linux/drivers/hwmon/max1111.c
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   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
  25enum 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
  39struct 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
  52static 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
  84static struct max1111_data *the_max1111;
  85
  86int max1111_read_channel(int channel)
  87{
  88        return max1111_read(&the_max1111->spi->dev, channel);
  89}
  90EXPORT_SYMBOL(max1111_read_channel);
  91#endif
  92
  93/*
  94 * NOTE: SPI devices do not have a default 'name' attribute, which is
  95 * likely to be used by hwmon applications to distinguish between
  96 * different devices, explicitly add a name attribute here.
  97 */
  98static ssize_t show_name(struct device *dev,
  99                         struct device_attribute *attr, char *buf)
 100{
 101        return sprintf(buf, "%s\n", to_spi_device(dev)->modalias);
 102}
 103
 104static ssize_t show_adc(struct device *dev,
 105                        struct device_attribute *attr, char *buf)
 106{
 107        struct max1111_data *data = dev_get_drvdata(dev);
 108        int channel = to_sensor_dev_attr(attr)->index;
 109        int ret;
 110
 111        ret = max1111_read(dev, channel);
 112        if (ret < 0)
 113                return ret;
 114
 115        /*
 116         * Assume the reference voltage to be 2.048V or 4.096V, with an 8-bit
 117         * sample. The LSB weight is 8mV or 16mV depending on the chip type.
 118         */
 119        return sprintf(buf, "%d\n", ret * data->lsb);
 120}
 121
 122#define MAX1111_ADC_ATTR(_id)           \
 123        SENSOR_DEVICE_ATTR(in##_id##_input, S_IRUGO, show_adc, NULL, _id)
 124
 125static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 126static MAX1111_ADC_ATTR(0);
 127static MAX1111_ADC_ATTR(1);
 128static MAX1111_ADC_ATTR(2);
 129static MAX1111_ADC_ATTR(3);
 130static MAX1111_ADC_ATTR(4);
 131static MAX1111_ADC_ATTR(5);
 132static MAX1111_ADC_ATTR(6);
 133static MAX1111_ADC_ATTR(7);
 134
 135static struct attribute *max1111_attributes[] = {
 136        &dev_attr_name.attr,
 137        &sensor_dev_attr_in0_input.dev_attr.attr,
 138        &sensor_dev_attr_in1_input.dev_attr.attr,
 139        &sensor_dev_attr_in2_input.dev_attr.attr,
 140        &sensor_dev_attr_in3_input.dev_attr.attr,
 141        NULL,
 142};
 143
 144static const struct attribute_group max1111_attr_group = {
 145        .attrs  = max1111_attributes,
 146};
 147
 148static struct attribute *max1110_attributes[] = {
 149        &sensor_dev_attr_in4_input.dev_attr.attr,
 150        &sensor_dev_attr_in5_input.dev_attr.attr,
 151        &sensor_dev_attr_in6_input.dev_attr.attr,
 152        &sensor_dev_attr_in7_input.dev_attr.attr,
 153        NULL,
 154};
 155
 156static const struct attribute_group max1110_attr_group = {
 157        .attrs  = max1110_attributes,
 158};
 159
 160static int setup_transfer(struct max1111_data *data)
 161{
 162        struct spi_message *m;
 163        struct spi_transfer *x;
 164
 165        m = &data->msg;
 166        x = &data->xfer[0];
 167
 168        spi_message_init(m);
 169
 170        x->tx_buf = &data->tx_buf[0];
 171        x->len = MAX1111_TX_BUF_SIZE;
 172        spi_message_add_tail(x, m);
 173
 174        x++;
 175        x->rx_buf = &data->rx_buf[0];
 176        x->len = MAX1111_RX_BUF_SIZE;
 177        spi_message_add_tail(x, m);
 178
 179        return 0;
 180}
 181
 182static int max1111_probe(struct spi_device *spi)
 183{
 184        enum chips chip = spi_get_device_id(spi)->driver_data;
 185        struct max1111_data *data;
 186        int err;
 187
 188        spi->bits_per_word = 8;
 189        spi->mode = SPI_MODE_0;
 190        err = spi_setup(spi);
 191        if (err < 0)
 192                return err;
 193
 194        data = devm_kzalloc(&spi->dev, sizeof(struct max1111_data), GFP_KERNEL);
 195        if (data == NULL) {
 196                dev_err(&spi->dev, "failed to allocate memory\n");
 197                return -ENOMEM;
 198        }
 199
 200        switch (chip) {
 201        case max1110:
 202                data->lsb = 8;
 203                data->sel_sh = MAX1110_CTRL_SEL_SH;
 204                break;
 205        case max1111:
 206                data->lsb = 8;
 207                data->sel_sh = MAX1111_CTRL_SEL_SH;
 208                break;
 209        case max1112:
 210                data->lsb = 16;
 211                data->sel_sh = MAX1110_CTRL_SEL_SH;
 212                break;
 213        case max1113:
 214                data->lsb = 16;
 215                data->sel_sh = MAX1111_CTRL_SEL_SH;
 216                break;
 217        }
 218        err = setup_transfer(data);
 219        if (err)
 220                return err;
 221
 222        mutex_init(&data->drvdata_lock);
 223
 224        data->spi = spi;
 225        spi_set_drvdata(spi, data);
 226
 227        err = sysfs_create_group(&spi->dev.kobj, &max1111_attr_group);
 228        if (err) {
 229                dev_err(&spi->dev, "failed to create attribute group\n");
 230                return err;
 231        }
 232        if (chip == max1110 || chip == max1112) {
 233                err = sysfs_create_group(&spi->dev.kobj, &max1110_attr_group);
 234                if (err) {
 235                        dev_err(&spi->dev,
 236                                "failed to create extended attribute group\n");
 237                        goto err_remove;
 238                }
 239        }
 240
 241        data->hwmon_dev = hwmon_device_register(&spi->dev);
 242        if (IS_ERR(data->hwmon_dev)) {
 243                dev_err(&spi->dev, "failed to create hwmon device\n");
 244                err = PTR_ERR(data->hwmon_dev);
 245                goto err_remove;
 246        }
 247
 248#ifdef CONFIG_SHARPSL_PM
 249        the_max1111 = data;
 250#endif
 251        return 0;
 252
 253err_remove:
 254        sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group);
 255        sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
 256        return err;
 257}
 258
 259static int max1111_remove(struct spi_device *spi)
 260{
 261        struct max1111_data *data = spi_get_drvdata(spi);
 262
 263        hwmon_device_unregister(data->hwmon_dev);
 264        sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group);
 265        sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
 266        mutex_destroy(&data->drvdata_lock);
 267        return 0;
 268}
 269
 270static const struct spi_device_id max1111_ids[] = {
 271        { "max1110", max1110 },
 272        { "max1111", max1111 },
 273        { "max1112", max1112 },
 274        { "max1113", max1113 },
 275        { },
 276};
 277MODULE_DEVICE_TABLE(spi, max1111_ids);
 278
 279static struct spi_driver max1111_driver = {
 280        .driver         = {
 281                .name   = "max1111",
 282                .owner  = THIS_MODULE,
 283        },
 284        .id_table       = max1111_ids,
 285        .probe          = max1111_probe,
 286        .remove         = max1111_remove,
 287};
 288
 289module_spi_driver(max1111_driver);
 290
 291MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
 292MODULE_DESCRIPTION("MAX1110/MAX1111/MAX1112/MAX1113 ADC Driver");
 293MODULE_LICENSE("GPL");
 294
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