From: Russell King - ARM Linux <linux@arm.linux.org.uk> To: Jean-Francois Moine <moinejf@free.fr> Cc: dri-devel@lists.freedesktop.org, Dave Airlie <airlied@gmail.com>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Rob Clark <robdclark@gmail.com> Subject: Re: [PATCH v5 09/23] drm/i2c: tda998x: don't read write-only registers Date: Sun, 2 Feb 2014 16:23:09 +0000 [thread overview] Message-ID: <20140202162309.GF26684@n2100.arm.linux.org.uk> (raw) In-Reply-To: <5269e596e16dfe40253dce38ceb0dc4a617384c1.1390986083.git.moinejf@free.fr> On Sat, Jan 25, 2014 at 06:14:42PM +0100, Jean-Francois Moine wrote: > This patch takes care of the write-only registers of the tda998x. > > The registers SOFTRESET, TBG_CNTRL_0 and TBG_CNTRL_1 have all bits > cleared after reset, so, they may be fully re-written. > > The register MAT_CONTRL is set to > MAT_CONTRL_MAT_BP | MAT_CONTRL_MAT_SC(1) > after reset, so, it may be fully set again to this value. I said in v3 of this patch, which seems to remain unaddressed: > /* must be last register set: */ > - reg_clear(priv, REG_TBG_CNTRL_0, TBG_CNTRL_0_SYNC_ONCE); > + reg_write(priv, REG_TBG_CNTRL_0, 0); Register changes which have a potential effect shouldn't be part of a patch which is really only trying to avoid reading from write only registers. This could be a potential functional change - and it's probably one which Rob Clark should at least be made aware of. As I commented last time, when you're changing register values in an otherwise innocuous patch, you should comment about them in the patch description. -- FTTC broadband for 0.8mile line: 5.8Mbps down 500kbps up. Estimation in database were 13.1 to 19Mbit for a good line, about 7.5+ for a bad. Estimate before purchase was "up to 13.2Mbit".
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From: linux@arm.linux.org.uk (Russell King - ARM Linux) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v5 09/23] drm/i2c: tda998x: don't read write-only registers Date: Sun, 2 Feb 2014 16:23:09 +0000 [thread overview] Message-ID: <20140202162309.GF26684@n2100.arm.linux.org.uk> (raw) In-Reply-To: <5269e596e16dfe40253dce38ceb0dc4a617384c1.1390986083.git.moinejf@free.fr> On Sat, Jan 25, 2014 at 06:14:42PM +0100, Jean-Francois Moine wrote: > This patch takes care of the write-only registers of the tda998x. > > The registers SOFTRESET, TBG_CNTRL_0 and TBG_CNTRL_1 have all bits > cleared after reset, so, they may be fully re-written. > > The register MAT_CONTRL is set to > MAT_CONTRL_MAT_BP | MAT_CONTRL_MAT_SC(1) > after reset, so, it may be fully set again to this value. I said in v3 of this patch, which seems to remain unaddressed: > /* must be last register set: */ > - reg_clear(priv, REG_TBG_CNTRL_0, TBG_CNTRL_0_SYNC_ONCE); > + reg_write(priv, REG_TBG_CNTRL_0, 0); Register changes which have a potential effect shouldn't be part of a patch which is really only trying to avoid reading from write only registers. This could be a potential functional change - and it's probably one which Rob Clark should at least be made aware of. As I commented last time, when you're changing register values in an otherwise innocuous patch, you should comment about them in the patch description. -- FTTC broadband for 0.8mile line: 5.8Mbps down 500kbps up. Estimation in database were 13.1 to 19Mbit for a good line, about 7.5+ for a bad. Estimate before purchase was "up to 13.2Mbit".
