| Message ID | 1428629414.5384.2.camel@phoenix |
|---|---|
| State | New |
| Headers | show |
Hi Axel, On 4/9/2015 6:30 PM, Axel Lin wrote: > Implement gpio_chip's get_direction() callback, that lets other drivers get > particular GPIOs direction using gpiod_get_direction(). > > Signed-off-by: Axel Lin <axel.lin@ingics.com> > --- > drivers/gpio/gpio-bcm-kona.c | 24 ++++++++++++++---------- > 1 file changed, 14 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpio/gpio-bcm-kona.c b/drivers/gpio/gpio-bcm-kona.c > index 632352d..3649ed5 100644 > --- a/drivers/gpio/gpio-bcm-kona.c > +++ b/drivers/gpio/gpio-bcm-kona.c > @@ -129,6 +129,14 @@ static int bcm_kona_gpio_unlock_gpio(struct bcm_kona_gpio *kona_gpio, > return 0; > } > > +static int bcm_kona_gpio_get_dir(struct gpio_chip *chip, unsigned gpio) > +{ > + struct bcm_kona_gpio *kona_gpio = to_kona_gpio(chip); > + void __iomem *reg_base = kona_gpio->reg_base; > + > + return readl(reg_base + GPIO_CONTROL(gpio)) & GPIO_GPCTR0_IOTR_MASK; You are making assumption of actual values of GPIOF_DIR_IN and GPIOF_DIR_OUT. I think it would be better to return GPIOF_DIR_IN or GPIOF_DIR_OUT based on the register readling. In addition, with your change, when bcm_kona_gpio_get_dir is called within bcm_kona_gpio_set and bcm_kona_gpio_get, it's protected by the kona_gpio->lock spinlock. But no lock protection while being invoked through the upper layer get_direction callback. Thanks, Ray > +} > + > static void bcm_kona_gpio_set(struct gpio_chip *chip, unsigned gpio, int value) > { > struct bcm_kona_gpio *kona_gpio; > @@ -142,12 +150,8 @@ static void bcm_kona_gpio_set(struct gpio_chip *chip, unsigned gpio, int value) > reg_base = kona_gpio->reg_base; > spin_lock_irqsave(&kona_gpio->lock, flags); > > - /* determine the GPIO pin direction */ > - val = readl(reg_base + GPIO_CONTROL(gpio)); > - val &= GPIO_GPCTR0_IOTR_MASK; > - > /* this function only applies to output pin */ > - if (GPIO_GPCTR0_IOTR_CMD_INPUT == val) > + if (bcm_kona_gpio_get_dir(chip, gpio) == GPIOF_DIR_IN) > goto out; > > reg_offset = value ? GPIO_OUT_SET(bank_id) : GPIO_OUT_CLEAR(bank_id); > @@ -173,13 +177,12 @@ static int bcm_kona_gpio_get(struct gpio_chip *chip, unsigned gpio) > reg_base = kona_gpio->reg_base; > spin_lock_irqsave(&kona_gpio->lock, flags); > > - /* determine the GPIO pin direction */ > - val = readl(reg_base + GPIO_CONTROL(gpio)); > - val &= GPIO_GPCTR0_IOTR_MASK; > + if (bcm_kona_gpio_get_dir(chip, gpio) == GPIOF_DIR_IN) > + reg_offset = GPIO_IN_STATUS(bank_id); > + else > + reg_offset = GPIO_OUT_STATUS(bank_id); > > /* read the GPIO bank status */ > - reg_offset = (GPIO_GPCTR0_IOTR_CMD_INPUT == val) ? > - GPIO_IN_STATUS(bank_id) : GPIO_OUT_STATUS(bank_id); > val = readl(reg_base + reg_offset); > > spin_unlock_irqrestore(&kona_gpio->lock, flags); > @@ -316,6 +319,7 @@ static struct gpio_chip template_chip = { > .owner = THIS_MODULE, > .request = bcm_kona_gpio_request, > .free = bcm_kona_gpio_free, > + .get_direction = bcm_kona_gpio_get_dir, > .direction_input = bcm_kona_gpio_direction_input, > .get = bcm_kona_gpio_get, > .direction_output = bcm_kona_gpio_direction_output, > -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
