Re: [PATCH v2] usb: typec: intel_pmc_mux: Expose IOM port status to debugfs

[Rajat Khandelwal]

Hi,

On 4/15/2023 11:01 AM, Greg KH wrote:
> On Fri, Apr 14, 2023 at 01:49:10PM +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@xxxxxxxxxxxxxxx>
> > ---
> >
> > 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 | 34 +++++++++++++++++++++++++++
> >   1 file changed, 34 insertions(+)
> >
> > diff --git a/drivers/usb/typec/mux/intel_pmc_mux.c b/drivers/usb/typec/mux/intel_pmc_mux.c
> > index 34e4188a40ff..1d43b111781e 100644
> > --- a/drivers/usb/typec/mux/intel_pmc_mux.c
> > +++ b/drivers/usb/typec/mux/intel_pmc_mux.c
> > @@ -15,6 +15,7 @@
> >   #include <linux/usb/typec_mux.h>
> >   #include <linux/usb/typec_dp.h>
> >   #include <linux/usb/typec_tbt.h>
> > +#include <linux/debugfs.h>
> >   
> >   #include <asm/intel_scu_ipc.h>
> >   
> > @@ -639,9 +640,34 @@ static int pmc_usb_probe_iom(struct pmc_usb *pmc)
> >   	return 0;
> >   }
> >   
> > +static int port_iom_status_show(struct seq_file *s, void *unused)
> > +{
> > +	struct pmc_usb_port *port = s->private;
> > +
> > +	update_port_status(port);
> > +	seq_printf(s, "0x%08x\n", port->iom_status);
> > +
> > +	return 0;
> > +}
> > +DEFINE_SHOW_ATTRIBUTE(port_iom_status);
> > +
> > +static void pmc_mux_port_debugfs_init(struct pmc_usb_port *port,
> > +				      struct dentry *pmc_mux_debugfs_root)
> > +{
> > +	struct dentry *debugfs_dir;
> > +	char name[6];
> > +
> > +	snprintf(name, sizeof(name), "port%d", port->usb3_port - 1);
> > +
> > +	debugfs_dir = debugfs_create_dir(name, pmc_mux_debugfs_root);
> > +	debugfs_create_file("iom_status", 0400, debugfs_dir, port,
> > +			    &port_iom_status_fops);
> > +}
> > +
> >   static int pmc_usb_probe(struct platform_device *pdev)
> >   {
> >   	struct fwnode_handle *fwnode = NULL;
> > +	struct dentry *pmc_mux_debugfs_root;
> >   	struct pmc_usb *pmc;
> >   	int i = 0;
> >   	int ret;
> > @@ -674,6 +700,8 @@ static int pmc_usb_probe(struct platform_device *pdev)
> >   	if (ret)
> >   		return ret;
> >   
> > +	pmc_mux_debugfs_root = debugfs_create_dir("intel_pmc_mux", NULL);
> What happens when you have more than one device in the system at the
> same time?

I'm sorry I didn't understand the question. We would have separate directories
for all the ports which would contain the 'iom_status' file, thus representing
status for all the ports individually.
Can you rephrase the question since I guess you had something else in mind?

Thanks
Rajat

> thanks,
>
> greg k-h