drivers/hwmon/max1111.c

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