Re: [PATCH 3/9] phy: qcom-m31: Introduce qcom,m31 USB phy driver

From: Varadarajan Narayanan
Date: Thu Jun 15 2023 - 01:50:57 EST

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On Wed, Jun 07, 2023 at 01:54:23PM +0200, Konrad Dybcio wrote:
>
>
> On 7.06.2023 12:56, Varadarajan Narayanan wrote:
> > Add the M31 USB2 phy driver
> >
> > Signed-off-by: Varadarajan Narayanan <quic_varada@xxxxxxxxxxx>
> > ---
> > drivers/phy/qualcomm/phy-qcom-m31.c | 360 ++++++++++++++++++++++++++++++++++++
> > 1 file changed, 360 insertions(+)
> > create mode 100644 drivers/phy/qualcomm/phy-qcom-m31.c
> >
> > diff --git a/drivers/phy/qualcomm/phy-qcom-m31.c b/drivers/phy/qualcomm/phy-qcom-m31.c
> > new file mode 100644
> > index 0000000..d29a91e
> > --- /dev/null
> > +++ b/drivers/phy/qualcomm/phy-qcom-m31.c
> > @@ -0,0 +1,360 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright (c) 2014-2016, 2020, The Linux Foundation. All rights reserved.
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/kernel.h>
> > +#include <linux/err.h>
> > +#include <linux/slab.h>
> > +#include <linux/clk.h>
> > +#include <linux/delay.h>
> > +#include <linux/io.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/usb/phy.h>
> > +#include <linux/reset.h>
> > +#include <linux/of_device.h>
> Please sort these

Ok.

> > +
> > +enum clk_reset_action {
> > + CLK_RESET_DEASSERT = 0,
> > + CLK_RESET_ASSERT = 1
> > +};
> > +
> > +#define USB2PHY_PORT_POWERDOWN 0xA4
> > +#define POWER_UP BIT(0)
> > +#define POWER_DOWN 0
> > +
> > +#define USB2PHY_PORT_UTMI_CTRL1 0x40
> > +
> > +#define USB2PHY_PORT_UTMI_CTRL2 0x44
> > +#define UTMI_ULPI_SEL BIT(7)
> > +#define UTMI_TEST_MUX_SEL BIT(6)
> > +
> > +#define HS_PHY_CTRL_REG 0x10
> > +#define UTMI_OTG_VBUS_VALID BIT(20)
> > +#define SW_SESSVLD_SEL BIT(28)
> > +
> > +#define USB_PHY_CFG0 0x94
> > +#define USB_PHY_UTMI_CTRL5 0x50
> > +#define USB_PHY_FSEL_SEL 0xB8
> > +#define USB_PHY_HS_PHY_CTRL_COMMON0 0x54
> > +#define USB_PHY_REFCLK_CTRL 0xA0
> > +#define USB_PHY_HS_PHY_CTRL2 0x64
> > +#define USB_PHY_UTMI_CTRL0 0x3c
> > +#define USB2PHY_USB_PHY_M31_XCFGI_1 0xBC
> > +#define USB2PHY_USB_PHY_M31_XCFGI_4 0xC8
> > +#define USB2PHY_USB_PHY_M31_XCFGI_5 0xCC
> > +#define USB2PHY_USB_PHY_M31_XCFGI_11 0xE4
> Could you sort them address-wise?

Ok.

> > +
> > +#define USB2_0_TX_ENABLE BIT(2)
> > +#define HSTX_SLEW_RATE_565PS 3
> > +#define PLL_CHARGING_PUMP_CURRENT_35UA (3 << 3)
> > +#define ODT_VALUE_38_02_OHM (3 << 6)
> > +#define ODT_VALUE_45_02_OHM BIT(2)
> > +#define HSTX_PRE_EMPHASIS_LEVEL_0_55MA (1)
> Weird mix of values, bits, bitfields.. perhaps BIT(n) and
> GENMASK() (+ FIELD_PREP) would be more suitable?

Ok.

