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    SubjectRe: [PATCH v2 11/27] drm/sun4i: tcon: Add support for tcon-top gate
    Hi,

    On Tue, Jun 12, 2018 at 10:00:20PM +0200, Jernej Skrabec wrote:
    > TV TCONs connected to TCON TOP have to enable additional gate in order
    > to work.
    >
    > Add support for such TCONs.
    >
    > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
    > ---
    > drivers/gpu/drm/sun4i/sun4i_tcon.c | 11 +++++++++++
    > drivers/gpu/drm/sun4i/sun4i_tcon.h | 4 ++++
    > 2 files changed, 15 insertions(+)
    >
    > diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
    > index 08747fc3ee71..0afb5a94a414 100644
    > --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
    > +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
    > @@ -688,6 +688,16 @@ static int sun4i_tcon_init_clocks(struct device *dev,
    > dev_err(dev, "Couldn't get the TCON bus clock\n");
    > return PTR_ERR(tcon->clk);
    > }
    > +
    > + if (tcon->quirks->has_tcon_top_gate) {
    > + tcon->top_clk = devm_clk_get(dev, "tcon-top");
    > + if (IS_ERR(tcon->top_clk)) {
    > + dev_err(dev, "Couldn't get the TCON TOP bus clock\n");
    > + return PTR_ERR(tcon->top_clk);
    > + }
    > + clk_prepare_enable(tcon->top_clk);
    > + }
    > +

    Is it required for the TCON itself to operate, or does the TCON
    requires the TCON TOP, which in turn requires that clock to be
    functional?

    I find it quite odd to have a clock that isn't meant for a particular
    device to actually be wired to another device. I'm not saying this
    isn't the case, but it would be a first.

    Maxime

    --
    Maxime Ripard, Bootlin (formerly Free Electrons)
    Embedded Linux and Kernel engineering
    https://bootlin.com
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