Re: [RFC PATCH 1/6] phy: exynos-pcie: Add support for Exynos PCIe phy

[Jaehoon Chung <jh80.chung@samsung.com>]

Hi Vivek,

On 12/27/2016 02:53 PM, Vivek Gautam wrote:
> Hi Jaehoon,
> 
> 
> On Mon, Dec 26, 2016 at 10:50 AM, Jaehoon Chung <jh80.chung@samsung.com> wrote:
>> This patch supports to use Generic Phy framework for Exynos PCIe phy.
>> When Exynos that supported the pcie want to use the PCIe,
>> it needs to control the phy resgister.
>> But it should be more complex to control in their own PCIe device drivers.
>>
>> Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
>> ---
>>  drivers/phy/Kconfig           |   9 ++
>>  drivers/phy/Makefile          |   1 +
>>  drivers/phy/phy-exynos-pcie.c | 227 ++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 237 insertions(+)
>>  create mode 100644 drivers/phy/phy-exynos-pcie.c
>>
>> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
>> index fe00f91..94b0433 100644
>> --- a/drivers/phy/Kconfig
>> +++ b/drivers/phy/Kconfig
>> @@ -341,6 +341,15 @@ config PHY_EXYNOS5_USBDRD
>>           This driver provides PHY interface for USB 3.0 DRD controller
>>           present on Exynos5 SoC series.
>>
>> +config PHY_EXYNOS_PCIE
>> +       bool "Exynos PCIe PHY driver"
> 
> Is there a reason for this not being 'tristate' ?

Will change.

> 
>> +       depends on ARCH_EXYNOS && OF
>> +       depends on PCI_EXYNOS5433
>> +       select GENERIC_PHY
>> +       help
>> +         Enable PCIe PHY support for Exynos SoC series.
> 
> If this driver is for Exynos5433, then same should come in this help
> text as well.

will support the other exynos series.
I'm working on refactoring exynos5440 with PHY generic Framework.
Then this drive is not for only Exnyos5433. how about?

> 
>> +         This driver provides PHY interface for Exynos PCIe controller.
>> +
>>  config PHY_PISTACHIO_USB
>>         tristate "IMG Pistachio USB2.0 PHY driver"
>>         depends on MACH_PISTACHIO
>> diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
>> index a534cf5..586344d 100644
>> --- a/drivers/phy/Makefile
>> +++ b/drivers/phy/Makefile
>> @@ -38,6 +38,7 @@ phy-exynos-usb2-$(CONFIG_PHY_EXYNOS4X12_USB2) += phy-exynos4x12-usb2.o
>>  phy-exynos-usb2-$(CONFIG_PHY_EXYNOS5250_USB2)  += phy-exynos5250-usb2.o
>>  phy-exynos-usb2-$(CONFIG_PHY_S5PV210_USB2)     += phy-s5pv210-usb2.o
>>  obj-$(CONFIG_PHY_EXYNOS5_USBDRD)       += phy-exynos5-usbdrd.o
>> +obj-$(CONFIG_PHY_EXYNOS_PCIE)  += phy-exynos-pcie.o
>>  obj-$(CONFIG_PHY_QCOM_APQ8064_SATA)    += phy-qcom-apq8064-sata.o
>>  obj-$(CONFIG_PHY_ROCKCHIP_USB) += phy-rockchip-usb.o
>>  obj-$(CONFIG_PHY_ROCKCHIP_INNO_USB2)   += phy-rockchip-inno-usb2.o
>> diff --git a/drivers/phy/phy-exynos-pcie.c b/drivers/phy/phy-exynos-pcie.c
>> new file mode 100644
>> index 0000000..0f5eefd
>> --- /dev/null
>> +++ b/drivers/phy/phy-exynos-pcie.c
>> @@ -0,0 +1,227 @@
>> +/*
>> + * Samsung EXYNOS SoC series PCIe PHY driver
>> + *
>> + * Phy provider for PCIe controller on Exynos SoC series
>> + *
>> + * Copyright (C) 2016 Samsung Electronics Co., Ltd.
>> + * Jaehoon Chung <jh80.chung@samsung.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + */
>> +
>> +#include <linux/delay.h>
>> +#include <linux/io.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_platform.h>
>> +#include <linux/phy/phy.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/regmap.h>
>> +#include <linux/mfd/syscon.h>
> 
> nit: It's good to have these includes in alphabetical order.

Will fix.

