android充电这块,有的电源管理芯片内部包含充电管理,如s5pv210上常用的AT8937。我们这次用的max77686没有充电控制这块,所以我们加入一个充电IC来控制,选用PM2301.
一、PM2301和主控、电池的逻辑
如下图所示:
1、蓝色部分:IIC控制接口,这个说得太多了,好多外围器件都是通过IIC控制的,这个一定要熟悉、熟悉、熟烂了,然后可以完成比较多的工作。
2、黄色部分:中断、使能控制脚,CHG_STATUS(IRQ)、 DC_IN_INT(WAKE_UP) 、 PM2301_LP(LPN)、CHARGER_EN(ENN)控制引脚;
IRQ:充电IC的状态,如果有动作通知主控;
WAKE_UP:如果有DC插入,产生中断通知主控;
LPN:
ENN:充电IC使能;
3、PM2301 、电池、系统电压的大致逻辑
标号1:系统电压有PM2301提供;
标号2:PM2301给电池充电;
标号3:系统电压有电池提供;
标号:1和标号:3不同时提供电压给系统,中间有一个MOS管切换;分两种情况:
(1)、不插充电器时,有电池提供电压给系统,走通道标号:3给系统供电;
(2)、插入DC后,系统侦测到DC插入,把3的通道关闭,打开1给系统供电,同时有2给电池充电;
二、PM2301硬件电路
如下所示:
Q5这个MOS管,就是控制系统供电的,没有充电时,VBATT有VBAT+提供,充电时,VBATT有SENSE_COMM提供。
控制脚对应主控的引脚:
IIC | IIC ID 为2 |
CHG_STATUS(IRQ) | EXYNOS4_GPX1(3) |
DC_IN_INT(WAKE_UP) | EXYNOS4_GPX0(7) |
PM2301_LP(LPN) | EXYNOS4_GPX1(7) |
CHARGER_EN(ENN) | EXYNOS4_GPL2(0) |
下图为PM2301的参考电路解法,同样看到P1控制VSYSTEM电源部分的切换控制。
下图为整个电池充电的过程控制:
Trickle mode、Constant current mode (CC mode or fast charge mode)、Constant voltage mode (CV mode) 、End of charge feature
三、PL2301驱动部分
PL2301的硬件、工作原理做简单的解释,接下来我们分析驱动程序:
驱动用到知识点:
IIC的注册;
任务初始化宏(在上一篇我们简单提过);
中断线程化;
1、IIC的注册
这个和上一篇所说的电量计相似;
(1)、pm2301驱动部分
[cpp] view plain copy
1. static const struct i2c_device_id pm2301_id[] = {
2. "pm2301", 0 },
3. { }
4. };
5. MODULE_DEVICE_TABLE(i2c, pm2301_id);
6.
7. static struct i2c_driver pm2301_i2c_driver = {
8. .driver = {
9. "pm2301",
10. },
11. .probe = pm2301_probe,
12. .remove = __devexit_p(pm2301_remove),
13. .suspend = pm2301_suspend,
14. .resume = pm2301_resume,
15. .id_table = pm2301_id,
16. };
17.
18. static int __init pm2301_init(void)
19. {
20. "pm2301_init !!\n");
21. return i2c_add_driver(&pm2301_i2c_driver);
22. }
23. module_init(pm2301_init);
(2)、平台驱动部分
arch/arm/mach-exynos/mach-smdk4x12.c
[cpp] view plain copy
1. static struct i2c_board_info i2c_devs1[] __initdata = {
2.
3. …………
4. #ifdef CONFIG_CHARGER_PM2301
5. {
6. "pm2301", 0x2c),
7. .platform_data = &pm2301_platform_data,
8. },
9. #endif
10. …………
11. };
下图就是我们IIC驱动注册生成的文件;
/sys/bus/i2c/drivers/pm2301
2、关于:pm2301_platform_data这个结构体
[cpp] view plain copy
1. static struct pm2301_platform_data pm2301_platform_data = {
2. //(1)、硬件接口初始化化;
3. //(2)、结构体初始化;
4. .gpio_irq = GPIO_CHARGER_STATUS,
5. .gpio_enn = GPIO_CHARGER_ENABLE,
6. .gpio_wakeup = GPIO_CHARGER_ONLINE,
7. };
arch/arm/mach-exynos/mach-smdk4x12.c
(1)、硬件接口初始化
[cpp] view plain copy
1. static int pm2301_hw_init(void)
2. {
3. "pm2301_hw_init !!\n");
4.