> > +
> > +#define UTMI_PHY_OVERRIDE_EN BIT(1)
> > +#define POR_EN BIT(1)
> Please associate these with their registers, like

Ok.

> #define FOO_REG 0xf00
> #define POR_EN BIT(1)
>
> > +#define FREQ_SEL BIT(0)
> > +#define COMMONONN BIT(7)
> > +#define FSEL BIT(4)
> > +#define RETENABLEN BIT(3)
> > +#define USB2_SUSPEND_N_SEL BIT(3)
> > +#define USB2_SUSPEND_N BIT(2)
> > +#define USB2_UTMI_CLK_EN BIT(1)
> > +#define CLKCORE BIT(1)
> > +#define ATERESET ~BIT(0)
> > +#define FREQ_24MHZ (5 << 4)
> > +#define XCFG_COARSE_TUNE_NUM (2 << 0)
> > +#define XCFG_FINE_TUNE_NUM (1 << 3)
> same comment

Ok.

> > +
> > +static void m31usb_write_readback(void *base, u32 offset,
> > + const u32 mask, u32 val);
> We don't need this forward-definition, just move the function up.
>
> > +
> > +struct m31usb_phy {
> > + struct usb_phy phy;
> > + void __iomem *base;
> > + void __iomem *qscratch_base;
> > +
> > + struct reset_control *phy_reset;
> > +
> > + bool cable_connected;
> > + bool suspended;
> > + bool ulpi_mode;
> > +};
> > +
> > +static void m31usb_reset(struct m31usb_phy *qphy, u32 action)
> > +{
> > + if (action == CLK_RESET_ASSERT)
> > + reset_control_assert(qphy->phy_reset);
> > + else
> > + reset_control_deassert(qphy->phy_reset);
> > + wmb(); /* ensure data is written to hw register */
> Please move the comment above the call.

This is used only once. Hence, will move it to the calling location itself.

