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

Rajat Khandelwal
2023-04-17T05:58:59Z

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@linux.intel.com>
>> ---
>>
>> 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