Date:   Mon, 28 Nov 2022 07:26:02 +0000
From:   Chunfeng Yun (云春峰) 
        <Chunfeng.Yun@...iatek.com>
To:     "vkoul@...nel.org" <vkoul@...nel.org>
CC:     "llvm@...ts.linux.dev" <llvm@...ts.linux.dev>,
        "linux-mediatek@...ts.infradead.org" 
        <linux-mediatek@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "nathan@...nel.org" <nathan@...nel.org>,
        "kishon@...com" <kishon@...com>,
        Eddie Hung (洪正鑫) 
        <Eddie.Hung@...iatek.com>,
        Tianping Fang (方天平) 
        <Tianping.Fang@...iatek.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "matthias.bgg@...il.com" <matthias.bgg@...il.com>,
        "linux-phy@...ts.infradead.org" <linux-phy@...ts.infradead.org>,
        "trix@...hat.com" <trix@...hat.com>,
        "angelogioacchino.delregno@...labora.com" 
        <angelogioacchino.delregno@...labora.com>,
        "ndesaulniers@...gle.com" <ndesaulniers@...gle.com>
Subject: Re: [PATCH v4 3/3] phy: mediatek: tphy: add debugfs files

On Thu, 2022-11-24 at 23:17 +0530, Vinod Koul wrote:
> On 10-11-22, 21:27, Chunfeng Yun wrote:
> > These debugfs files are mainly used to make eye diagram test
> > easier,
> > especially helpful to do HQA test for a new IC without efuse
> > enabled.
> > 
> > Signed-off-by: Chunfeng Yun <chunfeng.yun@...iatek.com>
> > ---
> > v4: fix build warning of sometimes uninitialized variable
> > 
> > v3: fix typo of "debugfs" suggested by AngeloGioacchino
> > 
> > v2: add CONFIG_PHY_MTK_TPHY_DEBUGFS suggested by AngeloGioacchino
> > ---
> >  drivers/phy/mediatek/Kconfig        |   5 +
> >  drivers/phy/mediatek/phy-mtk-tphy.c | 405
> > +++++++++++++++++++++++++++-
> >  2 files changed, 409 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/phy/mediatek/Kconfig
> > b/drivers/phy/mediatek/Kconfig
> > index 3125ecb5d119..e9fdfe9f519f 100644
> > --- a/drivers/phy/mediatek/Kconfig
> > +++ b/drivers/phy/mediatek/Kconfig
> > @@ -27,6 +27,11 @@ config PHY_MTK_TPHY
> >  	  multi-ports is first version, otherwise is second version,
> >  	  so you can easily distinguish them by banks layout.
> >  
> > +config PHY_MTK_TPHY_DEBUGFS
> > +	bool "Add T-PHY Debugfs Files"
> > +	help
> > +	  Say Y here to add debugfs files mainly for T-PHY HQA test.
> 
> Why do we need a config option for this, is debugfs config option not
> sufficient?
We may want to disable these files even debugfs config is enabled in
release image, and prefer to use them only when bring up new IC. 

