Re: [PATCH v5 7/7] drm/rockchip: dsi: add dual mipi support

[Heiko Stuebner <heiko@sntech.de>]

Hi Andrzej,

Am Montag, 27. August 2018, 13:34:07 CEST schrieb Andrzej Hajda:
> On 21.08.2018 16:05, Heiko Stuebner wrote:
> > Add the Rockchip-sepcific dual-dsi setup and hook it into the VOP as well.
> > As described in the general dual-dsi devicetree binding, the panel should
> > define two input ports and point each of them to one of the used dsi-
> > controllers, as well as declare one of them as clock-master.
> > This is used to determine the dual-dsi state and get access to both
> > controller instances.
> >
> > Signed-off-by: Heiko Stuebner <heiko@sntech.de>
> > v4:
> >   add component directly in probe when adding empty dsi slave controller
> > v5:
> >   use driver-internal mechanism to find dual dsi slave
> > ---
> >  .../gpu/drm/rockchip/dw-mipi-dsi-rockchip.c   | 105 ++++++++++++++++++
> >  drivers/gpu/drm/rockchip/rockchip_drm_drv.h   |   1 +
> >  drivers/gpu/drm/rockchip/rockchip_drm_vop.c   |   3 +
> >  drivers/gpu/drm/rockchip/rockchip_drm_vop.h   |   4 +
> >  drivers/gpu/drm/rockchip/rockchip_vop_reg.c   |   1 +
> >  5 files changed, 114 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
> > index b3aae8439aa3..e4aee2ccbf4d 100644
> > --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
> > +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
> > @@ -218,6 +218,10 @@ struct dw_mipi_dsi_rockchip {
> >  	struct clk *grf_clk;
> >  	struct clk *phy_cfg_clk;
> >  
> > +	/* dual-channel */
> > +	bool is_slave;
> > +	struct dw_mipi_dsi_rockchip *slave;
> > +
> >  	unsigned int lane_mbps; /* per lane */
> >  	u16 input_div;
> >  	u16 feedback_div;
> > @@ -226,6 +230,7 @@ struct dw_mipi_dsi_rockchip {
> >  	struct dw_mipi_dsi *dmd;
> >  	const struct rockchip_dw_dsi_chip_data *cdata;
> >  	struct dw_mipi_dsi_plat_data pdata;
> > +	int devcnt;
> >  };
> >  
> >  struct dphy_pll_parameter_map {
> > @@ -602,6 +607,8 @@ dw_mipi_dsi_encoder_atomic_check(struct drm_encoder *encoder,
> >  	}
> >  
> >  	s->output_type = DRM_MODE_CONNECTOR_DSI;
> > +	if (dsi->slave)
> > +		s->output_flags = ROCKCHIP_OUTPUT_DSI_DUAL;
> >  
> >  	return 0;
> >  }
> > @@ -617,6 +624,8 @@ static void dw_mipi_dsi_encoder_enable(struct drm_encoder *encoder)
> >  		return;
> >  
> >  	pm_runtime_get_sync(dsi->dev);
> > +	if (dsi->slave)
> > +		pm_runtime_get_sync(dsi->slave->dev);
> >  
> >  	/*
> >  	 * For the RK3399, the clk of grf must be enabled before writing grf
> > @@ -630,6 +639,8 @@ static void dw_mipi_dsi_encoder_enable(struct drm_encoder *encoder)
> >  	}
> >  
> >  	dw_mipi_dsi_rockchip_config(dsi, mux);
> > +	if (dsi->slave)
> > +		dw_mipi_dsi_rockchip_config(dsi->slave, mux);
> >  
> >  	clk_disable_unprepare(dsi->grf_clk);
> >  }
> > @@ -638,6 +649,8 @@ static void dw_mipi_dsi_encoder_disable(struct drm_encoder *encoder)
> >  {
> >  	struct dw_mipi_dsi_rockchip *dsi = to_dsi(encoder);
> >  
> > +	if (dsi->slave)
> > +		pm_runtime_put(dsi->slave->dev);
> >  	pm_runtime_put(dsi->dev);
> >  }
> >  
> > @@ -673,14 +686,76 @@ static int rockchip_dsi_drm_create_encoder(struct dw_mipi_dsi_rockchip *dsi,
> >  	return 0;
> >  }
> >  
> > +static int dw_mipi_dsi_rockchip_match_second(struct device *dev, void *data)
> > +{
> > +	struct dw_mipi_dsi_rockchip *dsi = data;
> > +	struct drm_bridge *bridge1, *bridge2;
> > +	struct drm_panel *panel1, *panel2;
> > +	int ret;
> > +
> > +	if (dsi->dev->of_node == dev->of_node)
> > +		return 0;
> > +
> > +	ret = drm_of_find_panel_or_bridge(dsi->dev->of_node, 1, 0,
> > +					  &panel1, &bridge1);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = drm_of_find_panel_or_bridge(dev->of_node, 1, 0,
> > +					  &panel2, &bridge2);
> > +	if (ret)
> > +		return ret;
> > +
> > +	return (panel1 == panel2) && (bridge1 == bridge2);
> > +}
> > +
> >  static int dw_mipi_dsi_rockchip_bind(struct device *dev,
> >  				     struct device *master,
> >  				     void *data)
> >  {
> >  	struct dw_mipi_dsi_rockchip *dsi = dev_get_drvdata(dev);
> >  	struct drm_device *drm_dev = data;
> > +	struct device *second;
> > +	bool master1, master2;
> >  	int ret;
> >  
> > +	second = driver_find_device(dsi->dev->driver, NULL, dsi,
> > +					dw_mipi_dsi_rockchip_match_second);
> 
> This function performs get_device on the matched device, so you should
> probably call somewhere put_device to make the counter balanced.
> I hope second device is somehow guarded by component framework from
> being unbound in unexpected moments (ie. when in use by master).

