2019-01-08 05:28:46

by Pi-Hsun Shih

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

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 <[email protected]>
Cc: Guenter Roeck <[email protected]>
Signed-off-by: Pi-Hsun Shih <[email protected]>
---
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(&ec->class_dev);
cdev_init(&ec->cdev, &fops);

+ 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

2019-01-16 18:29:15

by Lee Jones

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

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 <[email protected]>
> Cc: Guenter Roeck <[email protected]>
> Signed-off-by: Pi-Hsun Shih <[email protected]>
> ---
> 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
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