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)); 129