Thanks for that catch, I'll add the put_device.


> > +	if (IS_ERR(second))
> > +		return PTR_ERR(second);
> > +
> > +	if (second) {
> > +		master1 = of_property_read_bool(dsi->dev->of_node,
> > +						"clock-master");
> > +		master2 = of_property_read_bool(second->of_node,
> > +						"clock-master");
> > +
> > +		if (master1 && master2) {
> > +			DRM_DEV_ERROR(dsi->dev, "only one clock-master allowed\n");
> > +			return -EINVAL;
> > +		}
> > +
> > +		if (!master1 && !master2) {
> > +			DRM_DEV_ERROR(dsi->dev, "no clock-master defined\n");
> > +			return -EINVAL;
> > +		}
> > +
> > +		/* we are the slave in dual-DSI */
> > +		if (!master1) {
> > +			dsi->is_slave = true;
> > +			return 0;
> > +		}
> > +
> > +		dsi->slave = dev_get_drvdata(second);
> > +		if (!dsi->slave) {
> > +			DRM_DEV_ERROR(dev, "could not get slaves data\n");
> > +			return -ENODEV;
> > +		}
> > +
> > +		dsi->slave->is_slave = true;
> > +		dw_mipi_dsi_set_slave(dsi->dmd, dsi->slave->dmd);
> > +	}
> > +
> >  	ret = clk_prepare_enable(dsi->pllref_clk);
> >  	if (ret) {
> >  		DRM_DEV_ERROR(dev, "Failed to enable pllref_clk: %d\n", ret);
> > @@ -708,6 +783,9 @@ static void dw_mipi_dsi_rockchip_unbind(struct device *dev,
> >  {
> >  	struct dw_mipi_dsi_rockchip *dsi = dev_get_drvdata(dev);
> >  
> > +	if (dsi->is_slave)
> > +		return;
> > +
> >  	dw_mipi_dsi_unbind(dsi->dmd);
> >  
> >  	clk_disable_unprepare(dsi->pllref_clk);
> > @@ -749,6 +827,14 @@ static const struct dw_mipi_dsi_host_ops dw_mipi_dsi_rockchip_host_ops = {
> >  	.detach = dw_mipi_dsi_rockchip_host_detach,
> >  };
> >  
> > +static int dw_mipi_dsi_rockchip_cnt_dev(struct device *dev, void *data)
> > +{
> > +	struct dw_mipi_dsi_rockchip *dsi = data;
> > +
> > +	dsi->devcnt++;
> > +	return 0;
> > +}
> > +
> >  static int dw_mipi_dsi_rockchip_probe(struct platform_device *pdev)
> >  {
> >  	struct device *dev = &pdev->dev;
> > @@ -835,6 +921,22 @@ static int dw_mipi_dsi_rockchip_probe(struct platform_device *pdev)
> >  		goto err_clkdisable;
> >  	}
> >  
> > +	/*
> > +	 * All dsi child devices will have been created, so we can check
> > +	 * their number and add the component here if there will be no
> > +	 * host-attach call.
> 
> I guess you mean that in this point all child devices have been created
> (remove 'will'), but it may be false assumption, there is always
> possibility to create device on the fly - see mipi_dsi_device_register_full.
> You cannot assume that in certain point in time there will be no more
> devices on the bus.
> 
> I am not sure of the purpose of this code. Why do you want to behave
> differently if there are no child devs?

That's all related to the suggestion of doing component_add in the
host-attach callback. If the device doesn't have active children its
component will never get added and the whole drm component structure
will wait forever and never probe the drm driver, hence add the component
when no child will be present.
[This is of course part of handling my empty dsi slave].

I don't think the whole dw-dsi driver currently expects more than one
device to exist, while the DSI bus can address multiple devices.

With the changes in this series with component_add being called from
dsi-attach, this creates even more issues with multiple devices, as
component_add and component_del would be called multiple times
for each dsi device on the bus.

Should I simply go back to my deferral if no panel found, or do you
have another sugestion?

Thanks
Heiko


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