linux-kernel - Re: [PATCH 3/3] phy: zynqmp: Add debugfs support

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Message-ID: <c5b749c4-5277-46f9-8218-a56e63dc9028@linux.dev>
Date: Mon, 6 May 2024 10:51:38 -0400
From: Sean Anderson <sean.anderson@...ux.dev>
To: Vinod Koul <vkoul@...nel.org>
Cc: Laurent Pinchart <laurent.pinchart@...asonboard.com>,
 linux-phy@...ts.infradead.org, linux-kernel@...r.kernel.org,
 Michal Simek <michal.simek@....com>, linux-arm-kernel@...ts.infradead.org,
 Kishon Vijay Abraham I <kishon@...nel.org>
Subject: Re: [PATCH 3/3] phy: zynqmp: Add debugfs support

On 5/4/24 07:58, Vinod Koul wrote:
> On 22-04-24, 14:58, Sean Anderson wrote:
>> Add support for printing some basic status information to debugfs. This
>> is helpful when debugging phy consumers to make sure they are configuring
>> the phy appropriately.
>> 
>> Signed-off-by: Sean Anderson <sean.anderson@...ux.dev>
>> ---
>> 
>>  drivers/phy/xilinx/phy-zynqmp.c | 54 +++++++++++++++++++++++++++++++++
>>  1 file changed, 54 insertions(+)
>> 
>> diff --git a/drivers/phy/xilinx/phy-zynqmp.c b/drivers/phy/xilinx/phy-zynqmp.c
>> index 08c88dcd7799..e2e86943e9f3 100644
>> --- a/drivers/phy/xilinx/phy-zynqmp.c
>> +++ b/drivers/phy/xilinx/phy-zynqmp.c
>> @@ -13,6 +13,7 @@
>>   */
>>  
>>  #include <linux/clk.h>
>> +#include <linux/debugfs.h>
>>  #include <linux/delay.h>
>>  #include <linux/io.h>
>>  #include <linux/kernel.h>
>> @@ -122,6 +123,15 @@
>>  #define ICM_PROTOCOL_DP			0x4
>>  #define ICM_PROTOCOL_SGMII		0x5
>>  
>> +static const char *const xpsgtr_icm_str[] = {
>> +	[ICM_PROTOCOL_PD] = "powered down",
>> +	[ICM_PROTOCOL_PCIE] = "PCIe",
>> +	[ICM_PROTOCOL_SATA] = "SATA",
>> +	[ICM_PROTOCOL_USB] = "USB",
>> +	[ICM_PROTOCOL_DP] = "DisplayPort",
>> +	[ICM_PROTOCOL_SGMII] = "SGMII",
>> +};
>> +
>>  /* Test Mode common reset control  parameters */
>>  #define TM_CMN_RST			0x10018
>>  #define TM_CMN_RST_EN			0x1
>> @@ -768,6 +778,48 @@ static struct phy *xpsgtr_xlate(struct device *dev,
>>  	return ERR_PTR(-EINVAL);
>>  }
>>  
>> +/*
>> + * DebugFS
>> + */
>> +
>> +static int xpsgtr_status_read(struct seq_file *seq, void *data)
>> +{
>> +	struct xpsgtr_phy *gtr_phy = seq->private;
>> +	struct clk *clk;
>> +	u32 pll_status;
>> +
>> +	mutex_lock(&gtr_phy->phy->mutex);
>> +	pll_status = xpsgtr_read_phy(gtr_phy, L0_PLL_STATUS_READ_1);
>> +	clk = gtr_phy->dev->clk[gtr_phy->refclk];
>> +
>> +	seq_printf(seq, "Lane:            %u\n", gtr_phy->lane);
>> +	seq_printf(seq, "Protocol:        %s\n",
>> +		   xpsgtr_icm_str[gtr_phy->protocol]);
>> +	seq_printf(seq, "Instance:        %u\n", gtr_phy->instance);
>> +	seq_printf(seq, "Reference clock: %u (%pC)\n", gtr_phy->refclk, clk);
>> +	seq_printf(seq, "Reference rate:  %lu\n", clk_get_rate(clk));
>> +	seq_printf(seq, "PLL locked:      %s\n",
>> +		   pll_status & PLL_STATUS_LOCKED ? "yes" : "no");
>> +
>> +	mutex_unlock(&gtr_phy->phy->mutex);
>> +	return 0;
>> +}
>> +
>> +static int xpsgtr_status_open(struct inode *inode, struct file *f)
>> +{
>> +	struct xpsgtr_phy *gtr_phy = inode->i_private;
>> +
>> +	return single_open(f, xpsgtr_status_read, gtr_phy);
>> +}
>> +
>> +static const struct file_operations xpsgtr_status_ops = {
>> +	.owner = THIS_MODULE,
>> +	.open = xpsgtr_status_open,
>> +	.release = single_release,
>> +	.read = seq_read,
>> +	.llseek = seq_lseek
>> +};
> 
> There are debugfs simple helpers which should help you avoid all this
> open coding and just have the read call

I assume you mean debugfs_create_devm_seqfile.

>> +
>>  /*
>>   * Power Management
>>   */
>> @@ -917,6 +969,8 @@ static int xpsgtr_probe(struct platform_device *pdev)
>>  
>>  		gtr_phy->phy = phy;
>>  		phy_set_drvdata(phy, gtr_phy);
>> +		debugfs_create_file("status", 0444, phy->debugfs, gtr_phy,
>> +				    &xpsgtr_status_ops);
> 
> generic status does not make sense, how about device-name-status

This file lives in the phy's debugfs directory already. The full path is

/sys/kernel/debug/phy/phy-fd400000.phy.0/status

so there is no need to add the phy name yet again.

--Sean