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Subject[PATCH v2 1/2] power: reset: gpio-poweroff: add force mode
Date
Property "force-mode" tells the driver to replace previously
initialized power-off kernel hook and allows gpio-poweroff to
probe and operate successfully in any case.

Signed-off-by: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
---

Changes in v2:
Call next pm_power_off handler if the current one
fails to power system off.

drivers/power/reset/gpio-poweroff.c | 34 ++++++++++++++++++++++++-----
1 file changed, 28 insertions(+), 6 deletions(-)

diff --git a/drivers/power/reset/gpio-poweroff.c b/drivers/power/reset/gpio-poweroff.c
index 6a4bbb506551..94056af9ba0d 100644
--- a/drivers/power/reset/gpio-poweroff.c
+++ b/drivers/power/reset/gpio-poweroff.c
@@ -24,6 +24,7 @@ static struct gpio_desc *reset_gpio;
static u32 timeout = DEFAULT_TIMEOUT_MS;
static u32 active_delay = 100;
static u32 inactive_delay = 100;
+static void (*next_pm_power_off)(void);

static void gpio_poweroff_do_poweroff(void)
{
@@ -43,20 +44,41 @@ static void gpio_poweroff_do_poweroff(void)
/* give it some time */
mdelay(timeout);

+ /*
+ * The kernel should not reach this code. If it does, fall back to
+ * the next registered power off method.
+ */
+ if (next_pm_power_off)
+ next_pm_power_off();
+
WARN_ON(1);
}

static int gpio_poweroff_probe(struct platform_device *pdev)
{
bool input = false;
+ bool force = false;
enum gpiod_flags flags;

- /* If a pm_power_off function has already been added, leave it alone */
+
+ force = device_property_read_bool(&pdev->dev, "force-mode");
+
+ /*
+ * If a pm_power_off function has already been added, leave it alone,
+ * if force-mode is not enabled.
+ */
if (pm_power_off != NULL) {
- dev_err(&pdev->dev,
- "%s: pm_power_off function already registered",
- __func__);
- return -EBUSY;
+ if (force) {
+ dev_warn(&pdev->dev,
+ "%s: pm_power_off function replaced",
+ __func__);
+ next_pm_power_off = pm_power_off;
+ } else {
+ dev_err(&pdev->dev,
+ "%s: pm_power_off function already registered",
+ __func__);
+ return -EBUSY;
+ }
}

input = device_property_read_bool(&pdev->dev, "input");
@@ -81,7 +103,7 @@ static int gpio_poweroff_probe(struct platform_device *pdev)
static int gpio_poweroff_remove(struct platform_device *pdev)
{
if (pm_power_off == &gpio_poweroff_do_poweroff)
- pm_power_off = NULL;
+ pm_power_off = next_pm_power_off;

return 0;
}
--
2.20.1
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