Date:	Tue, 17 Nov 2015 13:41:11 +0530
From:	Alim Akhtar <alim.akhtar@...sung.com>
To:	Kishon Vijay Abraham I <kishon@...com>, linux-scsi@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc:	JBottomley@...n.com, vinholikatti@...il.com,
	gautam.vivek@...sung.com, essuuj@...il.com,
	devicetree@...r.kernel.org
Subject: Re: [PATCH v5 02/11] phy: exynos-ufs: add UFS PHY driver for EXYNOS SoC

Hi
Thanks again for looking into this.

On 11/17/2015 11:46 AM, Kishon Vijay Abraham I wrote:
> Hi,
>
> On Monday 09 November 2015 10:56 AM, Alim Akhtar wrote:
>> From: Seungwon Jeon <essuuj@...il.com>
>>
>> This patch introduces Exynos UFS PHY driver. This driver
>> supports to deal with phy calibration and power control
>> according to UFS host driver's behavior.
>>
>> Signed-off-by: Seungwon Jeon <essuuj@...il.com>
>> Signed-off-by: Alim Akhtar <alim.akhtar@...sung.com>
>> Cc: Kishon Vijay Abraham I <kishon@...com>
>> ---
>>   drivers/phy/Kconfig                |    7 ++
>>   drivers/phy/Makefile               |    1 +
>>   drivers/phy/phy-exynos-ufs.c       |  241 ++++++++++++++++++++++++++++++++++++
>>   drivers/phy/phy-exynos-ufs.h       |   85 +++++++++++++
>>   drivers/phy/phy-exynos7-ufs.h      |   89 +++++++++++++
>>   include/linux/phy/phy-exynos-ufs.h |   85 +++++++++++++
>>   6 files changed, 508 insertions(+)
>>   create mode 100644 drivers/phy/phy-exynos-ufs.c
>>   create mode 100644 drivers/phy/phy-exynos-ufs.h
>>   create mode 100644 drivers/phy/phy-exynos7-ufs.h
>>   create mode 100644 include/linux/phy/phy-exynos-ufs.h
>>
>> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
>> index 7eb5859dd035..7d38a92e0297 100644
>> --- a/drivers/phy/Kconfig
>> +++ b/drivers/phy/Kconfig
>> @@ -389,4 +389,11 @@ config PHY_CYGNUS_PCIE
>>   	  Enable this to support the Broadcom Cygnus PCIe PHY.
>>   	  If unsure, say N.
>>
>> +config PHY_EXYNOS_UFS
>> +	tristate "EXYNOS SoC series UFS PHY driver"
>> +	depends on OF && ARCH_EXYNOS || COMPILE_TEST
>> +	select GENERIC_PHY
>> +	help
>> +	  Support for UFS PHY on Samsung EXYNOS chipsets.
>> +
>>   endmenu
>> diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
>> index 075db1a81aa5..9bec4d1a89e1 100644
>> --- a/drivers/phy/Makefile
>> +++ b/drivers/phy/Makefile
>> @@ -10,6 +10,7 @@ obj-$(CONFIG_ARMADA375_USBCLUSTER_PHY)	+= phy-armada375-usb2.o
>>   obj-$(CONFIG_BCM_KONA_USB2_PHY)		+= phy-bcm-kona-usb2.o
>>   obj-$(CONFIG_PHY_EXYNOS_DP_VIDEO)	+= phy-exynos-dp-video.o
>>   obj-$(CONFIG_PHY_EXYNOS_MIPI_VIDEO)	+= phy-exynos-mipi-video.o
>> +obj-$(CONFIG_PHY_EXYNOS_UFS)	+= phy-exynos-ufs.o
>>   obj-$(CONFIG_PHY_LPC18XX_USB_OTG)	+= phy-lpc18xx-usb-otg.o
>>   obj-$(CONFIG_PHY_PXA_28NM_USB2)		+= phy-pxa-28nm-usb2.o
>>   obj-$(CONFIG_PHY_PXA_28NM_HSIC)		+= phy-pxa-28nm-hsic.o
>> diff --git a/drivers/phy/phy-exynos-ufs.c b/drivers/phy/phy-exynos-ufs.c
>> new file mode 100644
>> index 000000000000..cb1aeaa3d4eb
>> --- /dev/null
>> +++ b/drivers/phy/phy-exynos-ufs.c
>> @@ -0,0 +1,241 @@
>> +/*
>> + * UFS PHY driver for Samsung EXYNOS SoC
>> + *
>> + * Copyright (C) 2015 Samsung Electronics Co., Ltd.
