Re: [PATCH 3/7] phy: qcom: Add Qualcomm PCIe2 PHY driver

From: Niklas Cassel
Date: Fri Feb 08 2019 - 09:14:24 EST

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On Fri, Jan 25, 2019 at 03:45:05PM -0800, Bjorn Andersson wrote:
> The Qualcomm PCIe2 PHY is based on design from Synopsys and found in
> several different platforms where the QMP PHY isn't used.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> ---
> drivers/phy/qualcomm/Kconfig | 8 +
> drivers/phy/qualcomm/Makefile | 1 +
> drivers/phy/qualcomm/phy-qcom-pcie2.c | 331 ++++++++++++++++++++++++++
> 3 files changed, 340 insertions(+)
> create mode 100644 drivers/phy/qualcomm/phy-qcom-pcie2.c
>
> diff --git a/drivers/phy/qualcomm/Kconfig b/drivers/phy/qualcomm/Kconfig
> index 32f7d34eb784..0edb5316972f 100644
> --- a/drivers/phy/qualcomm/Kconfig
> +++ b/drivers/phy/qualcomm/Kconfig
> @@ -24,6 +24,14 @@ config PHY_QCOM_IPQ806X_SATA
> depends on OF
> select GENERIC_PHY
>
> +config PHY_QCOM_PCIE2
> + tristate "Qualcomm PCIe PHY Driver"

Perhaps "Qualcomm PCIe2 PHY Driver" or "Qualcomm PCIe Gen2 PHY Driver"
as that is more descriptive.

