power/supply/bq27xxx_battery_hdq.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * BQ27xxx battery monitor HDQ/1-wire driver
0004  *
0005  * Copyright (C) 2007-2017 Texas Instruments Incorporated - https://www.ti.com/
0006  *
0007  */
0008
0009 #include <linux/kernel.h>
0010 #include <linux/module.h>
0011 #include <linux/device.h>
0012 #include <linux/types.h>
0013 #include <linux/platform_device.h>
0014 #include <linux/mutex.h>
0015 #include <linux/power/bq27xxx_battery.h>
0016
0017 #include <linux/w1.h>
0018
0019 #define W1_FAMILY_BQ27000   0x01
0020
0021 #define HDQ_CMD_READ    (0 << 7)
0022 #define HDQ_CMD_WRITE   (1 << 7)
0023
0024 static int F_ID;
0025 module_param(F_ID, int, S_IRUSR);
0026 MODULE_PARM_DESC(F_ID, "1-wire slave FID for BQ27xxx device");
0027
0028 static int w1_bq27000_read(struct w1_slave *sl, unsigned int reg)
0029 {
0030     u8 val;
0031
0032     mutex_lock(&sl->master->bus_mutex);
0033     w1_write_8(sl->master, HDQ_CMD_READ | reg);
0034     val = w1_read_8(sl->master);
0035     mutex_unlock(&sl->master->bus_mutex);
0036
0037     return val;
0038 }
0039
0040 static int bq27xxx_battery_hdq_read(struct bq27xxx_device_info *di, u8 reg,
0041                     bool single)
0042 {
0043     struct w1_slave *sl = dev_to_w1_slave(di->dev);
0044     unsigned int timeout = 3;
0045     int upper, lower;
0046     int temp;
0047
0048     if (!single) {
0049         /*
0050          * Make sure the value has not changed in between reading the
0051          * lower and the upper part
0052          */
0053         upper = w1_bq27000_read(sl, reg + 1);
0054         do {
0055             temp = upper;
0056             if (upper < 0)
0057                 return upper;
0058
0059             lower = w1_bq27000_read(sl, reg);
0060             if (lower < 0)
0061                 return lower;
0062
0063             upper = w1_bq27000_read(sl, reg + 1);
0064         } while (temp != upper && --timeout);
0065
0066         if (timeout == 0)
0067             return -EIO;
0068
0069         return (upper << 8) | lower;
0070     }
0071
0072     return w1_bq27000_read(sl, reg);
0073 }
0074
0075 static int bq27xxx_battery_hdq_add_slave(struct w1_slave *sl)
0076 {
0077     struct bq27xxx_device_info *di;
0078
0079     di = devm_kzalloc(&sl->dev, sizeof(*di), GFP_KERNEL);
0080     if (!di)
0081         return -ENOMEM;
0082
0083     dev_set_drvdata(&sl->dev, di);
0084
0085     di->dev = &sl->dev;
0086     di->chip = BQ27000;
0087     di->name = "bq27000-battery";
0088     di->bus.read = bq27xxx_battery_hdq_read;
0089
0090     return bq27xxx_battery_setup(di);
0091 }
0092
0093 static void bq27xxx_battery_hdq_remove_slave(struct w1_slave *sl)
0094 {
0095     struct bq27xxx_device_info *di = dev_get_drvdata(&sl->dev);
0096
0097     bq27xxx_battery_teardown(di);
0098 }
0099
0100 static const struct w1_family_ops bq27xxx_battery_hdq_fops = {
0101     .add_slave  = bq27xxx_battery_hdq_add_slave,
0102     .remove_slave   = bq27xxx_battery_hdq_remove_slave,
0103 };
0104
0105 static struct w1_family bq27xxx_battery_hdq_family = {
0106     .fid = W1_FAMILY_BQ27000,
0107     .fops = &bq27xxx_battery_hdq_fops,
0108 };
0109
0110 static int __init bq27xxx_battery_hdq_init(void)
0111 {
0112     if (F_ID)
0113         bq27xxx_battery_hdq_family.fid = F_ID;
0114
0115     return w1_register_family(&bq27xxx_battery_hdq_family);
0116 }
0117 module_init(bq27xxx_battery_hdq_init);
0118
0119 static void __exit bq27xxx_battery_hdq_exit(void)
0120 {
0121     w1_unregister_family(&bq27xxx_battery_hdq_family);
0122 }
0123 module_exit(bq27xxx_battery_hdq_exit);
0124
0125 MODULE_AUTHOR("Texas Instruments Ltd");
0126 MODULE_DESCRIPTION("BQ27xxx battery monitor HDQ/1-wire driver");
0127 MODULE_LICENSE("GPL");
0128 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_BQ27000));