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Date:   Mon, 21 Aug 2023 11:01:28 +0200
From:   Benjamin Tissoires <bentiss@kernel.org>
To:     Doug Anderson <dianders@google.com>
Cc:     Cong Yang <yangcong5@huaqin.corp-partner.google.com>,
        benjamin.tissoires@redhat.com, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
        dmitry.torokhov@gmail.com, jikos@kernel.org, hsinyi@google.com,
        linux-input@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 2/2] HID: i2c-hid: elan: Add ili9882t timing
Message-ID: <lyns4qkh57xhppnqroaooqtniypfsmr2l5fujlry3stmhrjww4@3iy5mmmrazl6>
References: <20230802071947.1683318-1-yangcong5@huaqin.corp-partner.google.com>
 <20230802071947.1683318-3-yangcong5@huaqin.corp-partner.google.com>
 <CAD=FV=Um8875aMt_kWvCvpNjb3EwSk8VjVTEgv_TJ9WDS+LniA@mail.gmail.com>
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On Aug 02 2023, Doug Anderson wrote:
> Benjamin,
> 
> On Wed, Aug 2, 2023 at 12:20 AM Cong Yang
> <yangcong5@huaqin.corp-partner.google.com> wrote:
> >
> > The ili9882t is a TDDI IC (Touch with Display Driver). The
> > datasheet specifies there should be 60ms between touch SDA
> > sleep and panel RESX. Doug's series[1] allows panels and
> > touchscreens to power on/off together, so we can add the 65 ms
> > delay in i2c_hid_core_suspend before panel_unprepare.
> >
> > Because ili9882t touchscrgeen is a panel follower, and
> > needs to use vccio-supply instead of vcc33-supply, so set
> > it NULL to ili9882t_chip_data, then not use vcc33 regulator.
> >
> > [1]: https://lore.kernel.org/all/20230727171750.633410-1-dianders@chromium.org
> >
> > Reviewed-by: Douglas Anderson <dianders@chromium.org>
> > Signed-off-by: Cong Yang <yangcong5@huaqin.corp-partner.google.com>
> > ---
> >  drivers/hid/i2c-hid/i2c-hid-of-elan.c | 50 ++++++++++++++++++++-------
> >  1 file changed, 38 insertions(+), 12 deletions(-)
> 
> 
> >
> > diff --git a/drivers/hid/i2c-hid/i2c-hid-of-elan.c b/drivers/hid/i2c-hid/i2c-hid-of-elan.c
> > index 029045d9661c..31abab57ad44 100644
> > --- a/drivers/hid/i2c-hid/i2c-hid-of-elan.c
> > +++ b/drivers/hid/i2c-hid/i2c-hid-of-elan.c
> > @@ -18,9 +18,11 @@
> >  #include "i2c-hid.h"
> >
> >  struct elan_i2c_hid_chip_data {
> > -       unsigned int post_gpio_reset_delay_ms;
> > +       unsigned int post_gpio_reset_on_delay_ms;
> > +       unsigned int post_gpio_reset_off_delay_ms;
> >         unsigned int post_power_delay_ms;
> >         u16 hid_descriptor_address;
> > +       const char *main_supply_name;
> >  };
> >
> >  struct i2c_hid_of_elan {
> > @@ -38,9 +40,11 @@ static int elan_i2c_hid_power_up(struct i2chid_ops *ops)
> >                 container_of(ops, struct i2c_hid_of_elan, ops);
> >         int ret;
> >
> > -       ret = regulator_enable(ihid_elan->vcc33);
> > -       if (ret)
> > -               return ret;
> > +       if (ihid_elan->vcc33) {
> > +               ret = regulator_enable(ihid_elan->vcc33);
> > +               if (ret)
> > +                       return ret;
> > +       }
> >
> >         ret = regulator_enable(ihid_elan->vccio);
> >         if (ret) {
> > @@ -52,8 +56,8 @@ static int elan_i2c_hid_power_up(struct i2chid_ops *ops)
> >                 msleep(ihid_elan->chip_data->post_power_delay_ms);
> >
> >         gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0);
> > -       if (ihid_elan->chip_data->post_gpio_reset_delay_ms)
> > -               msleep(ihid_elan->chip_data->post_gpio_reset_delay_ms);
> > +       if (ihid_elan->chip_data->post_gpio_reset_on_delay_ms)
> > +               msleep(ihid_elan->chip_data->post_gpio_reset_on_delay_ms);
> >
> >         return 0;
> >  }
> > @@ -64,8 +68,12 @@ static void elan_i2c_hid_power_down(struct i2chid_ops *ops)
