lkml.org 
[lkml]   [2016]   [Oct]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2 4/7] rtc: jz4740_rtc: Add support for acting as the system power controller
Date
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>
---
drivers/rtc/rtc-jz4740.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 81 insertions(+)

v2:
- Get a handle to the 'rtc' clock in the probe function, to handle errors early
- Call clk_prepare_enable() on the 'rtc' clock before calling clk_get_rate()
- Use the -msec suffix for the OF properties that deal with time
- Use of_property_read_32() instead of device_property_read_u32()

diff --git a/drivers/rtc/rtc-jz4740.c b/drivers/rtc/rtc-jz4740.c
index 4213554..3f9d0da 100644
--- a/drivers/rtc/rtc-jz4740.c
+++ b/drivers/rtc/rtc-jz4740.c
@@ -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-msec",
+ &rtc->reset_pin_assert_time);
+
+ /* Default: 100ms */
+ rtc->min_wakeup_pin_assert_time = 100;
+ of_property_read_u32(np,
+ "min-wakeup-pin-assert-time-msec",
+ &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;
}

--
2.9.3
\
 
 \ /
  Last update: 2016-10-31 00:11    [W:0.114 / U:0.164 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site