[PATCH 16/17] drm/sun4i: tcon-top: Remove mux configuration at probe time

Jernej Škrabec
2018-07-10T16:18:43Z

Dne torek, 10. julij 2018 ob 18:09:26 CEST je Chen-Yu Tsai napisal(a):
> On Sat, Jul 7, 2018 at 1:51 AM, Jernej Skrabec <jernej.skrabec@siol.net>
wrote:
> > Now that R40 TCON migrated to runtime mux configuration, old code can be
> > removed.
> >
> > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
> > ---
> >
> > drivers/gpu/drm/sun4i/sun8i_tcon_top.c | 81 +++-----------------------
> > 1 file changed, 7 insertions(+), 74 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/sun4i/sun8i_tcon_top.c
> > b/drivers/gpu/drm/sun4i/sun8i_tcon_top.c index c09b15b64192..78795d6cb174
> > 100644
> > --- a/drivers/gpu/drm/sun4i/sun8i_tcon_top.c
> > +++ b/drivers/gpu/drm/sun4i/sun8i_tcon_top.c
> > @@ -87,34 +87,6 @@ int sun8i_tcon_top_de_config(struct device *dev, int
> > mixer, int tcon)>
> > }
> > EXPORT_SYMBOL(sun8i_tcon_top_de_config);
> >
> > -static int sun8i_tcon_top_get_connected_ep_id(struct device_node *node,
> > - int port_id)
> > -{
> > - struct device_node *ep, *remote, *port;
> > - struct of_endpoint endpoint;
> > -
> > - port = of_graph_get_port_by_id(node, port_id);
> > - if (!port)
> > - return -ENOENT;
> > -
> > - for_each_available_child_of_node(port, ep) {
> > - remote = of_graph_get_remote_port_parent(ep);
> > - if (!remote)
> > - continue;
> > -
> > - if (of_device_is_available(remote)) {
> > - of_graph_parse_endpoint(ep, &endpoint);
> > -
> > - of_node_put(remote);
> > -
> > - return endpoint.id;
> > - }
> > -
> > - of_node_put(remote);
> > - }
> > -
> > - return -ENOENT;
> > -}
> >
> > static struct clk_hw *sun8i_tcon_top_register_gate(struct device *dev,
> >
> > const char *parent,
> >
> > @@ -149,11 +121,9 @@ static int sun8i_tcon_top_bind(struct device *dev,
> > struct device *master,>
> > struct platform_device *pdev = to_platform_device(dev);
> > struct clk_hw_onecell_data *clk_data;
> > struct sun8i_tcon_top *tcon_top;
> >
> > - bool mixer0_unused = false;
> >
> > struct resource *res;
> > void __iomem *regs;
> >
> > - int ret, i, id;
> > - u32 val;
> > + int ret, i;
> >
> > tcon_top = devm_kzalloc(dev, sizeof(*tcon_top), GFP_KERNEL);
> > if (!tcon_top)
> >
> > @@ -198,49 +168,12 @@ static int sun8i_tcon_top_bind(struct device *dev,
> > struct device *master,>
> > goto err_assert_reset;
> >
> > }
> >
> > - val = 0;
> > -
> > - /* check if HDMI mux output is connected */
> > - if (sun8i_tcon_top_get_connected_ep_id(dev->of_node, 5) >= 0) {
> > - /* find HDMI input endpoint id, if it is connected at
> > all*/
> > - id = sun8i_tcon_top_get_connected_ep_id(dev->of_node, 4);
> > - if (id >= 0)
> > - val = FIELD_PREP(TCON_TOP_HDMI_SRC_MSK, id + 1);
> > - else
> > - DRM_DEBUG_DRIVER("TCON TOP HDMI input is not
> > connected\n"); - } else {
> > - DRM_DEBUG_DRIVER("TCON TOP HDMI output is not
> > connected\n"); - }
> > -
> > - writel(val, regs + TCON_TOP_GATE_SRC_REG);
> > -
> > - val = 0;
> > -
> > - /* process mixer0 mux output */
> > - id = sun8i_tcon_top_get_connected_ep_id(dev->of_node, 1);
> > - if (id >= 0) {
> > - val = FIELD_PREP(TCON_TOP_PORT_DE0_MSK, id);
> > - } else {
> > - DRM_DEBUG_DRIVER("TCON TOP mixer0 output is not
> > connected\n"); - mixer0_unused = true;
> > - }
> > -
> > - /* process mixer1 mux output */
> > - id = sun8i_tcon_top_get_connected_ep_id(dev->of_node, 3);
> > - if (id >= 0) {
> > - val |= FIELD_PREP(TCON_TOP_PORT_DE1_MSK, id);
> > -
> > - /*
> > - * mixer0 mux has priority over mixer1 mux. We have to
> > - * make sure mixer0 doesn't overtake TCON from mixer1.
> > - */
> > - if (mixer0_unused && id == 0)
> > - val |= FIELD_PREP(TCON_TOP_PORT_DE0_MSK, 1);
> > - } else {
> > - DRM_DEBUG_DRIVER("TCON TOP mixer1 output is not
> > connected\n"); - }
> > -
> > - writel(val, regs + TCON_TOP_PORT_SEL_REG);
> > + /*
> > + * Default register values might have some reserved bits set,
> > which
> > + * prevents TCON TOP from working properly. Set them to 0 here.
> > + */
> > + writel(0, regs + TCON_TOP_GATE_SRC_REG);
> > + writel(0, regs + TCON_TOP_PORT_SEL_REG);
>
> Would it make sense to just force a reset using the reset control?

I wrote TCON TOP driver for H6 at first. For some reason, some registers had
reserved bits set after reset line was released. TCON TOP was not used in U-
Boot, so I guess this counts as full reset.

I never tried to find out how it behaves on R40 because setting those
registers to 0 seems like simple, good enough solution, which works
everywhere.

Best regards,
Jernej