Messages in this thread | | | Subject | Re: [PATCH v10 4/8] drm/ingenic: Add dw-hdmi driver for jz4780 | From | "H. Nikolaus Schaller" <> | Date | Wed, 1 Dec 2021 14:51:51 +0100 |
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Hi,
> Am 01.12.2021 um 14:39 schrieb Mark Brown <broonie@kernel.org>: > > On Wed, Dec 01, 2021 at 01:02:45PM +0000, Paul Cercueil wrote: >> Le mar., nov. 30 2021 at 22:26:37 +0100, H. Nikolaus Schaller > >>> + regulator = devm_regulator_get_optional(&pdev->dev, "hdmi-5v"); >>> + if (IS_ERR(regulator)) { >>> + ret = PTR_ERR(regulator); > > Why is this using _optional()? This should only be done when the supply > can be physically absent
There can be +5V for HDMI but without a regulator that is visible to or controllable by the driver.
So hdmi-5v can be simply missing in DTS in which case the driver does not need to care about. The driver just can't turn it on or off.
> (in which case I'd expect to see special > handling).
The special case is to not enable/disable the regulator if it does not exist and assume that there is hardware providing it otherwise (the driver can't know that except by using get_optional). This is done by the code below
>>> + if (IS_ERR(regulator)) {
...
> + if (!regulator) > + return 0; > > + ret = regulator_enable(regulator);
...
BR and thanks, Nikolaus
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