1. 概念:
Regulator : 电源芯片, 比如电压转换芯片
Consumer : 消费者,使用电源的部件, Regulator是给Consumer供电的
machine : 单板,上面焊接有Regulator和Consumer
Constraints : 约束, 比如某个电源管理芯片输出的电压范围
Supply : 提供电源的部件, Regulator就是一个Supply; Regulator A可以给Regulator B供电, 那么Regulator B的Supply就是A
2. 写驱动程序:
(1). regulator驱动:
注册一个platform_driver: 在它的probe函数里分配、设置、注册一个regulator
"设置"里要做的事情: 实现regulator的操作, 比如enable, disable, set_voltage
(2). machine(单板)驱动:
注册一个platform_device: 在它的私有数据里指定regulator和consume的对应关系(这个电源芯片给哪一个部件供电)
指定约束条件(比如电压范围)
(3). consumer使用此电源的设备驱动:
使用即可: regulator_get, regulator_enable, regulator_disable, regulator_set_voltage....
注: 这只是没有使用设备树的情况下是这样的，其实就是以平台设备模型注册一个regulator，然后consumer去使用。
3. 不使用设备树的regulator_register流程分析:
// 分配regulator_dev
rdev = kzalloc(sizeof(struct regulator_dev), GFP_KERNEL);
/* set regulator constraints */
set_machine_constraints
add_regulator_attributes
/* add consumers devices */
set_consumer_device_supply
在regulator_map_list链表里生成一项regulator_map: 它里面有dev_name(consumer的名字),supply(cosumer的电源引脚名字)
// 把regulator_dev放入regulator_list
list_add(&rdev->list, ®ulator_list);
4. 使用设备树的regulator_register()和regulator_get()流程分析:
regulator_register(const struct regulator_desc *, const struct regulator_config *) //drivers/regulator/core.c
先自行各种检查,然后构造一个struct regulator_dev，从设备树中获取它的各种属性
regulator_of_get_init_data //drivers/regulator/of_regulator.c
of_get_regulation_constraints //drivers/regulator/of_regulator.c 通过设备树构造init_data，和约束
若设备树中指定了“regulator-initial-mode”且regulator_desc.of_map_mode()存在，则调用它
初始化rdev->consumer_list，rdev->list，rdev->notifier，指定rdev->disable_work=regulator_disable_work
如果init_data->regulator_init()存在则调用
判断是不是gpio控制的regulator，如果是就调用regulator_ena_gpio_request()
使rdev->dev.class = ®ulator_class，此时sysfs下会有"regulator"文件夹，其下有regulator_dev_attrs中列出的文件。
自动递增设置&rdev->dev的name为"regulator.%lu" "regulator"下的"regulator.%lu"下才会有regulator_dev_attrs中列出的文件了。
set_machine_constraints
device_register(&rdev->dev) //注册到设备模型
dev_set_drvdata(&rdev->dev, rdev);
rdev_init_debugfs(rdev);
使用设备树的regulator_get()流程分析:
struct regulator *regulator_get(struct device *dev, const char *id) //drivers/regulator/core.c， arg2为consumer的电源引脚
regulator_dev_lookup //drivers/regulator/core.c
使用devname与全局链表regulator_map_list中的每一项struct regulator_map->dev_name进行匹配，并返回匹配的struct regulator_dev结构体。
regulator_resolve_supply 还要和rdev->supply_name的名字逐个比较
create_regulator 根据struct regulator_dev创建一个struct regulator并返回
5.驱动示例代码
/* 文件名：machine.c 作为一个regulator平台设备模型的设备端。
* 参考: arch\arm\mach-omap2\board-2430sdp.c
* 这里只是注册一个单板的所有regulator的平台设备端，目前这类文件应该被设备树给替代了
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/mfd/core.h>
/* 分配/设置/注册regulator_init_data */
#if 0
regulator_consumer_supply:
const char *dev_name; /* consumer的名字 */
const char *supply; /* consumer的电源引脚名称 */
#endif
static struct regulator_consumer_supply myregulator_supplies[] = {
REGULATOR_SUPPLY("VCC", "mylcd"), /*此regulator是对设备"mylcd"上的"VCC"引脚供电的*/
};
static struct regulator_init_data myregulator_init_data = {
.constraints = {
.min_uV = 12000000,
.max_uV = 12000000,
.valid_modes_mask = REGULATOR_MODE_NORMAL,
.valid_ops_mask = REGULATOR_CHANGE_STATUS,
},
.num_consumer_supplies = ARRAY_SIZE(myregulator_supplies),
.consumer_supplies = myregulator_supplies,
};
static void myregulator_release(struct device * dev)
{
}
static struct platform_device myregulator_dev = {
.name = "myregulator", /* 平台设备设备端名字*/
.id = -1,
.dev = {
.release = myregulator_release,
.platform_data = &myregulator_init_data,
},
};
/*使用设备树后就不再需要注册平台设备端了*/
static int myregulator_machine_init(void)
{
platform_device_register(&myregulator_dev);
return 0;
}
static void myregulator_machine_exit(void)
{
platform_device_unregister(&myregulator_dev);
}
module_init(myregulator_machine_init);
module_exit(myregulator_machine_exit);
MODULE_LICENSE("GPL v2");/* 文件名：regulator.c 作为一个regulator平台设备模型的驱动端。
* 参考: drivers/regulator/tps6105x-regulator.c
* 其实machine.c充当的是平台设备的设备端，将单板上的所有regulator写在了一起，目前已被设备树替代。
* regulator.c充当的是平台设备的驱动端，每个regulator都可能有一个平台设备驱动端。
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/mfd/core.h>
static volatile unsigned long *gpbcon;
static volatile unsigned long *gpbdat;
static int myregulator_enable(struct regulator_dev *rdev)
{
*gpbdat |= 1; /* 输出高电平 */
return 0;
}
static int myregulator_disable(struct regulator_dev *rdev)
{
