[AMD Official Use Only - General]

-----Original Message-----
From: Greg KH <gregkh@linuxfoundation.org>
Sent: Wednesday, August 3, 2022 6:02 PM
To: Gupta, Nipun <Nipun.Gupta@amd.com>
Cc: linux-kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
rafael@kernel.org; maz@kernel.org; tglx@linutronix.de; okaya@kernel.org;
Anand, Harpreet [off-list ref]; Simek, Michal
[off-list ref]; Agarwal, Nikhil [off-list ref]
Subject: Re: [RFC PATCH 2/2] driver core: add compatible string in sysfs for
platform devices

[CAUTION: External Email]

On Wed, Aug 03, 2022 at 05:56:55PM +0530, Nipun Gupta wrote:

quoted

For devices registered dynamically using platform_device_register
API, this patch exposes the sysfs entry for the compatible string.

Signed-off-by: Nipun Gupta <nipun.gupta@amd.com>
---
 drivers/base/platform.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 51bb2289865c..89949f88a0a1 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c

@@ -1289,10 +1289,25 @@ static ssize_t driver_override_store(struct device

*dev,

quoted

 }
 static DEVICE_ATTR_RW(driver_override);

+static ssize_t compatible_show(struct device *dev, struct device_attribute

*attr,

quoted

+                           char *buf)
+{
+     const char *compat;
+     int ret;
+
+     ret = device_property_read_string(dev, "compatible", &compat);
+     if (ret != 0)
+             return 0;
+
+     return sysfs_emit(buf, "%s", compat);
+}
+static DEVICE_ATTR_RO(compatible);

You forgot the Documentation/ABI/ update :(

Thanks for pointing. Will be adding the new sysfs entry as part
of the documentation.

Also, what happens if there is no such string to read?  Why are you
returning 0?  You should not create the attribute at all then, right?

Will be updating platform_dev_attrs_visible() API to have it visible
depending on if the attribute is available. Yes, then we may not need
this check here and would be part of the platform_dev_attrs_visible() API.

Thanks,
Nipun

thanks,

greg k-h

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