> >                 container_of(ops, struct i2c_hid_of_elan, ops);
> >
> >         gpiod_set_value_cansleep(ihid_elan->reset_gpio, 1);
> > +       if (ihid_elan->chip_data->post_gpio_reset_off_delay_ms)
> > +               msleep(ihid_elan->chip_data->post_gpio_reset_off_delay_ms);
> > +
> >         regulator_disable(ihid_elan->vccio);
> > -       regulator_disable(ihid_elan->vcc33);
> > +       if (ihid_elan->vcc33)
> > +               regulator_disable(ihid_elan->vcc33);
> >  }
> >
> >  static int i2c_hid_of_elan_probe(struct i2c_client *client)
> > @@ -89,24 +97,42 @@ static int i2c_hid_of_elan_probe(struct i2c_client *client)
> >         if (IS_ERR(ihid_elan->vccio))
> >                 return PTR_ERR(ihid_elan->vccio);
> >
> > -       ihid_elan->vcc33 = devm_regulator_get(&client->dev, "vcc33");
> > -       if (IS_ERR(ihid_elan->vcc33))
> > -               return PTR_ERR(ihid_elan->vcc33);
> > -
> >         ihid_elan->chip_data = device_get_match_data(&client->dev);
> >
> > +       if (ihid_elan->chip_data->main_supply_name) {
> > +               ihid_elan->vcc33 = devm_regulator_get(&client->dev,
> > +                                                     ihid_elan->chip_data->main_supply_name);
> > +               if (IS_ERR(ihid_elan->vcc33))
> > +                       return PTR_ERR(ihid_elan->vcc33);
> > +       }
> > +
> >         return i2c_hid_core_probe(client, &ihid_elan->ops,
> >                                   ihid_elan->chip_data->hid_descriptor_address, 0);
> >  }
> >
> >  static const struct elan_i2c_hid_chip_data elan_ekth6915_chip_data = {
> >         .post_power_delay_ms = 1,
> > -       .post_gpio_reset_delay_ms = 300,
> > +       .post_gpio_reset_on_delay_ms = 300,
> > +       .hid_descriptor_address = 0x0001,
> > +       .main_supply_name = "vcc33",
> > +};
> > +
> > +static const struct elan_i2c_hid_chip_data ilitek_ili9882t_chip_data = {
> > +       .post_power_delay_ms = 1,
> > +       .post_gpio_reset_on_delay_ms = 200,
> > +       .post_gpio_reset_off_delay_ms = 65,
> >         .hid_descriptor_address = 0x0001,
> > +       /*
> > +        * this touchscreen is tightly integrated with the panel and assumes
> > +        * that the relevant power rails (other than the IO rail) have already
> > +        * been turned on by the panel driver because we're a panel follower.
> > +        */
> > +       .main_supply_name = NULL,
> >  };
> >
> >  static const struct of_device_id elan_i2c_hid_of_match[] = {
> >         { .compatible = "elan,ekth6915", .data = &elan_ekth6915_chip_data },
> > +       { .compatible = "ilitek,ili9882t", .data = &ilitek_ili9882t_chip_data },
> 
> Logically, this patch depends on the panel-follower series that's now
> landed in drm-misc-next. With your Ack, I'm willing to land these two
> patches into drm-misc-next too. Other options:

If you are fine with the code, I think it could go with the drm tree
given that it depends on the panel-follower.

Unless it's too late for you to take 6.6 material (sorry I was off in
August and just came back).

Acked-By: Benjamin Tissoires <bentiss@kernel.org>

Cheers,
Benjamin

> 
> a) We could land the two patches in the i2c-hid tree since they don't
> appear to conflict. The touchscreen won't actually function until the
> patches meetup in linux-next but I don't think they'll give any
> compile errors (I haven't double-checked that, but I can). ...though
> it's possible that the dt bindings might generate errors? Again, I can
> investigate if we want to go this way.
> 
> b) We can snooze this for a few months and you can pick it to i2c-hid
> when my series reaches mainline.
> 
> Let me know how you'd like to proceed.
> 
> -Doug