> + depends on OF && COMMON_CLK && (ARCH_QCOM || COMPILE_TEST)
> + select GENERIC_PHY
> + help
> + Enable this to support the Qualcomm PCIe PHY, used with the Synopsys
> + based PCIe controller.
> +
> config PHY_QCOM_QMP
> tristate "Qualcomm QMP PHY Driver"
> depends on OF && COMMON_CLK && (ARCH_QCOM || COMPILE_TEST)
> diff --git a/drivers/phy/qualcomm/Makefile b/drivers/phy/qualcomm/Makefile
> index c56efd3af205..283251d6a5d9 100644
> --- a/drivers/phy/qualcomm/Makefile
> +++ b/drivers/phy/qualcomm/Makefile
> @@ -2,6 +2,7 @@
> obj-$(CONFIG_PHY_ATH79_USB) += phy-ath79-usb.o
> obj-$(CONFIG_PHY_QCOM_APQ8064_SATA) += phy-qcom-apq8064-sata.o
> obj-$(CONFIG_PHY_QCOM_IPQ806X_SATA) += phy-qcom-ipq806x-sata.o
> +obj-$(CONFIG_PHY_QCOM_PCIE2) += phy-qcom-pcie2.o
> obj-$(CONFIG_PHY_QCOM_QMP) += phy-qcom-qmp.o
> obj-$(CONFIG_PHY_QCOM_QUSB2) += phy-qcom-qusb2.o
> obj-$(CONFIG_PHY_QCOM_UFS) += phy-qcom-ufs.o
> diff --git a/drivers/phy/qualcomm/phy-qcom-pcie2.c b/drivers/phy/qualcomm/phy-qcom-pcie2.c
> new file mode 100644
> index 000000000000..2fa891c18b6f
> --- /dev/null
> +++ b/drivers/phy/qualcomm/phy-qcom-pcie2.c
> @@ -0,0 +1,331 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2014-2017, The Linux Foundation. All rights reserved.
> + * Copyright (c) 2019, Linaro Ltd.
> + */
> +
> +#include <linux/clk-provider.h>
> +#include <linux/clk.h>
> +#include <linux/iopoll.h>
> +#include <linux/module.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset.h>
> +#include <linux/slab.h>
> +
> +#include <dt-bindings/phy/phy.h>
> +
> +#define PCIE20_PARF_PHY_STTS 0x3c
> +#define PCIE2_PHY_RESET_CTRL 0x44
> +#define PCIE20_PARF_PHY_REFCLK_CTRL2 0xa0
> +#define PCIE20_PARF_PHY_REFCLK_CTRL3 0xa4
> +#define PCIE20_PARF_PCS_SWING_CTRL1 0x88
> +#define PCIE20_PARF_PCS_SWING_CTRL2 0x8c
> +#define PCIE20_PARF_PCS_DEEMPH1 0x74
> +#define PCIE20_PARF_PCS_DEEMPH2 0x78
> +#define PCIE20_PARF_PCS_DEEMPH3 0x7c
> +#define PCIE20_PARF_CONFIGBITS 0x84
> +#define PCIE20_PARF_PHY_CTRL3 0x94
> +#define PCIE20_PARF_PCS_CTRL 0x80
> +
> +#define TX_AMP_VAL 120
> +#define PHY_RX0_EQ_GEN1_VAL 0
> +#define PHY_RX0_EQ_GEN2_VAL 4
> +#define TX_DEEMPH_GEN1_VAL 24
> +#define TX_DEEMPH_GEN2_3_5DB_VAL 26
> +#define TX_DEEMPH_GEN2_6DB_VAL 36
> +#define PHY_TX0_TERM_OFFST_VAL 0
> +
> +struct qcom_phy {
> + struct device *dev;
> + void __iomem *base;
> +
> + struct regulator_bulk_data vregs[2];
> +
> + struct reset_control *phy_reset;
> + struct reset_control *pipe_reset;
> + struct clk *pipe_clk;
> +};
> +
> +static int qcom_pcie2_phy_init(struct phy *phy)
> +{
> + struct qcom_phy *qphy = phy_get_drvdata(phy);
> + int ret;
> +
> + ret = reset_control_deassert(qphy->phy_reset);
> + if (ret) {
> + dev_err(qphy->dev, "cannot deassert pipe reset\n");
> + return ret;
> + }
> +
> + ret = regulator_bulk_enable(ARRAY_SIZE(qphy->vregs), qphy->vregs);
> + if (ret)
> + reset_control_assert(qphy->phy_reset);
> +
> + return ret;
> +}
> +
> +static int qcom_pcie2_phy_power_on(struct phy *phy)
> +{
> + struct qcom_phy *qphy = phy_get_drvdata(phy);
> + int ret;
> + u32 val;
> +
> + /* Program REF_CLK source */
> + val = readl(qphy->base + PCIE20_PARF_PHY_REFCLK_CTRL2);
> + val &= ~BIT(1);
> + writel(val, qphy->base + PCIE20_PARF_PHY_REFCLK_CTRL2);
> +
> + usleep_range(1000, 2000);
> +
> + /* Don't use PAD for refclock */
> + val = readl(qphy->base + PCIE20_PARF_PHY_REFCLK_CTRL2);
> + val &= ~BIT(0);
> + writel(val, qphy->base + PCIE20_PARF_PHY_REFCLK_CTRL2);
> +
> + /* Program SSP ENABLE */
> + val = readl(qphy->base + PCIE20_PARF_PHY_REFCLK_CTRL3);
> + val |= BIT(0);
> + writel(val, qphy->base + PCIE20_PARF_PHY_REFCLK_CTRL3);
> +
> + usleep_range(1000, 2000);
> +
> + /* Assert Phy SW Reset */
> + val = readl(qphy->base + PCIE2_PHY_RESET_CTRL);
> + val |= BIT(0);
> + writel(val, qphy->base + PCIE2_PHY_RESET_CTRL);
