drivers/hwmon/mc13783-adc.c

   1 /*
   2  * Driver for the Freescale Semiconductor MC13783 adc.
   3  *
   4  * Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
   5  * Copyright (C) 2009 Sascha Hauer, Pengutronix
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version 2
  10  * of the License, or (at your option) any later version.
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along with
  17  * this program; if not, write to the Free Software Foundation, Inc., 51
  18  * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include <linux/mfd/mc13783-private.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/hwmon-sysfs.h>
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/hwmon.h>
  27 #include <linux/init.h>
  28 #include <linux/err.h>
  29
  30 #define MC13783_ADC_NAME        "mc13783-adc"
  31
  32 struct mc13783_adc_priv {
  33         struct mc13783 *mc13783;
  34         struct device *hwmon_dev;
  35 };
  36
  37 static ssize_t mc13783_adc_show_name(struct device *dev, struct device_attribute
  38                               *devattr, char *buf)
  39 {
  40         return sprintf(buf, "mc13783_adc\n");
  41 }
  42
  43 static int mc13783_adc_read(struct device *dev,
  44                 struct device_attribute *devattr, unsigned int *val)
  45 {
  46         struct platform_device *pdev = to_platform_device(dev);
  47         struct mc13783_adc_priv *priv = platform_get_drvdata(pdev);
  48         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  49         unsigned int channel = attr->index;
  50         unsigned int sample[4];
  51         int ret;
  52
  53         ret = mc13783_adc_do_conversion(priv->mc13783,
  54                         MC13783_ADC_MODE_MULT_CHAN,
  55                         channel, sample);
  56         if (ret)
  57                 return ret;
  58
  59         channel &= 0x7;
  60
  61         *val = (sample[channel % 4] >> (channel > 3 ? 14 : 2)) & 0x3ff;
  62
  63         return 0;
  64 }
  65
  66 static ssize_t mc13783_adc_read_bp(struct device *dev,
  67                 struct device_attribute *devattr, char *buf)
  68 {
  69         unsigned val;
  70         int ret = mc13783_adc_read(dev, devattr, &val);
  71
  72         if (ret)
  73                 return ret;
  74
  75         /*
  76          * BP (channel 2) reports with offset 2.4V to the actual value to fit
  77          * the input range of the ADC.  unit = 2.25mV = 9/4 mV.
  78          */
  79         val = DIV_ROUND_CLOSEST(val * 9, 4) + 2400;
  80
  81         return sprintf(buf, "%u\n", val);
  82 }
  83
  84 static ssize_t mc13783_adc_read_gp(struct device *dev,
  85                 struct device_attribute *devattr, char *buf)
  86 {
  87         unsigned val;
  88         int ret = mc13783_adc_read(dev, devattr, &val);
  89
  90         if (ret)
  91                 return ret;
  92
  93         /*
  94          * input range is [0, 2.3V], val has 10 bits, so each bit
  95          * is worth 9/4 mV.
  96          */
  97         val = DIV_ROUND_CLOSEST(val * 9, 4);
  98
  99         return sprintf(buf, "%u\n", val);
 100 }
 101
 102 static DEVICE_ATTR(name, S_IRUGO, mc13783_adc_show_name, NULL);
 103 static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, mc13783_adc_read_bp, NULL, 2);
 104 static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, mc13783_adc_read_gp, NULL, 5);
 105 static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, mc13783_adc_read_gp, NULL, 6);
 106 static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, mc13783_adc_read_gp, NULL, 7);
 107 static SENSOR_DEVICE_ATTR(in8_input, S_IRUGO, mc13783_adc_read_gp, NULL, 8);
 108 static SENSOR_DEVICE_ATTR(in9_input, S_IRUGO, mc13783_adc_read_gp, NULL, 9);
 109 static SENSOR_DEVICE_ATTR(in10_input, S_IRUGO, mc13783_adc_read_gp, NULL, 10);
 110 static SENSOR_DEVICE_ATTR(in11_input, S_IRUGO, mc13783_adc_read_gp, NULL, 11);
 111 static SENSOR_DEVICE_ATTR(in12_input, S_IRUGO, mc13783_adc_read_gp, NULL, 12);
 112 static SENSOR_DEVICE_ATTR(in13_input, S_IRUGO, mc13783_adc_read_gp, NULL, 13);
 113 static SENSOR_DEVICE_ATTR(in14_input, S_IRUGO, mc13783_adc_read_gp, NULL, 14);
