drivers/hwmon/max1111.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * max1111.c - +2.7V, Low-Power, Multichannel, Serial 8-bit ADCs
   4  *
   5  * Based on arch/arm/mach-pxa/corgi_ssp.c
   6  *
   7  * Copyright (C) 2004-2005 Richard Purdie
   8  *
   9  * Copyright (C) 2008 Marvell International Ltd.
  10  *      Eric Miao <eric.miao@marvell.com>
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/err.h>
  17 #include <linux/hwmon.h>
  18 #include <linux/hwmon-sysfs.h>
  19 #include <linux/spi/spi.h>
  20 #include <linux/slab.h>
  21
  22 enum chips { max1110, max1111, max1112, max1113 };
  23
  24 #define MAX1111_TX_BUF_SIZE     1
  25 #define MAX1111_RX_BUF_SIZE     2
  26
  27 /* MAX1111 Commands */
  28 #define MAX1111_CTRL_PD0      (1u << 0)
  29 #define MAX1111_CTRL_PD1      (1u << 1)
  30 #define MAX1111_CTRL_SGL      (1u << 2)
  31 #define MAX1111_CTRL_UNI      (1u << 3)
  32 #define MAX1110_CTRL_SEL_SH   (4)
  33 #define MAX1111_CTRL_SEL_SH   (5)       /* NOTE: bit 4 is ignored */
  34 #define MAX1111_CTRL_STR      (1u << 7)
  35
  36 struct max1111_data {
  37         struct spi_device       *spi;
  38         struct device           *hwmon_dev;
  39         struct spi_message      msg;
  40         struct spi_transfer     xfer[2];
  41         uint8_t tx_buf[MAX1111_TX_BUF_SIZE];
  42         uint8_t rx_buf[MAX1111_RX_BUF_SIZE];
  43         struct mutex            drvdata_lock;
  44         /* protect msg, xfer and buffers from multiple access */
  45         int                     sel_sh;
  46         int                     lsb;
  47 };
  48
  49 static int max1111_read(struct device *dev, int channel)
  50 {
  51         struct max1111_data *data = dev_get_drvdata(dev);
  52         uint8_t v1, v2;
  53         int err;
  54
  55         /* writing to drvdata struct is not thread safe, wait on mutex */
  56         mutex_lock(&data->drvdata_lock);
  57
  58         data->tx_buf[0] = (channel << data->sel_sh) |
  59                 MAX1111_CTRL_PD0 | MAX1111_CTRL_PD1 |
  60                 MAX1111_CTRL_SGL | MAX1111_CTRL_UNI | MAX1111_CTRL_STR;
  61
  62         err = spi_sync(data->spi, &data->msg);
  63         if (err < 0) {
  64                 dev_err(dev, "spi_sync failed with %d\n", err);
  65                 mutex_unlock(&data->drvdata_lock);
  66                 return err;
  67         }
  68
  69         v1 = data->rx_buf[0];
  70         v2 = data->rx_buf[1];
  71
  72         mutex_unlock(&data->drvdata_lock);
  73
  74         if ((v1 & 0xc0) || (v2 & 0x3f))
  75                 return -EINVAL;
  76
  77         return (v1 << 2) | (v2 >> 6);
  78 }
  79
  80 #ifdef CONFIG_SHARPSL_PM
  81 static struct max1111_data *the_max1111;
  82
  83 int max1111_read_channel(int channel);
  84 int max1111_read_channel(int channel)
  85 {
  86         if (!the_max1111 || !the_max1111->spi)
  87                 return -ENODEV;
  88
  89         return max1111_read(&the_max1111->spi->dev, channel);
  90 }
  91 EXPORT_SYMBOL(max1111_read_channel);
  92 #endif
  93
  94 /*
  95  * NOTE: SPI devices do not have a default 'name' attribute, which is
  96  * likely to be used by hwmon applications to distinguish between
  97  * different devices, explicitly add a name attribute here.
  98  */
  99 static ssize_t name_show(struct device *dev,
 100                          struct device_attribute *attr, char *buf)
 101 {
 102         return sprintf(buf, "%s\n", to_spi_device(dev)->modalias);
 103 }
 104
 105 static ssize_t show_adc(struct device *dev,
 106                         struct device_attribute *attr, char *buf)
 107 {
 108         struct max1111_data *data = dev_get_drvdata(dev);
 109         int channel = to_sensor_dev_attr(attr)->index;
 110         int ret;
 111
 112         ret = max1111_read(dev, channel);
 113         if (ret < 0)
 114                 return ret;
 115
 116         /*
 117          * Assume the reference voltage to be 2.048V or 4.096V, with an 8-bit
 118          * sample. The LSB weight is 8mV or 16mV depending on the chip type.
