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Subject[PATCH v2 4/4] platform/chrome: cros_ec_lightbar - Avoid I2C xfer to EC during suspend
Date
From: Jeffery Yu <jefferyy@nvidia.com>

A Mutex lock in cros_ec_cmd_xfer which may be held by frozen
Userspace thread during system suspending. So should not
call this routine in suspend thread.

Signed-off-by: Jeffery Yu <jefferyy@nvidia.com>
Signed-off-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
---
drivers/platform/chrome/cros_ec_dev.c | 12 ++++--------
drivers/platform/chrome/cros_ec_lightbar.c | 13 +++++++++----
2 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_dev.c b/drivers/platform/chrome/cros_ec_dev.c
index ef04523..df5894f 100644
--- a/drivers/platform/chrome/cros_ec_dev.c
+++ b/drivers/platform/chrome/cros_ec_dev.c
@@ -465,8 +465,7 @@ static int ec_device_probe(struct platform_device *pdev)
cros_ec_rtc_register(ec);

/* Take control of the lightbar from the EC. */
- if (ec_has_lightbar(ec))
- lb_manual_suspend_ctrl(ec, 1);
+ lb_manual_suspend_ctrl(ec, 1);

return 0;

@@ -484,8 +483,7 @@ static int ec_device_remove(struct platform_device *pdev)
struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);

/* Let the EC take over the lightbar again. */
- if (ec_has_lightbar(ec))
- lb_manual_suspend_ctrl(ec, 0);
+ lb_manual_suspend_ctrl(ec, 0);

cdev_del(&ec->cdev);
device_unregister(&ec->class_dev);
@@ -502,8 +500,7 @@ static int ec_device_suspend(struct device *dev)
{
struct cros_ec_dev *ec = dev_get_drvdata(dev);

- if (ec_has_lightbar(ec))
- lb_suspend(ec);
+ lb_suspend(ec);

return 0;
}
@@ -512,8 +509,7 @@ static int ec_device_resume(struct device *dev)
{
struct cros_ec_dev *ec = dev_get_drvdata(dev);

- if (ec_has_lightbar(ec))
- lb_resume(ec);
+ lb_resume(ec);

return 0;
}
diff --git a/drivers/platform/chrome/cros_ec_lightbar.c b/drivers/platform/chrome/cros_ec_lightbar.c
index e570c1e..fd2b047 100644
--- a/drivers/platform/chrome/cros_ec_lightbar.c
+++ b/drivers/platform/chrome/cros_ec_lightbar.c
@@ -43,6 +43,7 @@ static unsigned long lb_interval_jiffies = 50 * HZ / 1000;
* If this is true, we won't do anything during suspend/resume.
*/
static bool userspace_control;
+static struct cros_ec_dev *ec_with_lightbar;

static ssize_t interval_msec_show(struct device *dev,
struct device_attribute *attr, char *buf)
@@ -384,6 +385,9 @@ int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)
struct cros_ec_command *msg;
int ret;

+ if (ec != ec_with_lightbar)
+ return 0;
+
msg = alloc_lightbar_cmd_msg(ec);
if (!msg)
return -ENOMEM;
@@ -413,7 +417,7 @@ int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)

int lb_suspend(struct cros_ec_dev *ec)
{
- if (userspace_control)
+ if (userspace_control || ec != ec_with_lightbar)
return 0;

return lb_send_empty_cmd(ec, LIGHTBAR_CMD_SUSPEND);
@@ -421,7 +425,7 @@ int lb_suspend(struct cros_ec_dev *ec)

int lb_resume(struct cros_ec_dev *ec)
{
- if (userspace_control)
+ if (userspace_control || ec != ec_with_lightbar)
return 0;

return lb_send_empty_cmd(ec, LIGHTBAR_CMD_RESUME);
@@ -606,9 +610,10 @@ static umode_t cros_ec_lightbar_attrs_are_visible(struct kobject *kobj,
return 0;

/* Only instantiate this stuff if the EC has a lightbar */
- if (ec_has_lightbar(ec))
+ if (ec_has_lightbar(ec)) {
+ ec_with_lightbar = ec;
return a->mode;
-
+ }
return 0;
}

--
2.9.3
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