>> + * Author: Seungwon Jeon <essuuj@...il.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + */
>> +#include <linux/clk.h>
>> +#include <linux/delay.h>
>> +#include <linux/err.h>
>> +#include <linux/io.h>
>> +#include <linux/iopoll.h>
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/phy/phy.h>
>> +#include <linux/phy/phy-exynos-ufs.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/regmap.h>
>> +
>> +#include "phy-exynos-ufs.h"
>> +
>> +#define for_each_phy_lane(phy, i) \
>> +	for (i = 0; i < (phy)->lane_cnt; i++)
>> +#define for_each_phy_cfg(cfg) \
>> +	for (; (cfg)->id; (cfg)++)
>> +
>> +#define PHY_DEF_LANE_CNT	1
>> +
>> +static void exynos_ufs_phy_config(struct exynos_ufs_phy *phy,
>> +			const struct exynos_ufs_phy_cfg *cfg, u8 lane)
>> +{
>> +	enum {LANE_0, LANE_1}; /* lane index */
>> +
>> +	switch (lane) {
>> +	case LANE_0:
>> +		writel(cfg->val, (phy)->reg_pma + cfg->off_0);
>> +		break;
>> +	case LANE_1:
>> +		if (cfg->id == PHY_TRSV_BLK)
>> +			writel(cfg->val, (phy)->reg_pma + cfg->off_1);
>> +		break;
>> +	}
>> +}
>> +
>> +static bool match_cfg_to_pwr_mode(u8 desc, u8 required_pwr)
>> +{
>> +	if (IS_PWR_MODE_ANY(desc))
>> +		return true;
>> +
>> +	if (IS_PWR_MODE_HS(required_pwr) && IS_PWR_MODE_HS_ANY(desc))
>> +		return true;
>> +
>> +	if (COMP_PWR_MODE(required_pwr, desc))
>> +		return true;
>> +
>> +	if (COMP_PWR_MODE_MD(required_pwr, desc) &&
>> +	    COMP_PWR_MODE_GEAR(required_pwr, desc) &&
>> +	    COMP_PWR_MODE_SER(required_pwr, desc))
>> +		return true;
>> +
>> +	return false;
>> +}
>> +
>> +int exynos_ufs_phy_calibrate(struct phy *phy,
>> +				    enum phy_cfg_tag tag, u8 pwr)
>
> This is similar to the first version of your patch without EXPORT_SYMBOL.
>
> I think you have to create a new generic PHY_OPS for calibrate PHY while making
> sure that it is as generic as possible (which means calibrate_phy shouldn't
> have tag and pwr arguments or a strong justification as to why those arguments
> are required in a generic API).
I don't see the advantage to making this a generic phy_ops, this is 
exynos specific ufs-phy, please have a look at other implementations
drivers/phy/phy-qcom-ufs.c (which I belive mereged recently)
may be other vendors might come with there own implementation of phy.
I am using what is currently provided by the generic phy framework.
>> +{
>> +	struct exynos_ufs_phy *ufs_phy = get_exynos_ufs_phy(phy);
>> +	struct exynos_ufs_phy_cfg **cfgs = ufs_phy->cfg;
>> +	const struct exynos_ufs_phy_cfg *cfg;
>> +	int i;
>> +
>> +	if (unlikely(tag < CFG_PRE_INIT || tag >= CFG_TAG_MAX)) {
>> +		dev_err(ufs_phy->dev, "invalid phy config index %d\n", tag);
>> +		return -EINVAL;
>> +	}
>> +
>> +	cfg = cfgs[tag];
>> +	if (!cfg)
>> +		goto out;
>> +
>> +	for_each_phy_cfg(cfg) {
>> +		for_each_phy_lane(ufs_phy, i) {
>> +			if (match_cfg_to_pwr_mode(cfg->desc, pwr))
>> +				exynos_ufs_phy_config(ufs_phy, cfg, i);
>> +		}
>> +	}
>> +
>> +out:
>> +	return 0;
>> +}
>> +
>> +void exynos_ufs_phy_set_lane_cnt(struct phy *phy, u8 lane_cnt)
>
> why can't phy_set_bus_width be reused here?
Ah..I missed that, will take a look.
