drivers/mfd/tps65911-comparator.c

   1 /*
   2  * tps65910.c  --  TI TPS6591x
   3  *
   4  * Copyright 2010 Texas Instruments Inc.
   5  *
   6  * Author: Jorge Eduardo Candelaria <jedu@slimlogic.co.uk>
   7  *
   8  *  This program is free software; you can redistribute it and/or modify it
   9  *  under  the terms of the GNU General  Public License as published by the
  10  *  Free Software Foundation;  either version 2 of the License, or (at your
  11  *  option) any later version.
  12  *
  13  */
  14
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/init.h>
  18 #include <linux/slab.h>
  19 #include <linux/err.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/debugfs.h>
  22 #include <linux/gpio.h>
  23 #include <linux/mfd/tps65910.h>
  24
  25 #define COMP                                    0
  26 #define COMP1                                   1
  27 #define COMP2                                   2
  28
  29 /* Comparator 1 voltage selection table in millivolts */
  30 static const u16 COMP_VSEL_TABLE[] = {
  31         0, 2500, 2500, 2500, 2500, 2550, 2600, 2650,
  32         2700, 2750, 2800, 2850, 2900, 2950, 3000, 3050,
  33         3100, 3150, 3200, 3250, 3300, 3350, 3400, 3450,
  34         3500,
  35 };
  36
  37 struct comparator {
  38         const char *name;
  39         int reg;
  40         int uV_max;
  41         const u16 *vsel_table;
  42 };
  43
  44 static struct comparator tps_comparators[] = {
  45         {
  46                 .name = "COMP1",
  47                 .reg = TPS65911_VMBCH,
  48                 .uV_max = 3500,
  49                 .vsel_table = COMP_VSEL_TABLE,
  50         },
  51         {
  52                 .name = "COMP2",
  53                 .reg = TPS65911_VMBCH2,
  54                 .uV_max = 3500,
  55                 .vsel_table = COMP_VSEL_TABLE,
  56         },
  57 };
  58
  59 static int comp_threshold_set(struct tps65910 *tps65910, int id, int voltage)
  60 {
  61         struct comparator tps_comp = tps_comparators[id];
  62         int curr_voltage = 0;
  63         int ret;
  64         u8 index = 0, val;
  65
  66         if (id == COMP)
  67                 return 0;
  68
  69         while (curr_voltage < tps_comp.uV_max) {
  70                 curr_voltage = tps_comp.vsel_table[index];
  71                 if (curr_voltage >= voltage)
  72                         break;
  73                 else if (curr_voltage < voltage)
  74                         index ++;
  75         }
  76
  77         if (curr_voltage > tps_comp.uV_max)
  78                 return -EINVAL;
  79
  80         val = index << 1;
  81         ret = tps65910->write(tps65910, tps_comp.reg, 1, &val);
  82
  83         return ret;
  84 }
  85
  86 static int comp_threshold_get(struct tps65910 *tps65910, int id)
  87 {
  88         struct comparator tps_comp = tps_comparators[id];
  89         int ret;
  90         u8 val;
  91
  92         if (id == COMP)
  93                 return 0;
  94
  95         ret = tps65910->read(tps65910, tps_comp.reg, 1, &val);
  96         if (ret < 0)
  97                 return ret;
  98
  99         val >>= 1;
 100         return tps_comp.vsel_table[val];
 101 }
 102
 103 static ssize_t comp_threshold_show(struct device *dev,
 104                                 struct device_attribute *attr, char *buf)
 105 {
 106         struct tps65910 *tps65910 = dev_get_drvdata(dev->parent);
 107         struct attribute comp_attr = attr->attr;
 108         int id, uVolt;
 109
 110         if (!strcmp(comp_attr.name, "comp1_threshold"))
 111                 id = COMP1;
 112         else if (!strcmp(comp_attr.name, "comp2_threshold"))
 113                 id = COMP2;
 114         else
 115                 return -EINVAL;
 116
 117         uVolt = comp_threshold_get(tps65910, id);
 118
 119         return sprintf(buf, "%d\n", uVolt);
 120 }
 121
 122 static DEVICE_ATTR(comp1_threshold, S_IRUGO, comp_threshold_show, NULL);
 123 static DEVICE_ATTR(comp2_threshold, S_IRUGO, comp_threshold_show, NULL);
 124
 125 static __devinit int tps65911_comparator_probe(struct platform_device *pdev)
 126 {
 127         struct tps65910 *tps65910 = dev_get_drvdata(pdev->dev.parent);
 128         struct tps65910_board *pdata = dev_get_platdata(tps65910->dev);
 129         int ret;
 130
 131         ret = comp_threshold_set(tps65910, COMP1,  pdata->vmbch_threshold);
 132         if (ret < 0) {
 133                 dev_err(&pdev->dev, "cannot set COMP1 threshold\n");
 134                 return ret;
 135         }
 136
 137         ret = comp_threshold_set(tps65910, COMP2, pdata->vmbch2_threshold);
 138         if (ret < 0) {
 139                 dev_err(&pdev->dev, "cannot set COMP2 threshold\n");
 140                 return ret;
 141         }
 142
 143         /* Create sysfs entry */
 144         ret = device_create_file(&pdev->dev, &dev_attr_comp1_threshold);
 145         if (ret < 0)
 146                 dev_err(&pdev->dev, "failed to add COMP1 sysfs file\n");
 147
 148         ret = device_create_file(&pdev->dev, &dev_attr_comp2_threshold);
 149         if (ret < 0)
 150                 dev_err(&pdev->dev, "failed to add COMP2 sysfs file\n");
 151
 152         return ret;
 153 }
 154
 155 static __devexit int tps65911_comparator_remove(struct platform_device *pdev)
 156 {
 157         struct tps65910 *tps65910;
 158
 159         tps65910 = dev_get_drvdata(pdev->dev.parent);
 160         device_remove_file(&pdev->dev, &dev_attr_comp2_threshold);
 161         device_remove_file(&pdev->dev, &dev_attr_comp1_threshold);
 162
 163         return 0;
 164 }
 165
 166 static struct platform_driver tps65911_comparator_driver = {
 167         .driver = {
 168                 .name = "tps65911-comparator",
 169                 .owner = THIS_MODULE,
 170         },
 171         .probe = tps65911_comparator_probe,
 172         .remove = __devexit_p(tps65911_comparator_remove),
 173 };
 174
 175 static int __init tps65911_comparator_init(void)
 176 {
 177         return platform_driver_register(&tps65911_comparator_driver);
 178 }
 179 subsys_initcall(tps65911_comparator_init);
 180
 181 static void __exit tps65911_comparator_exit(void)
 182 {
 183         platform_driver_unregister(&tps65911_comparator_driver);
 184 }
 185 module_exit(tps65911_comparator_exit);
 186
 187 MODULE_AUTHOR("Jorge Eduardo Candelaria <jedu@slimlogic.co.uk>");
 188 MODULE_DESCRIPTION("TPS65911 comparator driver");
 189 MODULE_LICENSE("GPL v2");
 190 MODULE_ALIAS("platform:tps65911-comparator");