Hi dee Ho Laurent & All,
On 10/21/22 18:29, Neil Armstrong wrote:
> Hi,
>
> On 21/10/2022 17:02, Laurent Pinchart wrote:
>> Hi Matti,
>>
>> On Fri, Oct 21, 2022 at 04:18:01PM +0300, Matti Vaittinen wrote:
>>> Simplify using the devm_regulator_get_enable_optional(). Also drop the
>>> seemingly unused struct member 'hdmi_supply'.
>>>
>>> Signed-off-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx>
>>>
>>> ---
>>> v3 => v4:
>>> - split meson part to own patch
>>>
>>> RFCv1 => v2:
>>> - Change also sii902x to use devm_regulator_bulk_get_enable()
>>>
>>> Please note - this is only compile-tested due to the lack of HW. Careful
>>> review and testing is _highly_ appreciated.
>>> ---
>>> drivers/gpu/drm/meson/meson_dw_hdmi.c | 23 +++--------------------
>>> 1 file changed, 3 insertions(+), 20 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c
>>> b/drivers/gpu/drm/meson/meson_dw_hdmi.c
>>> index 5cd2b2ebbbd3..7642f740272b 100644
>>> --- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
>>> +++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
>>> @@ -140,7 +140,6 @@ struct meson_dw_hdmi {
>>> struct reset_control *hdmitx_apb;
>>> struct reset_control *hdmitx_ctrl;
>>> struct reset_control *hdmitx_phy;
>>> - struct regulator *hdmi_supply;
>>> u32 irq_stat;
>>> struct dw_hdmi *hdmi;
>>> struct drm_bridge *bridge;
>>> @@ -665,11 +664,6 @@ static void meson_dw_hdmi_init(struct
>>> meson_dw_hdmi *meson_dw_hdmi)
>>> }
>>> -static void meson_disable_regulator(void *data)
>>> -{
>>> - regulator_disable(data);
>>> -}
>>> -
>>> static void meson_disable_clk(void *data)
>>> {
>>> clk_disable_unprepare(data);
>>> @@ -723,20 +717,9 @@ static int meson_dw_hdmi_bind(struct device
>>> *dev, struct device *master,
>>> meson_dw_hdmi->data = match;
>>> dw_plat_data = &meson_dw_hdmi->dw_plat_data;
>>> - meson_dw_hdmi->hdmi_supply = devm_regulator_get_optional(dev,
>>> "hdmi");
>>> - if (IS_ERR(meson_dw_hdmi->hdmi_supply)) {
>>> - if (PTR_ERR(meson_dw_hdmi->hdmi_supply) == -EPROBE_DEFER)
>>> - return -EPROBE_DEFER;
>>> - meson_dw_hdmi->hdmi_supply = NULL;
>>> - } else {
>>> - ret = regulator_enable(meson_dw_hdmi->hdmi_supply);
>>> - if (ret)
>>> - return ret;
>>> - ret = devm_add_action_or_reset(dev, meson_disable_regulator,
>>> - meson_dw_hdmi->hdmi_supply);
>>> - if (ret)
>>> - return ret;
>>> - }
>>> + ret = devm_regulator_get_enable_optional(dev, "hdmi");
>>> + if (ret != -ENODEV)
>>> + return ret;
>>
>> As noted in the review of the series that introduced
>> devm_regulator_get_enable_optional(), the right thing to do is to
>> implement runtime PM in this driver to avoid wasting power.
>
> While I agree, it's not really the same level of effort as this patch
> should be functionally equivalent.
While we all agree that power savings gained by runtime PM would be
great - I don't think we should stop minor improvements while waiting
for that to magically happen ;)
I like the saying I first heard from Jonathan Cameron - "Don't let the
perfect be an enemy of good".
After that being said, should I re-spin this or just drop it? (I am
cleaning up my local git from old stuff, and these are about to vanish
from my books).
Yours,
-- Matti
--
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland
~~ When things go utterly wrong vim users can always type :help! ~~
