usb: chipidea: imx: add one fsl picophy parameter tuning implementation

In some cases, the user may need to tune the rise/fall time of the
high-speed transmitter waveform for USB Certification. This will add
a parameter for this purpose. The value will be fetched from dtb and
finally written to the register.
Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
Acked-by: Peter Chen <peter.chen@kernel.org>
Link: https://lore.kernel.org/r/20230627112126.1882666-3-xu.yang_2@nxp.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/chipidea/ci_hdrc_imx.c

@@ -182,6 +182,9 @@ static struct imx_usbmisc_data *usbmisc_get_init_data(struct device *dev)
 	if (of_property_read_u32(np, "samsung,picophy-dc-vol-level-adjust",
 			&data->dc_vol_level_adjust))
 		data->dc_vol_level_adjust = -1;
+	if (of_property_read_u32(np, "fsl,picophy-rise-fall-time-adjust",
+			&data->rise_fall_time_adjust))
+		data->rise_fall_time_adjust = -1;
 
 	return data;
 }

drivers/usb/chipidea/ci_hdrc_imx.h

@@ -28,6 +28,7 @@ struct imx_usbmisc_data {
 	enum usb_dr_mode available_role; /* runtime usb dr mode */
 	int emp_curr_control;
 	int dc_vol_level_adjust;
+	int rise_fall_time_adjust;
 };
 
 int imx_usbmisc_init(struct imx_usbmisc_data *data);

drivers/usb/chipidea/usbmisc_imx.c

@@ -131,6 +131,8 @@
 #define MX7D_USB_OTG_PHY_CFG1		0x30
 #define TXPREEMPAMPTUNE0_BIT		28
 #define TXPREEMPAMPTUNE0_MASK		(3 << 28)
+#define TXRISETUNE0_BIT			24
+#define TXRISETUNE0_MASK		(3 << 24)
 #define TXVREFTUNE0_BIT			20
 #define TXVREFTUNE0_MASK		(0xf << 20)
 
@@ -674,6 +676,13 @@ static int usbmisc_imx7d_init(struct imx_usbmisc_data *data)
 			reg |= (data->dc_vol_level_adjust << TXVREFTUNE0_BIT);
 		}
 
+		if (data->rise_fall_time_adjust >= 0 &&
+			data->rise_fall_time_adjust <=
+			(TXRISETUNE0_MASK >> TXRISETUNE0_BIT)) {
+			reg &= ~TXRISETUNE0_MASK;
+			reg |= (data->rise_fall_time_adjust << TXRISETUNE0_BIT);
+		}
+
 		writel(reg, usbmisc->base + MX7D_USB_OTG_PHY_CFG1);
 	}