[PATCH 3/3] usb: dwc3-exynos: Make provision for vdd regulators

[Vivek Gautam]

Hi Anton,


On Wed, Apr 23, 2014 at 2:56 PM, Anton Tikhomirov
<av.tikhomirov at samsung.com> wrote:
> Hello,
>
>> -----Original Message-----
>> From: Vivek Gautam [mailto:gautamvivek1987 at gmail.com] On Behalf Of
>> Vivek Gautam
>> Sent: Monday, April 21, 2014 9:17 PM
>> To: linux-usb at vger.kernel.org; linux-samsung-soc at vger.kernel.org
>> Cc: linux-kernel at vger.kernel.org; linux-omap at vger.kernel.org; linux-
>> arm-kernel at lists.infradead.org; gregkh at linuxfoundation.org;
>> stern at rowland.harvard.edu; balbi at ti.com; kgene.kim at samsung.com; Vivek
>> Gautam; Anton Tikhomirov
>> Subject: [PATCH 3/3] usb: dwc3-exynos: Make provision for vdd
>> regulators
>>
>> Facilitate getting required 3.3V and 1.0V VDD supply for
>> DWC3 controller on Exynos.
>>
>> With patches for regulators' nodes merged in 3.15:
>> c8c253f ARM: dts: Add regulator entries to smdk5420
>> 275dcd2 ARM: dts: add max77686 pmic node for smdk5250,
>>
>> certain perripherals will now need to ensure that,
>> they request VDD regulators in their drivers, and enable
>> them so as to make them working.
>>
>> Signed-off-by: Vivek Gautam <gautam.vivek at samsung.com>
>> Cc: Anton Tikhomirov <av.tikhomirov at samsung.com>
>> ---
>>
>> Based on 'usb-next' branch of Greg's USB tree.
>> Also cleanly applies on 'next' branch of Balbi's USB tree.
>>
>>  drivers/usb/dwc3/dwc3-exynos.c |   51
>> ++++++++++++++++++++++++++++++++++++++--
>>  1 file changed, 49 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/usb/dwc3/dwc3-exynos.c b/drivers/usb/dwc3/dwc3-
>> exynos.c
>> index 28c8ad7..c9d9102 100644
>> --- a/drivers/usb/dwc3/dwc3-exynos.c
>> +++ b/drivers/usb/dwc3/dwc3-exynos.c
>> @@ -27,6 +27,7 @@
>>  #include <linux/usb/usb_phy_gen_xceiv.h>
>>  #include <linux/of.h>
>>  #include <linux/of_platform.h>
>> +#include <linux/regulator/consumer.h>
>>
>>  struct dwc3_exynos {
>>       struct platform_device  *usb2_phy;
>> @@ -34,6 +35,8 @@ struct dwc3_exynos {
>>       struct device           *dev;
>>
>>       struct clk              *clk;
>> +     struct regulator        *vdd33;
>> +     struct regulator        *vdd10;
>>  };
>>
>>  static int dwc3_exynos_register_phys(struct dwc3_exynos *exynos)
>> @@ -144,20 +147,46 @@ static int dwc3_exynos_probe(struct
>> platform_device *pdev)
>>
>>       clk_prepare_enable(exynos->clk);
>>
>> +     exynos->vdd33 = devm_regulator_get(dev, "vdd33");
>> +     if (IS_ERR(exynos->vdd33)) {
>> +             ret = PTR_ERR(exynos->vdd33);
>> +             goto err2;
>
> Is regulator property mandatory for dwc3-exynos? If it is not
> and device tree doesn't provide it, dwc3-exynos driver probe shouldn't
> fail here.

These are the VDD regulators (from PMIC ldo supplies), in absence of
which the controller will not be powered up.
So doesn't it make sense to stop the probe when these are not supplied
by device tree ?

[snip]