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power: reset: ltc2952: make trigger delay configurable

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Make trigger delay configurable through device tree with
trigger-delay-ms property.

Trigger delay is the time to wait before starting shutdown
sequence after trigger line assertion.
Trigger delay must take into account the OFFT time configured
with the capacitor connected to OFFT pin of the LTC2952 chip.
Basically, the higher the capacitance connected to OFFT pin,
the larger trigger delay must be.

Signed-off-by: Marek Czerski <ma.czerski@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
This commit is contained in:
Marek Czerski 2021-02-03 22:49:00 +01:00 committed by Sebastian Reichel
parent 816aacd541
commit 52473b0740
2 changed files with 12 additions and 0 deletions
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4
Documentation/devicetree/bindings/power/reset/ltc2952-poweroff.txt
View File

@ -17,6 +17,9 @@ Optional properties:
chip's trigger line. If this property is not set, the
trigger function is ignored and the chip is kept alive
until an explicit kill signal is received
- trigger-delay-ms The number of milliseconds to wait after trigger line
assertion before executing shut down procedure.
The default is 2500ms.
Example:
@ -24,6 +27,7 @@ ltc2952 {
compatible = "lltc,ltc2952";
trigger-gpios = <&gpio0 1 GPIO_ACTIVE_LOW>;
trigger-delay-ms = <2000>;
watchdog-gpios = <&gpio1 2 GPIO_ACTIVE_HIGH>;
kill-gpios = <&gpio0 2 GPIO_ACTIVE_LOW>;
};

8
drivers/power/reset/ltc2952-poweroff.c
View File

@ -55,6 +55,7 @@
#include <linux/mod_devicetable.h>
#include <linux/gpio/consumer.h>
#include <linux/reboot.h>
#include <linux/property.h>
struct ltc2952_poweroff {
struct hrtimer timer_trigger;
@ -172,10 +173,17 @@ static void ltc2952_poweroff_default(struct ltc2952_poweroff *data)
static int ltc2952_poweroff_init(struct platform_device *pdev)
{
int ret;
u32 trigger_delay_ms;
struct ltc2952_poweroff *data = platform_get_drvdata(pdev);
ltc2952_poweroff_default(data);
if (!device_property_read_u32(&pdev->dev, "trigger-delay-ms",
&trigger_delay_ms)) {
data->trigger_delay = ktime_set(trigger_delay_ms / MSEC_PER_SEC,
(trigger_delay_ms % MSEC_PER_SEC) * NSEC_PER_MSEC);
}
data->gpio_watchdog = devm_gpiod_get(&pdev->dev, "watchdog",
GPIOD_OUT_LOW);
if (IS_ERR(data->gpio_watchdog)) {