From: rogerq@ti•com (Roger Quadros)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 5/8] gpio: twl4030: Fix regression for twl gpio output
Date: Tue, 3 Dec 2013 15:30:11 +0200 [thread overview]
Message-ID: <529DDCE3.5020902@ti.com> (raw)
In-Reply-To: <1384396537-3486-6-git-send-email-tony@atomide.com>
Hi Tony,
On 11/14/2013 04:35 AM, Tony Lindgren wrote:
> Commit c111feabe2e2 (gpio: twl4030: Cache the direction and output
> states in private data) improved things in general, but caused a
> regression for setting the GPIO output direction.
>
> The change reorganized twl_direction_out() and twl_set() and swapped
> the function names around in the process. While doing that, a bug got
> introduced that's not obvious while reading the patch as it appears
> as no change to the code.
>
> The bug is we now call function twl4030_set_gpio_dataout() twice in
> both twl_direction_out() and twl_set(). Instead, we should first
> call twl_direction_out() in twl_direction_out() followed by
> twl4030_set_gpio_dataout() in twl_set().
>
> This regression probably has gone unnoticed for a long time as the
> bootloader may have set the GPIO direction properly in many cases.
> This fixes at least the LCD panel not turning on omap3 LDP for
> example.
>
> Cc: Linus Walleij <linus.walleij@linaro•org>
> Cc: Peter Ujfalusi <peter.ujfalusi@ti•com>
> Cc: linux-gpio at vger.kernel.org
> Signed-off-by: Tony Lindgren <tony@atomide•com>
> ---
>
> If this looks OK, I'd like to merge this as a fix via arm-soc tree
> along with the other patches in this series as my later patches
> depend on patches in this series.
This patch causes a regression with LED outputs (GPO) on twl4030 on 3.13-rc2.
As one of the LED GPO is used for USB host on beagleboard, it will cause failure
of USB host probe.
I'll explain why below.
>
> ---
> drivers/gpio/gpio-twl4030.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpio/gpio-twl4030.c b/drivers/gpio/gpio-twl4030.c
> index 0c7e891..5738d5a 100644
> --- a/drivers/gpio/gpio-twl4030.c
> +++ b/drivers/gpio/gpio-twl4030.c
> @@ -354,17 +354,18 @@ static void twl_set(struct gpio_chip *chip, unsigned offset, int value)
> static int twl_direction_out(struct gpio_chip *chip, unsigned offset, int value)
> {
> struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip);
> + int ret = -EINVAL;
>
> mutex_lock(&priv->mutex);
> if (offset < TWL4030_GPIO_MAX)
> - twl4030_set_gpio_dataout(offset, value);
> + ret = twl4030_set_gpio_direction(offset, 0);
twl_direction_out() is supposed to return 0 on success and non-zero only on failure.
for (offset >= TWL4030_GPIO_MAX) i.e. LED output case we now return -EINVAL, which
causes the LED GPO set_direction_out to fail. LED outputs are always outputs so
this function shouldn't fail.
>
> priv->direction |= BIT(offset);
> mutex_unlock(&priv->mutex);
>
> twl_set(chip, offset, value);
>
> - return 0;
> + return ret;
> }
>
> static int twl_to_irq(struct gpio_chip *chip, unsigned offset)
>
Below is a proposed fix for this.
>From 7c36c8952ee3c7220ea21396cd3f84a1f9e9ea73 Mon Sep 17 00:00:00 2001
From: Roger Quadros <rogerq@ti•com>
Date: Tue, 3 Dec 2013 15:24:05 +0200
Subject: [PATCH] gpio: twl4030: Fix regression for twl gpio LED output
Commit 0b2aa8be introduced a regression that causes failure
in setting LED GPO direction to OUT.
This causes USB host probe failures for Beagleboard C4.
[ 2.075469] platform usb_phy_gen_xceiv.2: Driver usb_phy_gen_xceiv requests probe deferral
[ 2.090454] hsusb2_vcc: Failed to request enable GPIO510: -22
[ 2.100982] reg-fixed-voltage reg-fixed-voltage.0.auto: Failed to register regulator: -22
[ 2.109954] reg-fixed-voltage: probe of reg-fixed-voltage.0.auto failed with error -22
direction_out/direction_in must return 0 if the operation succeeded.