> 
> > +
> >  config PHY_MTK_UFS
> >  	tristate "MediaTek UFS M-PHY driver"
> >  	depends on ARCH_MEDIATEK || COMPILE_TEST
> > diff --git a/drivers/phy/mediatek/phy-mtk-tphy.c
> > b/drivers/phy/mediatek/phy-mtk-tphy.c
> > index e906a82791bd..f220a9a409bf 100644
> > --- a/drivers/phy/mediatek/phy-mtk-tphy.c
> > +++ b/drivers/phy/mediatek/phy-mtk-tphy.c
> > @@ -7,6 +7,7 @@
> >  
> >  #include <dt-bindings/phy/phy.h>
> >  #include <linux/clk.h>
> > +#include <linux/debugfs.h>
> >  #include <linux/delay.h>
> >  #include <linux/iopoll.h>
> >  #include <linux/mfd/syscon.h>
> > @@ -264,6 +265,8 @@
> >  
> >  #define TPHY_CLKS_CNT	2
> >  
> > +#define USER_BUF_LEN(count) min_t(size_t, 8, (count))
> > +
> >  enum mtk_phy_version {
> >  	MTK_PHY_V1 = 1,
> >  	MTK_PHY_V2,
> > @@ -310,6 +313,7 @@ struct mtk_phy_instance {
> >  	struct clk_bulk_data clks[TPHY_CLKS_CNT];
> >  	u32 index;
> >  	u32 type;
> > +	struct dentry *dbgfs;
> >  	struct regmap *type_sw;
> >  	u32 type_sw_reg;
> >  	u32 type_sw_index;
> > @@ -332,10 +336,391 @@ struct mtk_tphy {
> >  	const struct mtk_phy_pdata *pdata;
> >  	struct mtk_phy_instance **phys;
> >  	int nphys;
> > +	struct dentry *dbgfs_root;
> >  	int src_ref_clk; /* MHZ, reference clock for slew rate
> > calibrate */
> >  	int src_coef; /* coefficient for slew rate calibrate */
> >  };
> >  
> > +#if IS_ENABLED(CONFIG_PHY_MTK_TPHY_DEBUGFS)
> > +
> > +enum u2_phy_params {
> > +	U2P_EYE_VRT = 0,
> > +	U2P_EYE_TERM,
> > +	U2P_EFUSE_EN,
> > +	U2P_EFUSE_INTR,
> > +	U2P_DISCTH,
> > +	U2P_PRE_EMPHASIS,
> > +};
> > +
> > +enum u3_phy_params {
> > +	U3P_EFUSE_EN = 0,
> > +	U3P_EFUSE_INTR,
> > +	U3P_EFUSE_TX_IMP,
> > +	U3P_EFUSE_RX_IMP,
> > +};
> > +
> > +static const char *const u2_phy_files[] = {
> > +	[U2P_EYE_VRT] = "vrt",
> > +	[U2P_EYE_TERM] = "term",
> > +	[U2P_EFUSE_EN] = "efuse",
> > +	[U2P_EFUSE_INTR] = "intr",
> > +	[U2P_DISCTH] = "discth",
> > +	[U2P_PRE_EMPHASIS] = "preemph",
> > +};
> > +
> > +static const char *const u3_phy_files[] = {
> > +	[U3P_EFUSE_EN] = "efuse",
> > +	[U3P_EFUSE_INTR] = "intr",
> > +	[U3P_EFUSE_TX_IMP] = "tx-imp",
> > +	[U3P_EFUSE_RX_IMP] = "rx-imp",
> > +};
> > +
> > +static int u2_phy_params_show(struct seq_file *sf, void *unused)
> > +{
> > +	struct mtk_phy_instance *inst = sf->private;
> > +	const char *fname = file_dentry(sf->file)->d_iname;
> > +	struct u2phy_banks *u2_banks = &inst->u2_banks;
> > +	void __iomem *com = u2_banks->com;
> > +	u32 max = 0;
> > +	u32 tmp = 0;
> > +	u32 val = 0;
> > +	int ret;
> > +
> > +	ret = match_string(u2_phy_files, ARRAY_SIZE(u2_phy_files),
> > fname);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	switch (ret) {
> > +	case U2P_EYE_VRT:
> > +		tmp = readl(com + U3P_USBPHYACR1);
> > +		val = FIELD_GET(PA1_RG_VRT_SEL, tmp);
