[PATCH v2] mfd: cros_ec: instantiate properly CrOS ISH MCU device

[Rushikesh S Kadam]

Integrated Sensor Hub (ISH) is also a MCU running EC
having feature bit EC_FEATURE_ISH. Instantiate it as
a special CrOS EC device with device name 'cros_ish'.

Signed-off-by: Rushikesh S Kadam <rushikesh.s.ka...@intel.com>
---
v2
- Addressed review comments to term the CrOS EC device as a generic
  Integrated Sensor Hub. 
v1
- Initial version.

 drivers/mfd/cros_ec_dev.c            | 13 +++++++++++++
 include/linux/mfd/cros_ec.h          |  1 +
 include/linux/mfd/cros_ec_commands.h |  2 ++
 3 files changed, 16 insertions(+)

diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index 2d0fee4..46963c2 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -415,6 +415,19 @@ static int ec_device_probe(struct platform_device *pdev)
        cdev_init(&ec->cdev, &fops);
 
        /*
+        * Check whether this is actually an Integrated Sensor Hub (ISH)
+        * rather than an EC.
+        */
+       if (cros_ec_check_features(ec, EC_FEATURE_ISH)) {
+               dev_info(dev, "CrOS ISH MCU detected.\n");
+               /*
+                * Help userspace differentiating ECs from ISH MCU,
+                * regardless of the probing order.
+                */
+               ec_platform->ec_name = CROS_EC_DEV_ISH_NAME;
+       }
+
+       /*
         * Add the class device
         * Link to the character device for creating the /dev entry
         * in devtmpfs.
diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
index de8b588..00c5765 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_ISH_NAME "cros_ish"
 
 /*
  * 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 fc91082..9276c3c 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 is an Intel Integrated Sensor Hub */
+       EC_FEATURE_ISH = 40,
 };
 
 #define EC_FEATURE_MASK_0(event_code) (1UL << (event_code % 32))
-- 
1.9.1