From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752754AbeD3JEU (ORCPT ); Mon, 30 Apr 2018 05:04:20 -0400 Received: from mail.bootlin.com ([62.4.15.54]:43987 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752024AbeD3JET (ORCPT ); Mon, 30 Apr 2018 05:04:19 -0400 Date: Mon, 30 Apr 2018 11:04:18 +0200 From: Boris Brezillon To: Eric Anholt Cc: dri-devel@lists.freedesktop.org, Thierry Reding , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] drm/panel: Enable DSI transactions on the RPi panel. Message-ID: <20180430110418.5ba6baab@bbrezillon> In-Reply-To: <20171031193258.17373-2-eric@anholt.net> References: <20171031193258.17373-1-eric@anholt.net> <20171031193258.17373-2-eric@anholt.net> X-Mailer: Claws Mail 3.15.0-dirty (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 31 Oct 2017 12:32:58 -0700 Eric Anholt wrote: > It turns out that I had just mistaken what type of write the register > writes were supposed to be, using DCS instead of generic long writes. > > Switching to transactions instead of using the atmel as a bridge also > seems to resolve the sparkling pixels problem I've had. > > Signed-off-by: Eric Anholt > Fixes: 2f733d6194bd ("drm/panel: Add support for the Raspberry Pi 7" Touchscreen.") Reviewed-by: Boris Brezillon > --- > drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c | 14 +------------- > 1 file changed, 1 insertion(+), 13 deletions(-) > > diff --git a/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c b/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c > index d964d454e4ae..2c9c9722734f 100644 > --- a/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c > +++ b/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c > @@ -238,12 +238,6 @@ static void rpi_touchscreen_i2c_write(struct rpi_touchscreen *ts, > > static int rpi_touchscreen_write(struct rpi_touchscreen *ts, u16 reg, u32 val) > { > -#if 0 > - /* The firmware uses LP DSI transactions like this to bring up > - * the hardware, which should be faster than using I2C to then > - * pass to the Toshiba. However, I was unable to get it to > - * work. > - */ > u8 msg[] = { > reg, > reg >> 8, > @@ -253,13 +247,7 @@ static int rpi_touchscreen_write(struct rpi_touchscreen *ts, u16 reg, u32 val) > val >> 24, > }; > > - mipi_dsi_dcs_write_buffer(ts->dsi, msg, sizeof(msg)); > -#else > - rpi_touchscreen_i2c_write(ts, REG_WR_ADDRH, reg >> 8); > - rpi_touchscreen_i2c_write(ts, REG_WR_ADDRL, reg); > - rpi_touchscreen_i2c_write(ts, REG_WRITEH, val >> 8); > - rpi_touchscreen_i2c_write(ts, REG_WRITEL, val); > -#endif > + mipi_dsi_generic_write(ts->dsi, msg, sizeof(msg)); > > return 0; > } -- Boris Brezillon, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com