> > +		max = FIELD_MAX(PA1_RG_VRT_SEL);
> > +		break;
> > +
> > +	case U2P_EYE_TERM:
> > +		tmp = readl(com + U3P_USBPHYACR1);
> > +		val = FIELD_GET(PA1_RG_TERM_SEL, tmp);
> > +		max = FIELD_MAX(PA1_RG_TERM_SEL);
> > +		break;
> > +
> > +	case U2P_EFUSE_EN:
> > +		if (u2_banks->misc) {
> > +			tmp = readl(u2_banks->misc + U3P_MISC_REG1);
> > +			max = 1;
> > +		}
> > +
> > +		val = !!(tmp & MR1_EFUSE_AUTO_LOAD_DIS);
> > +		break;
> > +
> > +	case U2P_EFUSE_INTR:
> > +		tmp = readl(com + U3P_USBPHYACR1);
> > +		val = FIELD_GET(PA1_RG_INTR_CAL, tmp);
> > +		max = FIELD_MAX(PA1_RG_INTR_CAL);
> > +		break;
> > +
> > +	case U2P_DISCTH:
> > +		tmp = readl(com + U3P_USBPHYACR6);
> > +		val = FIELD_GET(PA6_RG_U2_DISCTH, tmp);
> > +		max = FIELD_MAX(PA6_RG_U2_DISCTH);
> > +		break;
> > +
> > +	case U2P_PRE_EMPHASIS:
> > +		tmp = readl(com + U3P_USBPHYACR6);
> > +		val = FIELD_GET(PA6_RG_U2_PRE_EMP, tmp);
> > +		max = FIELD_MAX(PA6_RG_U2_PRE_EMP);
> > +		break;
> > +
> > +	default:
> > +		seq_printf(sf, "invalid, %d\n", ret);
> > +		break;
> > +	}
> > +
> > +	seq_printf(sf, "%s : %d [0, %d]\n", fname, val, max);
> > +
> > +	return 0;
> > +}
> > +
> > +static int u2_phy_params_open(struct inode *inode, struct file
> > *file)
> > +{
> > +	return single_open(file, u2_phy_params_show, inode->i_private);
> > +}
> > +
> > +static ssize_t u2_phy_params_write(struct file *file, const char
> > __user *ubuf,
> > +				   size_t count, loff_t *ppos)
> 
> so are we writing to phy registers from userspace, why?
Mainly because when bring up a new ic which efuse is not set, we need
to tune some parameters many times for eye diagram test, using debugfs
files will make it easier at runtime.

Thanks a lot

> 
> > +{
> > +	const char *fname = file_dentry(file)->d_iname;
> > +	struct seq_file *sf = file->private_data;
> > +	struct mtk_phy_instance *inst = sf->private;
> > +	struct u2phy_banks *u2_banks = &inst->u2_banks;
> > +	void __iomem *com = u2_banks->com;
> > +	ssize_t rc;
> > +	u32 val;
> > +	int ret;
> > +
> > +	rc = kstrtouint_from_user(ubuf, USER_BUF_LEN(count), 0, &val);
> > +	if (rc)
> > +		return rc;
> > +
> > +	ret = match_string(u2_phy_files, ARRAY_SIZE(u2_phy_files),
> > fname);
> > +	if (ret < 0)
> > +		return (ssize_t)ret;
> > +
> > +	switch (ret) {
> > +	case U2P_EYE_VRT:
> > +		mtk_phy_update_field(com + U3P_USBPHYACR1,
> > PA1_RG_VRT_SEL, val);
> > +		break;
> > +
> > +	case U2P_EYE_TERM:
> > +		mtk_phy_update_field(com + U3P_USBPHYACR1,
> > PA1_RG_TERM_SEL, val);
> > +		break;
> > +
> > +	case U2P_EFUSE_EN:
> > +		if (u2_banks->misc)
> > +			mtk_phy_update_field(u2_banks->misc +
> > U3P_MISC_REG1,
> > +					     MR1_EFUSE_AUTO_LOAD_DIS,
> > !!val);
> > +		break;
> > +
> > +	case U2P_EFUSE_INTR:
