bq27xxx_battery_hdq.c 2.8 KB

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