2015-04-11 0:13 GMT+08:00 Ray Jui <rjui@broadcom.com>: > Hi Axel, > > On 4/9/2015 6:30 PM, Axel Lin wrote: >> Implement gpio_chip's get_direction() callback, that lets other drivers get >> particular GPIOs direction using gpiod_get_direction(). >> >> Signed-off-by: Axel Lin <axel.lin@ingics.com> >> --- >> drivers/gpio/gpio-bcm-kona.c | 24 ++++++++++++++---------- >> 1 file changed, 14 insertions(+), 10 deletions(-) >> >> diff --git a/drivers/gpio/gpio-bcm-kona.c b/drivers/gpio/gpio-bcm-kona.c >> index 632352d..3649ed5 100644 >> --- a/drivers/gpio/gpio-bcm-kona.c >> +++ b/drivers/gpio/gpio-bcm-kona.c >> @@ -129,6 +129,14 @@ static int bcm_kona_gpio_unlock_gpio(struct bcm_kona_gpio *kona_gpio, >> return 0; >> } >> >> +static int bcm_kona_gpio_get_dir(struct gpio_chip *chip, unsigned gpio) >> +{ >> + struct bcm_kona_gpio *kona_gpio = to_kona_gpio(chip); >> + void __iomem *reg_base = kona_gpio->reg_base; >> + >> + return readl(reg_base + GPIO_CONTROL(gpio)) & GPIO_GPCTR0_IOTR_MASK; > > You are making assumption of actual values of GPIOF_DIR_IN and > GPIOF_DIR_OUT. I think it would be better to return GPIOF_DIR_IN or > GPIOF_DIR_OUT based on the register readling. Yes, it's because GPIO_GPCTR0_IOTR_CMD_INPUT == GPIOF_DIR_IN and GPIO_GPCTR0_IOTR_CMD_0UTPUT == GPIOF_DIR_OUT. I can change it to below if you prefer, but current patch is shorter and logically exactly the same. if (readl(reg_base + GPIO_CONTROL(gpio)) & GPIO_GPCTR0_IOTR_MASK) return GPIOF_DIR_IN; else return GPIOF_DIR_OUT; > > In addition, with your change, when bcm_kona_gpio_get_dir is called > within bcm_kona_gpio_set and bcm_kona_gpio_get, it's protected by the > kona_gpio->lock spinlock. But no lock protection while being invoked > through the upper layer get_direction callback. It is because bcm_kona_gpio_get_dir is a single register read. In bcm_kona_gpio_set/bcm_kona_gpio_get, the lock is to ensure read/write to both the DIR and LEVEL registers so we won't set/get wrong level value in wrong DIR status. Regards, Axel -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Axel, On 4/10/2015 4:13 PM, Axel Lin wrote: > 2015-04-11 0:13 GMT+08:00 Ray Jui <rjui@broadcom.com>: >> Hi Axel, >> >> On 4/9/2015 6:30 PM, Axel Lin wrote: >>> Implement gpio_chip's get_direction() callback, that lets other drivers get >>> particular GPIOs direction using gpiod_get_direction(). >>> >>> Signed-off-by: Axel Lin <axel.lin@ingics.com> >>> --- >>> drivers/gpio/gpio-bcm-kona.c | 24 ++++++++++++++---------- >>> 1 file changed, 14 insertions(+), 10 deletions(-) >>> >>> diff --git a/drivers/gpio/gpio-bcm-kona.c b/drivers/gpio/gpio-bcm-kona.c >>> index 632352d..3649ed5 100644 >>> --- a/drivers/gpio/gpio-bcm-kona.c >>> +++ b/drivers/gpio/gpio-bcm-kona.c >>> @@ -129,6 +129,14 @@ static int bcm_kona_gpio_unlock_gpio(struct bcm_kona_gpio *kona_gpio, >>> return 0; >>> } >>> >>> +static int bcm_kona_gpio_get_dir(struct gpio_chip *chip, unsigned gpio) >>> +{ >>> + struct bcm_kona_gpio *kona_gpio = to_kona_gpio(chip); >>> + void __iomem *reg_base = kona_gpio->reg_base; >>> + >>> + return readl(reg_base + GPIO_CONTROL(gpio)) & GPIO_GPCTR0_IOTR_MASK; >> >> You are making assumption of actual values of GPIOF_DIR_IN and >> GPIOF_DIR_OUT. I think it would be better to return GPIOF_DIR_IN or >> GPIOF_DIR_OUT based on the register readling. > > Yes, it's because GPIO_GPCTR0_IOTR_CMD_INPUT == GPIOF_DIR_IN and > GPIO_GPCTR0_IOTR_CMD_0UTPUT == GPIOF_DIR_OUT. > > I can change it to below if