Subject: [PATCH v4] PHY: sunxi: Add driver for sunxi usb phy

From: [email-masked] (Hans de Goede)
Date: Tue, 04 Mar 2014 18:03:14 +0100

Hi,

On 03/03/2014 02:18 PM, Kishon Vijay Abraham I wrote:
> Hi,
>
>
> On Sunday 02 March 2014 12:49 AM, Hans de Goede wrote:
>> Hi,
>>
>> On 03/01/2014 06:37 PM, Kishon Vijay Abraham I wrote:
>>> Hi,
>>>
>>> On Saturday 01 March 2014 10:39 PM, Hans de Goede wrote:
>>>> The Allwinner A1x / A2x SoCs have 2 or 3 usb phys which are all accessed
>>>> through a single set of registers. Besides this there are also some other
>>>> phy related bits which need poking, which are per phy, but shared between the
>>>> ohci and ehci controllers, so these are also controlled from this new phy
>>>> driver.
>>>>
>>>> Signed-off-by: Hans de Goede <[email-masked]>
>>>> Acked-by: Maxime Ripard <[email-masked]>
>>>> ---
>>>>    .../devicetree/bindings/phy/sun4i-usb-phy.txt      |  26 ++
>>>>    drivers/phy/Kconfig                                |  11 +
>>>>    drivers/phy/Makefile                               |   1 +
>>>>    drivers/phy/phy-sun4i-usb.c                        | 331 +++++++++++++++++++++
>>>>    4 files changed, 369 insertions(+)
>>>>    create mode 100644 Documentation/devicetree/bindings/phy/sun4i-usb-phy.txt
>>>>    create mode 100644 drivers/phy/phy-sun4i-usb.c
>>>>
>>> ..
>>> <snip>
>>> .
>>> .
>>>
>>>> +static int sun4i_usb_phy_init(struct phy *_phy)
>>>> +{
>>>> +    struct sun4i_usb_phy *phy = phy_get_drvdata(_phy);
>>>> +    struct sun4i_usb_phy_data *data = to_sun4i_usb_phy_data(phy);
>>>> +    int ret;
>>>> +
>>>> +    ret = clk_prepare_enable(data->clk);
>>>> +    if (ret)
>>> dev_err here?
>>
>> I would expect the clk subsys to print an error if anything goes
>> wrong here, repeating that error in the device driver seems
>> not useful to me.
>>
>> Note that this practice of simply propagating the error is a common
>> pattern in many many users of the clk / reset / regulator framework.
>>
>> Also can I please get one final review of this patch rather then
>> a round of comments ending with:
>>
>> "If you can fix these minor comments while changing the $subject (PHY: sunxi) it
>> should be good to get merged."
>>
>> Only to get more review comments when I've already fixed the minor
>> comments ?
>>
>>>> +        return ret;
>>>> +
>>>> +    ret = reset_control_deassert(phy->reset);
>>>> +    if (ret) {
>>>
>>> here too..
>>
>> idem.
>>
>>>> +        clk_disable_unprepare(data->clk);
>>>> +        return ret;
>>>> +    }
>>>> +
>>>> +    /* Adjust PHY's magnitude and rate */
>>>> +    sun4i_usb_phy_write(phy, PHY_TX_AMPLITUDE_TUNE, 0x14, 5);
>>>> +
>>>> +    /* Disconnect threshold adjustment */
>>>> +    sun4i_usb_phy_write(phy, PHY_DISCON_TH_SEL, data->disc_thresh, 2);
>>>> +
>>>> +    sun4i_usb_phy_passby(phy, 1);
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static int sun4i_usb_phy_exit(struct phy *_phy)
>>>> +{
>>>> +    struct sun4i_usb_phy *phy = phy_get_drvdata(_phy);
>>>> +    struct sun4i_usb_phy_data *data = to_sun4i_usb_phy_data(phy);
>>>> +
>>>> +    sun4i_usb_phy_passby(phy, 0);
>>>> +    reset_control_assert(phy->reset);
>>>> +    clk_disable_unprepare(data->clk);
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static int sun4i_usb_phy_power_on(struct phy *_phy)
>>>> +{
>>>> +    struct sun4i_usb_phy *phy = phy_get_drvdata(_phy);
>>>> +    int ret = 0;
>>>> +
>>>> +    if (phy->vbus)
>>>> +        ret = regulator_enable(phy->vbus);