>> +{
>> +	struct exynos_ufs_phy *ufs_phy = get_exynos_ufs_phy(phy);
>> +
>> +	ufs_phy->lane_cnt = lane_cnt;
>> +}
>> +
>> +int exynos_ufs_phy_wait_for_lock_acq(struct phy *phy)
>> +{
>
> As I mentioned before the only interface to the PHY driver should be using PHY
> ops. So ideally the PHY driver should have only static functions.
>> +	struct exynos_ufs_phy *ufs_phy = get_exynos_ufs_phy(phy);
>> +	const unsigned int timeout_us = 100000;
>> +	const unsigned int sleep_us = 10;
>> +	u32 val;
>> +	int err;
>> +
>> +	err = readl_poll_timeout(
>> +			ufs_phy->reg_pma + PHY_APB_ADDR(PHY_PLL_LOCK_STATUS),
>> +			val, (val & PHY_PLL_LOCK_BIT), sleep_us, timeout_us);
>> +	if (err) {
>> +		dev_err(ufs_phy->dev,
>> +			"failed to get phy pll lock acquisition %d\n", err);
>> +		goto out;
>> +	}
>> +
>> +	err = readl_poll_timeout(
>> +			ufs_phy->reg_pma + PHY_APB_ADDR(PHY_CDR_LOCK_STATUS),
>> +			val, (val & PHY_CDR_LOCK_BIT), sleep_us, timeout_us);
>> +	if (err) {
>> +		dev_err(ufs_phy->dev,
>> +			"failed to get phy cdr lock acquisition %d\n", err);
>> +		goto out;
>> +	}
>> +
>> +out:
>> +	return err;
>> +}
>> +
>> +static int exynos_ufs_phy_power_on(struct phy *phy)
>> +{
>> +	struct exynos_ufs_phy *_phy = get_exynos_ufs_phy(phy);
>> +
>> +	exynos_ufs_phy_ctrl_isol(_phy, false);
>> +	return 0;
>> +}
>> +
>> +static int exynos_ufs_phy_power_off(struct phy *phy)
>> +{
>> +	struct exynos_ufs_phy *_phy = get_exynos_ufs_phy(phy);
>> +
>> +	exynos_ufs_phy_ctrl_isol(_phy, true);
>> +	return 0;
>> +}
>> +
>> +static struct phy_ops exynos_ufs_phy_ops = {
>> +	.power_on	= exynos_ufs_phy_power_on,
>> +	.power_off	= exynos_ufs_phy_power_off,
> .owner is required for phy_ops.
ok
>> +}
>> +;
>> +static const struct of_device_id exynos_ufs_phy_match[];
>> +
>> +static int exynos_ufs_phy_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	struct resource *res;
>> +	const struct of_device_id *match;
>> +	struct exynos_ufs_phy *phy;
>> +	struct phy *gen_phy;
>> +	struct phy_provider *phy_provider;
>> +	const struct exynos_ufs_phy_drvdata *drvdata;
>> +	int err = 0;
>> +
>> +	match = of_match_node(exynos_ufs_phy_match, dev->of_node);
>> +	if (!match) {
>> +		err = -EINVAL;
>> +		dev_err(dev, "failed to get match_node\n");
>> +		goto out;
>> +	}
>> +
>> +	phy = devm_kzalloc(dev, sizeof(*phy), GFP_KERNEL);
>> +	if (!phy) {
>> +		err = -ENOMEM;
>> +		goto out;
>> +	}
>> +
>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "phy-pma");
>> +	phy->reg_pma = devm_ioremap_resource(dev, res);
>> +	if (IS_ERR(phy->reg_pma)) {
>> +		err = PTR_ERR(phy->reg_pma);
>> +		goto out;
>> +	}
>> +
>> +	phy->reg_pmu = syscon_regmap_lookup_by_phandle(
>> +				dev->of_node, "samsung,pmu-syscon");
>> +	if (IS_ERR(phy->reg_pmu)) {
>> +		err = PTR_ERR(phy->reg_pmu);
>> +		dev_err(dev, "failed syscon remap for pmu\n");
>> +		goto out;
>> +	}
>> +
>> +	gen_phy = devm_phy_create(dev, NULL, &exynos_ufs_phy_ops);
>> +	if (IS_ERR(gen_phy)) {
>> +		err = PTR_ERR(gen_phy);
>> +		dev_err(dev, "failed to create PHY for ufs-phy\n");
>> +		goto out;
>> +	}
>> +
>> +	drvdata = match->data;
