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.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/slab.h>
  28 #include <linux/init.h>
  29 #include <linux/err.h>
  30
  31 #define MC13783_ADC_NAME        "mc13783-adc"
  32
  33 struct mc13783_adc_priv {
  34         struct mc13783 *mc13783;
  35         struct device *hwmon_dev;
  36 };
  37
  38 static ssize_t mc13783_adc_show_name(struct device *dev, struct device_attribute
  39                               *devattr, char *buf)
  40 {
  41         return sprintf(buf, "mc13783_adc\n");
  42 }
  43
  44 static int mc13783_adc_read(struct device *dev,
  45                 struct device_attribute *devattr, unsigned int *val)
  46 {
  47         struct platform_device *pdev = to_platform_device(dev);
  48         struct mc13783_adc_priv *priv = platform_get_drvdata(pdev);
  49         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  50         unsigned int channel = attr->index;
  51         unsigned int sample[4];
  52         int ret;
  53
  54         ret = mc13783_adc_do_conversion(priv->mc13783,
  55                         MC13783_ADC_MODE_MULT_CHAN,
  56                         channel, sample);
  57         if (ret)
  58                 return ret;
  59
  60         channel &= 0x7;
  61
  62         *val = (sample[channel % 4] >> (channel > 3 ? 14 : 2)) & 0x3ff;
  63
  64         return 0;
  65 }
  66
  67 static ssize_t mc13783_adc_read_bp(struct device *dev,
  68                 struct device_attribute *devattr, char *buf)
  69 {
  70         unsigned val;
  71         int ret = mc13783_adc_read(dev, devattr, &val);
  72
  73         if (ret)
  74                 return ret;
  75
  76         /*
  77          * BP (channel 2) reports with offset 2.4V to the actual value to fit
  78          * the input range of the ADC.  unit = 2.25mV = 9/4 mV.
  79          */
  80         val = DIV_ROUND_CLOSEST(val * 9, 4) + 2400;
  81
  82         return sprintf(buf, "%u\n", val);
  83 }
  84
  85 static ssize_t mc13783_adc_read_gp(struct device *dev,
  86                 struct device_attribute *devattr, char *buf)
  87 {
  88         unsigned val;
  89         int ret = mc13783_adc_read(dev, devattr, &val);
  90
  91         if (ret)
  92                 return ret;
  93
  94         /*
  95          * input range is [0, 2.3V], val has 10 bits, so each bit
  96          * is worth 9/4 mV.
  97          */
  98         val = DIV_ROUND_CLOSEST(val * 9, 4);
  99
 100         return sprintf(buf, "%u\n", val);
 101 }
 102
 103 static DEVICE_ATTR(name, S_IRUGO, mc13783_adc_show_name, NULL);
 104 static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, mc13783_adc_read_bp, NULL, 2);
 105 static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, mc13783_adc_read_gp, NULL, 5);
 106 static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, mc13783_adc_read_gp, NULL, 6);
 107 static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, mc13783_adc_read_gp, NULL, 7);
 108 static SENSOR_DEVICE_ATTR(in8_input, S_IRUGO, mc13783_adc_read_gp, NULL, 8);
 109 static SENSOR_DEVICE_ATTR(in9_input, S_IRUGO, mc13783_adc_read_gp, NULL, 9);
 110 static SENSOR_DEVICE_ATTR(in10_input, S_IRUGO, mc13783_adc_read_gp, NULL, 10);
 111 static SENSOR_DEVICE_ATTR(in11_input, S_IRUGO, mc13783_adc_read_gp, NULL, 11);
 112 static SENSOR_DEVICE_ATTR(in12_input, S_IRUGO, mc13783_adc_read_gp, NULL, 12);
 113 static SENSOR_DEVICE_ATTR(in13_input, S_IRUGO, mc13783_adc_read_gp, NULL, 13);
 114 static SENSOR_DEVICE_ATTR(in14_input, S_IRUGO, mc13783_adc_read_gp, NULL, 14);
 115 static SENSOR_DEVICE_ATTR(in15_input, S_IRUGO, mc13783_adc_read_gp, NULL, 15);
 116
 117 static struct attribute *mc13783_attr[] = {
 118         &dev_attr_name.attr,
 119         &sensor_dev_attr_in2_input.dev_attr.attr,
 120         &sensor_dev_attr_in5_input.dev_attr.attr,
 121         &sensor_dev_attr_in6_input.dev_attr.attr,
 122         &sensor_dev_attr_in7_input.dev_attr.attr,
 123         &sensor_dev_attr_in8_input.dev_attr.attr,
