linux-kernel - Re: [PATCH v4] usb: typec: intel_pmc_mux: Expose IOM port status to debugfs

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Message-ID: <2023052215-skilled-polygraph-33dd@gregkh>
Date:   Mon, 22 May 2023 17:26:43 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Rajat Khandelwal <rajat.khandelwal@...ux.intel.com>
Cc:     heikki.krogerus@...ux.intel.com, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4] usb: typec: intel_pmc_mux: Expose IOM port status to
 debugfs

On Mon, May 22, 2023 at 03:24:13PM +0530, Rajat Khandelwal wrote:
> Hi,
> 
> On 5/22/2023 1:07 PM, Greg KH wrote:
> > On Mon, May 22, 2023 at 12:33:43PM +0530, Rajat Khandelwal wrote:
> > > IOM status has a crucial role during debugging to check the
> > > current state of the type-C port.
> > > There are ways to fetch the status, but all those require the
> > > IOM port status offset, which could change with platform.
> > > 
> > > Make a debugfs directory for intel_pmc_mux and expose the status
> > > under it per port basis.
> > > 
> > > Signed-off-by: Rajat Khandelwal <rajat.khandelwal@...ux.intel.com>
> > > Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
> > > ---
> > > 
> > > v4:
> > > 1. Maintain a root directory for PMC module and incorporate devices
> > > under it
> > > 2. Add the debugfs module under '/sys/kernel/debug/usb'
> > > 3. Use the platform device 'pmc->dev' to assign the device's name
> > > 
> > > v3: Allocate the debugfs directory name for the platform device with
> > > its ACPI dev name included
> > > 
> > > v2:
> > > 1. Remove static declaration of the debugfs root for 'intel_pmc_mux'
> > > 2. Remove explicitly defined one-liner functions
> > > 
> > >   drivers/usb/typec/mux/intel_pmc_mux.c | 54 ++++++++++++++++++++++++++-
> > >   1 file changed, 53 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/usb/typec/mux/intel_pmc_mux.c b/drivers/usb/typec/mux/intel_pmc_mux.c
> > > index 34e4188a40ff..f400094c76f2 100644
> > > --- a/drivers/usb/typec/mux/intel_pmc_mux.c
> > > +++ b/drivers/usb/typec/mux/intel_pmc_mux.c
> > > @@ -15,6 +15,8 @@
> > >   #include <linux/usb/typec_mux.h>
> > >   #include <linux/usb/typec_dp.h>
> > >   #include <linux/usb/typec_tbt.h>
> > > +#include <linux/debugfs.h>
> > > +#include <linux/usb.h>
> > >   #include <asm/intel_scu_ipc.h>
> > > @@ -143,8 +145,14 @@ struct pmc_usb {
> > >   	struct acpi_device *iom_adev;
> > >   	void __iomem *iom_base;
> > >   	u32 iom_port_status_offset;
> > > +
> > > +#ifdef CONFIG_DEBUG_FS
> > > +	struct dentry *dentry;
> > > +#endif
> > No need for the #ifdef anymore, right?  In fact, I think it will break
> > the build if you have it this way and CONFIG_DEBUG_FS is not enabled,
> > right?
> 
> I guess you're right. Maybe it'd have been fine if the rest of the
> debugfs stuff was also enclosed within the conditional macros.

Which is not needed and not good kernel coding style, so it's right that
they are not there.

> Anyways, removing it seems appropriate now.
> 
> Also, is it OK to send you v5 on the public list directly?

Where else would you send it?

confused,

greg k-h