[v2,3/4] 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";

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
---
Changes in v2:
- "utmi_clk" renamed "utmi" as per Krzysztof comment on dt-bindings
---
 drivers/usb/dwc2/core.h     |  2 ++
 drivers/usb/dwc2/platform.c | 20 +++++++++++++++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

On 4/14/23 12:41, Fabrice Gasnier wrote:
> 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";
> 
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>

Acked-by: Minas Harutyunyan <hminas@synopsys.com>

> ---
> Changes in v2:
> - "utmi_clk" renamed "utmi" as per Krzysztof comment on dt-bindings
> ---
>   drivers/usb/dwc2/core.h     |  2 ++
>   drivers/usb/dwc2/platform.c | 20 +++++++++++++++++++-
>   2 files changed, 21 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
> index 40cf2880d7e5..0bb4c0c845bf 100644
> --- a/drivers/usb/dwc2/core.h
> +++ b/drivers/usb/dwc2/core.h
> @@ -1003,6 +1003,7 @@ struct dwc2_hregs_backup {
>    * @ctrl_out_desc:	EP0 OUT data phase desc chain pointer
>    * @irq:		Interrupt request line number
>    * @clk:		Pointer to otg clock
> + * @utmi_clk:		Pointer to utmi_clk clock
>    * @reset:		Pointer to dwc2 reset controller
>    * @reset_ecc:          Pointer to dwc2 optional reset controller in Stratix10.
>    * @regset:		A pointer to a struct debugfs_regset32, which contains
> @@ -1065,6 +1066,7 @@ struct dwc2_hsotg {
>   	void *priv;
>   	int     irq;
>   	struct clk *clk;
> +	struct clk *utmi_clk;
>   	struct reset_control *reset;
>   	struct reset_control *reset_ecc;
>   
> 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 @@ static int __dwc2_lowlevel_hw_enable(struct dwc2_hsotg *hsotg)
>   	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];