usb: dwc2: platform: add support for utmi optional clock

Add support for the utmi clock. It's needed on STM32MP15, when using
the integrated full-speed PHY. This clock is an output of USBPHYC, but
HS USBPHYC is not attached as PHY in this case: Full-Speed PHY is directly
managed in dwc2 glue, through GGPIO register. Typical DT when using FS PHY
&usbotg_hs {
	compatible = "st,stm32mp15-fsotg", "snps,dwc2";
	pinctrl-names = "default";
	pinctrl-0 = <&usbotg_hs_pins_a &usbotg_fs_dp_dm_pins_a>;
	vbus-supply = <&vbus_otg>;
	status = "okay";
};

In this configuration, USBPHYC clock output must be defined, so it can
be properly enabled as a clock provider:
	clocks = <&rcc USBO_K>, <&usbphyc>;
	clock-names = "otg", "utmi";

Acked-by: Minas Harutyunyan <hminas@synopsys.com>
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20230414084137.1050487-4-fabrice.gasnier@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 19 insertions, 1 deletions

diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
index c431ce6c119f..5aee284018c0 100644
--- a/drivers/usb/dwc2/platform.c
+++ b/drivers/usb/dwc2/platform.c
@@ -101,10 +101,16 @@ static int __dwc2_lowlevel_hw_enable(struct dwc2_hsotg *hsotg)
 	if (ret)
 		return ret;
 
+	if (hsotg->utmi_clk) {
+		ret = clk_prepare_enable(hsotg->utmi_clk);
+		if (ret)
+			goto err_dis_reg;
+	}
+
 	if (hsotg->clk) {
 		ret = clk_prepare_enable(hsotg->clk);
 		if (ret)
-			goto err_dis_reg;
+			goto err_dis_utmi_clk;
 	}
 
 	if (hsotg->uphy) {
@@ -129,6 +135,10 @@ err_dis_clk:
 	if (hsotg->clk)
 		clk_disable_unprepare(hsotg->clk);
 
+err_dis_utmi_clk:
+	if (hsotg->utmi_clk)
+		clk_disable_unprepare(hsotg->utmi_clk);
+
 err_dis_reg:
 	regulator_bulk_disable(ARRAY_SIZE(hsotg->supplies), hsotg->supplies);
 
@@ -171,6 +181,9 @@ static int __dwc2_lowlevel_hw_disable(struct dwc2_hsotg *hsotg)
 	if (hsotg->clk)
 		clk_disable_unprepare(hsotg->clk);
 
+	if (hsotg->utmi_clk)
+		clk_disable_unprepare(hsotg->utmi_clk);
+
 	return regulator_bulk_disable(ARRAY_SIZE(hsotg->supplies), hsotg->supplies);
 }
 
@@ -247,6 +260,11 @@ static int dwc2_lowlevel_hw_init(struct dwc2_hsotg *hsotg)
 	if (IS_ERR(hsotg->clk))
 		return dev_err_probe(hsotg->dev, PTR_ERR(hsotg->clk), "cannot get otg clock\n");
 
+	hsotg->utmi_clk = devm_clk_get_optional(hsotg->dev, "utmi");
+	if (IS_ERR(hsotg->utmi_clk))
+		return dev_err_probe(hsotg->dev, PTR_ERR(hsotg->utmi_clk),
+				     "cannot get utmi clock\n");
+
 	/* Regulators */
 	for (i = 0; i < ARRAY_SIZE(hsotg->supplies); i++)
 		hsotg->supplies[i].supply = dwc2_hsotg_supply_names[i];