you prefer, but current patch is shorter > and logically exactly the same. > > if (readl(reg_base + GPIO_CONTROL(gpio)) & GPIO_GPCTR0_IOTR_MASK) > return GPIOF_DIR_IN; > else > return GPIOF_DIR_OUT; > Or one line like: return readl(reg_base + GPIO_CONTROL(gpio)) & GPIO_GPCTR0_IOTR_MASK ? GPIOF_DIR_IN : GPIOF_DIR_OUT; >> >> In addition, with your change, when bcm_kona_gpio_get_dir is called >> within bcm_kona_gpio_set and bcm_kona_gpio_get, it's protected by the >> kona_gpio->lock spinlock. But no lock protection while being invoked >> through the upper layer get_direction callback. > > It is because bcm_kona_gpio_get_dir is a single register read. > In bcm_kona_gpio_set/bcm_kona_gpio_get, the lock is to ensure > read/write to both the DIR and LEVEL registers so we won't set/get > wrong level value in wrong DIR status. Yes, you are right. The locking part is fine! > > Regards, > Axel > -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/gpio/gpio-bcm-kona.c b/drivers/gpio/gpio-bcm-kona.c index 632352d..3649ed5 100644 --- a/drivers/gpio/gpio-bcm-kona.c +++ b/drivers/gpio/gpio-bcm-kona.c @@ -129,6 +129,14 @@ static int bcm_kona_gpio_unlock_gpio(struct bcm_kona_gpio *kona_gpio, return 0; } +static int bcm_kona_gpio_get_dir(struct gpio_chip *chip, unsigned gpio) +{ + struct bcm_kona_gpio *kona_gpio = to_kona_gpio(chip); + void __iomem *reg_base = kona_gpio->reg_base; + + return readl(reg_base + GPIO_CONTROL(gpio)) & GPIO_GPCTR0_IOTR_MASK; +} + static void bcm_kona_gpio_set(struct gpio_chip *chip, unsigned gpio, int value) { struct bcm_kona_gpio *kona_gpio; @@ -142,12 +150,8 @@ static void bcm_kona_gpio_set(struct gpio_chip *chip, unsigned gpio, int value) reg_base = kona_gpio->reg_base; spin_lock_irqsave(&kona_gpio->lock, flags); - /* determine the GPIO pin direction */ - val = readl(reg_base + GPIO_CONTROL(gpio)); - val &= GPIO_GPCTR0_IOTR_MASK; - /* this function only applies to output pin */ - if (GPIO_GPCTR0_IOTR_CMD_INPUT == val) + if (bcm_kona_gpio_get_dir(chip, gpio) == GPIOF_DIR_IN) goto out; reg_offset = value ? GPIO_OUT_SET(bank_id) : GPIO_OUT_CLEAR(bank_id); @@ -173,13 +177,12 @@ static int bcm_kona_gpio_get(struct gpio_chip *chip, unsigned gpio) reg_base = kona_gpio->reg_base; spin_lock_irqsave(&kona_gpio->lock, flags); - /* determine the GPIO pin direction */ - val = readl(reg_base + GPIO_CONTROL(gpio)); - val &= GPIO_GPCTR0_IOTR_MASK; + if (bcm_kona_gpio_get_dir(chip, gpio) == GPIOF_DIR_IN) + reg_offset = GPIO_IN_STATUS(bank_id); + else + reg_offset = GPIO_OUT_STATUS(bank_id); /* read the GPIO bank status */ - reg_offset = (GPIO_GPCTR0_IOTR_CMD_INPUT == val) ? - GPIO_IN_STATUS(bank_id) : GPIO_OUT_STATUS(bank_id); val = readl(reg_base + reg_offset); spin_unlock_irqrestore(&kona_gpio->lock, flags); @@ -316,6 +319,7 @@ static struct gpio_chip template_chip = { .owner = THIS_MODULE, .request = bcm_kona_gpio_request, .free = bcm_kona_gpio_free, + .get_direction = bcm_kona_gpio_get_dir, .direction_input = bcm_kona_gpio_direction_input, .get = bcm_kona_gpio_get, .direction_output = bcm_kona_gpio_direction_output,
Implement gpio_chip's get_direction() callback, that lets other drivers get particular GPIOs direction using gpiod_get_direction(). Signed-off-by: Axel Lin <axel.lin@ingics.com> --- drivers/gpio/gpio-bcm-kona.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-)