Re: [PATCH 1/2] input: adp5588-keys - get value from data out when dir out
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: 2012-04-21 06:47:17
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Hi Jean-François, On Fri, Apr 20, 2012 at 11:32:00AM -0400, Jean-François Dagenais wrote:
quoted hunk ↗ jump to hunk
As discussed here: http://ez.analog.com/message/35852, the 5587 revC and 5588 revB spec sheets contain a mistake in the GPIO_DAT_STATx register description. According to R.Shnell at ADI, as well as my own observations, it should read: "GPIO data status (shows GPIO state when read for inputs)". This commit changes the get value function accordingly. A similar patch for gpio-adp5588 follows. Signed-off-by: Jean-François Dagenais <redacted> Acked-by: Michael Hennerich <michael.hennerich@analog.com> --- drivers/input/keyboard/adp5588-keys.c | 7 +++++++ 1 files changed, 7 insertions(+), 0 deletions(-)diff --git a/drivers/input/keyboard/adp5588-keys.c b/drivers/input/keyboard/adp5588-keys.c index 6412ced..b7a0f1a 100644 --- a/drivers/input/keyboard/adp5588-keys.c +++ b/drivers/input/keyboard/adp5588-keys.c@@ -78,6 +78,13 @@ static int adp5588_gpio_get_value(struct gpio_chip *chip, unsigned off) unsigned int bank = ADP5588_BANK(kpad->gpiomap[off]); unsigned int bit = ADP5588_BIT(kpad->gpiomap[off]); + mutex_lock(&kpad->gpio_lock); + if (kpad->dir[bank] & bit) { + int result = !!(kpad->dat_out[bank] & bit); + mutex_unlock(&kpad->gpio_lock); + return result; + } + mutex_unlock(&kpad->gpio_lock); return !!(adp5588_read(kpad->client, GPIO_DAT_STAT1 + bank) & bit);
This locking looks wrong as it is possible for adp5588_gpio_get_value() to get scheduled out after checking kpad->dir[bank] and releasing kpad->gpio_lock while another thread executes adp5588_gpio_direction_output() and modifies kpad->dir[bank]. You should keep mutex for the entire duration; something like this: mutex_lock(&kpad->gpio_lock); if (kpad->dir[bank] & bit) val = kpad->dat_out[bank]; else val = adp5588_read(kpad->client, GPIO_DAT_STAT1 + bank); mutex_unlock(&kpad->gpio_lock); return !!(val & bit); Thanks. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html