[PATCH v2] [media] davinci: vpif: adaptions for DT support

[Sakari Ailus]

On Fri, Jun 16, 2017 at 10:49:24AM -0700, Kevin Hilman wrote:
> Sakari Ailus <sakari.ailus at iki.fi> writes:
> 
> > Hi Kevin,
> >
> > On Fri, Jun 09, 2017 at 09:10:26AM -0700, Kevin Hilman wrote:
> >> The davinci VPIF is a single hardware block, but the existing driver
> >> is broken up into a common library (vpif.c), output (vpif_display.c) and
> >> intput (vpif_capture.c).
> >> 
> >> When migrating to DT, to better model the hardware, and because
> >> registers, interrupts, etc. are all common,it was decided to
> >> have a single VPIF hardware node[1].
> >> 
> >> Because davinci uses legacy, non-DT boot on several SoCs still, the
> >> platform_drivers need to remain.  But they are also needed in DT boot.
> >> Since there are no DT nodes for the display/capture parts in DT
> >> boot (there is a single node for the parent/common device) we need to
> >> create platform_devices somewhere to instansiate the platform_drivers.
> >> 
> >> When VPIF display/capture are needed for a DT boot, the VPIF node
> >> will have endpoints defined for its subdevs.  Therefore, vpif_probe()
> >> checks for the presence of endpoints, and if detected manually creates
> >> the platform_devices for the display and capture platform_drivers.
> >> 
> >> [1] Documentation/devicetree/bindings/media/ti,da850-vpif.txt
> >> 
> >> Signed-off-by: Kevin Hilman <khilman at baylibre.com>
> >> ---
> >> Changes since v1:
> >> - added proper error checking to kzalloc calls
> >> - rebased onto media/master
> >> 
> >>  drivers/media/platform/davinci/vpif.c | 57 ++++++++++++++++++++++++++++++++++-
> >>  1 file changed, 56 insertions(+), 1 deletion(-)
> >> 
> >> diff --git a/drivers/media/platform/davinci/vpif.c b/drivers/media/platform/davinci/vpif.c
> >> index 1b02a6363f77..c2d214dfaa3e 100644
> >> --- a/drivers/media/platform/davinci/vpif.c
> >> +++ b/drivers/media/platform/davinci/vpif.c
> >> @@ -26,6 +26,7 @@
> >>  #include <linux/pm_runtime.h>
> >>  #include <linux/spinlock.h>
> >>  #include <linux/v4l2-dv-timings.h>
> >> +#include <linux/of_graph.h>
> >>  
> >>  #include "vpif.h"
> >>  
> >> @@ -423,7 +424,9 @@ EXPORT_SYMBOL(vpif_channel_getfid);
> >>  
> >>  static int vpif_probe(struct platform_device *pdev)
> >>  {
> >> -	static struct resource	*res;
> >> +	static struct resource	*res, *res_irq;
> >> +	struct platform_device *pdev_capture, *pdev_display;
> >> +	struct device_node *endpoint = NULL;
> >>  
> >>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >>  	vpif_base = devm_ioremap_resource(&pdev->dev, res);
> >> @@ -435,6 +438,58 @@ static int vpif_probe(struct platform_device *pdev)
> >>  
> >>  	spin_lock_init(&vpif_lock);
> >>  	dev_info(&pdev->dev, "vpif probe success\n");
> >> +
> >> +	/*
> >> +	 * If VPIF Node has endpoints, assume "new" DT support,
> >> +	 * where capture and display drivers don't have DT nodes
> >> +	 * so their devices need to be registered manually here
> >> +	 * for their legacy platform_drivers to work.
> >> +	 */
> >> +	endpoint = of_graph_get_next_endpoint(pdev->dev.of_node,
> >> +					      endpoint);
> >> +	if (!endpoint) 
> >> +		return 0;
> >> +
> >> +	/*
> >> +	 * For DT platforms, manually create platform_devices for
> >> +	 * capture/display drivers.
> >> +	 */
> >> +	res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
> >> +	if (!res_irq) {
> >> +		dev_warn(&pdev->dev, "Missing IRQ resource.\n");
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	pdev_capture = devm_kzalloc(&pdev->dev, sizeof(*pdev_capture),
> >> +				    GFP_KERNEL);
> >> +	if (pdev_capture) {
> >> +		pdev_capture->name = "vpif_capture";
> >> +		pdev_capture->id = -1;
> >> +		pdev_capture->resource = res_irq;
> >> +		pdev_capture->num_resources = 1;
> >> +		pdev_capture->dev.dma_mask = pdev->dev.dma_mask;
> >> +		pdev_capture->dev.coherent_dma_mask = pdev->dev.coherent_dma_mask;
> >> +		pdev_capture->dev.parent = &pdev->dev;
> >> +		platform_device_register(pdev_capture);
> >
> > Don't both of these (vpif_capture and vpif_display) depend on platform data?
> > Or do I miss something?
> 
> The driver can (continue to) work in legacy mode with platform_data.  In
> that case, there is no VPIF DT node (or a node without endpoints).
> 
> However, with recent changes, it can also work in DT mode, where the
> VPIF node and endpoints used for display/capture come from DT, in which
> case these nodes are created an don't depend on platform_data at all.
> 
> Hope that clarifies things, and thanks for the review,

Oh, I think I missed the fact that what is parsed from DT is still referred
to as platform data in the driver. (Both of the drivers are testing if
dev->platform_data is non-NULL twice in a row. Unrelated to this patch, just
FYI.)

How do the newly created child devices get their OF nodes?

If endpoint is non-NULL, it needs to be put using of_node_put().

-- 
Regards,

Sakari Ailus
e-mail: sakari.ailus at iki.fi	XMPP: sailus at retiisi.org.uk