From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from perceval.ideasonboard.com ([213.167.242.64]:51718 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752121AbeE3Mh6 (ORCPT ); Wed, 30 May 2018 08:37:58 -0400 From: Laurent Pinchart To: jacopo mondi Cc: Geert Uytterhoeven , Jacopo Mondi , Yoshinori Sato , Rich Felker , Hans Verkuil , Linux-sh list , Linux Media Mailing List , Linux-Renesas Subject: Re: [PATCH] media: arch: sh: migor: Fix TW9910 PDN gpio Date: Wed, 30 May 2018 15:38:01 +0300 Message-ID: <14986389.IZxnRVqLam@avalon> In-Reply-To: <20180530122343.GA10472@w540> References: <1527671604-18768-1-git-send-email-jacopo+renesas@jmondi.org> <2981239.tGoCg7U0XF@avalon> <20180530122343.GA10472@w540> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-renesas-soc-owner@vger.kernel.org List-ID: Hi Jacopo, On Wednesday, 30 May 2018 15:23:43 EEST jacopo mondi wrote: > On Wed, May 30, 2018 at 02:52:31PM +0300, Laurent Pinchart wrote: > > On Wednesday, 30 May 2018 12:30:49 EEST Geert Uytterhoeven wrote: > >> On Wed, May 30, 2018 at 11:13 AM, Jacopo Mondi wrote: > >>> The TW9910 PDN gpio (power down) is listed as active high in the chip > >>> manual. It turns out it is actually active low as when set to physical > >>> level 0 it actually turns the video decoder power off. > >> > >> So the picture "Typical TW9910 External Circuitry" in the datasheet, > >> which ties PDN to GND permanently, is wrong? > > Also the definition of PDN pin in TW9910 manual, as reported by Laurent made > me think the pin had to stay in logical state 1 to have the chip powered > down. That's why my initial 'ACTIVE_HIGH' flag. The chip was not > recognized, but I thought it was a local problem of the Migo-R board I > was using. > > Then one day I tried inverting the pin active state just to be sure, > and it started being fully operational :/ > > > The SH PTT2 line is connected directory to the TW9910 PDN signal, without > > any inverter on the board. The PDN signal is clearly documented as > > active-high in the TW9910 datasheet. Something is thus weird. > > I suspect the 'active high' definition in datasheet is different from > our understanding. Their 'active' means the chip is operational, which > is not what one would expect from a powerdown pin. > > > Jacopo, is it possible to measure the PDN signal on the board as close as > > possible to the TW9910 to see if it works as expected ? > > Not for me. The board is in Japan and my multimeter doesn't have cables > that long, unfortunately. How about trying that during your next trip to Japan ? :-) -- Regards, Laurent Pinchart From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Pinchart Date: Wed, 30 May 2018 12:38:01 +0000 Subject: Re: [PATCH] media: arch: sh: migor: Fix TW9910 PDN gpio Message-Id: <14986389.IZxnRVqLam@avalon> List-Id: References: <1527671604-18768-1-git-send-email-jacopo+renesas@jmondi.org> <2981239.tGoCg7U0XF@avalon> <20180530122343.GA10472@w540> In-Reply-To: <20180530122343.GA10472@w540> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: jacopo mondi Cc: Geert Uytterhoeven , Jacopo Mondi , Yoshinori Sato , Rich Felker , Hans Verkuil , Linux-sh list , Linux Media Mailing List , Linux-Renesas Hi Jacopo, On Wednesday, 30 May 2018 15:23:43 EEST jacopo mondi wrote: > On Wed, May 30, 2018 at 02:52:31PM +0300, Laurent Pinchart wrote: > > On Wednesday, 30 May 2018 12:30:49 EEST Geert Uytterhoeven wrote: > >> On Wed, May 30, 2018 at 11:13 AM, Jacopo Mondi wrote: > >>> The TW9910 PDN gpio (power down) is listed as active high in the chip > >>> manual. It turns out it is actually active low as when set to physical > >>> level 0 it actually turns the video decoder power off. > >> > >> So the picture "Typical TW9910 External Circuitry" in the datasheet, > >> which ties PDN to GND permanently, is wrong? > > Also the definition of PDN pin in TW9910 manual, as reported by Laurent made > me think the pin had to stay in logical state 1 to have the chip powered > down. That's why my initial 'ACTIVE_HIGH' flag. The chip was not > recognized, but I thought it was a local problem of the Migo-R board I > was using. > > Then one day I tried inverting the pin active state just to be sure, > and it started being fully operational :/ > > > The SH PTT2 line is connected directory to the TW9910 PDN signal, without > > any inverter on the board. The PDN signal is clearly documented as > > active-high in the TW9910 datasheet. Something is thus weird. > > I suspect the 'active high' definition in datasheet is different from > our understanding. Their 'active' means the chip is operational, which > is not what one would expect from a powerdown pin. > > > Jacopo, is it possible to measure the PDN signal on the board as close as > > possible to the TW9910 to see if it works as expected ? > > Not for me. The board is in Japan and my multimeter doesn't have cables > that long, unfortunately. How about trying that during your next trip to Japan ? :-) -- Regards, Laurent Pinchart