>>> dev_err here too..
>>
>> idem.
>>
>>>> +
>>>> +    return ret;
>>>> +}
>>>> +
>>>> +static int sun4i_usb_phy_power_off(struct phy *_phy)
>>>> +{
>>>> +    struct sun4i_usb_phy *phy = phy_get_drvdata(_phy);
>>>> +
>>>> +    if (phy->vbus)
>>>> +        regulator_disable(phy->vbus);
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static struct phy_ops sun4i_usb_phy_ops = {
>>>> +    .init        = sun4i_usb_phy_init,
>>>> +    .exit        = sun4i_usb_phy_exit,
>>>> +    .power_on    = sun4i_usb_phy_power_on,
>>>> +    .power_off    = sun4i_usb_phy_power_off,
>>>> +    .owner        = THIS_MODULE,
>>>> +};
>>>> +
>>>> +static struct phy *sun4i_usb_phy_xlate(struct device *dev,
>>>> +                    struct of_phandle_args *args)
>>>> +{
>>>> +    struct sun4i_usb_phy_data *data = dev_get_drvdata(dev);
>>>> +
>>>> +    if (WARN_ON(args->args[0] == 0 || args->args[0] >= data->num_phys))
>>>> +        return ERR_PTR(-ENODEV);
>>>> +
>>>> +    return data->phys[args->args[0]].phy;
>>>> +}
>>>> +
>>>> +static int sun4i_usb_phy_probe(struct platform_device *pdev)
>>>> +{
>>>> +    struct sun4i_usb_phy_data *data;
>>>> +    struct device *dev = &pdev->dev;
>>>> +    struct device_node *np = dev->of_node;
>>>> +    void __iomem *pmu = NULL;
>>>> +    struct phy_provider *phy_provider;
>>>> +    struct reset_control *reset;
>>>> +    struct regulator *vbus;
>>>> +    struct resource *res;
>>>> +    struct phy *phy;
>>>> +    char name[16];
>>>> +    int i;
>>>> +
>>>> +    data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
>>>> +    if (!data)
>>>> +        return -ENOMEM;
>>>> +
>>>> +    mutex_init(&data->mutex);
>>>> +
>>>> +    if (of_device_is_compatible(np, "allwinner,sun5i-a13-usb-phy"))
>>>> +        data->num_phys = 2;
>>>> +    else
>>>> +        data->num_phys = 3;
>>>> +
>>>> +    if (of_device_is_compatible(np, "allwinner,sun4i-a10-usb-phy"))
>>>> +        data->disc_thresh = 3;
>>>> +    else
>>>> +        data->disc_thresh = 2;
>>>
>>> These 'data' can actually be part of 'of_device_id' table and can be obtained by using 'of_match_device'.
>>
>> This was already suggested by Maxime around the time of v2, and
>> I responded with this:
>>
>> "The problem with using the of_device_id .data field is that I can only
>> store a single integer there. To store 2 I need to: define a struct,
>> create an array of these structs with initialization. Create an enum for
>> indexing the array which must be kept in sync with the initializers
>> manually, store either the index, or a direct pointer to the correct array
>> entry into the .data field, add code to get the of_device_id from the
>> compatible string, and then finally extract the settings from the struct
>> again.
>>
>> See IE how this is done in drivers/ata/ahci_platform.c, I've tried
>> to come up with a simpler way and failed, for ahci_platform.c the
>> struct with per compatible-string data is quite big so it makes some
>> sense to use this construction. Here however not so much, this adds a
>> whole lot of unnecessary extra code + indirection. I esp. object against
>> the indirection as that unnecessarily makes it harder to follow whats
>> going on."
>
> alright.. missed that earlier. Sorry.

So does this mean you're going to take v4 as is, or do you want me to add
the dev_err calls you've pointed out before (note I still prefer to not
add these, but if you insist...) ?

Regards,

Hans