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 18:15:19 +0100 [thread overview]
Message-ID: <50CF5327.6070205@antcom.de> (raw)
In-Reply-To: <50CF4838.9000401@grandegger.com>
On 12/17/2012 05:28 PM, Wolfgang Grandegger wrote:
> On 12/17/2012 02:51 PM, Roland Stigge wrote:
>> Hi Wolfgang,
>>> 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.
>>
>> Can you please test the following:
>>
>> +static void at91_gpiolib_set_block(struct gpio_chip *chip, unsigned long mask, unsigned long val)
>> +{
>> + struct at91_gpio_chip *at91_gpio = to_at91_gpio_chip(chip);
>> + void __iomem *pio = at91_gpio->regbase;
>> +
>> + __raw_writel(~mask, pio + PIO_OWDR);
>
> This would also disable normal GPIOs configured for output! From the
> manual I understand that if the pin is configured for output, we could
> either use PIO_SODR/PIO_CODR to set/clear the bits individually or
> PIO_ODSR for synchronous data output. But than we need to care about the
> non-block GPIO outputs as well... requiring a read-modify-write cycle :(.
>From the manual, I read about OWER: "Enables writing PIO_ODSR for the
I/O line" (analogous for OWDR). Would interpret this as affecting ODSR
(for block GPIO) but not SODR/CODR (as currently with single GPIOs).
Have you tried? ;-)
Thanks in advance,
Roland
next prev parent reply other threads:[~2012-12-17 17:15 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
2012-12-17 13:51 ` Roland Stigge
2012-12-17 16:28 ` Wolfgang Grandegger
2012-12-17 17:15 ` Roland Stigge [this message]
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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