5. if (gpio_request(GPIO_CHARGER_ONLINE, "GPIO_CHARGER_ONLINE")) {
6. "%s :GPIO_CHARGER_ONLINE request port error!\n", __func__);
7. goto err_gpio_failed;
8. else {
9. s3c_gpio_setpull(GPIO_CHARGER_ONLINE, S3C_GPIO_PULL_NONE);
10. s3c_gpio_cfgpin(GPIO_CHARGER_ONLINE, S3C_GPIO_SFN(0));
11. gpio_direction_input(GPIO_CHARGER_ONLINE);
12. gpio_free(GPIO_CHARGER_ONLINE);
13. }
14.
15. if (gpio_request(GPIO_CHARGER_STATUS, "GPIO_CHARGER_STATUS")) {
16. "%s :GPIO_CHARGER_STATUS request port error!\n", __func__);
17. goto err_gpio_failed;
18. else {
19. s3c_gpio_setpull(GPIO_CHARGER_STATUS, S3C_GPIO_PULL_NONE);
20. s3c_gpio_cfgpin(GPIO_CHARGER_STATUS, S3C_GPIO_SFN(0));
21. gpio_direction_input(GPIO_CHARGER_STATUS);
22. gpio_free(GPIO_CHARGER_STATUS);
23. }
24.
25.
26. if (gpio_request(GPIO_CHARGER_ENABLE, "GPIO_CHARGER_ENABLE")) {
27. "%s :GPIO_CHARGER_ENABLE request port error!\n", __func__);
28. goto err_gpio_failed;
29. else {
30. s3c_gpio_setpull(GPIO_CHARGER_ENABLE, S3C_GPIO_PULL_NONE);
31. s3c_gpio_cfgpin(GPIO_CHARGER_ENABLE, S3C_GPIO_SFN(1));
32. gpio_direction_output(GPIO_CHARGER_ENABLE, 0);
33. gpio_free(GPIO_CHARGER_ENABLE);
34. }
35.
36. if (gpio_request(GPIO_PM2301_LP, "GPIO_PM2301_LP")) {
37. "%s :GPIO_PM2301_LP request port error!\n", __func__);
38. goto err_gpio_failed;
39. else {
40. s3c_gpio_setpull(GPIO_PM2301_LP, S3C_GPIO_PULL_NONE);
41. s3c_gpio_cfgpin(GPIO_PM2301_LP, S3C_GPIO_SFN(1));
42. gpio_direction_output(GPIO_PM2301_LP, 1);
43. gpio_free(GPIO_PM2301_LP);
44. }
45.
46. return 1;
47.
48. err_gpio_failed:
49. return 0;
50. }
(2)、结构体初始化
Include/Linux/pm2301_charger.h
[cpp] view plain copy
1. #define GPIO_CHARGER_ONLINE EXYNOS4_GPX0(7)//对应控制脚的主控接口
2. #define GPIO_CHARGER_STATUS EXYNOS4_GPX1(3)
3. #define GPIO_CHARGER_ENABLE EXYNOS4_GPL2(0)
4. #define GPIO_PM2301_LP EXYNOS4_GPX1(7)
5. struct pm2301_platform_data {
6. int (*hw_init)(void);
7. int gpio_enn;
8. int gpio_wakeup;
9. int gpio_irq;
10. int gpio_lpn;
11. };
12. extern int pm2301_get_online(void);
13. extern int pm2301_get_status(void);
3、probe函数分析
如果你是初学者,建议多看程序,你会发现,其实驱动程序的格式大多都是相同的,如这个IIC 器件的, 队列、定时器之类的东西。
[cpp] view plain copy
1. static int __devinit pm2301_probe(struct i2c_client *client,
2. const struct i2c_device_id *id)
3. {
4. struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
5. struct pm2301_chip *chip;
6. int ret;
7. "PM2301 probe !!\n");
8. //(1)、前面这部分是对IIC的初始化;
9. if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
10. return -EIO;
11.