> > +		mtk_phy_update_field(com + U3P_USBPHYACR1,
> > PA1_RG_INTR_CAL, val);
> > +		break;
> > +
> > +	case U2P_DISCTH:
> > +		mtk_phy_update_field(com + U3P_USBPHYACR6,
> > PA6_RG_U2_DISCTH, val);
> > +		break;
> > +
> > +	case U2P_PRE_EMPHASIS:
> > +		mtk_phy_update_field(com + U3P_USBPHYACR6,
> > PA6_RG_U2_PRE_EMP, val);
> > +		break;
> > +
> > +	default:
> > +		break;
> > +	}
> > +
> > +	return count;
> > +}
> > +
> > +static const struct file_operations u2_phy_fops = {
> > +	.open = u2_phy_params_open,
> > +	.write = u2_phy_params_write,
> > +	.read = seq_read,
> > +	.llseek = seq_lseek,
> > +	.release = single_release,
> > +};
> > +
> > +static void u2_phy_dbgfs_files_create(struct mtk_phy_instance
> > *inst)
> > +{
> > +	u32 count = ARRAY_SIZE(u2_phy_files);
> > +	int i;
> > +
> > +	for (i = 0; i < count; i++)
> > +		debugfs_create_file(u2_phy_files[i], 0644, inst->dbgfs, 
> > inst, &u2_phy_fops);
> 
> pls use 
> > +}
> > +
> > +static int u3_phy_params_show(struct seq_file *sf, void *unused)
> > +{
> > +	struct mtk_phy_instance *inst = sf->private;
> > +	const char *fname = file_dentry(sf->file)->d_iname;
> > +	struct u3phy_banks *u3_banks = &inst->u3_banks;
> > +	u32 val = 0;
> > +	u32 max = 0;
> > +	u32 tmp;
> > +	int ret;
> > +
> > +	ret = match_string(u3_phy_files, ARRAY_SIZE(u3_phy_files),
> > fname);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	switch (ret) {
> > +	case U3P_EFUSE_EN:
> > +		tmp = readl(u3_banks->phyd + U3P_U3_PHYD_RSV);
> > +		val = !!(tmp & P3D_RG_EFUSE_AUTO_LOAD_DIS);
> > +		max = 1;
> > +		break;
> > +
> > +	case U3P_EFUSE_INTR:
> > +		tmp = readl(u3_banks->phya + U3P_U3_PHYA_REG0);
> > +		val = FIELD_GET(P3A_RG_IEXT_INTR, tmp);
> > +		max = FIELD_MAX(P3A_RG_IEXT_INTR);
> > +		break;
> > +
> > +	case U3P_EFUSE_TX_IMP:
> > +		tmp = readl(u3_banks->phyd + U3P_U3_PHYD_IMPCAL0);
> > +		val = FIELD_GET(P3D_RG_TX_IMPEL, tmp);
> > +		max = FIELD_MAX(P3D_RG_TX_IMPEL);
> > +		break;
> > +
> > +	case U3P_EFUSE_RX_IMP:
> > +		tmp = readl(u3_banks->phyd + U3P_U3_PHYD_IMPCAL1);
> > +		val = FIELD_GET(P3D_RG_RX_IMPEL, tmp);
> > +		max = FIELD_MAX(P3D_RG_RX_IMPEL);
> > +		break;
> > +
> > +	default:
> > +		seq_printf(sf, "invalid, %d\n", ret);
> > +		break;
> > +	}
> > +
> > +	seq_printf(sf, "%s : %d [0, %d]\n", fname, val, max);
> > +
> > +	return 0;
> > +}
> > +
> > +static int u3_phy_params_open(struct inode *inode, struct file
> > *file)
> > +{
> > +	return single_open(file, u3_phy_params_show, inode->i_private);
> > +}
> > +
> > +static ssize_t u3_phy_params_write(struct file *file, const char
> > __user *ubuf,
> > +				   size_t count, loff_t *ppos)
> > +{
> > +	const char *fname = file_dentry(file)->d_iname;
> > +	struct seq_file *sf = file->private_data;
