,2,3,4,5,6,7}_{min,max} */
 115 static ssize_t max197_store_range(struct device *dev,
 116                                   struct device_attribute *devattr,
 117                                   const char *buf, size_t count)
 118 {
 119         struct max197_data *data = dev_get_drvdata(dev);
 120         struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
 121         int channel = attr->index;
 122         bool is_min = attr->nr;
 123         long value;
 124         int half = data->limit / 2;
 125         int full = data->limit;
 126
 127         if (kstrtol(buf, 10, &value))
 128                 return -EINVAL;
 129
 130         if (is_min) {
 131                 if (value <= -full)
 132                         value = -full;
 133                 else if (value < 0)
 134                         value = -half;
 135                 else
 136                         value = 0;
 137         } else {
 138                 if (value >= full)
 139                         value = full;
 140                 else
 141                         value = half;
 142         }
 143
 144         if (mutex_lock_interruptible(&data->lock))
 145                 return -ERESTARTSYS;
 146
 147         if (value == 0) {
 148                 /* We can deduce only the polarity */
 149                 max197_set_unipolarity(data, channel);
 150         } else if (value == -half) {
 151                 max197_set_bipolarity(data, channel);
 152                 max197_set_half_range(data, channel);
 153         } else if (value == -full) {
 154                 max197_set_bipolarity(data, channel);
 155                 max197_set_full_range(data, channel);
 156         } else if (value == half) {
 157                 /* We can deduce only the range */
 158                 max197_set_half_range(data, channel);
 159         } else if (value == full) {
 160                 /* We can deduce only the range */
 161                 max197_set_full_range(data, channel);
 162         }
 163
 164         mutex_unlock(&data->lock);
 165
 166         return count;
 167 }
 168
 169 /* Function called on read access on in{0,1,2,3,4,5,6,7}_input */
 170 static ssize_t max197_show_input(struct device *dev,
 171                                  struct device_attribute *devattr,
 172                                  char *buf)
 173 {
 174         struct max197_data *data = dev_get_drvdata(dev);
 175         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 176         int channel = attr->index;
 177         s32 value;
 178         int ret;
 179
 180         if (mutex_lock_interruptible(&data->lock))
 181                 return -ERESTARTSYS;
 182
 183         ret = data->pdata->convert(data->ctrl_bytes[channel]);
 184         if (ret < 0) {
 185                 dev_err(dev, "conversion failed\n");
 186                 goto unlock;
 187         }
 188         value = ret;
 189
 190         /*
 191          * Coefficient to apply on raw value.
 192          * See Table 1. Full Scale and Zero Scale in the MAX197 datasheet.
 193          */
 194         if (data->scale) {
 195                 value *= MAX197_SCALE;
 196                 if (max197_is_full_range(data, channel))
 197                         value *= 2;
 198                 value /= 10000;
 199         }
 200
 201         ret = sprintf(buf, "%d\n", value);
 202
 203 unlock:
 204         mutex_unlock(&data->lock);
 205         return ret;
 206 }
 207
 208 static ssize_t name_show(struct device *dev, struct device_attribute *attr,
 209                          char *buf)
 210 {
 211         struct platform_device *pdev = to_platform_device(dev);
 212         return sprintf(buf, "%s\n", pdev->name);
 213 }
 214
 215 #define MAX197_SENSOR_DEVICE_ATTR_CH(chan)                              \
 216         static SENSOR_DEVICE_ATTR(in##chan##_input, S_IRUGO,            \
 217                                   max197_show_input, NULL, chan);       \
 218         static SENSOR_DEVICE_ATTR_2(in##chan##_min, S_IRUGO | S_IWUSR,  \
 219                                     max197_show_range,                  \
 220                                     max197_store_range,                 \
 221                                     true, chan);                        \
 222         static SENSOR_DEVICE_ATTR_2(in##chan##_max, S_IRUGO | S_IWUSR,  \
 223                                     max197_show_range,                  \