12. sizeof(*chip), GFP_KERNEL);
13.
14. if (!chip)
15. return -ENOMEM;
16.
17. g_chip = chip;
18. chip->client = client;
19. chip->pdata = client->dev.platform_data;
20. i2c_set_clientdata(client, chip);
21.
22. /* Hardware Init for PM2301 */
23. if (chip->pdata->hw_init && !(chip->pdata->hw_init())) {
24. "hardware initial failed.\n");
25. goto err_hw_failed;
26. }
27.
28. mutex_init(&i2c_lock);
29. //(2)、初始化两个队列
30. INIT_DELAYED_WORK_DEFERRABLE(&chip->work_online, pm2301_online_work);
31. INIT_DELAYED_WORK_DEFERRABLE(&chip->work_status, pm2301_ststus_work);
32. //(3)、中断线程化
33. chip->irq_online = gpio_to_irq(chip->pdata->gpio_wakeup);
34. chip->irq_status = gpio_to_irq(chip->pdata->gpio_irq);
35. /* Request IRQ for PM2301 */
36. ret = request_threaded_irq(chip->irq_online,
37. NULL, pm2301_dcin,
38. IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
39. "PM2301 DC IN", chip);
40.
41. if (ret) {
42. "Cannot request irq %d for DC (%d)\n",
43. chip->irq_online, ret);
44. goto err_hw_failed;
45. }
46.
47. #ifdef PM2301_REPORT_STATUS_BY_IRQ
48.
49. ret = request_threaded_irq(chip->irq_status,
50. NULL, pm2301_status,
51. IRQF_TRIGGER_FALLING,
52. "PM2301 STATUS", chip);
53.
54. if (ret) {
55. "Cannot request irq %d for CHARGE STATUS (%d)\n",
56. chip->irq_status, ret);
57. goto err_hw_failed;
58. }
59. #endif
60.
61.
62. charger_initial = 1;
63. g_has_charged = 0;
64. g_has_charging_full_or_stop = 0;
65.
66. #ifdef PM2301_REPORT_STATUS_BY_IRQ
67. /* Set wakeup source for online pin*/
68. irq_set_irq_wake(chip->irq_status, 1);
69. #endif
70. /* Set wakeup source for online pin*/
71. irq_set_irq_wake(chip->irq_online, 1);
72.
73. /* Init default interrupt route for PM2301 */
74. pm2301_reg_init(chip->client);
75. /* Init online & status value */
76. chip->online = pm2301_charger_online(chip);
77. /* Sync to global */
78. pm2301_charger_enable(chip->client, chip->online);
79. pm2301_charger_status(chip);
80.
81. "PM2301 probe success!!\n");
82. return 0;
83. err_hw_failed:
84. "failed: power supply register\n");
85. i2c_set_clientdata(client, NULL);
86. kfree(chip);
87. return ret;
88. }
(1)、前面这部分是对IIC的初始化
这部分就不再多说了,搞来搞去都是这个老样子;
(2)、任务初始化宏
[cpp] view plain copy
1. INIT_DELAYED_WORK_DEFERRABLE(&chip->work_online, pm2301_online_work);
2. INIT_DELAYED_WORK_DEFERRABLE(&chip->work_status, pm2301_ststus_work);
把pm2301_online_work加入队列chip->work_online, pm2301_ststus_work加入chip->work_status队列。
(3)、中断线程化 request_threaded_irq
为什么要提出中断线程化?