Signed-off-by: Roger Quadros <rogerq@ti•com>
---
drivers/gpio/gpio-twl4030.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/drivers/gpio/gpio-twl4030.c b/drivers/gpio/gpio-twl4030.c
index b97d6a6..0999ed1 100644
--- a/drivers/gpio/gpio-twl4030.c
+++ b/drivers/gpio/gpio-twl4030.c
@@ -294,13 +294,13 @@ out:
static int twl_direction_in(struct gpio_chip *chip, unsigned offset)
{
struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip);
- int ret;
+ int ret = 0;
mutex_lock(&priv->mutex);
if (offset < TWL4030_GPIO_MAX)
- ret = twl4030_set_gpio_direction(offset, 1);
+ twl4030_set_gpio_direction(offset, 1);
else
- ret = -EINVAL;
+ ret = -EINVAL; /* LED outputs can't be set as input */
if (!ret)
priv->direction &= ~BIT(offset);
@@ -354,18 +354,21 @@ static void twl_set(struct gpio_chip *chip, unsigned offset, int value)
static int twl_direction_out(struct gpio_chip *chip, unsigned offset, int value)
{
struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip);
- int ret = -EINVAL;
mutex_lock(&priv->mutex);
if (offset < TWL4030_GPIO_MAX)
- ret = twl4030_set_gpio_direction(offset, 0);
+ twl4030_set_gpio_direction(offset, 0);
+
+ /*
+ * LED gpio's i.e. offset >= TWL4030_GPIO_MAX are always output
+ */
priv->direction |= BIT(offset);
mutex_unlock(&priv->mutex);
twl_set(chip, offset, value);
- return ret;
+ return 0;
}
static int twl_to_irq(struct gpio_chip *chip, unsigned offset)
--
1.8.3.2
next prev parent reply other threads:[~2013-12-03 13:30 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-14 2:35 [PATCH 0/8] Various omap device tree usability fixes for v3.13 merge window Tony Lindgren
2013-11-14 2:35 ` [PATCH 1/8] net: smc91x: Fix device tree based configuration so it's usable Tony Lindgren
2013-11-14 11:03 ` Mark Rutland
2013-11-14 16:08 ` Tony Lindgren
2013-11-16 15:16 ` Tony Lindgren
2013-11-27 18:36 ` Tony Lindgren
2013-11-14 2:35 ` [PATCH 2/8] mmc: omap: Fix DMA configuration to not rely on device id Tony Lindgren
2013-11-18 18:47 ` Tony Lindgren
2013-11-26 23:33 ` Chris Ball
2013-11-26 23:52 ` Tony Lindgren
2013-11-27 20:57 ` Jarkko Nikula
2013-11-27 21:37 ` Tony Lindgren
2013-11-28 17:02 ` Jarkko Nikula
2013-11-29 16:34 ` Tony Lindgren
2013-11-27 21:47 ` Chris Ball
2013-11-27 21:59 ` Tony Lindgren
2013-11-28 16:13 ` Jarkko Nikula
2013-11-29 17:13 ` Tony Lindgren
2013-11-30 0:38 ` Joel Fernandes
2013-11-30 17:33 ` Tony Lindgren
2013-11-14 2:35 ` [PATCH 3/8] mmc: omap: Fix I2C dependency and make driver usable with device tree Tony Lindgren
2013-11-14 11:05 ` Mark Rutland
2013-11-14 17:25 ` Tony Lindgren
2013-11-26 23:34 ` Chris Ball
2013-11-14 2:35 ` [PATCH 4/8] i2c: omap: Fix missing device tree flags for omap2 Tony Lindgren
2013-11-14 6:58 ` Wolfram Sang
2013-11-14 17:34 ` Tony Lindgren
2013-11-14 17:49 ` Wolfram Sang
2013-11-14 17:53 ` Tony Lindgren
2013-11-14 11:07 ` Mark Rutland
2013-11-14 17:30 ` Tony Lindgren
2013-11-14 2:35 ` [PATCH 5/8] gpio: twl4030: Fix regression for twl gpio output Tony Lindgren
2013-11-14 9:45 ` Peter Ujfalusi
2013-11-14 17:37 ` Tony Lindgren
2013-11-18 22:45 ` Linus Walleij
2013-12-03 13:30 ` Roger Quadros [this message]
2013-12-09 13:09 ` Linus Walleij
2013-12-09 17:10 ` Tony Lindgren
2013-12-10 12:17 ` Linus Walleij
2013-12-10 15:20 ` Tony Lindgren
2013-11-14 2:35 ` [PATCH 6/8] gpio: twl4030: Fix passing of pdata in the device tree case Tony Lindgren
2013-11-18 18:27 ` Tony Lindgren
2013-11-18 22:46 ` Linus Walleij
2013-11-14 2:35 ` [PATCH 7/8] ARM: OMAP2+: Fix GPMC and simplify bootloader timings for 8250 and smc91x Tony Lindgren
2013-11-14 2:35 ` [PATCH 8/8] ARM: dts: Fix omap2 specific dtsi files by adding the missing entries Tony Lindgren
2013-11-14 23:08 ` [PATCH 9/8] i2c: Fix device tree binding for i2c-cbus-gpio Tony Lindgren
2013-11-15 18:49 ` Aaro Koskinen
2013-11-15 22:26 ` Wolfram Sang
2013-11-15 22:30 ` Tony Lindgren
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