Re: [RFC v2 6/6] cros_ec: differentiate SCP from EC by feature bit.

[Lee Jones]

On Tue, 08 Jan 2019, Pi-Hsun Shih wrote:

> Since a SCP and EC would both exist on a system, and use the cros_ec_dev
> driver, we need to differentiate between them for the userspace, or they
> would both be registered at /dev/cros_ec, causing a conflict.
> 
> Cc: Enric Balletbo Serra 
> Cc: Guenter Roeck 
> Signed-off-by: Pi-Hsun Shih 
> ---
> Changes from v1:
>  - New patch extracted from Patch 5.
> ---
>  drivers/mfd/cros_ec_dev.c| 9 +
>  include/linux/mfd/cros_ec.h  | 1 +
>  include/linux/mfd/cros_ec_commands.h | 2 ++
>  3 files changed, 12 insertions(+)

The (other) Chromium guys are usually pretty active and are more
familiar with this hardware and group of (MFD/Platform) drivers than I
am.  Thus I'm waiting for one of them to provide their thoughts before
applying this.

Just make sure you Cc:ed enough of them!

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

[RFC v2 6/6] cros_ec: differentiate SCP from EC by feature bit.

[Pi-Hsun Shih]

Since a SCP and EC would both exist on a system, and use the cros_ec_dev
driver, we need to differentiate between them for the userspace, or they
would both be registered at /dev/cros_ec, causing a conflict.

Cc: Enric Balletbo Serra 
Cc: Guenter Roeck 
Signed-off-by: Pi-Hsun Shih 
---
Changes from v1:
 - New patch extracted from Patch 5.
---
 drivers/mfd/cros_ec_dev.c| 9 +
 include/linux/mfd/cros_ec.h  | 1 +
 include/linux/mfd/cros_ec_commands.h | 2 ++
 3 files changed, 12 insertions(+)

diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index 2d0fee488c5aa8..67983853413d07 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -414,6 +414,15 @@ static int ec_device_probe(struct platform_device *pdev)
device_initialize(>class_dev);
cdev_init(>cdev, );
 
+   if (cros_ec_check_features(ec, EC_FEATURE_SCP)) {
+   dev_info(dev, "SCP detected.\n");
+   /*
+* Help userspace differentiating ECs from SCP,
+* regardless of the probing order.
+*/
+   ec_platform->ec_name = CROS_EC_DEV_SCP_NAME;
+   }
+
/*
 * Add the class device
 * Link to the character device for creating the /dev entry
diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
index de8b588c8776da..fd297cf8f97295 100644
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -24,6 +24,7 @@
 
 #define CROS_EC_DEV_NAME "cros_ec"
 #define CROS_EC_DEV_PD_NAME "cros_pd"
+#define CROS_EC_DEV_SCP_NAME "cros_scp"
 
 /*
  * The EC is unresponsive for a time after a reboot command.  Add a
diff --git a/include/linux/mfd/cros_ec_commands.h 
b/include/linux/mfd/cros_ec_commands.h
index fc91082d4c357b..3e5da6e93b2f42 100644
--- a/include/linux/mfd/cros_ec_commands.h
+++ b/include/linux/mfd/cros_ec_commands.h
@@ -856,6 +856,8 @@ enum ec_feature_code {
EC_FEATURE_RTC = 27,
/* EC supports CEC commands */
EC_FEATURE_CEC = 35,
+   /* The MCU exposes a SCP */
+   EC_FEATURE_SCP = 39,
 };
 
 #define EC_FEATURE_MASK_0(event_code) (1UL << (event_code % 32))
-- 
2.20.1.97.g81188d93c3-goog