 224                                     max197_store_range,                 \
 225                                     false, chan)
 226
 227 #define MAX197_SENSOR_DEV_ATTR_IN(chan)                                 \
 228         &sensor_dev_attr_in##chan##_input.dev_attr.attr,                \
 229         &sensor_dev_attr_in##chan##_max.dev_attr.attr,                  \
 230         &sensor_dev_attr_in##chan##_min.dev_attr.attr
 231
 232 static DEVICE_ATTR_RO(name);
 233
 234 MAX197_SENSOR_DEVICE_ATTR_CH(0);
 235 MAX197_SENSOR_DEVICE_ATTR_CH(1);
 236 MAX197_SENSOR_DEVICE_ATTR_CH(2);
 237 MAX197_SENSOR_DEVICE_ATTR_CH(3);
 238 MAX197_SENSOR_DEVICE_ATTR_CH(4);
 239 MAX197_SENSOR_DEVICE_ATTR_CH(5);
 240 MAX197_SENSOR_DEVICE_ATTR_CH(6);
 241 MAX197_SENSOR_DEVICE_ATTR_CH(7);
 242
 243 static const struct attribute_group max197_sysfs_group = {
 244         .attrs = (struct attribute *[]) {
 245                 &dev_attr_name.attr,
 246                 MAX197_SENSOR_DEV_ATTR_IN(0),
 247                 MAX197_SENSOR_DEV_ATTR_IN(1),
 248                 MAX197_SENSOR_DEV_ATTR_IN(2),
 249                 MAX197_SENSOR_DEV_ATTR_IN(3),
 250                 MAX197_SENSOR_DEV_ATTR_IN(4),
 251                 MAX197_SENSOR_DEV_ATTR_IN(5),
 252                 MAX197_SENSOR_DEV_ATTR_IN(6),
 253                 MAX197_SENSOR_DEV_ATTR_IN(7),
 254                 NULL
 255         },
 256 };
 257
 258 static int max197_probe(struct platform_device *pdev)
 259 {
 260         int ch, ret;
 261         struct max197_data *data;
 262         struct max197_platform_data *pdata = dev_get_platdata(&pdev->dev);
 263         enum max197_chips chip = platform_get_device_id(pdev)->driver_data;
 264
 265         if (pdata == NULL) {
 266                 dev_err(&pdev->dev, "no platform data supplied\n");
 267                 return -EINVAL;
 268         }
 269
 270         if (pdata->convert == NULL) {
 271                 dev_err(&pdev->dev, "no convert function supplied\n");
 272                 return -EINVAL;
 273         }
 274
 275         data = devm_kzalloc(&pdev->dev, sizeof(struct max197_data), GFP_KERNEL);
 276         if (!data)
 277                 return -ENOMEM;
 278
 279         data->pdata = pdata;
 280         mutex_init(&data->lock);
 281
 282         if (chip == max197) {
 283                 data->limit = MAX197_LIMIT;
 284                 data->scale = true;
 285         } else {
 286                 data->limit = MAX199_LIMIT;
 287                 data->scale = false;
 288         }
 289
 290         for (ch = 0; ch < MAX197_NUM_CH; ch++)
 291                 data->ctrl_bytes[ch] = (u8) ch;
 292
 293         platform_set_drvdata(pdev, data);
 294
 295         ret = sysfs_create_group(&pdev->dev.kobj, &max197_sysfs_group);
 296         if (ret) {
 297                 dev_err(&pdev->dev, "sysfs create group failed\n");
 298                 return ret;
 299         }
 300
 301         data->hwmon_dev = hwmon_device_register(&pdev->dev);
 302         if (IS_ERR(data->hwmon_dev)) {
 303                 ret = PTR_ERR(data->hwmon_dev);
 304                 dev_err(&pdev->dev, "hwmon device register failed\n");
 305                 goto error;
 306         }
 307
 308         return 0;
 309
 310 error:
 311         sysfs_remove_group(&pdev->dev.kobj, &max197_sysfs_group);
 312         return ret;
 313 }
 314
 315 static int max197_remove(struct platform_device *pdev)
 316 {
 317         struct max197_data *data = platform_get_drvdata(pdev);
 318
 319         hwmon_device_unregister(data->hwmon_dev);
 320         sysfs_remove_group(&pdev->dev.kobj, &max197_sysfs_group);
 321
 322         return 0;
 323 }
 324
 325 static const struct platform_device_id max197_device_ids[] = {
 326         { "max197", max197 },
 327         { "max199", max199 },
 328         { }
 329 };
 330 MODULE_DEVICE_TABLE(platform, max197_device_ids);
 331
 332 static struct platform_driver max197_driver = {
 333         .driver = {
 334                 .name = "max197",
 335         },
 336         .probe = max197_probe,
 337         .remove = max197_remove,
 338         .id_table = max197_device_ids,
 339 };
 340 module_platform_driver(max197_driver);
 341
 342 MODULE_LICENSE("GPL");
 343 MODULE_AUTHOR("Savoir-faire Linux Inc. <kernel@savoirfairelinux.com>");
 344 MODULE_DESCRIPTION("Maxim MAX197 A/D Converter driver");