On Apr 21, 2012, at 2:47, Dmitry Torokhov wrote: > Hi Jean-François, > > On Fri, Apr 20, 2012 at 11:32:00AM -0400, Jean-François Dagenais wrote: >> 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 <jeff.dagenais@xxxxxxxxx> >> Acked-by: Michael Hennerich <michael.hennerich@xxxxxxxxxx> >> --- >> 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); > Agreed, I think I wanted to minimize refactoring a bit too much and got distracted. I will send V2 shortly for both drivers. > Thanks. Thank you! > > -- > Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
