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Subject: Re: [PATCH v6 6/7] phy: amlogic: Add Amlogic AXG PCIE PHY Driver
To:     Kishon Vijay Abraham I <kishon@ti.com>,
        Remi Pommarel <repk@triplefau.lt>
References: <20200123232943.10229-1-repk@triplefau.lt>
 <20200123232943.10229-7-repk@triplefau.lt>
 <14627e42-4894-6674-4911-3205ea8f5e55@ti.com> <20200304130811.GP2248@voidbox>
 <a6f8ac2f-f49a-f53e-1b44-fc446c3d7964@ti.com>
Cc:     Yue Wang <yue.wang@amlogic.com>,
        Kevin Hilman <khilman@baylibre.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Jerome Brunet <jbrunet@baylibre.com>,
        linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org, linux-pci@vger.kernel.org
From:   Neil Armstrong <narmstrong@baylibre.com>
Message-ID: <6f5cad19-3879-84ae-26bf-2fd065af2e0d@baylibre.com>
Date:   Thu, 5 Mar 2020 08:00:42 +0100
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Hi,

Le 05/03/2020 à 05:56, Kishon Vijay Abraham I a écrit :
> Hi,
> 
> On 04/03/20 6:38 pm, Remi Pommarel wrote:
>> On Wed, Mar 04, 2020 at 04:31:24PM +0530, Kishon Vijay Abraham I wrote:
>>>
>>>
>>> On 24/01/20 4:59 am, Remi Pommarel wrote:
>>>> This adds support for the PCI PHY found in the Amlogic AXG SoC Family.
>>>> This will allow to mutualize code in pci-meson.c between AXG and G12A
>>>> SoC.
>>>>
>>>> This PHY also uses and chains an analog PHY, which on AXG platform
>>>> is needed to have reliable PCIe communication.
>>>
>>> Is the analog PHY an independent block and can be used with other PHYs?
>>
>> It is documented as a separate block yes, but I think it is unlikely
>> that it will be used with other PHYs than the PCIe or the MIPI one of
>> the AXG SoC.
> 
> Shouldn't we then have a single PHY driver instead of chaining PHYs?

The chaining is necessary because the MIPI/PCIe analogi PHY will be reused on
recent platform with similar MIPI DSI PHY, but these platforms have their PCIe PHY
combined with USB3 (see g12a-usb3-pcie combo phy).

Neil

> 
> Thanks
> Kishon
> 
>>
>> Thanks,
>> Remi
>>
>>>
>>> For the patch itself
>>> Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
>>>
>>> Thanks
>>> Kishon
>>>>
>>>> Signed-off-by: Remi Pommarel <repk@triplefau.lt>
>>>> ---
>>>>  drivers/phy/amlogic/Kconfig              |  11 ++
>>>>  drivers/phy/amlogic/Makefile             |   1 +
>>>>  drivers/phy/amlogic/phy-meson-axg-pcie.c | 192 +++++++++++++++++++++++
>>>>  3 files changed, 204 insertions(+)
>>>>  create mode 100644 drivers/phy/amlogic/phy-meson-axg-pcie.c
>>>>
>>>> diff --git a/drivers/phy/amlogic/Kconfig b/drivers/phy/amlogic/Kconfig
>>>> index 8c9cf2403591..71801e30d601 100644
>>>> --- a/drivers/phy/amlogic/Kconfig
>>>> +++ b/drivers/phy/amlogic/Kconfig
>>>> @@ -60,6 +60,17 @@ config PHY_MESON_G12A_USB3_PCIE
>>>>  	  in Meson G12A SoCs.
>>>>  	  If unsure, say N.
>>>>  
>>>> +config PHY_MESON_AXG_PCIE
>>>> +	tristate "Meson AXG PCIE PHY driver"
>>>> +	default ARCH_MESON
>>>> +	depends on OF && (ARCH_MESON || COMPILE_TEST)
>>>> +	select GENERIC_PHY
>>>> +	select REGMAP_MMIO
>>>> +	help
>>>> +	  Enable this to support the Meson MIPI + PCIE PHY found
>>>> +	  in Meson AXG SoCs.
>>>> +	  If unsure, say N.