> > +	struct mtk_phy_instance *inst = sf->private;
> > +	struct u3phy_banks *u3_banks = &inst->u3_banks;
> > +	void __iomem *phyd = u3_banks->phyd;
> > +	ssize_t rc;
> > +	u32 val;
> > +	int ret;
> > +
> > +	rc = kstrtouint_from_user(ubuf, USER_BUF_LEN(count), 0, &val);
> > +	if (rc)
> > +		return rc;
> > +
> > +	ret = match_string(u3_phy_files, ARRAY_SIZE(u3_phy_files),
> > fname);
> > +	if (ret < 0)
> > +		return (ssize_t)ret;
> > +
> > +	switch (ret) {
> > +	case U3P_EFUSE_EN:
> > +		mtk_phy_update_field(phyd + U3P_U3_PHYD_RSV,
> > +				     P3D_RG_EFUSE_AUTO_LOAD_DIS,
> > !!val);
> > +		break;
> > +
> > +	case U3P_EFUSE_INTR:
> > +		mtk_phy_update_field(u3_banks->phya + U3P_U3_PHYA_REG0,
> > P3A_RG_IEXT_INTR, val);
> > +		break;
> > +
> > +	case U3P_EFUSE_TX_IMP:
> > +		mtk_phy_update_field(phyd + U3P_U3_PHYD_IMPCAL0,
> > P3D_RG_TX_IMPEL, val);
> > +		mtk_phy_set_bits(phyd + U3P_U3_PHYD_IMPCAL0,
> > P3D_RG_FORCE_TX_IMPEL);
> > +		break;
> > +
> > +	case U3P_EFUSE_RX_IMP:
> > +		mtk_phy_update_field(phyd + U3P_U3_PHYD_IMPCAL1,
> > P3D_RG_RX_IMPEL, val);
> > +		mtk_phy_set_bits(phyd + U3P_U3_PHYD_IMPCAL1,
> > P3D_RG_FORCE_RX_IMPEL);
> > +		break;
> > +
> > +	default:
> > +		break;
> > +	}
> > +
> > +	return count;
> > +}
> > +
> > +static const struct file_operations u3_phy_fops = {
> > +	.open = u3_phy_params_open,
> > +	.write = u3_phy_params_write,
> > +	.read = seq_read,
> > +	.llseek = seq_lseek,
> > +	.release = single_release,
> > +};
> > +
> > +static void u3_phy_dbgfs_files_create(struct mtk_phy_instance
> > *inst)
> > +{
> > +	u32 count = ARRAY_SIZE(u3_phy_files);
> > +	int i;
> > +
> > +	for (i = 0; i < count; i++)
> > +		debugfs_create_file(u3_phy_files[i], 0644, inst->dbgfs, 
> > inst, &u3_phy_fops);
> > +}
> > +
> > +static int tphy_type_show(struct seq_file *sf, void *unused)
> > +{
> > +	struct mtk_phy_instance *inst = sf->private;
> > +	const char *type;
> > +
> > +	switch (inst->type) {
> > +	case PHY_TYPE_USB2:
> > +		type = "USB2";
> > +		break;
> > +	case PHY_TYPE_USB3:
> > +		type = "USB3";
> > +		break;
> > +	case PHY_TYPE_PCIE:
> > +		type = "PCIe";
> > +		break;
> > +	case PHY_TYPE_SGMII:
> > +		type = "SGMII";
> > +		break;
> > +	case PHY_TYPE_SATA:
> > +		type = "SATA";
> > +		break;
> > +	default:
> > +		type = "";
> > +	}
> > +
> > +	seq_printf(sf, "%s\n", type);
> > +
> > +	return 0;
> > +}
> > +
> > +DEFINE_SHOW_ATTRIBUTE(tphy_type);
> > +
> > +static void tphy_debugfs_init(struct mtk_tphy *tphy, struct
> > mtk_phy_instance *inst)
> > +{
> > +	char name[16];
> > +
> > +	snprintf(name, sizeof(name) - 1, "phy.%d", inst->index);
> > +	inst->dbgfs = debugfs_create_dir(name, tphy->dbgfs_root);
> > +
> > +	debugfs_create_file("type", 0444, inst->dbgfs, inst,
