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From: stigge@antcom•de (Roland Stigge)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH RESEND 0/6 v10] gpio: Add block GPIO
Date: Mon, 17 Dec 2012 14:32:33 +0100	[thread overview]
Message-ID: <50CF1EF1.2070601@antcom.de> (raw)
In-Reply-To: <50CF0744.7040404@grandegger.com>

On 12/17/2012 12:51 PM, Wolfgang Grandegger wrote:
>>> Without having an AT91 available right now, I guess the hardware
>>> interface of this GPIO chip is different from the GPIO block API. While
>>> the hardware has clear and set registers, the val parameter of
>>> at91_gpiolib_set_block() should be interpreted as the actual output
>>> values. See lpc32xx_gpo_set_block() for an example for handling set and
>>> clear registers like this: First, set_bits and clear_bits words are
>>> calculated from mask and val parameters, and finally written to the
>>> respective hardware registers.
>>>
>>> Note that one .set_block() can result in writing both the set and clear
>>> registers of the hardware when val contains both 0s and 1s in
>>> respectively masked positions.
>>
>> Oops, I obviously did not test GPIO block write. The patch below does
>> work now. Feel free to add it to the next version of your series.
> 
> The patch lacks an important fix, sorry. Please consider the updated
> patch below.

Thanks!

And I guess Russell is right: If possible, we should write outputs
simultaneously via ODSR (plus OWER/OWDR/OWSR) instead of separate set/clear.

I wonder if we need to save/restore the state of OWSR at every write
operation or if we need/can cache it. Assuming that block GPIO are the
only code in the kernel that manipulates ODSR.

Further: Can we include this patch for arch/arm/mach-at91 via the gpio
subsystem or does it need to go separately via arm-soc.git?

Thanks,

Roland

next prev parent reply	other threads:[~2012-12-17 13:32 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-14 14:26 [PATCH RESEND 0/6 v10] gpio: Add block GPIO Roland Stigge
2012-12-14 14:26 ` [PATCH RESEND 1/6 v10] gpio: Add a block GPIO API to gpiolib Roland Stigge
2012-12-14 14:26 ` [PATCH RESEND 2/6 v10] gpio: Add sysfs support to block GPIO API Roland Stigge
2012-12-14 14:26 ` [PATCH RESEND 3/6 v10] gpio: Add userland device interface to block GPIO Roland Stigge
2012-12-14 14:26 ` [PATCH RESEND 4/6 v10] gpiolib: Fix default attributes for class Roland Stigge
2012-12-14 14:26 ` [PATCH RESEND 5/6 v10] gpio: Add device tree support to block GPIO API Roland Stigge
2012-12-17 15:51   ` Mark Rutland
2012-12-18 14:30     ` Roland Stigge
2012-12-18 16:35       ` Mark Rutland
2012-12-14 14:26 ` [PATCH RESEND 6/6 v10] gpio: Add block gpio to several gpio drivers Roland Stigge
2012-12-14 17:58 ` [PATCH RESEND 0/6 v10] gpio: Add block GPIO Wolfgang Grandegger
2012-12-14 23:49   ` Roland Stigge
2012-12-15 10:51     ` Russell King - ARM Linux
2012-12-17 11:37     ` Wolfgang Grandegger
2012-12-17 11:51       ` Wolfgang Grandegger
2012-12-17 12:10         ` Russell King - ARM Linux
2012-12-17 14:57           ` Wolfgang Grandegger
2012-12-17 13:32         ` Roland Stigge [this message]
2012-12-17 13:51           ` Roland Stigge
2012-12-17 16:28             ` Wolfgang Grandegger
2012-12-17 17:15               ` Roland Stigge
2012-12-17 17:37                 ` Wolfgang Grandegger
2012-12-17 18:02                   ` Roland Stigge
2012-12-17 19:47                     ` Wolfgang Grandegger
2012-12-17 21:33                       ` Roland Stigge
2012-12-18  6:51                         ` Wolfgang Grandegger
2012-12-18  5:55                       ` Jean-Christophe PLAGNIOL-VILLARD
2012-12-18  6:58                         ` Wolfgang Grandegger
2012-12-18  7:54                           ` Jean-Christophe PLAGNIOL-VILLARD

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