next prev parent reply other threads:[~2014-02-02 16:23 UTC|newest] Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-01-29 9:01 [PATCH v5 00/23] Jean-Francois Moine 2014-01-29 9:01 ` Jean-Francois Moine 2014-01-29 9:01 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 23/23] drm/i2c: tda998x: adjust the audio clock divider for S/PDIF Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 17/23] drm/i2c: tda998x: set the PLL division factor in range 0..3 Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-29 15:16 ` Joe Perches 2014-01-29 15:16 ` Joe Perches 2014-01-25 17:14 ` [PATCH v5 16/23] drm/i2c: tda998x: fix the ENABLE_SPACE register Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 15/23] drm/i2c: tda998x: add DT documentation Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 13/23] drm/i2c: tda998x: always enable EDID read IRQ Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 14/23] drm/i2c: tda998x: use irq for connection status and EDID read Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 22/23] drm/i2c: tda998x: code optimization Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 21/23] drm/i2c: tda998x: change the frequence in the audio channel Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 20/23] drm/i2c: tda998x: add the active aspect in HDMI AVI frame Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 18/23] drm/i2c: tda998x: make the audio code more readable Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 19/23] drm/i2c: tda998x: remove the unused variable ca_i2s Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 08/23] drm/i2c: tda998x: use HDMI constants Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 12/23] drm/i2c: tda998x: add DT support Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 09/23] drm/i2c: tda998x: don't read write-only registers Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-02-02 16:23 ` Russell King - ARM Linux [this message] 2014-02-02 16:23 ` Russell King - ARM Linux 2014-02-02 17:45 ` Jean-Francois Moine 2014-02-02 17:45 ` Jean-Francois Moine 2014-02-02 17:45 ` Jean-Francois Moine 2014-02-02 17:57 ` Russell King - ARM Linux 2014-02-02 17:57 ` Russell King - ARM Linux 2014-01-25 17:14 ` [PATCH v5 10/23] drm/i2c: tda998x: free the CEC device on encoder_destroy Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 11/23] drm/i2c: tda998x: check the CEC device creation Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 07/23] drm/i2c: tda998x: fix bad value in the AIF Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 05/23] drm/i2c: tda998x: don't freeze the system at audio startup time Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 02/23] drm/i2c: tda998x: check more I/O errors Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-02-02 16:20 ` Russell King - ARM Linux 2014-02-02 16:20 ` Russell King - ARM Linux 2014-02-02 17:30 ` Jean-Francois Moine 2014-02-02 17:30 ` Jean-Francois Moine 2014-02-02 17:30 ` Jean-Francois Moine 2014-02-02 17:56 ` Russell King - ARM Linux 2014-02-02 17:56 ` Russell King - ARM Linux 2014-01-25 17:14 ` [PATCH v5 06/23] drm/i2c: tda998x: force the page register at startup time Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 03/23] drm/i2c: tda998x: code cleanup Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 04/23] drm/i2c: tda998x: change probe message origin Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` [PATCH v5 01/23] drm/i2c: tda998x: simplify the i2c read/write functions Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-01-25 17:14 ` Jean-Francois Moine 2014-02-02 12:43 ` [PATCH v5 00/23] Russell King - ARM Linux 2014-02-02 12:43 ` Russell King - ARM Linux 2014-02-02 12:43 ` Russell King - ARM Linux 2014-02-02 18:04 ` Russell King - ARM Linux 2014-02-02 18:04 ` Russell King - ARM Linux 2014-02-02 19:00 ` Jean-Francois Moine 2014-02-02 19:00 ` Jean-Francois Moine 2014-02-02 19:00 ` Jean-Francois Moine 2014-02-02 18:06 ` Jean-Francois Moine 2014-02-02 18:06 ` Jean-Francois Moine 2014-02-02 18:23 ` Russell King - ARM Linux 2014-02-02 18:23 ` Russell King - ARM Linux 2014-02-02 18:23 ` Russell King - ARM Linux 2014-02-02 18:41 ` Sebastian Hesselbarth 2014-02-02 18:41 ` Sebastian Hesselbarth 2014-02-02 18:54 ` Jean-Francois Moine 2014-02-02 18:54 ` Jean-Francois Moine 2014-02-02 18:54 ` Jean-Francois Moine 2014-02-02 19:15 ` Russell King - ARM Linux 2014-02-02 19:15 ` Russell King - ARM Linux 2014-02-02 20:07 ` Jean-Francois Moine 2014-02-02 20:07 ` Jean-Francois Moine 2014-02-02 20:07 ` Jean-Francois Moine 2014-02-03 12:46 ` Mark Brown 2014-02-03 12:46 ` Mark Brown
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