[PATCH RESEND 13/13] platform/chrome: cros_ec_lightbar - Avoid I2C xfer to EC during suspend

[Enric Balletbo i Serra]

From: Jeffery Yu <jeffe...@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 <jeffe...@nvidia.com>
Signed-off-by: Guenter Roeck <gro...@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balle...@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 7c26223..b9bf086 100644
--- a/drivers/platform/chrome/cros_ec_dev.c
+++ b/drivers/platform/chrome/cros_ec_dev.c
@@ -437,8 +437,7 @@ static int ec_device_probe(struct platform_device *pdev)
                cros_ec_sensors_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;
 
@@ -452,8 +451,7 @@ 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);
 
        cros_ec_debugfs_remove(ec);
 
@@ -472,8 +470,7 @@ 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;
 }
@@ -482,8 +479,7 @@ 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