Re: [PATCH 3/3] drm/ingenic: ipu: Only enable clock when needed

On Thu, Jul 30, 2020 at 03:46:26AM +0200, Paul Cercueil wrote:

Instead of keeping the IPU clock enabled constantly, enable and disable it on demand, when the IPU plane is used.

This explains what the patch does - but fails to mention why. Could you please add the why part too.

With the chagelog updated: Reviewed-by: Sam Ravnborg sam@ravnborg.org

Sam

Signed-off-by: Paul Cercueil paul@crapouillou.net

drivers/gpu/drm/ingenic/ingenic-ipu.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/ingenic/ingenic-ipu.c b/drivers/gpu/drm/ingenic/ingenic-ipu.c index f4f0abcd6692..17e682cf1eba 100644 --- a/drivers/gpu/drm/ingenic/ingenic-ipu.c +++ b/drivers/gpu/drm/ingenic/ingenic-ipu.c @@ -49,6 +49,7 @@ struct ingenic_ipu { struct regmap *map; struct clk *clk; const struct soc_info *soc_info;

• bool clk_enabled;

  unsigned int num_w, num_h, denom_w, denom_h;

@@ -288,12 +289,23 @@ static void ingenic_ipu_plane_atomic_update(struct drm_plane *plane, const struct drm_format_info *finfo; u32 ctrl, stride = 0, coef_index = 0, format = 0; bool needs_modeset, upscaling_w, upscaling_h;

• int err;

  if (!state || !state->fb) return;

  finfo = drm_format_info(state->fb->format->format);

• if (!ipu->clk_enabled) {

• err = clk_enable(ipu->clk);
  

• if (err) {
  

• 	dev_err(ipu->dev, "Unable to enable clock: %d\n", err);
  

• 	return;
  

• }
  

• ipu->clk_enabled = true;
  

• }

• /* Reset all the registers if needed */ needs_modeset = drm_atomic_crtc_needs_modeset(state->crtc->state); if (needs_modeset) {

@@ -578,6 +590,11 @@ static void ingenic_ipu_plane_atomic_disable(struct drm_plane *plane, regmap_clear_bits(ipu->map, JZ_REG_IPU_CTRL, JZ_IPU_CTRL_CHIP_EN);

ingenic_drm_plane_disable(ipu->master, plane);

• if (ipu->clk_enabled) {

• clk_disable(ipu->clk);
  

• ipu->clk_enabled = false;
  

• }

}

static const struct drm_plane_helper_funcs ingenic_ipu_plane_helper_funcs = { @@ -761,9 +778,9 @@ static int ingenic_ipu_bind(struct device *dev, struct device *master, void *d) drm_object_attach_property(&plane->base, ipu->sharpness_prop, ipu->sharpness);

• err = clk_prepare_enable(ipu->clk);

• err = clk_prepare(ipu->clk); if (err) {

• dev_err(dev, "Unable to enable clock\n");
  

• dev_err(dev, "Unable to prepare clock\n");
  

  return err; }

@@ -775,7 +792,7 @@ static void ingenic_ipu_unbind(struct device *dev, { struct ingenic_ipu *ipu = dev_get_drvdata(dev);

• clk_disable_unprepare(ipu->clk);

• clk_unprepare(ipu->clk);

}

static const struct component_ops ingenic_ipu_ops = {

2.27.0