> > +}
> > +
> > +static void m31usb_phy_enable_clock(struct m31usb_phy *qphy)
> > +{
> > + /* Enable override ctrl */
> > + writel(UTMI_PHY_OVERRIDE_EN, qphy->base + USB_PHY_CFG0);
> Some of the comments are missing a space before '*/'
>
> Also, please consider adding some newlines to logically split the
> actions.
>
> > + /* Enable POR*/
> > + writel(POR_EN, qphy->base + USB_PHY_UTMI_CTRL5);
> > + udelay(15);
> > + /* Configure frequency select value*/
> > + writel(FREQ_SEL, qphy->base + USB_PHY_FSEL_SEL);
> > + /* Configure refclk frequency */
> > + writel(COMMONONN | FSEL | RETENABLEN,
> > + qphy->base + USB_PHY_HS_PHY_CTRL_COMMON0);
> > + /* select refclk source */
> > + writel(CLKCORE, qphy->base + USB_PHY_REFCLK_CTRL);
> > + /* select ATERESET*/
> > + writel(POR_EN & ATERESET, qphy->base + USB_PHY_UTMI_CTRL5);
> > + writel(USB2_SUSPEND_N_SEL | USB2_SUSPEND_N | USB2_UTMI_CLK_EN,
> > + qphy->base + USB_PHY_HS_PHY_CTRL2);
> > + writel(0x0, qphy->base + USB_PHY_UTMI_CTRL5);
> > + writel(USB2_SUSPEND_N | USB2_UTMI_CLK_EN,
> > + qphy->base + USB_PHY_HS_PHY_CTRL2);
> > + /* Disable override ctrl */
> > + writel(0x0, qphy->base + USB_PHY_CFG0);
> > +}
> > +
> > +static void ipq5332_m31usb_phy_enable_clock(struct m31usb_phy *qphy)
> > +{
> > + /* Enable override ctrl */
> > + writel(UTMI_PHY_OVERRIDE_EN, qphy->base + USB_PHY_CFG0);
> > + /* Enable POR*/
> ditto
>
> > + writel(POR_EN, qphy->base + USB_PHY_UTMI_CTRL5);
> > + udelay(15);
> > + /* Configure frequency select value*/
> > + writel(FREQ_SEL, qphy->base + USB_PHY_FSEL_SEL);
> > + /* Configure refclk frequency */
> > + writel(COMMONONN | FREQ_24MHZ | RETENABLEN,
> > + qphy->base + USB_PHY_HS_PHY_CTRL_COMMON0);
> > + /* select ATERESET*/
> > + writel(POR_EN & ATERESET, qphy->base + USB_PHY_UTMI_CTRL5);
> > + writel(USB2_SUSPEND_N_SEL | USB2_SUSPEND_N | USB2_UTMI_CLK_EN,
> > + qphy->base + USB_PHY_HS_PHY_CTRL2);
> > + writel(XCFG_COARSE_TUNE_NUM | XCFG_FINE_TUNE_NUM,
> > + qphy->base + USB2PHY_USB_PHY_M31_XCFGI_11);
> > + /* Adjust HSTX slew rate to 565 ps*/
> > + /* Adjust PLL lock Time counter for release clock to 35uA */
> > + /* Adjust Manual control ODT value to 38.02 Ohm */
> > + writel(HSTX_SLEW_RATE_565PS | PLL_CHARGING_PUMP_CURRENT_35UA |
> > + ODT_VALUE_38_02_OHM, qphy->base + USB2PHY_USB_PHY_M31_XCFGI_4);
> These functions seem very similar, with the main difference being that
> IPQ5332 adds some more writes at the end. Perhaps some commonizing could
> be done?
>
> > + /*
> > + * Enable to always turn on USB 2.0 TX driver
> > + * when system is in USB 2.0 HS mode
> > + */
> > + writel(USB2_0_TX_ENABLE, qphy->base + USB2PHY_USB_PHY_M31_XCFGI_1);
> > + /* Adjust Manual control ODT value to 45.02 Ohm */
> > + /* Adjust HSTX Pre-emphasis level to 0.55mA */
> > + writel(ODT_VALUE_45_02_OHM | HSTX_PRE_EMPHASIS_LEVEL_0_55MA,
> > + qphy->base + USB2PHY_USB_PHY_M31_XCFGI_5);
> > + udelay(4);
> > + writel(0x0, qphy->base + USB_PHY_UTMI_CTRL5);
> > + writel(USB2_SUSPEND_N | USB2_UTMI_CLK_EN,
> > + qphy->base + USB_PHY_HS_PHY_CTRL2);
> > +}

Will change the above to table based register init, based on
compatible/data.

> > +
> > +static int m31usb_phy_init(struct usb_phy *phy)
> > +{
> > + struct m31usb_phy *qphy = container_of(phy, struct m31usb_phy, phy);
> > +
> > + /* Perform phy reset */
> > + m31usb_reset(qphy, CLK_RESET_ASSERT);
> > + usleep_range(1, 5);
> https://www.kernel.org/doc/Documentation/timers/timers-howto.txt
>
> this may not work as intended

Will change it to udelay(5).

> > + m31usb_reset(qphy, CLK_RESET_DEASSERT);
> > +
> > + /* configure for ULPI mode if requested */
> > + if (qphy->ulpi_mode)
> > + writel_relaxed(0x0, qphy->base + USB2PHY_PORT_UTMI_CTRL2);
> > +
> > + /* Enable the PHY */
> > + writel_relaxed(POWER_UP, qphy->base + USB2PHY_PORT_POWERDOWN);
> > +
> > + /* Make sure above write completed */
> > + wmb();
> As you're calling wmb in the reset func, dropping _relaxed from the
> ULPI and PORT_POWERDOWN writes should work the same

Ok.

> > +
> > + /* Turn on phy ref clock*/
> > + if (of_device_is_compatible(phy->dev->of_node,
> > + "qcom,ipq5332-m31-usb-hsphy"))
> > + ipq5332_m31usb_phy_enable_clock(qphy);
> > + else
> > + m31usb_phy_enable_clock(qphy);
> This should be done using OF match data.

Ok.

