drivers/power/supply/bq27xxx_battery_hdq.c

   1 /*
   2  * BQ27xxx battery monitor HDQ/1-wire driver
   3  *
   4  * Copyright (C) 2007-2017 Texas Instruments Incorporated - http://www.ti.com/
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  11  * kind, whether express or implied; without even the implied warranty
  12  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/device.h>
  19 #include <linux/types.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/mutex.h>
  22 #include <linux/power/bq27xxx_battery.h>
  23
  24 #include <linux/w1.h>
  25
  26 #define W1_FAMILY_BQ27000       0x01
  27
  28 #define HDQ_CMD_READ    (0 << 7)
  29 #define HDQ_CMD_WRITE   (1 << 7)
  30
  31 static int F_ID;
  32 module_param(F_ID, int, S_IRUSR);
  33 MODULE_PARM_DESC(F_ID, "1-wire slave FID for BQ27xxx device");
  34
  35 static int w1_bq27000_read(struct w1_slave *sl, unsigned int reg)
  36 {
  37         u8 val;
  38
  39         mutex_lock(&sl->master->bus_mutex);
  40         w1_write_8(sl->master, HDQ_CMD_READ | reg);
  41         val = w1_read_8(sl->master);
  42         mutex_unlock(&sl->master->bus_mutex);
  43
  44         return val;
  45 }
  46
  47 static int bq27xxx_battery_hdq_read(struct bq27xxx_device_info *di, u8 reg,
  48                                     bool single)
  49 {
  50         struct w1_slave *sl = dev_to_w1_slave(di->dev);
  51         unsigned int timeout = 3;
  52         int upper, lower;
  53         int temp;
  54
  55         if (!single) {
  56                 /*
  57                  * Make sure the value has not changed in between reading the
  58                  * lower and the upper part
  59                  */
  60                 upper = w1_bq27000_read(sl, reg + 1);
  61                 do {
  62                         temp = upper;
  63                         if (upper < 0)
  64                                 return upper;
  65
  66                         lower = w1_bq27000_read(sl, reg);
  67                         if (lower < 0)
  68                                 return lower;
  69
  70                         upper = w1_bq27000_read(sl, reg + 1);
  71                 } while (temp != upper && --timeout);
  72
  73                 if (timeout == 0)
  74                         return -EIO;
  75
  76                 return (upper << 8) | lower;
  77         }
  78
  79         return w1_bq27000_read(sl, reg);
  80 }
  81
  82 static int bq27xxx_battery_hdq_add_slave(struct w1_slave *sl)
  83 {
  84         struct bq27xxx_device_info *di;
  85
  86         di = devm_kzalloc(&sl->dev, sizeof(*di), GFP_KERNEL);
  87         if (!di)
  88                 return -ENOMEM;
  89
  90         dev_set_drvdata(&sl->dev, di);
  91
  92         di->dev = &sl->dev;
  93         di->chip = BQ27000;
  94         di->name = "bq27000-battery";
  95         di->bus.read = bq27xxx_battery_hdq_read;
  96
  97         return bq27xxx_battery_setup(di);
  98 }
  99
 100 static void bq27xxx_battery_hdq_remove_slave(struct w1_slave *sl)
 101 {
 102         struct bq27xxx_device_info *di = dev_get_drvdata(&sl->dev);
 103
 104         bq27xxx_battery_teardown(di);
 105 }
 106
 107 static struct w1_family_ops bq27xxx_battery_hdq_fops = {
 108         .add_slave      = bq27xxx_battery_hdq_add_slave,
 109         .remove_slave   = bq27xxx_battery_hdq_remove_slave,
 110 };
 111
 112 static struct w1_family bq27xxx_battery_hdq_family = {
 113         .fid = W1_FAMILY_BQ27000,
 114         .fops = &bq27xxx_battery_hdq_fops,
 115 };
 116
 117 static int __init bq27xxx_battery_hdq_init(void)
 118 {
 119         if (F_ID)
 120                 bq27xxx_battery_hdq_family.fid = F_ID;
 121
 122         return w1_register_family(&bq27xxx_battery_hdq_family);
 123 }
 124 module_init(bq27xxx_battery_hdq_init);
 125
 126 static void __exit bq27xxx_battery_hdq_exit(void)
 127 {
 128         w1_unregister_family(&bq27xxx_battery_hdq_family);
 129 }
 130 module_exit(bq27xxx_battery_hdq_exit);
 131
 132 MODULE_AUTHOR("Texas Instruments Ltd");
 133 MODULE_DESCRIPTION("BQ27xxx battery monitor HDQ/1-wire driver");
 134 MODULE_LICENSE("GPL");
 135 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_BQ27000));