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rtc: jz4740: Add support for acting as the system power controller 

The 'system-power-controller' singleton entry can be used in the
devicetree node of the jz4740-rtc driver to specify that the driver is
granted the right to power off the system through the registers of the
RTC unit.

See the documentation for more details:
Documentation/devicetree/bindings/rtc/ingenic,jz4740-rtc.txt

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Maarten ter Huurne <maarten@treewalker.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This commit is contained in:
Paul Cercueil 2016-10-31 21:39:48 +01:00 committed by Alexandre Belloni
parent c05229a893
commit f9eb69d1ae
1 changed files with 81 additions and 0 deletions
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81
drivers/rtc/rtc-jz4740.c
View File

@ -14,11 +14,13 @@
*
*/
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
@ -28,6 +30,8 @@
#define JZ_REG_RTC_SEC_ALARM 0x08
#define JZ_REG_RTC_REGULATOR 0x0C
#define JZ_REG_RTC_HIBERNATE 0x20
#define JZ_REG_RTC_WAKEUP_FILTER 0x24
#define JZ_REG_RTC_RESET_COUNTER 0x28
#define JZ_REG_RTC_SCRATCHPAD 0x34
/* The following are present on the jz4780 */
@ -45,6 +49,9 @@
/* Magic value to enable writes on jz4780 */
#define JZ_RTC_WENR_MAGIC 0xA55A
#define JZ_RTC_WAKEUP_FILTER_MASK 0x0000FFE0
#define JZ_RTC_RESET_COUNTER_MASK 0x00000FE0
enum jz4740_rtc_type {
ID_JZ4740,
ID_JZ4780,
@ -55,12 +62,18 @@ struct jz4740_rtc {
enum jz4740_rtc_type type;
struct rtc_device *rtc;
struct clk *clk;
int irq;
spinlock_t lock;
unsigned int min_wakeup_pin_assert_time;
unsigned int reset_pin_assert_time;
};
static struct device *dev_for_power_off;
static inline uint32_t jz4740_rtc_reg_read(struct jz4740_rtc *rtc, size_t reg)
{
return readl(rtc->base + reg);
@ -246,6 +259,46 @@ void jz4740_rtc_poweroff(struct device *dev)
}
EXPORT_SYMBOL_GPL(jz4740_rtc_poweroff);
static void jz4740_rtc_power_off(void)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev_for_power_off);
unsigned long rtc_rate;
unsigned long wakeup_filter_ticks;
unsigned long reset_counter_ticks;
clk_prepare_enable(rtc->clk);
rtc_rate = clk_get_rate(rtc->clk);
/*
* Set minimum wakeup pin assertion time: 100 ms.
* Range is 0 to 2 sec if RTC is clocked at 32 kHz.
*/
wakeup_filter_ticks =
(rtc->min_wakeup_pin_assert_time * rtc_rate) / 1000;
if (wakeup_filter_ticks < JZ_RTC_WAKEUP_FILTER_MASK)
wakeup_filter_ticks &= JZ_RTC_WAKEUP_FILTER_MASK;
else
wakeup_filter_ticks = JZ_RTC_WAKEUP_FILTER_MASK;
jz4740_rtc_reg_write(rtc,
JZ_REG_RTC_WAKEUP_FILTER, wakeup_filter_ticks);
/*
* Set reset pin low-level assertion time after wakeup: 60 ms.
* Range is 0 to 125 ms if RTC is clocked at 32 kHz.
*/
reset_counter_ticks = (rtc->reset_pin_assert_time * rtc_rate) / 1000;
if (reset_counter_ticks < JZ_RTC_RESET_COUNTER_MASK)
reset_counter_ticks &= JZ_RTC_RESET_COUNTER_MASK;
else
reset_counter_ticks = JZ_RTC_RESET_COUNTER_MASK;
jz4740_rtc_reg_write(rtc,
JZ_REG_RTC_RESET_COUNTER, reset_counter_ticks);
jz4740_rtc_poweroff(dev_for_power_off);
machine_halt();
}
static const struct of_device_id jz4740_rtc_of_match[] = {
{ .compatible = "ingenic,jz4740-rtc", .data = (void *)ID_JZ4740 },
{ .compatible = "ingenic,jz4780-rtc", .data = (void *)ID_JZ4780 },
@ -262,6 +315,7 @@ static int jz4740_rtc_probe(struct platform_device *pdev)
const struct platform_device_id *id = platform_get_device_id(pdev);
const struct of_device_id *of_id = of_match_device(
jz4740_rtc_of_match, &pdev->dev);
struct device_node *np = pdev->dev.of_node;
rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
if (!rtc)
@ -283,6 +337,12 @@ static int jz4740_rtc_probe(struct platform_device *pdev)
if (IS_ERR(rtc->base))
return PTR_ERR(rtc->base);
rtc->clk = devm_clk_get(&pdev->dev, "rtc");
if (IS_ERR(rtc->clk)) {
dev_err(&pdev->dev, "Failed to get RTC clock\n");
return PTR_ERR(rtc->clk);
}
spin_lock_init(&rtc->lock);
platform_set_drvdata(pdev, rtc);
@ -314,6 +374,27 @@ static int jz4740_rtc_probe(struct platform_device *pdev)
}
}
if (np && of_device_is_system_power_controller(np)) {
if (!pm_power_off) {
/* Default: 60ms */
rtc->reset_pin_assert_time = 60;
of_property_read_u32(np, "reset-pin-assert-time-ms",
&rtc->reset_pin_assert_time);
/* Default: 100ms */
rtc->min_wakeup_pin_assert_time = 100;
of_property_read_u32(np,
"min-wakeup-pin-assert-time-ms",
&rtc->min_wakeup_pin_assert_time);
dev_for_power_off = &pdev->dev;
pm_power_off = jz4740_rtc_power_off;
} else {
dev_warn(&pdev->dev,
"Poweroff handler already present!\n");
}
}
return 0;
}