>>>> +
>>>>  config PHY_MESON_AXG_MIPI_PCIE_ANALOG
>>>>  	tristate "Meson AXG MIPI + PCIE analog PHY driver"
>>>>  	default ARCH_MESON
>>>> diff --git a/drivers/phy/amlogic/Makefile b/drivers/phy/amlogic/Makefile
>>>> index 0aecf92d796a..e2baa133f7af 100644
>>>> --- a/drivers/phy/amlogic/Makefile
>>>> +++ b/drivers/phy/amlogic/Makefile
>>>> @@ -4,4 +4,5 @@ obj-$(CONFIG_PHY_MESON_GXL_USB2)		+= phy-meson-gxl-usb2.o
>>>>  obj-$(CONFIG_PHY_MESON_G12A_USB2)		+= phy-meson-g12a-usb2.o
>>>>  obj-$(CONFIG_PHY_MESON_GXL_USB3)		+= phy-meson-gxl-usb3.o
>>>>  obj-$(CONFIG_PHY_MESON_G12A_USB3_PCIE)		+= phy-meson-g12a-usb3-pcie.o
>>>> +obj-$(CONFIG_PHY_MESON_AXG_PCIE)		+= phy-meson-axg-pcie.o
>>>>  obj-$(CONFIG_PHY_MESON_AXG_MIPI_PCIE_ANALOG)	+= phy-meson-axg-mipi-pcie-analog.o
>>>> diff --git a/drivers/phy/amlogic/phy-meson-axg-pcie.c b/drivers/phy/amlogic/phy-meson-axg-pcie.c
>>>> new file mode 100644
>>>> index 000000000000..377ed0dcd0d9
>>>> --- /dev/null
>>>> +++ b/drivers/phy/amlogic/phy-meson-axg-pcie.c
>>>> @@ -0,0 +1,192 @@
>>>> +// SPDX-License-Identifier: GPL-2.0
>>>> +/*
>>>> + * Amlogic AXG PCIE PHY driver
>>>> + *
>>>> + * Copyright (C) 2020 Remi Pommarel <repk@triplefau.lt>
>>>> + */
>>>> +#include <linux/module.h>
>>>> +#include <linux/phy/phy.h>
>>>> +#include <linux/regmap.h>
>>>> +#include <linux/reset.h>
>>>> +#include <linux/platform_device.h>
>>>> +#include <linux/bitfield.h>
>>>> +#include <dt-bindings/phy/phy.h>
>>>> +
>>>> +#define MESON_PCIE_REG0 0x00
>>>> +#define		MESON_PCIE_COMMON_CLK	BIT(4)
>>>> +#define		MESON_PCIE_PORT_SEL	GENMASK(3, 2)
>>>> +#define		MESON_PCIE_CLK		BIT(1)
>>>> +#define		MESON_PCIE_POWERDOWN	BIT(0)
>>>> +
>>>> +#define MESON_PCIE_TWO_X1		FIELD_PREP(MESON_PCIE_PORT_SEL, 0x3)
>>>> +#define MESON_PCIE_COMMON_REF_CLK	FIELD_PREP(MESON_PCIE_COMMON_CLK, 0x1)
>>>> +#define MESON_PCIE_PHY_INIT		(MESON_PCIE_TWO_X1 |		\
>>>> +					 MESON_PCIE_COMMON_REF_CLK)
>>>> +#define MESON_PCIE_RESET_DELAY		500
>>>> +
>>>> +struct phy_axg_pcie_priv {
>>>> +	struct phy *phy;
>>>> +	struct phy *analog;
>>>> +	struct regmap *regmap;
>>>> +	struct reset_control *reset;
>>>> +};
>>>> +
>>>> +static const struct regmap_config phy_axg_pcie_regmap_conf = {
>>>> +	.reg_bits = 8,
>>>> +	.val_bits = 32,
>>>> +	.reg_stride = 4,
>>>> +	.max_register = MESON_PCIE_REG0,
>>>> +};
>>>> +
>>>> +static int phy_axg_pcie_power_on(struct phy *phy)
>>>> +{
>>>> +	struct phy_axg_pcie_priv *priv = phy_get_drvdata(phy);
>>>> +	int ret;
>>>> +
>>>> +	ret = phy_power_on(priv->analog);
>>>> +	if (ret != 0)
>>>> +		return ret;
>>>> +
>>>> +	regmap_update_bits(priv->regmap, MESON_PCIE_REG0,
>>>> +			   MESON_PCIE_POWERDOWN, 0);
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int phy_axg_pcie_power_off(struct phy *phy)
>>>> +{
>>>> +	struct phy_axg_pcie_priv *priv = phy_get_drvdata(phy);
>>>> +	int ret;
>>>> +
>>>> +	ret = phy_power_off(priv->analog);
>>>> +	if (ret != 0)
>>>> +		return ret;
>>>> +
>>>> +	regmap_update_bits(priv->regmap, MESON_PCIE_REG0,
>>>> +			   MESON_PCIE_POWERDOWN, 1);
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int phy_axg_pcie_init(struct phy *phy)
>>>> +{
>>>> +	struct phy_axg_pcie_priv *priv = phy_get_drvdata(phy);
>>>> +	int ret;
>>>> +
>>>> +	ret = phy_init(priv->analog);
>>>> +	if (ret != 0)
>>>> +		return ret;
>>>> +
>>>> +	regmap_write(priv->regmap, MESON_PCIE_REG0, MESON_PCIE_PHY_INIT);
