Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755170Ab0LOT2R (ORCPT ); Wed, 15 Dec 2010 14:28:17 -0500 Received: from LUNGE.MIT.EDU ([18.54.1.69]:60126 "EHLO lunge.queued.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755152Ab0LOT2O (ORCPT ); Wed, 15 Dec 2010 14:28:14 -0500 Date: Wed, 15 Dec 2010 11:28:07 -0800 From: Andres Salomon To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-geode@lists.infradead.org, dsd@laptop.org, pgf@laptop.org Subject: [PATCH 1/2] cs5535-gpio: don't apply errata #36 to edge detect GPIOs Message-ID: <20101215112807.2c85e991@queued.net> X-Mailer: Claws Mail 3.7.6 (GTK+ 2.20.1; i486-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 Content-Length: 2438 Lines: 68 The edge detect status GPIOs function differently from the other atomic model CS5536 GPIO registers; writing 1 to the high bits clears the GPIO, but writing 1 to the lower bits also clears the bit. This means that read-modify-write doesn't actually work for it, so don't apply the errata here. If a negative edge status gets lost after resume.. well, we tried our best! Signed-off-by: Andres Salomon Tested-by: Daniel Drake --- drivers/gpio/cs5535-gpio.c | 15 +++++++++++---- 1 files changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/gpio/cs5535-gpio.c b/drivers/gpio/cs5535-gpio.c index 599f6c9..79eb9c5 100644 --- a/drivers/gpio/cs5535-gpio.c +++ b/drivers/gpio/cs5535-gpio.c @@ -56,15 +56,22 @@ static struct cs5535_gpio_chip { * registers, see include/linux/cs5535.h. */ -static void errata_outl(u32 val, unsigned long addr) +static void errata_outl(struct cs5535_gpio_chip *chip, u32 val, + unsigned int reg) { + unsigned long addr = chip->base + 0x80 + reg; + /* * According to the CS5536 errata (#36), after suspend * a write to the high bank GPIO register will clear all * non-selected bits; the recommended workaround is a * read-modify-write operation. + * + * Don't apply this errata to the edge status GPIOs, as writing + * to their lower bits will clear them. */ - val |= inl(addr); + if (reg != GPIO_POSITIVE_EDGE_STS && reg != GPIO_NEGATIVE_EDGE_STS) + val |= inl(addr); outl(val, addr); } @@ -76,7 +83,7 @@ static void __cs5535_gpio_set(struct cs5535_gpio_chip *chip, unsigned offset, outl(1 << offset, chip->base + reg); else /* high bank register */ - errata_outl(1 << (offset - 16), chip->base + 0x80 + reg); + errata_outl(chip, 1 << (offset - 16), reg); } void cs5535_gpio_set(unsigned offset, unsigned int reg) @@ -98,7 +105,7 @@ static void __cs5535_gpio_clear(struct cs5535_gpio_chip *chip, unsigned offset, outl(1 << (offset + 16), chip->base + reg); else /* high bank register */ - errata_outl(1 << offset, chip->base + 0x80 + reg); + errata_outl(chip, 1 << offset, reg); } void cs5535_gpio_clear(unsigned offset, unsigned int reg) -- 1.7.2.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/