>> +	phy->dev = dev;
>> +	phy->drvdata = drvdata;
>> +	phy->cfg = (struct exynos_ufs_phy_cfg **)drvdata->cfg;
>> +	phy->isol = &drvdata->isol;
>> +	phy->lane_cnt = PHY_DEF_LANE_CNT;
>> +
>> +	phy_set_drvdata(gen_phy, phy);
>> +
>> +	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
>> +	if (IS_ERR(phy_provider)) {
>> +		err = PTR_ERR(phy_provider);
>> +		dev_err(dev, "failed to register phy-provider\n");
>> +		goto out;
>> +	}
>> +out:
>> +	return err;
>> +}
>> +
>> +static const struct of_device_id exynos_ufs_phy_match[] = {
>> +	{
>> +		.compatible = "samsung,exynos7-ufs-phy",
>> +		.data = &exynos7_ufs_phy,
>> +	},
>> +	{},
>> +};
>> +MODULE_DEVICE_TABLE(of, exynos_ufs_phy_match);
>> +
>> +static struct platform_driver exynos_ufs_phy_driver = {
>> +	.probe  = exynos_ufs_phy_probe,
>> +	.driver = {
>> +		.name = "exynos-ufs-phy",
>> +		.of_match_table = exynos_ufs_phy_match,
>> +	},
>> +};
>> +module_platform_driver(exynos_ufs_phy_driver);
>> +MODULE_DESCRIPTION("EXYNOS SoC UFS PHY Driver");
>> +MODULE_AUTHOR("Seungwon Jeon <essuuj@...il.com>");
>> +MODULE_LICENSE("GPL v2");
>> diff --git a/drivers/phy/phy-exynos-ufs.h b/drivers/phy/phy-exynos-ufs.h
>> new file mode 100644
>> index 000000000000..820d879f393c
>> --- /dev/null
>> +++ b/drivers/phy/phy-exynos-ufs.h
>> @@ -0,0 +1,85 @@
>> +/*
>> + * UFS PHY driver for Samsung EXYNOS SoC
>> + *
>> + * Copyright (C) 2015 Samsung Electronics Co., Ltd.
>> + * Author: Seungwon Jeon <essuuj@...il.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + */
>> +#ifndef _PHY_EXYNOS_UFS_
>> +#define _PHY_EXYNOS_UFS_
>> +
>> +#define PHY_COMN_BLK	1
>> +#define PHY_TRSV_BLK	2
>> +#define END_UFS_PHY_CFG { 0 }
>> +#define PHY_TRSV_CH_OFFSET	0x30
>> +#define PHY_APB_ADDR(off)	((off) << 2)
>> +
>> +#define PHY_COMN_REG_CFG(o, v, d) {	\
>> +	.off_0 = PHY_APB_ADDR((o)),	\
>> +	.off_1 = 0,		\
>> +	.val = (v),		\
>> +	.desc = (d),		\
>> +	.id = PHY_COMN_BLK,	\
>> +}
>> +
>> +#define PHY_TRSV_REG_CFG(o, v, d) {	\
>> +	.off_0 = PHY_APB_ADDR((o)),	\
>> +	.off_1 = PHY_APB_ADDR((o) + PHY_TRSV_CH_OFFSET),	\
>> +	.val = (v),		\
>> +	.desc = (d),		\
>> +	.id = PHY_TRSV_BLK,	\
>> +}
>> +
>> +/* UFS PHY registers */
>> +#define PHY_PLL_LOCK_STATUS	0x1e
>> +#define PHY_CDR_LOCK_STATUS	0x5e
>> +
>> +#define PHY_PLL_LOCK_BIT	BIT(5)
>> +#define PHY_CDR_LOCK_BIT	BIT(4)
>> +
>> +struct exynos_ufs_phy_cfg {
>> +	u32 off_0;
>> +	u32 off_1;
>> +	u32 val;
>> +	u8 desc;
>> +	u8 id;
>> +};
>> +
>> +struct exynos_ufs_phy_drvdata {
>> +	const struct exynos_ufs_phy_cfg **cfg;
>> +	struct pmu_isol {
>> +		u32 offset;
>> +		u32 mask;
>> +		u32 en;
>> +	} isol;
>> +};
>> +
>> +struct exynos_ufs_phy {
>> +	struct device *dev;
>> +	void __iomem *reg_pma;
>> +	struct regmap *reg_pmu;
>> +	const struct exynos_ufs_phy_drvdata *drvdata;
>> +	struct exynos_ufs_phy_cfg **cfg;
>> +	const struct pmu_isol *isol;
>> +	u8 lane_cnt;
>> +};
>> +
>> +static inline struct exynos_ufs_phy *get_exynos_ufs_phy(struct phy *phy)
>> +{
>> +	return (struct exynos_ufs_phy *)phy_get_drvdata(phy);
>> +}
>
> This wrapper function for phy_get_drvdata is unnecessary.
