| 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 void 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 | |
| 323 | static const struct platform_device_id max197_device_ids[] = { |
| 324 | { "max197", max197 }, |
| 325 | { "max199", max199 }, |
| 326 | { } |
| 327 | }; |
| 328 | MODULE_DEVICE_TABLE(platform, max197_device_ids); |
| 329 | |
| 330 | static struct platform_driver max197_driver = { |
| 331 | .driver = { |
| 332 | .name = "max197", |
| 333 | }, |
| 334 | .probe = max197_probe, |
| 335 | .remove_new = max197_remove, |
| 336 | .id_table = max197_device_ids, |
| 337 | }; |
| 338 | module_platform_driver(max197_driver); |
| 339 | |
| 340 | MODULE_LICENSE("GPL"); |
| 341 | MODULE_AUTHOR("Savoir-faire Linux Inc. <kernel@savoirfairelinux.com>"); |
| 342 | MODULE_DESCRIPTION("Maxim MAX197 A/D Converter driver"); |