linux-kernel - Re: [PATCH 4/5] phy: tegra: xusb: Add support for power supplies

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Date:   Tue, 5 Feb 2019 18:25:04 +0530
From:   Kishon Vijay Abraham I <kishon@...com>
To:     Thierry Reding <thierry.reding@...il.com>, jckuo <jckuo@...dia.com>
CC:     Jonathan Hunter <jonathanh@...dia.com>,
        <linux-tegra@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 4/5] phy: tegra: xusb: Add support for power supplies

Hi,

On 28/01/19 1:30 PM, Thierry Reding wrote:
> On Mon, Jan 28, 2019 at 03:22:09PM +0800, jckuo wrote:
>> Hi Thierry,
>>
>> I think any non-zero return value of
>> regulator_bulk_enable()/devm_regulator_bulk_get() means error.
>>
>> Thanks,
>>
>> JC
> 
> Theoretically I think only regulator_bulk_enable() could return a
> positive value, but even so it never will in practice because all of the
> regulator_enable() (see _regulator_enable()) calls will only ever return
> negative error codes.
> 
> I can change this and resend if you have strong concerns about this
> possibly missing legitimate error cases.

All error codes are negative, so this is fine IMO.

Thanks
Kishon
> 
> Thierry
> 
>> On 1/25/19 7:25 PM, Thierry Reding wrote:
>>> From: Thierry Reding <treding@...dia.com>
>>>
>>> Support enabling various supplies needed to provide power to the PLLs
>>> and logic used to drive the USB, PCI and SATA pads.
>>>
>>> Signed-off-by: Thierry Reding <treding@...dia.com>
>>> ---
>>>   drivers/phy/tegra/xusb.c | 34 +++++++++++++++++++++++++++++++++-
>>>   drivers/phy/tegra/xusb.h |  5 +++++
>>>   2 files changed, 38 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/phy/tegra/xusb.c b/drivers/phy/tegra/xusb.c
>>> index 57a2d08ef6da..e510629f4f1c 100644
>>> --- a/drivers/phy/tegra/xusb.c
>>> +++ b/drivers/phy/tegra/xusb.c
>>> @@ -864,6 +864,7 @@ static int tegra_xusb_padctl_probe(struct platform_device *pdev)
>>>   	struct tegra_xusb_padctl *padctl;
>>>   	const struct of_device_id *match;
>>>   	struct resource *res;
>>> +	unsigned int i;
>>>   	int err;
>>>   	/* for backwards compatibility with old device trees */
>>> @@ -901,14 +902,38 @@ static int tegra_xusb_padctl_probe(struct platform_device *pdev)
>>>   		goto remove;
>>>   	}
>>> +	padctl->supplies = devm_kcalloc(&pdev->dev, padctl->soc->num_supplies,
>>> +					sizeof(*padctl->supplies), GFP_KERNEL);
>>> +	if (!padctl->supplies) {
>>> +		err = -ENOMEM;
>>> +		goto remove;
>>> +	}
>>> +
>>> +	for (i = 0; i < padctl->soc->num_supplies; i++)
>>> +		padctl->supplies[i].supply = padctl->soc->supply_names[i];
>>> +
>>> +	err = devm_regulator_bulk_get(&pdev->dev, padctl->soc->num_supplies,
>>> +				      padctl->supplies);
>>> +	if (err < 0) {
>>> +		dev_err(&pdev->dev, "failed to get regulators: %d\n", err);
>>> +		goto remove;
>>> +	}
>>> +
>>>   	err = reset_control_deassert(padctl->rst);
>>>   	if (err < 0)
>>>   		goto remove;
>>> +	err = regulator_bulk_enable(padctl->soc->num_supplies,
>>> +				    padctl->supplies);
>>> +	if (err < 0) {
>>> +		dev_err(&pdev->dev, "failed to enable supplies: %d\n", err);
>>> +		goto reset;
>>> +	}
>>> +
>>>   	err = tegra_xusb_setup_pads(padctl);
>>>   	if (err < 0) {
>>>   		dev_err(&pdev->dev, "failed to setup pads: %d\n", err);
>>> -		goto reset;
>>> +		goto power_down;
>>>   	}
>>>   	err = tegra_xusb_setup_ports(padctl);
>>> @@ -921,6 +946,8 @@ static int tegra_xusb_padctl_probe(struct platform_device *pdev)
>>>   remove_pads:
>>>   	tegra_xusb_remove_pads(padctl);
>>> +power_down:
>>> +	regulator_bulk_disable(padctl->soc->num_supplies, padctl->supplies);
>>>   reset:
>>>   	reset_control_assert(padctl->rst);
>>>   remove:
>>> @@ -936,6 +963,11 @@ static int tegra_xusb_padctl_remove(struct platform_device *pdev)
>>>   	tegra_xusb_remove_ports(padctl);
>>>   	tegra_xusb_remove_pads(padctl);
>>> +	err = regulator_bulk_disable(padctl->soc->num_supplies,
>>> +				     padctl->supplies);
>>> +	if (err < 0)
>>> +		dev_err(&pdev->dev, "failed to disable supplies: %d\n", err);
>>> +
>>>   	err = reset_control_assert(padctl->rst);
>>>   	if (err < 0)
>>>   		dev_err(&pdev->dev, "failed to assert reset: %d\n", err);
>>> diff --git a/drivers/phy/tegra/xusb.h b/drivers/phy/tegra/xusb.h
>>> index bb60fc09c752..5d5d22f6cb41 100644
>>> --- a/drivers/phy/tegra/xusb.h
>>> +++ b/drivers/phy/tegra/xusb.h
>>> @@ -370,6 +370,9 @@ struct tegra_xusb_padctl_soc {
>>>   	} ports;
>>>   	const struct tegra_xusb_padctl_ops *ops;
>>> +
>>> +	const char * const *supply_names;
>>> +	unsigned int num_supplies;
>>>   };
>>>   struct tegra_xusb_padctl {
>>> @@ -393,6 +396,8 @@ struct tegra_xusb_padctl {
>>>   	unsigned int enable;
>>>   	struct clk *clk;
>>> +
>>> +	struct regulator_bulk_data *supplies;
>>>   };
>>>   static inline void padctl_writel(struct tegra_xusb_padctl *padctl, u32 value,