> 
>> +
>> +#define PCIE_EXYNOS5433_PMU_PHY_OFFSET         0x730
>> +#define PCIE_PHY_OFFSET(x)             ((x) * 0x4)
>> +
>> +/* Sysreg Fsys register offset and bit for Exynos5433 */
>> +#define PCIE_PHY_MAC_RESET             0x208
>> +#define PCIE_MAC_RESET_MASK            0xFF
>> +#define PCIE_MAC_RESET                 BIT(4)
>> +#define PCIE_L1SUB_CM_CON              0x1010
>> +#define PCIE_REFCLK_GATING_EN          BIT(0)
>> +#define PCIE_PHY_COMMON_RESET          0x1020
>> +#define PCIE_PHY_RESET                 BIT(0)
>> +#define PCIE_PHY_GLOBAL_RESET          0x1040
>> +#define PCIE_GLOBAL_RESET              BIT(0)
>> +#define PCIE_REFCLK                    BIT(1)
>> +#define PCIE_REFCLK_MASK               0x16
>> +#define PCIE_APP_REQ_EXIT_L1_MODE      BIT(5)
>> +
>> +enum exynos_pcie_phy_data_type {
>> +       PCIE_PHY_TYPE_EXYNOS5433,
>> +};
>> +
>> +struct exynos_pcie_phy_data {
>> +       enum exynos_pcie_phy_data_type  ctrl_type;
> 
> Why do we need this controller type ?
> If there are changes in the IP between different version,
> then you can as well use different compatibles.

Do you mean is the using "of_device_is_compatible()"?

> 
>> +       u32     pmureg_offset; /* PMU_REG offset */
> 
> Please use top comments.
> 
>> +       struct phy_ops  *ops;
>> +};
>> +
>> +/* for Exynos pcie phy */
>> +struct exynos_pcie_phy {
>> +       const struct exynos_pcie_phy_data *drv_data;
>> +       struct regmap *pmureg;
>> +       struct regmap *fsysreg;
>> +       void __iomem *phy_base;
> 
> just 'base' ?

Will change

> 
>> +};
>> +
>> +static void exynos_pcie_phy_writel(void __iomem *base, u32 val, u32 offset)
>> +{
>> +       writel(val, base + offset);
>> +}
>> +
>> +static int exynos_pcie_phy_init(struct phy *phy)
>> +{
>> +       struct exynos_pcie_phy *ep = phy_get_drvdata(phy);
>> +
>> +       if (ep->fsysreg) {
>> +               regmap_update_bits(ep->fsysreg, PCIE_PHY_COMMON_RESET,
>> +                               PCIE_PHY_RESET, 1);
>> +               regmap_update_bits(ep->fsysreg, PCIE_PHY_MAC_RESET,
>> +                               PCIE_MAC_RESET, 0);
>> +               /* PHY refclk 24MHz */
>> +               regmap_update_bits(ep->fsysreg, PCIE_PHY_GLOBAL_RESET,
>> +                               PCIE_REFCLK_MASK, PCIE_REFCLK);
>> +               regmap_update_bits(ep->fsysreg, PCIE_PHY_GLOBAL_RESET,
>> +                               PCIE_GLOBAL_RESET, 0);
>> +       }
>> +
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x11, PCIE_PHY_OFFSET(0x3));
>> +
>> +       /* band gap reference on */
>> +       exynos_pcie_phy_writel(ep->phy_base, 0, PCIE_PHY_OFFSET(0x20));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0, PCIE_PHY_OFFSET(0x4b));
>> +
>> +       /* jitter tunning */
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x34, PCIE_PHY_OFFSET(0x4));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x02, PCIE_PHY_OFFSET(0x7));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x41, PCIE_PHY_OFFSET(0x21));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x7F, PCIE_PHY_OFFSET(0x14));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0xC0, PCIE_PHY_OFFSET(0x15));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x61, PCIE_PHY_OFFSET(0x36));
>> +
>> +       /* D0 uninit.. */
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x44, PCIE_PHY_OFFSET(0x3D));
>> +
>> +       /* 24MHz */
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x94, PCIE_PHY_OFFSET(0x8));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0xA7, PCIE_PHY_OFFSET(0x9));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x93, PCIE_PHY_OFFSET(0xA));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x6B, PCIE_PHY_OFFSET(0xC));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0xA5, PCIE_PHY_OFFSET(0xF));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x34, PCIE_PHY_OFFSET(0x16));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0xA3, PCIE_PHY_OFFSET(0x17));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0xA7, PCIE_PHY_OFFSET(0x1A));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x71, PCIE_PHY_OFFSET(0x23));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x4C, PCIE_PHY_OFFSET(0x24));
>> +
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x0E, PCIE_PHY_OFFSET(0x26));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x14, PCIE_PHY_OFFSET(0x7));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x48, PCIE_PHY_OFFSET(0x43));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x44, PCIE_PHY_OFFSET(0x44));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x03, PCIE_PHY_OFFSET(0x45));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0xA7, PCIE_PHY_OFFSET(0x48));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x13, PCIE_PHY_OFFSET(0x54));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0x04, PCIE_PHY_OFFSET(0x31));
>> +       exynos_pcie_phy_writel(ep->phy_base, 0, PCIE_PHY_OFFSET(0x32));
>> +
>> +       if (ep->fsysreg) {
>> +               regmap_update_bits(ep->fsysreg, PCIE_PHY_COMMON_RESET,
>> +                               PCIE_PHY_RESET, 0);
>> +               regmap_update_bits(ep->fsysreg, PCIE_PHY_MAC_RESET,
>> +                               PCIE_MAC_RESET_MASK, PCIE_MAC_RESET);
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static int exynos_pcie_phy_power_on(struct phy *phy)
>> +{
>> +       struct exynos_pcie_phy *ep = phy_get_drvdata(phy);
>> +
>> +       if (ep->pmureg) {
>> +               if (regmap_update_bits(ep->pmureg, ep->drv_data->pmureg_offset,
>> +                                       BIT(0), 1))
>> +                       dev_warn(&phy->dev, "Failed to update regmap bit.\n");
>> +       }
>> +
>> +       if (ep->fsysreg) {
>> +               regmap_update_bits(ep->fsysreg, PCIE_PHY_GLOBAL_RESET,
>> +                               PCIE_APP_REQ_EXIT_L1_MODE, 0);
>> +               regmap_update_bits(ep->fsysreg, PCIE_L1SUB_CM_CON,
>> +                               PCIE_REFCLK_GATING_EN, 0);
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static struct phy_ops exynos_phy_ops = {
> 
> const ?

