drivers/power/supply/bq27xxx_battery_hdq.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * BQ27xxx battery monitor HDQ/1-wire driver
   4  *
   5  * Copyright (C) 2007-2017 Texas Instruments Incorporated - https://www.ti.com/
   6  *
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/device.h>
  12 #include <linux/types.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/mutex.h>
  15 #include <linux/power/bq27xxx_battery.h>
  16
  17 #include <linux/w1.h>
  18
  19 #define W1_FAMILY_BQ27000       0x01
  20
  21 #define HDQ_CMD_READ    (0 << 7)
  22 #define HDQ_CMD_WRITE   (1 << 7)
  23
  24 static int F_ID;
  25 module_param(F_ID, int, S_IRUSR);
  26 MODULE_PARM_DESC(F_ID, "1-wire slave FID for BQ27xxx device");
  27
  28 static int w1_bq27000_read(struct w1_slave *sl, unsigned int reg)
  29 {
  30         u8 val;
  31
  32         mutex_lock(&sl->master->bus_mutex);
  33         w1_write_8(sl->master, HDQ_CMD_READ | reg);
  34         val = w1_read_8(sl->master);
  35         mutex_unlock(&sl->master->bus_mutex);
  36
  37         return val;
  38 }
  39
  40 static int bq27xxx_battery_hdq_read(struct bq27xxx_device_info *di, u8 reg,
  41                                     bool single)
  42 {
  43         struct w1_slave *sl = dev_to_w1_slave(di->dev);
  44         unsigned int timeout = 3;
  45         int upper, lower;
  46         int temp;
  47
  48         if (!single) {
  49                 /*
  50                  * Make sure the value has not changed in between reading the
  51                  * lower and the upper part
  52                  */
  53                 upper = w1_bq27000_read(sl, reg + 1);
  54                 do {
  55                         temp = upper;
  56                         if (upper < 0)
  57                                 return upper;
  58
  59                         lower = w1_bq27000_read(sl, reg);
  60                         if (lower < 0)
  61                                 return lower;
  62
  63                         upper = w1_bq27000_read(sl, reg + 1);
  64                 } while (temp != upper && --timeout);
  65
  66                 if (timeout == 0)
  67                         return -EIO;
  68
  69                 return (upper << 8) | lower;
  70         }
  71
  72         return w1_bq27000_read(sl, reg);
  73 }
  74
  75 static int bq27xxx_battery_hdq_add_slave(struct w1_slave *sl)
  76 {
  77         struct bq27xxx_device_info *di;
  78
  79         di = devm_kzalloc(&sl->dev, sizeof(*di), GFP_KERNEL);
  80         if (!di)
  81                 return -ENOMEM;
  82
  83         dev_set_drvdata(&sl->dev, di);
  84
  85         di->dev = &sl->dev;
  86         di->chip = BQ27000;
  87         di->name = "bq27000-battery";
  88         di->bus.read = bq27xxx_battery_hdq_read;
  89
  90         return bq27xxx_battery_setup(di);
  91 }
  92
  93 static void bq27xxx_battery_hdq_remove_slave(struct w1_slave *sl)
  94 {
  95         struct bq27xxx_device_info *di = dev_get_drvdata(&sl->dev);
  96
  97         bq27xxx_battery_teardown(di);
  98 }
  99
 100 static const struct w1_family_ops bq27xxx_battery_hdq_fops = {
 101         .add_slave      = bq27xxx_battery_hdq_add_slave,
 102         .remove_slave   = bq27xxx_battery_hdq_remove_slave,
 103 };
 104
 105 static struct w1_family bq27xxx_battery_hdq_family = {
 106         .fid = W1_FAMILY_BQ27000,
 107         .fops = &bq27xxx_battery_hdq_fops,
 108 };
 109
 110 static int __init bq27xxx_battery_hdq_init(void)
 111 {
 112         if (F_ID)
 113                 bq27xxx_battery_hdq_family.fid = F_ID;
 114
 115         return w1_register_family(&bq27xxx_battery_hdq_family);
 116 }
 117 module_init(bq27xxx_battery_hdq_init);
 118
 119 static void __exit bq27xxx_battery_hdq_exit(void)
 120 {
 121         w1_unregister_family(&bq27xxx_battery_hdq_family);
 122 }
 123 module_exit(bq27xxx_battery_hdq_exit);
 124
 125 MODULE_AUTHOR("Texas Instruments Ltd");
 126 MODULE_DESCRIPTION("BQ27xxx battery monitor HDQ/1-wire driver");
 127 MODULE_LICENSE("GPL");
 128 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_BQ27000));