> > +
> > + /* Set OTG VBUS Valid from HSPHY to controller */
> > + m31usb_write_readback(qphy->qscratch_base, HS_PHY_CTRL_REG,
> > + UTMI_OTG_VBUS_VALID, UTMI_OTG_VBUS_VALID);
> > + /* Indicate value is driven by UTMI_OTG_VBUS_VALID bit */
> > + m31usb_write_readback(qphy->qscratch_base, HS_PHY_CTRL_REG,
> > + SW_SESSVLD_SEL, SW_SESSVLD_SEL);
> > +
> > + return 0;
> > +}
> > +
> > +static void m31usb_phy_shutdown(struct usb_phy *phy)
> > +{
> > + struct m31usb_phy *qphy = container_of(phy, struct m31usb_phy, phy);
> > +
> > + /* Disable the PHY */
> > + writel_relaxed(POWER_DOWN, qphy->base + USB2PHY_PORT_POWERDOWN);
> > + /* Make sure above write completed */
> > + wmb();
> > +}
> > +
> > +static void m31usb_write_readback(void *base, u32 offset,
> > + const u32 mask, u32 val)
> The indentation here makes `const u32..` misaligned.
>
> > +{
> > + u32 write_val, tmp = readl_relaxed(base + offset);
> > +
> > + tmp &= ~mask; /* retain other bits */
> > + write_val = tmp | val;
> > +
> > + writel_relaxed(write_val, base + offset);
> > + /* Make sure above write completed */
> > + wmb();
> > +
> > + /* Read back to see if val was written */
> > + tmp = readl_relaxed(base + offset);
> > + tmp &= mask; /* clear other bits */
> > +
> > + if (tmp != val)
> > + pr_err("%s: write: %x to QSCRATCH: %x FAILED\n",
> > + __func__, val, offset);
> > +}
> > +
> > +static int m31usb_phy_notify_connect(struct usb_phy *phy,
> > + enum usb_device_speed speed)
> > +{
> > + struct m31usb_phy *qphy = container_of(phy, struct m31usb_phy, phy);
> > +
> > + qphy->cable_connected = true;
> > +
> > + dev_dbg(phy->dev, " cable_connected=%d\n", qphy->cable_connected);
> spurious space at the beginning of the string
>
> > +
> > + /* Set OTG VBUS Valid from HSPHY to controller */
> > + m31usb_write_readback(qphy->qscratch_base, HS_PHY_CTRL_REG,
> > + UTMI_OTG_VBUS_VALID,
> > + UTMI_OTG_VBUS_VALID);
> Please align the lines with the previous opening bracket
>
> > +
> > + /* Indicate value is driven by UTMI_OTG_VBUS_VALID bit */
> > + m31usb_write_readback(qphy->qscratch_base, HS_PHY_CTRL_REG,
> > + SW_SESSVLD_SEL, SW_SESSVLD_SEL);
> > +
> > + dev_dbg(phy->dev, "M31USB2 phy connect notification\n");
> > + return 0;
> > +}
> > +
> > +static int m31usb_phy_notify_disconnect(struct usb_phy *phy,
> > + enum usb_device_speed speed)
> > +{
> > + struct m31usb_phy *qphy = container_of(phy, struct m31usb_phy, phy);
> > +
> > + qphy->cable_connected = false;
> > +
> > + dev_dbg(phy->dev, " cable_connected=%d\n", qphy->cable_connected);
> > +
> > + /* Set OTG VBUS Valid from HSPHY to controller */
> > + m31usb_write_readback(qphy->qscratch_base, HS_PHY_CTRL_REG,
> > + UTMI_OTG_VBUS_VALID, 0);
> > +
> > + /* Indicate value is driven by UTMI_OTG_VBUS_VALID bit */
> > + m31usb_write_readback(qphy->qscratch_base, HS_PHY_CTRL_REG,
> > + SW_SESSVLD_SEL, 0);
> > +
> > + dev_dbg(phy->dev, "M31USB2 phy disconnect notification\n");
> > + return 0;
> > +}

Will remove these functions. They are accessing 'qscratch' area that
is part of the controller space. It doesn't belong in this driver.