> +
> + /* Program Tx Amplitude */
> + val = readl(qphy->base + PCIE20_PARF_PCS_SWING_CTRL1);
> + val &= ~0x7f;
> + val |= TX_AMP_VAL;
> + writel(val, qphy->base + PCIE20_PARF_PCS_SWING_CTRL1);
> +
> + val = readl(qphy->base + PCIE20_PARF_PCS_SWING_CTRL2);
> + val &= ~0x7f;
> + val |= TX_AMP_VAL;
> + writel(val, qphy->base + PCIE20_PARF_PCS_SWING_CTRL2);
> +
> + /* Program De-Emphasis */
> + val = readl(qphy->base + PCIE20_PARF_PCS_DEEMPH1);
> + val &= ~0x3f;
> + val |= TX_DEEMPH_GEN2_6DB_VAL;
> + writel(val, qphy->base + PCIE20_PARF_PCS_DEEMPH1);
> +
> + val = readl(qphy->base + PCIE20_PARF_PCS_DEEMPH2);
> + val &= ~0x3f;
> + val |= TX_DEEMPH_GEN2_3_5DB_VAL;
> + writel(val, qphy->base + PCIE20_PARF_PCS_DEEMPH2);
> +
> + val = readl(qphy->base + PCIE20_PARF_PCS_DEEMPH3);
> + val &= ~0x3f;
> + val |= TX_DEEMPH_GEN1_VAL;
> + writel(val, qphy->base + PCIE20_PARF_PCS_DEEMPH3);
> +
> + /* Program Rx_Eq */
> + val = readl(qphy->base + PCIE20_PARF_CONFIGBITS);
> + val &= ~0x7;
> + val |= PHY_RX0_EQ_GEN2_VAL;
> + writel(val, qphy->base + PCIE20_PARF_CONFIGBITS);
> +
> + /* Program Tx0_term_offset */
> + val = readl(qphy->base + PCIE20_PARF_PHY_CTRL3);
> + val &= ~0x1f;
> + val |= PHY_TX0_TERM_OFFST_VAL;
> + writel(val, qphy->base + PCIE20_PARF_PHY_CTRL3);
> +
> + /* disable Tx2Rx Loopback */
> + val = readl(qphy->base + PCIE20_PARF_PCS_CTRL);
> + val &= ~BIT(1);
> + writel(val, qphy->base + PCIE20_PARF_PCS_CTRL);
> +
> + /* De-assert Phy SW Reset */
> + val = readl(qphy->base + PCIE2_PHY_RESET_CTRL);
> + val &= ~BIT(0);
> + writel(val, qphy->base + PCIE2_PHY_RESET_CTRL);
> +
> + usleep_range(1000, 2000);
> +
> + ret = reset_control_deassert(qphy->pipe_reset);
> + if (ret) {
> + dev_err(qphy->dev, "cannot deassert pipe reset\n");
> + goto out;
> + }
> +
> + clk_set_rate(qphy->pipe_clk, 250000000);
> +
> + ret = clk_prepare_enable(qphy->pipe_clk);
> + if (ret) {
> + dev_err(qphy->dev, "failed to enable pipe clock\n");
> + goto out;
> + }
> +
> + ret = readl_poll_timeout(qphy->base + PCIE20_PARF_PHY_STTS, val,
> + !(val & BIT(0)), 1000, 10);
> + if (ret)
> + dev_err(qphy->dev, "phy initialization failed\n");
> +
> +out:
> + return ret;
> +}
> +
> +static int qcom_pcie2_phy_power_off(struct phy *phy)
> +{
> + struct qcom_phy *qphy = phy_get_drvdata(phy);
> + u32 val;
> +
> + val = readl(qphy->base + PCIE2_PHY_RESET_CTRL);
> + val |= BIT(0);
> + writel(val, qphy->base + PCIE2_PHY_RESET_CTRL);
> +
> + clk_disable_unprepare(qphy->pipe_clk);
> + reset_control_assert(qphy->pipe_reset);
> +
> + return 0;
> +}
> +
> +static int qcom_pcie2_phy_exit(struct phy *phy)
> +{
> + struct qcom_phy *qphy = phy_get_drvdata(phy);
> +
> + regulator_bulk_disable(ARRAY_SIZE(qphy->vregs), qphy->vregs);
> + reset_control_assert(qphy->phy_reset);
> +
> + return 0;
> +}
<> +
> +static const struct phy_ops qcom_pcie2_ops = {
> + .init = qcom_pcie2_phy_init,
> + .power_on = qcom_pcie2_phy_power_on,
> + .power_off = qcom_pcie2_phy_power_off,
> + .exit = qcom_pcie2_phy_exit,
> + .owner = THIS_MODULE,
> +};
> +
> +/*
> + * Register a fixed rate pipe clock.
> + *
> + * The <s>_pipe_clksrc generated by PHY goes to the GCC that gate
> + * controls it. The <s>_pipe_clk coming out of the GCC is requested
> + * by the PHY driver for its operations.
> + * We register the <s>_pipe_clksrc here. The gcc driver takes care
> + * of assigning this <s>_pipe_clksrc as parent to <s>_pipe_clk.
> + * Below picture shows this relationship.
> + *
> + * +---------------+
> + * | PHY block |<<---------------------------------------+
> + * | | |
> + * | +-------+ | +-----+ |
> + * I/P---^-->| PLL |---^--->pipe_clksrc--->| GCC |--->pipe_clk---+
> + * clk | +-------+ | +-----+
> + * +---------------+
> + */
> +static int phy_pipe_clk_register(struct qcom_phy *qphy)

