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

[Varadarajan Narayanan]

On Wed, Jun 07, 2023 at 03:29:18PM +0300, Dmitry Baryshkov wrote:
> Two minor nits on top of the review:
>
> On 07/06/2023 14:54, 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
> >
> >>+
> >>+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?
>
> ... and lowercase the hex values, please.

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?
> >
> >>+
> >>+#define UTMI_PHY_OVERRIDE_EN		BIT(1)
> >>+#define POR_EN				BIT(1)
> >Please associate these with their registers, like
> >
> >#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
> >
> >>+
> >>+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.
> >
> >>+}
>
> Or even better just inline the function. I was never a fan of such
> multiplexers.
>
> Also does wmb() make sense here? Doesn't regmap (which is used by reset
> controller) remove the need for it?

Will inline and remove the wmb.

Thanks
Varada

> >>+
> >>+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.
>
>
> --
> With best wishes
> Dmitry
>