Re: [PATCH 2/3] usb: chipidea: imx: turn off vbus comparator when suspend

[Peter Chen <peter.chen@kernel.org>]

On 23-05-17 16:19:06, Xu Yang wrote:
> As we use bvalid for vbus wakeup source, to save power when
> suspend, turn off the vbus comparator for imx7d and imx8mm.
> 
> Below is this bit description from RM of iMX8MM
> "VBUS Valid Comparator Enable:
> 
> This signal controls the USB OTG PHY VBUS Valid comparator which
> indicates whether the voltage on the USB_OTG*_VBUS pin is below
> the VBUS Valid threshold. The VBUS Valid threshold is nominally
> 4.75V on this USB PHY. The VBUS Valid threshold can be adjusted
> using the USBNC_OTGn_PHY_CFG1[OTGTUNE0] bit field. Status of the
> VBUS Valid comparator, when it is enabled, is reported on the
> USBNC_OTGn_PHY_STATUS[VBUS_VLD] bit.
> When OTGDISABLE0 (USBNC_USB_OTGx_PHY_CFG2[10])is set to 1'b0 and
> DRVVBUS0 is set to 1'b1, the Bandgap circuitry and VBUS Valid
> comparator are powered, even in Suspend or Sleep mode.
> DRVVBUS0 should be reset to 1'b0 when the internal VBUS Valid comparator
> is not required, to reduce quiescent current in Suspend or Sleep mode.
>  - 0 The VBUS Valid comparator is disabled
>   - 1 The VBUS Valid comparator is enabled"
> 
> Signed-off-by: Li Jun <jun.li@nxp.com>
> Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
> ---
>  drivers/usb/chipidea/usbmisc_imx.c | 35 ++++++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
> 
> diff --git a/drivers/usb/chipidea/usbmisc_imx.c b/drivers/usb/chipidea/usbmisc_imx.c
> index be939e77719d..9566022a2183 100644
> --- a/drivers/usb/chipidea/usbmisc_imx.c
> +++ b/drivers/usb/chipidea/usbmisc_imx.c
> @@ -151,6 +151,7 @@ struct usbmisc_ops {
>  	int (*charger_detection)(struct imx_usbmisc_data *data);
>  	/* It's called when system resume from usb power lost */
>  	int (*power_lost_check)(struct imx_usbmisc_data *data);
> +	void (*vbus_comparator_on)(struct imx_usbmisc_data *data, bool on);
>  };
>  
>  struct imx_usbmisc {
> @@ -874,6 +875,33 @@ static int imx7d_charger_detection(struct imx_usbmisc_data *data)
>  	return ret;
>  }
>  
> +static void usbmisc_imx7d_vbus_comparator_on(struct imx_usbmisc_data *data,
> +					     bool on)
> +{
> +	unsigned long flags;
> +	struct imx_usbmisc *usbmisc = dev_get_drvdata(data->dev);
> +	u32 val;
> +
> +	if (data->hsic)
> +		return;
> +
> +	spin_lock_irqsave(&usbmisc->lock, flags);
> +	/*
> +	 * Disable VBUS valid comparator when in suspend mode,
> +	 * when OTG is disabled and DRVVBUS0 is asserted case
> +	 * the Bandgap circuitry and VBUS Valid comparator are
> +	 * still powered, even in Suspend or Sleep mode.
> +	 */
> +	val = readl(usbmisc->base + MX7D_USB_OTG_PHY_CFG2);
> +	if (on)
> +		val |= MX7D_USB_OTG_PHY_CFG2_DRVVBUS0;
> +	else
> +		val &= ~MX7D_USB_OTG_PHY_CFG2_DRVVBUS0;
> +
> +	writel(val, usbmisc->base + MX7D_USB_OTG_PHY_CFG2);
> +	spin_unlock_irqrestore(&usbmisc->lock, flags);
> +}
> +
>  static int usbmisc_imx7ulp_init(struct imx_usbmisc_data *data)
>  {
>  	struct imx_usbmisc *usbmisc = dev_get_drvdata(data->dev);
> @@ -1017,6 +1045,7 @@ static const struct usbmisc_ops imx7d_usbmisc_ops = {
>  	.set_wakeup = usbmisc_imx7d_set_wakeup,
>  	.charger_detection = imx7d_charger_detection,
>  	.power_lost_check = usbmisc_imx7d_power_lost_check,
> +	.vbus_comparator_on = usbmisc_imx7d_vbus_comparator_on,
>  };
>  
>  static const struct usbmisc_ops imx7ulp_usbmisc_ops = {
> @@ -1131,6 +1160,9 @@ int imx_usbmisc_suspend(struct imx_usbmisc_data *data, bool wakeup)
>  
>  	usbmisc = dev_get_drvdata(data->dev);
>  
> +	if (usbmisc->ops->vbus_comparator_on)
> +		usbmisc->ops->vbus_comparator_on(data, false);
> +
>  	if (wakeup && usbmisc->ops->set_wakeup)
>  		ret = usbmisc->ops->set_wakeup(data, true);
>  	if (ret) {
> @@ -1184,6 +1216,9 @@ int imx_usbmisc_resume(struct imx_usbmisc_data *data, bool wakeup)
>  		goto hsic_set_clk_fail;
>  	}
>  
> +	if (usbmisc->ops->vbus_comparator_on)
> +		usbmisc->ops->vbus_comparator_on(data, true);
> +
>  	return 0;
>  

Acked-by: Peter Chen <peter.chen@kernel.org>

-- 

Thanks,
Peter Chen