Perhaps rename this function to

phy_pipe_clksrc_register()

since it is that clock that we register here.

With those two minor nits:
Reviewed-by: Niklas Cassel <niklas.cassel@xxxxxxxxxx>

> +{
> + struct device_node *np = qphy->dev->of_node;
> + struct clk_fixed_rate *fixed;
> + struct clk_init_data init = { };
> + int ret;
> +
> + ret = of_property_read_string(np, "clock-output-names", &init.name);
> + if (ret) {
> + dev_err(qphy->dev, "%s: No clock-output-names\n", np->name);
> + return ret;
> + }
> +
> + fixed = devm_kzalloc(qphy->dev, sizeof(*fixed), GFP_KERNEL);
> + if (!fixed)
> + return -ENOMEM;
> +
> + init.ops = &clk_fixed_rate_ops;
> +
> + /* controllers using QMP phys use 250MHz pipe clock interface */
> + fixed->fixed_rate = 250000000;
> + fixed->hw.init = &init;
> +
> + return devm_clk_hw_register(qphy->dev, &fixed->hw);
> +}
> +
> +static int qcom_pcie2_phy_probe(struct platform_device *pdev)
> +{
> + struct phy_provider *phy_provider;
> + struct qcom_phy *qphy;
> + struct resource *res;
> + struct device *dev = &pdev->dev;
> + struct phy *phy;
> + int ret;
> +
> + qphy = devm_kzalloc(dev, sizeof(*qphy), GFP_KERNEL);
> + if (!qphy)
> + return -ENOMEM;
> +
> + qphy->dev = dev;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + qphy->base = devm_ioremap_resource(dev, res);
> + if (IS_ERR(qphy->base))
> + return PTR_ERR(qphy->base);
> +
> + ret = phy_pipe_clk_register(qphy);
> + if (ret) {
> + dev_err(dev, "failed to register pipe_clk\n");
> + return ret;
> + }
> +
> + qphy->vregs[0].supply = "vdda-vp";
> + qphy->vregs[1].supply = "vdda-vph";
> + ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(qphy->vregs), qphy->vregs);
> + if (ret < 0)
> + return ret;
> +
> + qphy->pipe_clk = devm_clk_get(dev, NULL);
> + if (IS_ERR(qphy->pipe_clk)) {
> + dev_err(dev, "failed to acquire pipe clock\n");
> + return PTR_ERR(qphy->pipe_clk);
> + }
> +
> + qphy->phy_reset = devm_reset_control_get_exclusive(dev, "phy");
> + if (IS_ERR(qphy->phy_reset)) {
> + dev_err(dev, "failed to acquire phy reset\n");
> + return PTR_ERR(qphy->phy_reset);
> + }
> +
> + qphy->pipe_reset = devm_reset_control_get_exclusive(dev, "pipe");
> + if (IS_ERR(qphy->pipe_reset)) {
> + dev_err(dev, "failed to acquire pipe reset\n");
> + return PTR_ERR(qphy->pipe_reset);
> + }
> +
> + phy = devm_phy_create(dev, dev->of_node, &qcom_pcie2_ops);
> + if (IS_ERR(phy)) {
> + dev_err(dev, "failed to create phy\n");
> + return PTR_ERR(phy);
> + }
> +
> + phy_set_drvdata(phy, qphy);
> +
> + phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
> + if (IS_ERR(phy_provider))
> + dev_err(dev, "failed to register phy provider\n");
> +
> + return PTR_ERR_OR_ZERO(phy_provider);
> +}
> +
> +static const struct of_device_id qcom_pcie2_phy_match_table[] = {
> + { .compatible = "qcom,pcie2-phy" },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, qcom_pcie2_phy_match_table);
> +
> +static struct platform_driver qcom_pcie2_phy_driver = {
> + .probe = qcom_pcie2_phy_probe,
> + .driver = {
> + .name = "qcom-pcie2-phy",
> + .of_match_table = qcom_pcie2_phy_match_table,
> + },
> +};
> +
> +module_platform_driver(qcom_pcie2_phy_driver);
> +
> +MODULE_DESCRIPTION("Qualcomm PCIe PHY driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.18.0
>

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