linux-kernel - Re: [PATCH] phy: renesas: rcar-gen3-usb2: Add suspend/resume support

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Message-ID: <ab085051-27fd-415c-83b4-5ca087bdb0c8@linaro.org>
Date: Tue, 18 Nov 2025 16:03:39 +0100
From: Neil Armstrong <neil.armstrong@...aro.org>
To: Claudiu Beznea <claudiu.beznea@...on.dev>,
 yoshihiro.shimoda.uh@...esas.com, vkoul@...nel.org, kishon@...nel.org,
 geert+renesas@...der.be, magnus.damm@...il.com, p.zabel@...gutronix.de
Cc: linux-renesas-soc@...r.kernel.org, linux-phy@...ts.infradead.org,
 linux-kernel@...r.kernel.org,
 Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: Re: [PATCH] phy: renesas: rcar-gen3-usb2: Add suspend/resume support

On 11/18/25 15:13, Claudiu Beznea wrote:
> Hi, Neil,
> 
> On 11/18/25 15:54, Neil Armstrong wrote:
>> On 11/6/25 15:41, Claudiu wrote:
>>> From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
>>>
>>> The Renesas RZ/G3S supports a power saving mode where power to most of the
>>> SoC components is turned off. The USB PHY is among these components.
>>> Because of this the settings applied in driver probe need to be executed
>>> also on resume path. On suspend path only reset signal need to be asserted.
>>> Add suspend/resume support.
>>>
>>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
>>> ---
>>>
>>> This patch is built on top of patches 1/7, 2/7 at [1]
>>>
>>> [1] https://lore.kernel.org/all/20251023135810.1688415-2-
>>> claudiu.beznea.uj@...renesas.com
>>>
>>>    drivers/phy/renesas/phy-rcar-gen3-usb2.c | 66 +++++++++++++++++-------
>>>    1 file changed, 47 insertions(+), 19 deletions(-)
>>>
>>> diff --git a/drivers/phy/renesas/phy-rcar-gen3-usb2.c b/drivers/phy/
>>> renesas/phy-rcar-gen3-usb2.c
>>> index a38ead7c8055..3c063e4dea41 100644
>>> --- a/drivers/phy/renesas/phy-rcar-gen3-usb2.c
>>> +++ b/drivers/phy/renesas/phy-rcar-gen3-usb2.c
>>> @@ -132,6 +132,7 @@ struct rcar_gen3_chan {
>>>        struct device *dev;    /* platform_device's device */
>>>        const struct rcar_gen3_phy_drv_data *phy_data;
>>>        struct extcon_dev *extcon;
>>> +    struct reset_control *rstc;
>>>        struct rcar_gen3_phy rphys[NUM_OF_PHYS];
>>>        struct regulator *vbus;
>>>        struct work_struct work;
>>> @@ -778,35 +779,24 @@ static void rcar_gen3_reset_assert(void *data)
>>>    static int rcar_gen3_phy_usb2_init_bus(struct rcar_gen3_chan *channel)
>>>    {
>>>        struct device *dev = channel->dev;
>>> -    struct reset_control *rstc;
>>>        int ret;
>>>        u32 val;
>>>    -    rstc = devm_reset_control_array_get_shared(dev);
>>> -    if (IS_ERR(rstc))
>>> -        return PTR_ERR(rstc);
>>> +    if (!channel->phy_data->init_bus)
>>> +        return 0;
>>>          ret = pm_runtime_resume_and_get(dev);
>>>        if (ret)
>>>            return ret;
>>>    -    ret = reset_control_deassert(rstc);
>>> -    if (ret)
>>> -        goto rpm_put;
>>> -
>>> -    ret = devm_add_action_or_reset(dev, rcar_gen3_reset_assert, rstc);
>>> -    if (ret)
>>> -        goto rpm_put;
>>> -
>>>        val = readl(channel->base + USB2_AHB_BUS_CTR);
>>>        val &= ~USB2_AHB_BUS_CTR_MBL_MASK;
>>>        val |= USB2_AHB_BUS_CTR_MBL_INCR4;
>>>        writel(val, channel->base + USB2_AHB_BUS_CTR);
>>>    -rpm_put:
>>>        pm_runtime_put(dev);
>>>    -    return ret;
>>> +    return 0;
>>>    }
>>>      static int rcar_gen3_phy_usb2_probe(struct platform_device *pdev)
>>> @@ -846,6 +836,18 @@ static int rcar_gen3_phy_usb2_probe(struct
>>> platform_device *pdev)
>>>            }
>>>        }
>>>    +    channel->rstc = devm_reset_control_array_get_optional_shared(dev);
>>> +    if (IS_ERR(channel->rstc))
>>> +        return PTR_ERR(channel->rstc);
>>> +
>>> +    ret = reset_control_deassert(channel->rstc);
>>> +    if (ret)
>>> +        return ret;
>>> +
>>> +    ret = devm_add_action_or_reset(dev, rcar_gen3_reset_assert, channel-
>>>> rstc);
>>> +    if (ret)
>>> +        return ret;
>>> +
>>>        /*
>>>         * devm_phy_create() will call pm_runtime_enable(&phy->dev);
>>>         * And then, phy-core will manage runtime pm for this device.
>>> @@ -861,11 +863,9 @@ static int rcar_gen3_phy_usb2_probe(struct
>>> platform_device *pdev)
>>>        platform_set_drvdata(pdev, channel);
>>>        channel->dev = dev;
>>>    -    if (channel->phy_data->init_bus) {
>>> -        ret = rcar_gen3_phy_usb2_init_bus(channel);
>>> -        if (ret)
>>> -            goto error;
>>> -    }
>>
>> I don't see why you changed the logic of calling
>> rcar_gen3_phy_usb2_init_bus(),
>> moving the reset setup and handling should be enough, no ?
>>
> Sorry, I missed to mention it. I did it like this just to avoid this pattern:
> 
> 	if (channel->phy_data->init_bus) {
> 		ret = rcar_gen3_phy_usb2_init_bus(channel);
> 		if (ret)
> 			return ret;
> 	}
> 
> in both probe and resume path. The channel->phy_data->init_bus check is not
> embedded in rcar_gen3_phy_usb2_init_bus(). Please let me know if you want
> me to revert it.

It's an unrelated change, so I think it should be moved to a separate cleanup patch.

Thanks,
Neil


> 
> Thank you,
> Claudiu