 119          */
 120         return sprintf(buf, "%d\n", ret * data->lsb);
 121 }
 122
 123 #define MAX1111_ADC_ATTR(_id)           \
 124         SENSOR_DEVICE_ATTR(in##_id##_input, S_IRUGO, show_adc, NULL, _id)
 125
 126 static DEVICE_ATTR_RO(name);
 127 static MAX1111_ADC_ATTR(0);
 128 static MAX1111_ADC_ATTR(1);
 129 static MAX1111_ADC_ATTR(2);
 130 static MAX1111_ADC_ATTR(3);
 131 static MAX1111_ADC_ATTR(4);
 132 static MAX1111_ADC_ATTR(5);
 133 static MAX1111_ADC_ATTR(6);
 134 static MAX1111_ADC_ATTR(7);
 135
 136 static struct attribute *max1111_attributes[] = {
 137         &dev_attr_name.attr,
 138         &sensor_dev_attr_in0_input.dev_attr.attr,
 139         &sensor_dev_attr_in1_input.dev_attr.attr,
 140         &sensor_dev_attr_in2_input.dev_attr.attr,
 141         &sensor_dev_attr_in3_input.dev_attr.attr,
 142         NULL,
 143 };
 144
 145 static const struct attribute_group max1111_attr_group = {
 146         .attrs  = max1111_attributes,
 147 };
 148
 149 static struct attribute *max1110_attributes[] = {
 150         &sensor_dev_attr_in4_input.dev_attr.attr,
 151         &sensor_dev_attr_in5_input.dev_attr.attr,
 152         &sensor_dev_attr_in6_input.dev_attr.attr,
 153         &sensor_dev_attr_in7_input.dev_attr.attr,
 154         NULL,
 155 };
 156
 157 static const struct attribute_group max1110_attr_group = {
 158         .attrs  = max1110_attributes,
 159 };
 160
 161 static int setup_transfer(struct max1111_data *data)
 162 {
 163         struct spi_message *m;
 164         struct spi_transfer *x;
 165
 166         m = &data->msg;
 167         x = &data->xfer[0];
 168
 169         spi_message_init(m);
 170
 171         x->tx_buf = &data->tx_buf[0];
 172         x->len = MAX1111_TX_BUF_SIZE;
 173         spi_message_add_tail(x, m);
 174
 175         x++;
 176         x->rx_buf = &data->rx_buf[0];
 177         x->len = MAX1111_RX_BUF_SIZE;
 178         spi_message_add_tail(x, m);
 179
 180         return 0;
 181 }
 182
 183 static int max1111_probe(struct spi_device *spi)
 184 {
 185         enum chips chip = spi_get_device_id(spi)->driver_data;
 186         struct max1111_data *data;
 187         int err;
 188
 189         spi->bits_per_word = 8;
 190         spi->mode = SPI_MODE_0;
 191         err = spi_setup(spi);
 192         if (err < 0)
 193                 return err;
 194
 195         data = devm_kzalloc(&spi->dev, sizeof(struct max1111_data), GFP_KERNEL);
 196         if (data == NULL)
 197                 return -ENOMEM;
 198
 199         switch (chip) {
 200         case max1110:
 201                 data->lsb = 8;
 202                 data->sel_sh = MAX1110_CTRL_SEL_SH;
 203                 break;
 204         case max1111:
 205                 data->lsb = 8;
 206                 data->sel_sh = MAX1111_CTRL_SEL_SH;
 207                 break;
 208         case max1112:
 209                 data->lsb = 16;
 210                 data->sel_sh = MAX1110_CTRL_SEL_SH;
 211                 break;
 212         case max1113:
 213                 data->lsb = 16;
 214                 data->sel_sh = MAX1111_CTRL_SEL_SH;
 215                 break;
 216         }
 217         err = setup_transfer(data);
 218         if (err)
 219                 return err;
 220
 221         mutex_init(&data->drvdata_lock);
 222
 223         data->spi = spi;
 224         spi_set_drvdata(spi, data);
 225
 226         err = sysfs_create_group(&spi->dev.kobj, &max1111_attr_group);
 227         if (err) {
 228                 dev_err(&spi->dev, "failed to create attribute group\n");
 229                 return err;
 230         }
 231         if (chip == max1110 || chip == max1112) {
 232                 err = sysfs_create_group(&spi->dev.kobj, &max1110_attr_group);
 233                 if (err) {
 234                         dev_err(&spi->dev,
 235                                 "failed to create extended attribute group\n");
 236                         goto err_remove;
 237                 }
 238         }
 239
 240         data->hwmon_dev = hwmon_device_register(&spi->dev);
 241         if (IS_ERR(data->hwmon_dev)) {
 242                 dev_err(&spi->dev, "failed to create hwmon device\n");
 243                 err = PTR_ERR(data->hwmon_dev);
 244                 goto err_remove;
 245         }
 246
 247 #ifdef CONFIG_SHARPSL_PM
 248         the_max1111 = data;
 249 #endif
 250         return 0;
 251
 252 err_remove:
 253         sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group);
 254         sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
 255         return err;
 256 }
 257
 258 static void max1111_remove(struct spi_device *spi)
 259 {
 260         struct max1111_data *data = spi_get_drvdata(spi);
 261
 262 #ifdef CONFIG_SHARPSL_PM
 263         the_max1111 = NULL;
 264 #endif
 265         hwmon_device_unregister(data->hwmon_dev);
 266         sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group);
 267         sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
 268         mutex_destroy(&data->drvdata_lock);
 269 }
 270
 271 static const struct spi_device_id max1111_ids[] = {
 272         { "max1110", max1110 },
 273         { "max1111", max1111 },
 274         { "max1112", max1112 },
 275         { "max1113", max1113 },
 276         { },
 277 };
 278 MODULE_DEVICE_TABLE(spi, max1111_ids);
 279
 280 static struct spi_driver max1111_driver = {
 281         .driver         = {
 282                 .name   = "max1111",
 283         },
 284         .id_table       = max1111_ids,
 285         .probe          = max1111_probe,
 286         .remove         = max1111_remove,
 287 };
 288
 289 module_spi_driver(max1111_driver);
 290
 291 MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
 292 MODULE_DESCRIPTION("MAX1110/MAX1111/MAX1112/MAX1113 ADC Driver");
 293 MODULE_LICENSE("GPL");