*gpbdat &= ~1; /* 输出低电平 */
return 0;
}
static int myregulator_is_enabled(struct regulator_dev *rdev)
{
if (*gpbdat & 1)
return 1;
else
return 0;
}
static struct regulator_ops myregulator_ops = {
.enable = myregulator_enable,
.disable = myregulator_disable,
.is_enabled = myregulator_is_enabled,
};
static struct regulator_desc myregulator_desc = {
.name = "myregulator",
.ops = &myregulator_ops,
.type = REGULATOR_VOLTAGE,
.id = 0,
.owner = THIS_MODULE,
.n_voltages = 1, /*只提供一种电压值得*/
};
static struct regulator_dev *myregulator_dev;
static int myregulator_probe(struct platform_device *pdev)
{
struct regulator_init_data *init_data = dev_get_platdata(&pdev->dev); /*可以在platform_driver初始化的时候对dev赋值*//* 分配/设置/注册 regulator */
myregulator_dev = regulator_register(&myregulator_desc,
&pdev->dev,
init_data, NULL,
NULL);
if (IS_ERR(myregulator_dev)) {
printk("regulator_register error!\n");
return -EIO;
}
return 0;
}
static int myregulator_remove(struct platform_device *pdev)
{
regulator_unregister(myregulator_dev);
return 0;
}
struct platform_driver myregulator_drv = {
.probe = myregulator_probe,
.remove = myregulator_remove,
.driver = {
.name = "myregulator", /* 驱动上面regulator平台设备的设备端 */
}
};
static int myregulator_init(void)
{
platform_driver_register(&myregulator_drv);
return 0;
}
static void myregulator_exit(void)
{
platform_driver_unregister(&myregulator_drv);
}
module_init(myregulator_init);
module_exit(myregulator_exit);
MODULE_LICENSE("GPL v2");/* 文件名：consumer_lcd.c 作为一个consumer驱动
*
*/
static int mylcd_open(struct fb_info *info, int user)
{
pm_runtime_get_sync(&lcd_dev.dev);
return 0;
}
static int mylcd_release(struct fb_info *info, int user)
{
pm_runtime_mark_last_busy(&lcd_dev.dev);
pm_runtime_put_sync_autosuspend(&lcd_dev.dev);
return 0;
}
static int lcd_suspend_notifier(struct notifier_block *nb,
unsigned long event,
void *dummy)
{
switch (event) {
case PM_SUSPEND_PREPARE:
printk("lcd suspend notifiler test: PM_SUSPEND_PREPARE\n");
return NOTIFY_OK;
case PM_POST_SUSPEND:
printk("lcd suspend notifiler test: PM_POST_SUSPEND\n");
return NOTIFY_OK;
default:
return NOTIFY_DONE;
}
}
static struct notifier_block lcd_pm_notif_block = {
.notifier_call = lcd_suspend_notifier,
};
static void lcd_release(struct device * dev)
{
}
static struct platform_device lcd_dev = { /* regulator匹配1 */
.name = "mylcd",
.id = -1,
.dev = {
.release = lcd_release,
},
};
static struct regulator *myregulator;
static int lcd_probe(struct platform_device *pdev)
{
myregulator = regulator_get(pdev->dev, "VCC"); /* regulator 匹配2 */
if (IS_ERR(myregulator)) {
printk("regulator_get error!\n");
return -EIO;
}
regulator_enable(myregulator); /*没有它会报unblance regulator disable of myregulator*/
pm_runtime_set_active(&pdev->dev);
pm_runtime_use_autosuspend(&pdev->dev);
pm_runtime_enable(&pdev->dev);
return 0;
}
static int lcd_remove(struct platform_device *pdev)
{
regulator_put(myregulator);
pm_runtime_disable(&pdev->dev);
return 0;
}
static int lcd_suspend(struct device *dev)
{
int i;
unsigned long *dest = &lcd_regs_backup;
unsigned long *src = lcd_regs;
for (i = 0; i < sizeof(lcd_regs_backup)/sizeof(unsigned long); i++)
{
dest[i] = src[i];
}
lcd_regs->lcdcon1 &= ~(1<<0); /* 关闭LCD本身 */
//*gpbdat &= ~1; /* 关闭背光 */
regulator_disable(myregulator);
return 0;
}
static int lcd_resume(struct device *dev)
{
int i;
unsigned long *dest = lcd_regs;
unsigned long *src = &lcd_regs_backup;
struct clk *clk = clk_get(NULL, "lcd");
clk_enable(clk);
clk_put(clk);
for (i = 0; i < sizeof(lcd_regs_backup)/sizeof(unsigned long); i++)
{
dest[i] = src[i];
}
regulator_enable(myregulator);
return 0;
}
static struct dev_pm_ops lcd_pm = {
.suspend = lcd_suspend,
.resume = lcd_resume,
.runtime_suspend = lcd_suspend,
.runtime_resume = lcd_resume,
};
struct platform_driver lcd_drv = {
.probe = lcd_probe,
.remove = lcd_remove,
.driver = {
.name = "mylcd",
.pm = &lcd_pm,
}
};
static int lcd_init(void)
{
/* 电源管理 */
register_pm_notifier(&lcd_pm_notif_block);
platform_device_register(&lcd_dev);
platform_driver_register(&lcd_drv);
return 0;
}
static void lcd_exit(void)
{
unregister_pm_notifier(&lcd_pm_notif_block);
platform_device_unregister(&lcd_dev);
platform_driver_unregister(&lcd_drv);
}
module_init(lcd_init);
module_exit(lcd_exit);
MODULE_LICENSE("GPL");
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