 114 static SENSOR_DEVICE_ATTR(in15_input, S_IRUGO, mc13783_adc_read_gp, NULL, 15);
 115
 116 static struct attribute *mc13783_attr[] = {
 117         &dev_attr_name.attr,
 118         &sensor_dev_attr_in2_input.dev_attr.attr,
 119         &sensor_dev_attr_in5_input.dev_attr.attr,
 120         &sensor_dev_attr_in6_input.dev_attr.attr,
 121         &sensor_dev_attr_in7_input.dev_attr.attr,
 122         &sensor_dev_attr_in8_input.dev_attr.attr,
 123         &sensor_dev_attr_in9_input.dev_attr.attr,
 124         &sensor_dev_attr_in10_input.dev_attr.attr,
 125         &sensor_dev_attr_in11_input.dev_attr.attr,
 126         NULL
 127 };
 128
 129 static const struct attribute_group mc13783_group = {
 130         .attrs = mc13783_attr,
 131 };
 132
 133 /* last four channels may be occupied by the touchscreen */
 134 static struct attribute *mc13783_attr_ts[] = {
 135         &sensor_dev_attr_in12_input.dev_attr.attr,
 136         &sensor_dev_attr_in13_input.dev_attr.attr,
 137         &sensor_dev_attr_in14_input.dev_attr.attr,
 138         &sensor_dev_attr_in15_input.dev_attr.attr,
 139         NULL
 140 };
 141
 142 static const struct attribute_group mc13783_group_ts = {
 143         .attrs = mc13783_attr_ts,
 144 };
 145
 146 static int __init mc13783_adc_probe(struct platform_device *pdev)
 147 {
 148         struct mc13783_adc_priv *priv;
 149         int ret;
 150
 151         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 152         if (!priv)
 153                 return -ENOMEM;
 154
 155         priv->mc13783 = dev_get_drvdata(pdev->dev.parent);
 156
 157         platform_set_drvdata(pdev, priv);
 158
 159         /* Register sysfs hooks */
 160         ret = sysfs_create_group(&pdev->dev.kobj, &mc13783_group);
 161         if (ret)
 162                 goto out_err_create1;
 163
 164         if (!(priv->mc13783->flags & MC13783_USE_TOUCHSCREEN))
 165                 ret = sysfs_create_group(&pdev->dev.kobj, &mc13783_group_ts);
 166                 if (ret)
 167                         goto out_err_create2;
 168
 169         priv->hwmon_dev = hwmon_device_register(&pdev->dev);
 170         if (IS_ERR(priv->hwmon_dev)) {
 171                 ret = PTR_ERR(priv->hwmon_dev);
 172                 dev_err(&pdev->dev,
 173                                 "hwmon_device_register failed with %d.\n", ret);
 174                 goto out_err_register;
 175         }
 176
 177
 178         return 0;
 179
 180 out_err_register:
 181
 182         if (!(priv->mc13783->flags & MC13783_USE_TOUCHSCREEN))
 183                 sysfs_remove_group(&pdev->dev.kobj, &mc13783_group_ts);
 184 out_err_create2:
 185
 186         sysfs_remove_group(&pdev->dev.kobj, &mc13783_group);
 187 out_err_create1:
 188
 189         platform_set_drvdata(pdev, NULL);
 190         kfree(priv);
 191
 192         return ret;
 193 }
 194
 195 static int __devexit mc13783_adc_remove(struct platform_device *pdev)
 196 {
 197         struct mc13783_adc_priv *priv = platform_get_drvdata(pdev);
 198
 199         hwmon_device_unregister(priv->hwmon_dev);
 200
 201         if (!(priv->mc13783->flags & MC13783_USE_TOUCHSCREEN))
 202                 sysfs_remove_group(&pdev->dev.kobj, &mc13783_group_ts);
 203
 204         sysfs_remove_group(&pdev->dev.kobj, &mc13783_group);
 205
 206         platform_set_drvdata(pdev, NULL);
 207         kfree(priv);
 208
 209         return 0;
 210 }
 211
 212 static struct platform_driver mc13783_adc_driver = {
 213         .remove         = __devexit_p(mc13783_adc_remove),
 214         .driver         = {
 215                 .owner  = THIS_MODULE,
 216                 .name   = MC13783_ADC_NAME,
 217         },
 218 };
 219
 220 static int __init mc13783_adc_init(void)
 221 {
 222         return platform_driver_probe(&mc13783_adc_driver, mc13783_adc_probe);
 223 }
 224
 225 static void __exit mc13783_adc_exit(void)
 226 {
 227         platform_driver_unregister(&mc13783_adc_driver);
 228 }
 229
 230 module_init(mc13783_adc_init);
 231 module_exit(mc13783_adc_exit);
 232
 233 MODULE_DESCRIPTION("MC13783 ADC driver");
 234 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
 235 MODULE_LICENSE("GPL");
 236 MODULE_ALIAS("platform:" MC13783_ADC_NAME);