>>>> +	return reset_control_reset(priv->reset);
>>>> +}
>>>> +
>>>> +static int phy_axg_pcie_exit(struct phy *phy)
>>>> +{
>>>> +	struct phy_axg_pcie_priv *priv = phy_get_drvdata(phy);
>>>> +	int ret;
>>>> +
>>>> +	ret = phy_exit(priv->analog);
>>>> +	if (ret != 0)
>>>> +		return ret;
>>>> +
>>>> +	return reset_control_reset(priv->reset);
>>>> +}
>>>> +
>>>> +static int phy_axg_pcie_reset(struct phy *phy)
>>>> +{
>>>> +	struct phy_axg_pcie_priv *priv = phy_get_drvdata(phy);
>>>> +	int ret = 0;
>>>> +
>>>> +	ret = phy_reset(priv->analog);
>>>> +	if (ret != 0)
>>>> +		goto out;
>>>> +
>>>> +	ret = reset_control_assert(priv->reset);
>>>> +	if (ret != 0)
>>>> +		goto out;
>>>> +	udelay(MESON_PCIE_RESET_DELAY);
>>>> +
>>>> +	ret = reset_control_deassert(priv->reset);
>>>> +	if (ret != 0)
>>>> +		goto out;
>>>> +	udelay(MESON_PCIE_RESET_DELAY);
>>>> +
>>>> +out:
>>>> +	return ret;
>>>> +}
>>>> +
>>>> +static const struct phy_ops phy_axg_pcie_ops = {
>>>> +	.init = phy_axg_pcie_init,
>>>> +	.exit = phy_axg_pcie_exit,
>>>> +	.power_on = phy_axg_pcie_power_on,
>>>> +	.power_off = phy_axg_pcie_power_off,
>>>> +	.reset = phy_axg_pcie_reset,
>>>> +	.owner = THIS_MODULE,
>>>> +};
>>>> +
>>>> +static int phy_axg_pcie_probe(struct platform_device *pdev)
>>>> +{
>>>> +	struct phy_provider *pphy;
>>>> +	struct device *dev = &pdev->dev;
>>>> +	struct phy_axg_pcie_priv *priv;
>>>> +	struct device_node *np = dev->of_node;
>>>> +	struct resource *res;
>>>> +	void __iomem *base;
>>>> +	int ret;
>>>> +
>>>> +	priv = devm_kmalloc(dev, sizeof(*priv), GFP_KERNEL);
>>>> +	if (!priv)
>>>> +		return -ENOMEM;
>>>> +
>>>> +	priv->phy = devm_phy_create(dev, np, &phy_axg_pcie_ops);
>>>> +	if (IS_ERR(priv->phy)) {
>>>> +		ret = PTR_ERR(priv->phy);
>>>> +		if (ret != -EPROBE_DEFER)
>>>> +			dev_err(dev, "failed to create PHY\n");
>>>> +		return ret;
>>>> +	}
>>>> +
>>>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>>> +	base = devm_ioremap_resource(dev, res);
>>>> +	if (IS_ERR(base))
>>>> +		return PTR_ERR(base);
>>>> +
>>>> +	priv->regmap = devm_regmap_init_mmio(dev, base,
>>>> +					     &phy_axg_pcie_regmap_conf);
>>>> +	if (IS_ERR(priv->regmap))
>>>> +		return PTR_ERR(priv->regmap);
>>>> +
>>>> +	priv->reset = devm_reset_control_array_get(dev, false, false);
>>>> +	if (IS_ERR(priv->reset))
>>>> +		return PTR_ERR(priv->reset);
>>>> +
>>>> +	priv->analog = devm_phy_get(dev, "analog");
>>>> +	if (IS_ERR(priv->analog))
>>>> +		return PTR_ERR(priv->analog);
>>>> +
>>>> +	phy_set_drvdata(priv->phy, priv);
>>>> +	dev_set_drvdata(dev, priv);
>>>> +	pphy = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
>>>> +
>>>> +	return PTR_ERR_OR_ZERO(pphy);
>>>> +}
>>>> +
>>>> +static const struct of_device_id phy_axg_pcie_of_match[] = {
>>>> +	{
>>>> +		.compatible = "amlogic,axg-pcie-phy",
>>>> +	},
>>>> +	{ },
>>>> +};
>>>> +MODULE_DEVICE_TABLE(of, phy_axg_pcie_of_match);
>>>> +
>>>> +static struct platform_driver phy_axg_pcie_driver = {
>>>> +	.probe = phy_axg_pcie_probe,
>>>> +	.driver = {
>>>> +		.name = "phy-axg-pcie",
>>>> +		.of_match_table = phy_axg_pcie_of_match,
>>>> +	},
>>>> +};
>>>> +module_platform_driver(phy_axg_pcie_driver);
>>>> +
>>>> +MODULE_AUTHOR("Remi Pommarel <repk@triplefau.lt>");
>>>> +MODULE_DESCRIPTION("Amlogic AXG PCIE PHY driver");
>>>> +MODULE_LICENSE("GPL v2");
>>>>