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 COMP1                                   0
  26 #define COMP2                                   1
  27
  28 /* Comparator 1 voltage selection table in millivolts */
  29 static const u16 COMP_VSEL_TABLE[] = {
  30         0, 2500, 2500, 2500, 2500, 2550, 2600, 2650,
  31         2700, 2750, 2800, 2850, 2900, 2950, 3000, 3050,
  32         3100, 3150, 3200, 3250, 3300, 3350, 3400, 3450,
  33         3500,
  34 };
  35
  36 struct comparator {
  37         const char *name;
  38         int reg;
  39         int uV_max;
  40         const u16 *vsel_table;
  41 };
  42
  43 static struct comparator tps_comparators[] = {
  44         {
  45                 .name = "COMP1",
  46                 .reg = TPS65911_VMBCH,
  47                 .uV_max = 3500,
  48                 .vsel_table = COMP_VSEL_TABLE,
  49         },
  50         {
  51                 .name = "COMP2",
  52                 .reg = TPS65911_VMBCH2,
  53                 .uV_max = 3500,
  54                 .vsel_table = COMP_VSEL_TABLE,
  55         },
  56 };
  57
  58 static int comp_threshold_set(struct tps65910 *tps65910, int id, int voltage)
  59 {
  60         struct comparator tps_comp = tps_comparators[id];
  61         int curr_voltage = 0;
  62         int ret;
  63         u8 index = 0, val;
  64
  65         while (curr_voltage < tps_comp.uV_max) {
  66                 curr_voltage = tps_comp.vsel_table[index];
  67                 if (curr_voltage >= voltage)
  68                         break;
  69                 else if (curr_voltage < voltage)
  70                         index ++;
  71         }
  72
  73         if (curr_voltage > tps_comp.uV_max)
  74                 return -EINVAL;
  75
  76         val = index << 1;
  77         ret = tps65910_reg_write(tps65910, tps_comp.reg, val);
  78
  79         return ret;
  80 }
  81
  82 static int comp_threshold_get(struct tps65910 *tps65910, int id)
  83 {
  84         struct comparator tps_comp = tps_comparators[id];
  85         unsigned int val;
  86         int ret;
  87
  88         ret = tps65910_reg_read(tps65910, tps_comp.reg, &val);
  89         if (ret < 0)
  90                 return ret;
  91
  92         val >>= 1;
  93         return tps_comp.vsel_table[val];
  94 }
  95
  96 static ssize_t comp_threshold_show(struct device *dev,
  97                                 struct device_attribute *attr, char *buf)
  98 {
  99         struct tps65910 *tps65910 = dev_get_drvdata(dev->parent);
 100         struct attribute comp_attr = attr->attr;
 101         int id, uVolt;
 102
 103         if (!strcmp(comp_attr.name, "comp1_threshold"))
 104                 id = COMP1;
 105         else if (!strcmp(comp_attr.name, "comp2_threshold"))
 106                 id = COMP2;
 107         else
 108                 return -EINVAL;
 109
 110         uVolt = comp_threshold_get(tps65910, id);
 111
 112         return sprintf(buf, "%d\n", uVolt);
 113 }
 114
 115 static DEVICE_ATTR(comp1_threshold, S_IRUGO, comp_threshold_show, NULL);
 116 static DEVICE_ATTR(comp2_threshold, S_IRUGO, comp_threshold_show, NULL);
 117
 118 static int tps65911_comparator_probe(struct platform_device *pdev)
 119 {
 120         struct tps65910 *tps65910 = dev_get_drvdata(pdev->dev.parent);
 121         struct tps65910_board *pdata = dev_get_platdata(tps65910->dev);
 122         int ret;
 123
 124         ret = comp_threshold_set(tps65910, COMP1,  pdata->vmbch_threshold);
 125         if (ret < 0) {
 126                 dev_err(&pdev->dev, "cannot set COMP1 threshold\n");
 127                 return ret;
 128         }
 129
 130         ret = comp_threshold_set(tps65910, COMP2, pdata->vmbch2_threshold);
 131         if (ret < 0) {
 132                 dev_err(&pdev->dev, "cannot set COMP2 threshold\n");
 133                 return ret;
 134         }
 135
 136         /* Create sysfs entry */
 137         ret = device_create_file(&pdev->dev, &dev_attr_comp1_threshold);
 138         if (ret < 0)
 139                 dev_err(&pdev->dev, "failed to add COMP1 sysfs file\n");
 140
 141         ret = device_create_file(&pdev->dev, &dev_attr_comp2_threshold);
 142         if (ret < 0)
 143                 dev_err(&pdev->dev, "failed to add COMP2 sysfs file\n");
 144
 145         return ret;
 146 }
 147
 148 static int tps65911_comparator_remove(struct platform_device *pdev)
 149 {
 150         struct tps65910 *tps65910;
 151
 152         tps65910 = dev_get_drvdata(pdev->dev.parent);
 153         device_remove_file(&pdev->dev, &dev_attr_comp2_threshold);
 154         device_remove_file(&pdev->dev, &dev_attr_comp1_threshold);
 155
 156         return 0;
 157 }
 158
 159 static struct platform_driver tps65911_comparator_driver = {
 160         .driver = {
 161                 .name = "tps65911-comparator",
 162         },
 163         .probe = tps65911_comparator_probe,
 164         .remove = tps65911_comparator_remove,
 165 };
 166
 167 static int __init tps65911_comparator_init(void)
 168 {
 169         return platform_driver_register(&tps65911_comparator_driver);
 170 }
 171 subsys_initcall(tps65911_comparator_init);
 172
 173 static void __exit tps65911_comparator_exit(void)
 174 {
 175         platform_driver_unregister(&tps65911_comparator_driver);
 176 }
 177 module_exit(tps65911_comparator_exit);
 178
 179 MODULE_AUTHOR("Jorge Eduardo Candelaria <jedu@slimlogic.co.uk>");
 180 MODULE_DESCRIPTION("TPS65911 comparator driver");
 181 MODULE_LICENSE("GPL v2");
 182 MODULE_ALIAS("platform:tps65911-comparator");