 124         &sensor_dev_attr_in9_input.dev_attr.attr,
 125         &sensor_dev_attr_in10_input.dev_attr.attr,
 126         &sensor_dev_attr_in11_input.dev_attr.attr,
 127         NULL
 128 };
 129
 130 static const struct attribute_group mc13783_group = {
 131         .attrs = mc13783_attr,
 132 };
 133
 134 /* last four channels may be occupied by the touchscreen */
 135 static struct attribute *mc13783_attr_ts[] = {
 136         &sensor_dev_attr_in12_input.dev_attr.attr,
 137         &sensor_dev_attr_in13_input.dev_attr.attr,
 138         &sensor_dev_attr_in14_input.dev_attr.attr,
 139         &sensor_dev_attr_in15_input.dev_attr.attr,
 140         NULL
 141 };
 142
 143 static const struct attribute_group mc13783_group_ts = {
 144         .attrs = mc13783_attr_ts,
 145 };
 146
 147 static int mc13783_adc_use_touchscreen(struct platform_device *pdev)
 148 {
 149         struct mc13783_adc_priv *priv = platform_get_drvdata(pdev);
 150         unsigned flags = mc13783_get_flags(priv->mc13783);
 151
 152         return flags & MC13783_USE_TOUCHSCREEN;
 153 }
 154
 155 static int __init mc13783_adc_probe(struct platform_device *pdev)
 156 {
 157         struct mc13783_adc_priv *priv;
 158         int ret;
 159
 160         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 161         if (!priv)
 162                 return -ENOMEM;
 163
 164         priv->mc13783 = dev_get_drvdata(pdev->dev.parent);
 165
 166         platform_set_drvdata(pdev, priv);
 167
 168         /* Register sysfs hooks */
 169         ret = sysfs_create_group(&pdev->dev.kobj, &mc13783_group);
 170         if (ret)
 171                 goto out_err_create1;
 172
 173         if (!mc13783_adc_use_touchscreen(pdev)) {
 174                 ret = sysfs_create_group(&pdev->dev.kobj, &mc13783_group_ts);
 175                 if (ret)
 176                         goto out_err_create2;
 177         }
 178
 179         priv->hwmon_dev = hwmon_device_register(&pdev->dev);
 180         if (IS_ERR(priv->hwmon_dev)) {
 181                 ret = PTR_ERR(priv->hwmon_dev);
 182                 dev_err(&pdev->dev,
 183                                 "hwmon_device_register failed with %d.\n", ret);
 184                 goto out_err_register;
 185         }
 186
 187
 188         return 0;
 189
 190 out_err_register:
 191
 192         if (!mc13783_adc_use_touchscreen(pdev))
 193                 sysfs_remove_group(&pdev->dev.kobj, &mc13783_group_ts);
 194 out_err_create2:
 195
 196         sysfs_remove_group(&pdev->dev.kobj, &mc13783_group);
 197 out_err_create1:
 198
 199         platform_set_drvdata(pdev, NULL);
 200         kfree(priv);
 201
 202         return ret;
 203 }
 204
 205 static int __devexit mc13783_adc_remove(struct platform_device *pdev)
 206 {
 207         struct mc13783_adc_priv *priv = platform_get_drvdata(pdev);
 208
 209         hwmon_device_unregister(priv->hwmon_dev);
 210
 211         if (!mc13783_adc_use_touchscreen(pdev))
 212                 sysfs_remove_group(&pdev->dev.kobj, &mc13783_group_ts);
 213
 214         sysfs_remove_group(&pdev->dev.kobj, &mc13783_group);
 215
 216         platform_set_drvdata(pdev, NULL);
 217         kfree(priv);
 218
 219         return 0;
 220 }
 221
 222 static struct platform_driver mc13783_adc_driver = {
 223         .remove         = __devexit_p(mc13783_adc_remove),
 224         .driver         = {
 225                 .owner  = THIS_MODULE,
 226                 .name   = MC13783_ADC_NAME,
 227         },
 228 };
 229
 230 static int __init mc13783_adc_init(void)
 231 {
 232         return platform_driver_probe(&mc13783_adc_driver, mc13783_adc_probe);
 233 }
 234
 235 static void __exit mc13783_adc_exit(void)
 236 {
 237         platform_driver_unregister(&mc13783_adc_driver);
 238 }
 239
 240 module_init(mc13783_adc_init);
 241 module_exit(mc13783_adc_exit);
 242
 243 MODULE_DESCRIPTION("MC13783 ADC driver");
 244 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
 245 MODULE_LICENSE("GPL");
 246 MODULE_ALIAS("platform:" MC13783_ADC_NAME);