linux-kernel - RE: [PATCH v2 4/4] phy: zynqmp: Add debugfs support

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Date: Thu, 13 Jun 2024 09:20:41 +0000
From: "Pandey, Radhey Shyam" <radhey.shyam.pandey@....com>
To: Sean Anderson <sean.anderson@...ux.dev>, Laurent Pinchart
	<laurent.pinchart@...asonboard.com>, "linux-phy@...ts.infradead.org"
	<linux-phy@...ts.infradead.org>
CC: Vinod Koul <vkoul@...nel.org>, "linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "Simek, Michal" <michal.simek@....com>,
	Kishon Vijay Abraham I <kishon@...nel.org>
Subject: RE: [PATCH v2 4/4] phy: zynqmp: Add debugfs support

> -----Original Message-----
> From: Sean Anderson <sean.anderson@...ux.dev>
> Sent: Monday, May 6, 2024 10:31 PM
> To: Laurent Pinchart <laurent.pinchart@...asonboard.com>; linux-
> phy@...ts.infradead.org
> Cc: Vinod Koul <vkoul@...nel.org>; linux-arm-kernel@...ts.infradead.org;
> linux-kernel@...r.kernel.org; Michal Simek <michal.simek@....com>;
> Kishon Vijay Abraham I <kishon@...nel.org>; Sean Anderson
> <sean.anderson@...ux.dev>
> Subject: [PATCH v2 4/4] phy: zynqmp: Add debugfs support
> 
> 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>
> ---
> 
> Changes in v2:
> - Use debugfs_create_devm_seqfile
> 
>  drivers/phy/xilinx/phy-zynqmp.c | 40
> +++++++++++++++++++++++++++++++++
>  1 file changed, 40 insertions(+)
> 
> diff --git a/drivers/phy/xilinx/phy-zynqmp.c b/drivers/phy/xilinx/phy-
> zynqmp.c
> index b86fe2a249a8..2520c75a4a77 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>
> @@ -123,6 +124,15 @@
>  #define ICM_PROTOCOL_DP			0x4
>  #define ICM_PROTOCOL_SGMII		0x5
> 
> +static const char *const xpsgtr_icm_str[] = {
> +	[ICM_PROTOCOL_PD] = "powered down",

Protocol saying powered down seems confusing.
Should we say None or None(power 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
> @@ -788,6 +798,34 @@ 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 device *dev = seq->private;
> +	struct xpsgtr_phy *gtr_phy = dev_get_drvdata(dev);
> +	struct clk *clk;
> +	u32 pll_status;
> +
> +	mutex_lock(&gtr_phy->phy->mutex);

Do we see any need for this lock? This function simply read hw register 
/phy members and decodes it.

> +	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;
> +}
> +
>  /*
>   * Power Management
>   */
> @@ -937,6 +975,8 @@ static int xpsgtr_probe(struct platform_device *pdev)
> 
>  		gtr_phy->phy = phy;
>  		phy_set_drvdata(phy, gtr_phy);
> +		debugfs_create_devm_seqfile(&phy->dev, "status", phy-
> >debugfs,
> +					    xpsgtr_status_read);
>  	}
> 
>  	/* Register the PHY provider. */
> --
> 2.35.1.1320.gc452695387.dirty