> > &tphy_type_fops);
> > +
> > +	switch (inst->type) {
> > +	case PHY_TYPE_USB2:
> > +		u2_phy_dbgfs_files_create(inst);
> > +		break;
> > +	case PHY_TYPE_USB3:
> > +	case PHY_TYPE_PCIE:
> > +		u3_phy_dbgfs_files_create(inst);
> > +		break;
> > +	default:
> > +		break;
> > +	}
> > +}
> > +
> > +static void tphy_debugfs_exit(struct mtk_phy_instance *inst)
> > +{
> > +	debugfs_remove_recursive(inst->dbgfs);
> > +	inst->dbgfs = NULL;
> > +}
> > +
> > +static void tphy_debugfs_root_create(struct mtk_tphy *tphy)
> > +{
> > +	tphy->dbgfs_root = debugfs_create_dir(dev_name(tphy->dev),
> > phy_debug_root);
> > +}
> > +
> > +static void tphy_debugfs_root_remove(struct mtk_tphy *tphy)
> > +{
> > +	debugfs_remove_recursive(tphy->dbgfs_root);
> > +	tphy->dbgfs_root = NULL;
> > +}
> > +
> > +#else
> > +
> > +static void tphy_debugfs_init(struct mtk_tphy *tphy, struct
> > mtk_phy_instance *inst)
> > +{}
> > +
> > +static void tphy_debugfs_exit(struct mtk_phy_instance *inst)
> > +{}
> > +
> > +static void tphy_debugfs_root_create(struct mtk_tphy *tphy)
> > +{}
> > +
> > +static void tphy_debugfs_root_remove(struct mtk_tphy *tphy)
> > +{}
> > +
> > +#endif
> > +
> >  static void hs_slew_rate_calibrate(struct mtk_tphy *tphy,
> >  	struct mtk_phy_instance *instance)
> >  {
> > @@ -1032,6 +1417,8 @@ static int mtk_phy_init(struct phy *phy)
> >  		return -EINVAL;
> >  	}
> >  
> > +	tphy_debugfs_init(tphy, instance);
> > +
> >  	return 0;
> >  }
> >  
> > @@ -1068,6 +1455,8 @@ static int mtk_phy_exit(struct phy *phy)
> >  	struct mtk_phy_instance *instance = phy_get_drvdata(phy);
> >  	struct mtk_tphy *tphy = dev_get_drvdata(phy->dev.parent);
> >  
> > +	tphy_debugfs_exit(instance);
> > +
> >  	if (instance->type == PHY_TYPE_USB2)
> >  		u2_phy_instance_exit(tphy, instance);
> >  
> > @@ -1295,15 +1684,29 @@ static int mtk_tphy_probe(struct
> > platform_device *pdev)
> >  	}
> >  
> >  	provider = devm_of_phy_provider_register(dev, mtk_phy_xlate);
> > +	if (IS_ERR(provider))
> > +		return dev_err_probe(dev, PTR_ERR(provider), "probe
> > failed\n");
> > +
> > +	tphy_debugfs_root_create(tphy);
> > +	return 0;
> >  
> > -	return PTR_ERR_OR_ZERO(provider);
> >  put_child:
> >  	of_node_put(child_np);
> >  	return retval;
> >  }
> >  
> > +static int mtk_tphy_remove(struct platform_device *pdev)
> > +{
> > +	struct mtk_tphy *tphy;
> > +
> > +	tphy = platform_get_drvdata(pdev);
> > +	tphy_debugfs_root_remove(tphy);
> > +	return 0;
> > +}
> > +
> >  static struct platform_driver mtk_tphy_driver = {
> >  	.probe		= mtk_tphy_probe,
> > +	.remove		= mtk_tphy_remove,
> >  	.driver		= {
> >  		.name	= "mtk-tphy",
> >  		.of_match_table = mtk_tphy_id_table,
> > -- 
> > 2.18.0
> 
> 

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