Yep.

> 
>> +       .init   = exynos_pcie_phy_init,
>> +       .power_on = exynos_pcie_phy_power_on,
>> +};
>> +
>> +static const struct exynos_pcie_phy_data exynos5433_pcie_phy_data = {
>> +       .ctrl_type      = PCIE_PHY_TYPE_EXYNOS5433,
>> +       .pmureg_offset  = PCIE_EXYNOS5433_PMU_PHY_OFFSET,
>> +       .ops            = &exynos_phy_ops,
>> +};
>> +
>> +static const struct of_device_id exynos_pcie_phy_match[] = {
>> +       {
>> +               .compatible = "samsung,exynos5433-pcie-phy",
>> +               .data = &exynos5433_pcie_phy_data,
>> +       },
>> +       {}
> 
> missing comma after braces.

Will fix.

> 
>> +};
>> +MODULE_DEVICE_TABLE(of, exynos_pcie_phy_match);
>> +
>> +static int exynos_pcie_phy_probe(struct platform_device *pdev)
>> +{
>> +       struct device *dev = &pdev->dev;
>> +       struct device_node *np = dev->of_node;
>> +       struct exynos_pcie_phy *exynos_phy;
>> +       struct phy *generic_phy;
>> +       struct phy_provider *phy_provider;
>> +       struct resource *res;
>> +       const struct exynos_pcie_phy_data *drv_data;
>> +       const struct of_device_id *match;
>> +
>> +       exynos_phy = devm_kzalloc(dev, sizeof(*exynos_phy), GFP_KERNEL);
>> +       if (!exynos_phy)
>> +               return -ENOMEM;
>> +
>> +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +       exynos_phy->phy_base = devm_ioremap_resource(dev, res);
>> +       if (IS_ERR(exynos_phy->phy_base))
>> +               return PTR_ERR(exynos_phy->phy_base);
>> +
>> +       exynos_phy->pmureg = syscon_regmap_lookup_by_phandle(np,
>> +                       "samsung,pmureg-phandle");
>> +       if (IS_ERR(exynos_phy->pmureg)) {
>> +               dev_warn(&pdev->dev, "pmureg syscon regmap lookup failed.\n");
>> +               exynos_phy->pmureg = NULL;
>> +       }
> 
> Is this really optional ? There should be a failure path for IP versions that
> require this compulsorily.

Agreed. Will fix.

> 
>> +
>> +       match = of_match_node(exynos_pcie_phy_match, pdev->dev.of_node);
>> +       drv_data = match->data;
> 
> Please use of_device_get_match_data().

Ok.

> 
>> +       exynos_phy->drv_data = drv_data;
>> +
>> +       exynos_phy->fsysreg = syscon_regmap_lookup_by_phandle(np,
>> +                       "samsung,fsys-sysreg");
>> +       if (IS_ERR(exynos_phy->fsysreg)) {
>> +               dev_warn(&pdev->dev, "Fsysreg syscon regmap lookup failed.\n");
>> +               exynos_phy->fsysreg = NULL;
>> +       }
> 
> Same here, is this optional ?

Will fix.

Thanks for reviewing.

Best Regards,
Jaehoon Chung

> 
>> +
>> +       generic_phy = devm_phy_create(dev, dev->of_node, drv_data->ops);
>> +       if (IS_ERR(generic_phy)) {
>> +               dev_err(dev, "failed to create PHY\n");
>> +               return PTR_ERR(generic_phy);
>> +       }
>> +
>> +       phy_set_drvdata(generic_phy, exynos_phy);
>> +       phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
>> +
>> +       return PTR_ERR_OR_ZERO(phy_provider);
>> +}
>> +
>> +static struct platform_driver exynos_pcie_phy_driver = {
>> +       .probe  = exynos_pcie_phy_probe,
>> +       .driver = {
>> +               .of_match_table = exynos_pcie_phy_match,
>> +               .name           = "exynos_pcie_phy",
>> +       }
>> +};
>> +module_platform_driver(exynos_pcie_phy_driver);
>> --
>> 2.10.2
>>
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> 
> 
> Thanks
> Vivek
>