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

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Message-ID: <047df95e-b1b6-4e7b-89f7-d7cb69559a49@tuxon.dev>
Date: Tue, 18 Nov 2025 16:13:02 +0200
From: Claudiu Beznea <claudiu.beznea@...on.dev>
To: Neil Armstrong <neil.armstrong@...aro.org>,
 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

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.

Thank you,
Claudiu