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From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: Venkateshwar Rao Gannavarapu 
	<venkateshwar.rao.gannavarapu@xilinx.com>,
	airlied@linux.ie, vgannava@xilinx.com,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [LINUX PATCH 2/2] drm: xlnx: dsi: driver for Xilinx DSI Tx subsystem
Date: Mon, 13 Jun 2022 00:21:37 +0300	[thread overview]
Message-ID: <YqZY4QMAkGiFOOWE@pendragon.ideasonboard.com> (raw)
In-Reply-To: <Yn47YsSH4fn/wjKN@ravnborg.org>

Hi Sam,

On Fri, May 13, 2022 at 01:05:06PM +0200, Sam Ravnborg wrote:
> On Thu, May 12, 2022 at 07:23:13PM +0530, Venkateshwar Rao Gannavarapu wrote:
> > The Xilinx MIPI DSI Tx Subsystem soft IP is used to display video
> > data from AXI-4 stream interface.
> > 
> > It supports upto 4 lanes, optional register interface for the DPHY
> > and multiple RGB color formats.
> > This is a MIPI-DSI host driver and provides DSI bus for panels.
> > This driver also helps to communicate with its panel using panel
> > framework.
> 
> Thanks for submitting this driver. I have added a few comments in the
> following that I hope you will find useful to improve the driver.
> 
> > Signed-off-by: Venkateshwar Rao Gannavarapu <venkateshwar.rao.gannavarapu@xilinx.com>
> > ---
> >  drivers/gpu/drm/xlnx/Kconfig    |  14 ++
> >  drivers/gpu/drm/xlnx/Makefile   |   1 +
> >  drivers/gpu/drm/xlnx/xlnx_dsi.c | 456 ++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 471 insertions(+)
> >  create mode 100644 drivers/gpu/drm/xlnx/xlnx_dsi.c

[snip]

> > diff --git a/drivers/gpu/drm/xlnx/xlnx_dsi.c b/drivers/gpu/drm/xlnx/xlnx_dsi.c
> > new file mode 100644
> > index 0000000..a5291f3
> > --- /dev/null
> > +++ b/drivers/gpu/drm/xlnx/xlnx_dsi.c

[snip]

> > +static inline void xlnx_dsi_writel(void __iomem *base, int offset, u32 val)
> > +{
> > +	writel(val, base + offset);
> > +}
> > +
> > +static inline u32 xlnx_dsi_readl(void __iomem *base, int offset)
> > +{
> > +	return readl(base + offset);
> > +}
> 
> When I see implementations like this I wonder if a regmap would be
> beneficial?

regmap often seems overkill to me when the driver only needs plain
32-bit mmio read/write, given the overhead it adds at runtime. Is it
just me ?

[snip]

-- 
Regards,

Laurent Pinchart

  reply	other threads:[~2022-06-12 21:21 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-12 13:53 [LINUX PATCH 0/2] Add Xilinx DSI-Tx DRM driver Venkateshwar Rao Gannavarapu
2022-05-12 13:53 ` [LINUX PATCH 1/2] dt-bindings: display: xlnx: Add DSI 2.0 Tx subsystem documentation Venkateshwar Rao Gannavarapu
2022-05-13 13:39   ` Laurent Pinchart
2022-05-12 13:53 ` [LINUX PATCH 2/2] drm: xlnx: dsi: driver for Xilinx DSI Tx subsystem Venkateshwar Rao Gannavarapu
2022-05-13 11:05   ` Sam Ravnborg
2022-06-12 21:21     ` Laurent Pinchart [this message]
2022-06-13  5:53       ` Sam Ravnborg
2022-06-12 21:28     ` Laurent Pinchart
2022-05-13 13:39   ` Laurent Pinchart

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