> > +static int m31usb_phy_probe(struct platform_device *pdev)
> > +{
> > + struct m31usb_phy *qphy;
> > + struct device *dev = &pdev->dev;
> > + struct resource *res;
> > + int ret;
> > + const char *phy_type;
> Please sort these in a reverse-Christmas-tree order.

ok.

> > +
> > + qphy = devm_kzalloc(dev, sizeof(*qphy), GFP_KERNEL);
> > + if (!qphy)
> > + return -ENOMEM;
> > +
> > + qphy->phy.dev = dev;
> > +
> > + res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > + "m31usb_phy_base");
> > + qphy->base = devm_ioremap_resource(dev, res);
> devm_platform_get_and_ioremap_resource?

ok.

> > + if (IS_ERR(qphy->base))
> > + return PTR_ERR(qphy->base);
> > +
> > + res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > + "qscratch_base");
> > + if (res) {
> Do we expect platforms without this register space?
>
> > + qphy->qscratch_base = devm_ioremap(dev, res->start,
> > + resource_size(res));
> > + if (IS_ERR(qphy->qscratch_base)) {
> > + dev_dbg(dev, "couldn't ioremap qscratch_base\n");
> > + qphy->qscratch_base = NULL;
> > + }
> > + }

Will remove this qscratch code.

> > + qphy->phy_reset = devm_reset_control_get(dev, "usb2_phy_reset");
> not _exclusive?

Ok.

> > + if (IS_ERR(qphy->phy_reset))
> > + return PTR_ERR(qphy->phy_reset);
> > +
> > + qphy->ulpi_mode = false;
> > + ret = of_property_read_string(dev->of_node, "phy_type", &phy_type);
> of_usb_get_phy_mode?

Ok.

> > +
> > + if (!ret) {
> > + if (!strcasecmp(phy_type, "ulpi"))
> > + qphy->ulpi_mode = true;
> > + } else {
> > + dev_err(dev, "error reading phy_type property\n");
> > + return ret;
> > + }
> > +
> > + platform_set_drvdata(pdev, qphy);
> > +
> > + qphy->phy.label = "qcom-m31usb-phy";
> > + qphy->phy.init = m31usb_phy_init;
> > + qphy->phy.shutdown = m31usb_phy_shutdown;
> > + qphy->phy.type = USB_PHY_TYPE_USB2;
> > +
> > + if (qphy->qscratch_base) {
> > + qphy->phy.notify_connect = m31usb_phy_notify_connect;
> > + qphy->phy.notify_disconnect = m31usb_phy_notify_disconnect;
> > + }
> > +
> > + ret = usb_add_phy_dev(&qphy->phy);
> > +
> > + return ret;
> > +}
> > +
> > +static int m31usb_phy_remove(struct platform_device *pdev)
> Please make this return void and pass it to .remove_new

Ok.

> > +{
> > + struct m31usb_phy *qphy = platform_get_drvdata(pdev);
> > +
> > + usb_remove_phy(&qphy->phy);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct of_device_id m31usb_phy_id_table[] = {
> > + { .compatible = "qcom,m31-usb-hsphy",},
> > + { .compatible = "qcom,ipq5332-m31-usb-hsphy",},
> > + { },
> > +};
> > +MODULE_DEVICE_TABLE(of, m31usb_phy_id_table);
> > +
> > +static struct platform_driver m31usb_phy_driver = {
> > + .probe = m31usb_phy_probe,
> > + .remove = m31usb_phy_remove,
> > + .driver = {
> > + .name = "qcom-m31usb-phy",
> > + .of_match_table = of_match_ptr(m31usb_phy_id_table),
> of_match_ptr is unnecessary, this driver depends on OF.

Ok.

Thanks
Varada

> Konrad
> > + },
> > +};
> > +
> > +module_platform_driver(m31usb_phy_driver);
> > +
> > +MODULE_DESCRIPTION("USB2 Qualcomm M31 HSPHY driver");
> > +MODULE_LICENSE("GPL");

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