>> +
>> +static inline void exynos_ufs_phy_ctrl_isol(
>> +		struct exynos_ufs_phy *phy, u32 isol)
>> +{
>> +	regmap_update_bits(phy->reg_pmu, phy->isol->offset,
>> +			phy->isol->mask, isol ? 0 : phy->isol->en);
>> +}
>> +
>> +#include "phy-exynos7-ufs.h"
>> +
>> +#endif /* _PHY_EXYNOS_UFS_ */
>> diff --git a/drivers/phy/phy-exynos7-ufs.h b/drivers/phy/phy-exynos7-ufs.h
>> new file mode 100644
>> index 000000000000..6cd29d7fb200
>> --- /dev/null
>> +++ b/drivers/phy/phy-exynos7-ufs.h
>> @@ -0,0 +1,89 @@
>> +/*
>> + * UFS PHY driver for Samsung EXYNOS SoC
>> + *
>> + * Copyright (C) 2015 Samsung Electronics Co., Ltd.
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + */
>> +#ifndef _PHY_EXYNOS7_UFS_H_
>> +#define _PHY_EXYNOS7_UFS_H_
>> +
>> +#include "phy-exynos-ufs.h"
>> +
>> +#define EXYNOS7_EMBEDDED_COMBO_PHY_CTRL	0x720
>> +#define EXYNOS7_EMBEDDED_COMBO_PHY_CTRL_MASK	0x1
>> +#define EXYNOS7_EMBEDDED_COMBO_PHY_CTRL_EN	BIT(0)
>> +
>> +/* Calibration for phy initialization */
>> +static const struct exynos_ufs_phy_cfg exynos7_pre_init_cfg[] = {
>> +	PHY_COMN_REG_CFG(0x00f, 0xfa, PWR_MODE_ANY),
>> +	PHY_COMN_REG_CFG(0x010, 0x82, PWR_MODE_ANY),
>> +	PHY_COMN_REG_CFG(0x011, 0x1e, PWR_MODE_ANY),
>> +	PHY_COMN_REG_CFG(0x017, 0x84, PWR_MODE_ANY),
>> +	PHY_TRSV_REG_CFG(0x035, 0x58, PWR_MODE_ANY),
>> +	PHY_TRSV_REG_CFG(0x036, 0x32, PWR_MODE_ANY),
>> +	PHY_TRSV_REG_CFG(0x037, 0x40, PWR_MODE_ANY),
>> +	PHY_TRSV_REG_CFG(0x03b, 0x83, PWR_MODE_ANY),
>> +	PHY_TRSV_REG_CFG(0x042, 0x88, PWR_MODE_ANY),
>> +	PHY_TRSV_REG_CFG(0x043, 0xa6, PWR_MODE_ANY),
>> +	PHY_TRSV_REG_CFG(0x048, 0x74, PWR_MODE_ANY),
>> +	PHY_TRSV_REG_CFG(0x04c, 0x5b, PWR_MODE_ANY),
>> +	PHY_TRSV_REG_CFG(0x04d, 0x83, PWR_MODE_ANY),
>> +	PHY_TRSV_REG_CFG(0x05c, 0x14, PWR_MODE_ANY),
>
> Are these the usual PHY calbiration settings swing, deemphasis, bias etc.. If
> so, we should think about adding standard dt properties and adding the values
> for these setting in dt.
>
Well these are the initial values need to programmed at a given 
offset/sequence  before we do a ufs linkstart up.
well we can explore dt option, but at this point of time this look 
simple, I have access to just a single h/w which using this phy, will 
try to get access/see how mush other exynos ufs-phy differs (if possible 
for me), till then I prefere to have this way.

> Thanks
> Kishon
>
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