在 Linux 中,中断具有最高的优先级。不论在任何时刻,只要产生中断事件,内核将立即执行相应的中断处理程序,等到所有挂起的中断和软中断处理完毕后才能执行正常的任务,因此有可能造成实时任务得不到及时的处理。中断线程化之后,中断将作为内核线程运行而且被赋予不同的实时优先级,实时任务可以有比中断线程更高的优先级。这样,具有最高优先级的实时任务就能得到优先处理,即使在严重负载下仍有实时性保证。但是,并不是所有的中断都可以被线程化,比如时钟中断,主要用来维护系统时间以及定时器等,其中定时器是操作系统的脉搏,一旦被线程化,就有可能被挂起,这样后果将不堪设想,所以不应当被线程化。
看下我们程序中如何把中断线程化的:
[cpp] view plain copy
1. chip->irq_online = gpio_to_irq(chip->pdata->gpio_wakeup);
2. chip->irq_status = gpio_to_irq(chip->pdata->gpio_irq);
看到这里是否想起:
[cpp] view plain copy
1. static struct pm2301_platform_data pm2301_platform_data = {
2. ………………
3. .gpio_lpn = GPIO_PM2301_LP,
4. .gpio_irq = GPIO_CHARGER_STATUS,
5. .gpio_enn = GPIO_CHARGER_ENABLE,
6. .gpio_wakeup = GPIO_CHARGER_ONLINE,
7. };
8.
9. #define GPIO_CHARGER_ONLINE EXYNOS4_GPX0(7)
10. #define GPIO_CHARGER_STATUS EXYNOS4_GPX1(3)
11. #define GPIO_CHARGER_ENABLE EXYNOS4_GPL2(0)
12. #define GPIO_PM2301_LP EXYNOS4_GPX1(7)
感觉申请个中断脚,这样有点费劲呀;
中断线程化:
[cpp] view plain copy
1. /* Request IRQ for PM2301 */
2. ret = request_threaded_irq(chip->irq_online,
3. NULL, pm2301_dcin,
4. IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
5. "PM2301 DC IN", chip);
当有插入DC中断出发时调用:
[cpp] view plain copy
1. static irqreturn_t pm2301_dcin(int irq, void *_data)
2. {
3. struct pm2301_chip *chip = _data;
4. schedule_delayed_work(&chip->work_online, PM2301_DELAY);
5. return IRQ_HANDLED;
6. }
Pm2301_dcin调度队列:chip->work_online执行:pm2301_online_work函数
[cpp] view plain copy
1. static void pm2301_online_work(struct work_struct *work)
2. {
3. struct pm2301_chip *chip;
4. struct pm2301_chip, work_online.work);
5. int new_online = pm2301_charger_online(chip);
6.
7. if (chip->online != new_online) {
8. chip->online = new_online;
9. /* Sync to global */
10. //①、初始化充电IC;
11. #ifdef PM2301_REPORT_STATUS_BY_IRQ
12.
13. /*To avoid status pin keep low*/
14. schedule_delayed_work(&chip->work_status, 1000);
15. #endif
16. #if defined(CONFIG_BATTERY_MAX17040)
17. //②、把DC状态更新到max17040;
18. #endif
19. }
20. }
①、初始化电IC
这里面主要是写一些寄存器
[cpp] view plain copy
1. static void pm2301_charger_enable(struct i2c_client *client, int online)
2. {
3. if (online) { /* Enabled Charging*/
4. int batt_capacity = 0;
5. batt_capacity = GetGasgaugeCapacity();
6. /* Don't start charging if battery capacity above 95% when DC plug in*/
7. if(0) {
8. //if( batt_capacity >= 95 ) {
9. pm2301_write_reg(client, 0x01, 0x02);
10. /* always keep the register to 0 */
11. else {
12. /* force resume of charging */
13. /* ChEn=1, AutoResume=1 */
14. /* ChEoccurrentLevel:150mA, ChPrechcurrentLevel:100mA, ChCCcurrentLevel:1000mA/2000mA */
15. /* ChVersumeVot:3.6V ChPrechVoltLevel:2.9V */
16. /* ChVoltLevel:4.25V */
17. /* always keep the register to 0 */
18. }
19. g_has_charged = 1;
20. else { /* Disable Charging*/
21. pm2301_write_reg(client, 0x01, 0x02);
22. /* always keep the register to 0 */
23. g_has_charged = 0;
24. }
25. }
②、把DC状态更新到max17040
[cpp] view plain copy
1. TriggerGasgaugeUpdate()
插入DC这部流程如下: