| Message ID | 1354791127-20545-3-git-send-email-peter.ujfalusi@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, 6 Dec 2012 11:52:06 +0100, Peter Ujfalusi <peter.ujfalusi@ti.com> wrote: > Use more coherent locking in the driver. Use bitfield to store the GPIO > direction and if the pin is configured as output store the status also in a > bitfiled. > In this way we can just look at these bitfields when we need information > about the pin status and only reach out to the chip when it is needed. > > Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Applied, thanks g. > --- > drivers/gpio/gpio-twl4030.c | 99 ++++++++++++++++++++++++++++++--------------- > 1 file changed, 66 insertions(+), 33 deletions(-) > > diff --git a/drivers/gpio/gpio-twl4030.c b/drivers/gpio/gpio-twl4030.c > index c092739..a38e6e9c 100644 > --- a/drivers/gpio/gpio-twl4030.c > +++ b/drivers/gpio/gpio-twl4030.c > @@ -64,14 +64,15 @@ > /* Mask for GPIO registers when aggregated into a 32-bit integer */ > #define GPIO_32_MASK 0x0003ffff > > -/* Data structures */ > -static DEFINE_MUTEX(gpio_lock); > - > struct gpio_twl4030_priv { > struct gpio_chip gpio_chip; > + struct mutex mutex; > int irq_base; > > + /* Bitfields for state caching */ > unsigned int usage_count; > + unsigned int direction; > + unsigned int out_state; > }; > > /*----------------------------------------------------------------------*/ > @@ -130,7 +131,7 @@ static inline int gpio_twl4030_read(u8 address) > > /*----------------------------------------------------------------------*/ > > -static u8 cached_leden; /* protected by gpio_lock */ > +static u8 cached_leden; > > /* The LED lines are open drain outputs ... a FET pulls to GND, so an > * external pullup is needed. We could also expose the integrated PWM > @@ -144,14 +145,12 @@ static void twl4030_led_set_value(int led, int value) > if (led) > mask <<= 1; > > - mutex_lock(&gpio_lock); > if (value) > cached_leden &= ~mask; > else > cached_leden |= mask; > status = twl_i2c_write_u8(TWL4030_MODULE_LED, cached_leden, > TWL4030_LED_LEDEN_REG); > - mutex_unlock(&gpio_lock); > } > > static int twl4030_set_gpio_direction(int gpio, int is_input) > @@ -162,7 +161,6 @@ static int twl4030_set_gpio_direction(int gpio, int is_input) > u8 base = REG_GPIODATADIR1 + d_bnk; > int ret = 0; > > - mutex_lock(&gpio_lock); > ret = gpio_twl4030_read(base); > if (ret >= 0) { > if (is_input) > @@ -172,7 +170,6 @@ static int twl4030_set_gpio_direction(int gpio, int is_input) > > ret = gpio_twl4030_write(base, reg); > } > - mutex_unlock(&gpio_lock); > return ret; > } > > @@ -212,7 +209,7 @@ static int twl_request(struct gpio_chip *chip, unsigned offset) > struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip); > int status = 0; > > - mutex_lock(&gpio_lock); > + mutex_lock(&priv->mutex); > > /* Support the two LED outputs as output-only GPIOs. */ > if (offset >= TWL4030_GPIO_MAX) { > @@ -271,7 +268,7 @@ done: > if (!status) > priv->usage_count |= BIT(offset); > > - mutex_unlock(&gpio_lock); > + mutex_unlock(&priv->mutex); > return status; > } > > @@ -279,64 +276,98 @@ static void twl_free(struct gpio_chip *chip, unsigned offset) > { > struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip); > > + mutex_lock(&priv->mutex); > if (offset >= TWL4030_GPIO_MAX) { > twl4030_led_set_value(offset - TWL4030_GPIO_MAX, 1); > return; > } > > - mutex_lock(&gpio_lock); > - > priv->usage_count &= ~BIT(offset); > > /* on last use, switch off GPIO module */ > if (!priv->usage_count) > gpio_twl4030_write(REG_GPIO_CTRL, 0x0); > > - mutex_unlock(&gpio_lock); > + mutex_unlock(&priv->mutex); > } > > static int twl_direction_in(struct gpio_chip *chip, unsigned offset) > { > - return (offset < TWL4030_GPIO_MAX) > - ? twl4030_set_gpio_direction(offset, 1) > - : -EINVAL; > + struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip); > + int ret; > + > + mutex_lock(&priv->mutex); > + if (offset < TWL4030_GPIO_MAX) > + ret = twl4030_set_gpio_direction(offset, 1); > + else > + ret = -EINVAL; > + > + if (!ret) > + priv->direction &= ~BIT(offset); > + > + mutex_unlock(&priv->mutex); > + > + return ret; > } > > static int twl_get(struct gpio_chip *chip, unsigned offset) > { > struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip); > + int ret; > int status = 0; > > - if (!(priv->usage_count & BIT(offset))) > - return -EPERM; > + mutex_lock(&priv->mutex); > + if (!(priv->usage_count & BIT(offset))) { > + ret = -EPERM; > + goto out; > + } > > - if (offset < TWL4030_GPIO_MAX) > - status = twl4030_get_gpio_datain(offset); > - else if (offset == TWL4030_GPIO_MAX) > - status = cached_leden & LEDEN_LEDAON; > + if (priv->direction & BIT(offset)) > + status = priv->out_state & BIT(offset); > else > - status = cached_leden & LEDEN_LEDBON; > + status = twl4030_get_gpio_datain(offset); > > - return (status < 0) ? 0 : status; > + ret = (status <= 0) ? 0 : 1; > +out: > + mutex_unlock(&priv->mutex); > + dev_err(chip->dev, "%s: offset %d value %d\n", __func__, offset, ret); > + return ret; > } > > -static int twl_direction_out(struct gpio_chip *chip, unsigned offset, int value) > +static void twl_set(struct gpio_chip *chip, unsigned offset, int value) > { > - if (offset < TWL4030_GPIO_MAX) { > + struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip); > + > + dev_err(chip->dev, "%s: offset %d value %d\n", __func__, offset, value); > + mutex_lock(&priv->mutex); > + if (offset < TWL4030_GPIO_MAX) > twl4030_set_gpio_dataout(offset, value); > - return twl4030_set_gpio_direction(offset, 0); > - } else { > + else > twl4030_led_set_value(offset - TWL4030_GPIO_MAX, value); > - return 0; > - } > + > + if (value) > + priv->out_state |= BIT(offset); > + else > + priv->out_state &= ~BIT(offset); > + > + mutex_unlock(&priv->mutex); > } > > -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); > + > + dev_err(chip->dev, "%s: offset %d value %d\n", __func__, offset, value); > + mutex_lock(&priv->mutex); > if (offset < TWL4030_GPIO_MAX) > twl4030_set_gpio_dataout(offset, value); > - else > - twl4030_led_set_value(offset - TWL4030_GPIO_MAX, value); > + > + priv->direction |= BIT(offset); > + mutex_unlock(&priv->mutex); > + > + twl_set(chip, offset, value); > + > + return 0; > } > > static int twl_to_irq(struct gpio_chip *chip, unsigned offset) > @@ -469,6 +500,8 @@ no_irqs: > priv->gpio_chip.ngpio = TWL4030_GPIO_MAX; > priv->gpio_chip.dev = &pdev->dev; > > + mutex_init(&priv->mutex); > + > if (node) > pdata = of_gpio_twl4030(&pdev->dev); > > -- > 1.8.0 >
Hi Grant Likely <grant.likely@secretlab.ca> wrote: >On Thu, 6 Dec 2012 11:52:06 +0100, Peter Ujfalusi ><peter.ujfalusi@ti.com> wrote: >> Use more coherent locking in the driver. Use bitfield to store the >GPIO >> direction and if the pin is configured as output store the status >also in a >> bitfiled. >> In this way we can just look at these bitfields when we need >information >> about the pin status and only reach out to the chip when it is >needed. >> >> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> > >Applied, thanks > >g. > >> --- >> drivers/gpio/gpio-twl4030.c | 99 >++++++++++++++++++++++++++++++--------------- >> 1 file changed, 66 insertions(+), 33 deletions(-) >> >> diff --git a/drivers/gpio/gpio-twl4030.c >b/drivers/gpio/gpio-twl4030.c >> index c092739..a38e6e9c 100644 >> --- a/drivers/gpio/gpio-twl4030.c >> +++ b/drivers/gpio/gpio-twl4030.c >> @@ -64,14 +64,15 @@ >> /* Mask for GPIO registers when aggregated into a 32-bit integer */ >> #define GPIO_32_MASK 0x0003ffff >> >> -/* Data structures */ >> -static DEFINE_MUTEX(gpio_lock); >> - >> struct gpio_twl4030_priv { >> struct gpio_chip gpio_chip; >> + struct mutex mutex; >> int irq_base; >> >> + /* Bitfields for state caching */ >> unsigned int usage_count; >> + unsigned int direction; >> + unsigned int out_state; >> }; >> >> >/*----------------------------------------------------------------------*/ >> @@ -130,7 +131,7 @@ static inline int gpio_twl4030_read(u8 address) >> >> >/*----------------------------------------------------------------------*/ >> >> -static u8 cached_leden; /* protected by gpio_lock */ >> +static u8 cached_leden; >> >> /* The LED lines are open drain outputs ... a FET pulls to GND, so >an >> * external pullup is needed. We could also expose the integrated >PWM >> @@ -144,14 +145,12 @@ static void twl4030_led_set_value(int led, int >value) >> if (led) >> mask <<= 1; >> >> - mutex_lock(&gpio_lock); >> if (value) >> cached_leden &= ~mask; >> else >> cached_leden |= mask; >> status = twl_i2c_write_u8(TWL4030_MODULE_LED, cached_leden, >> TWL4030_LED_LEDEN_REG); >> - mutex_unlock(&gpio_lock); >> } >> >> static int twl4030_set_gpio_direction(int gpio, int is_input) >> @@ -162,7 +161,6 @@ static int twl4030_set_gpio_direction(int gpio, >int is_input) >> u8 base = REG_GPIODATADIR1 + d_bnk; >> int ret = 0; >> >> - mutex_lock(&gpio_lock); >> ret = gpio_twl4030_read(base); >> if (ret >= 0) { >> if (is_input) >> @@ -172,7 +170,6 @@ static int twl4030_set_gpio_direction(int gpio, >int is_input) >> >> ret = gpio_twl4030_write(base, reg); >> } >> - mutex_unlock(&gpio_lock); >> return ret; >> } >> >> @@ -212,7 +209,7 @@ static int twl_request(struct gpio_chip *chip, >unsigned offset) >> struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip); >> int status = 0; >> >> - mutex_lock(&gpio_lock); >> + mutex_lock(&priv->mutex); >> >> /* Support the two LED outputs as output-only GPIOs. */ >> if (offset >= TWL4030_GPIO_MAX) { >> @@ -271,7 +268,7 @@ done: >> if (!status) >> priv->usage_count |= BIT(offset); >> >> - mutex_unlock(&gpio_lock); >> + mutex_unlock(&priv->mutex); >> return status; >> } >> >> @@ -279,64 +276,98 @@ static void twl_free(struct gpio_chip *chip, >unsigned offset) >> { >> struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip); >> >> + mutex_lock(&priv->mutex); >> if (offset >= TWL4030_GPIO_MAX) { >> twl4030_led_set_value(offset - TWL4030_GPIO_MAX, 1); I have the mobile but where is the unlock here? >> return; >> } >> >> - mutex_lock(&gpio_lock); >> - >> priv->usage_count &= ~BIT(offset); >> >> /* on last use, switch off GPIO module */ >> if (!priv->usage_count) >> gpio_twl4030_write(REG_GPIO_CTRL, 0x0); >> >> - mutex_unlock(&gpio_lock); >> + mutex_unlock(&priv->mutex); >> } >> >> static int twl_direction_in(struct gpio_chip *chip, unsigned offset) >> { >> - return (offset < TWL4030_GPIO_MAX) >> - ? twl4030_set_gpio_direction(offset, 1) >> - : -EINVAL; >> + struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip); >> + int ret; >> + >> + mutex_lock(&priv->mutex); >> + if (offset < TWL4030_GPIO_MAX) >> + ret = twl4030_set_gpio_direction(offset, 1); >> + else >> + ret = -EINVAL; >> + >> + if (!ret) >> + priv->direction &= ~BIT(offset); >> + >> + mutex_unlock(&priv->mutex); >> + >> + return ret; >> } >> >> static int twl_get(struct gpio_chip *chip, unsigned offset) >> { >> struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip); >> + int ret; >> int status = 0; >> >> - if (!(priv->usage_count & BIT(offset))) >> - return -EPERM; >> + mutex_lock(&priv->mutex); >> + if (!(priv->usage_count & BIT(offset))) { >> + ret = -EPERM; >> + goto out; >> + } >> >> - if (offset < TWL4030_GPIO_MAX) >> - status = twl4030_get_gpio_datain(offset); >> - else if (offset == TWL4030_GPIO_MAX) >> - status = cached_leden & LEDEN_LEDAON; >> + if (priv->direction & BIT(offset)) >> + status = priv->out_state & BIT(offset); >> else >> - status = cached_leden & LEDEN_LEDBON; >> + status = twl4030_get_gpio_datain(offset); >> >> - return (status < 0) ? 0 : status; >> + ret = (status <= 0) ? 0 : 1; >> +out: >> + mutex_unlock(&priv->mutex); >> + dev_err(chip->dev, "%s: offset %d value %d\n", __func__, offset, >ret); >> + return ret; >> } >> >> -static int twl_direction_out(struct gpio_chip *chip, unsigned >offset, int value) >> +static void twl_set(struct gpio_chip *chip, unsigned offset, int >value) >> { >> - if (offset < TWL4030_GPIO_MAX) { >> + struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip); >> + >> + dev_err(chip->dev, "%s: offset %d value %d\n", __func__, offset, >value); >> + mutex_lock(&priv->mutex); >> + if (offset < TWL4030_GPIO_MAX) >> twl4030_set_gpio_dataout(offset, value); >> - return twl4030_set_gpio_direction(offset, 0); >> - } else { >> + else >> twl4030_led_set_value(offset - TWL4030_GPIO_MAX, value); >> - return 0; >> - } >> + >> + if (value) >> + priv->out_state |= BIT(offset); >> + else >> + priv->out_state &= ~BIT(offset); >> + >> + mutex_unlock(&priv->mutex); >> } >> >> -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); >> + >> + dev_err(chip->dev, "%s: offset %d value %d\n", __func__, offset, >value); >> + mutex_lock(&priv->mutex); >> if (offset < TWL4030_GPIO_MAX) >> twl4030_set_gpio_dataout(offset, value); >> - else >> - twl4030_led_set_value(offset - TWL4030_GPIO_MAX, value); >> + >> + priv->direction |= BIT(offset); >> + mutex_unlock(&priv->mutex); >> + >> + twl_set(chip, offset, value); >> + >> + return 0; >> } >> >> static int twl_to_irq(struct gpio_chip *chip, unsigned offset) >> @@ -469,6 +500,8 @@ no_irqs: >> priv->gpio_chip.ngpio = TWL4030_GPIO_MAX; >> priv->gpio_chip.dev = &pdev->dev; >> >> + mutex_init(&priv->mutex); >> + >> if (node) >> pdata = of_gpio_twl4030(&pdev->dev); >> >> -- >> 1.8.0 >>
On Wed, 19 Dec 2012 21:53:23 +0100, Michael Trimarchi <michael@amarulasolutions.com> wrote: > Hi > > Grant Likely <grant.likely@secretlab.ca> wrote: > > >On Thu, 6 Dec 2012 11:52:06 +0100, Peter Ujfalusi > ><peter.ujfalusi@ti.com> wrote: > >> Use more coherent locking in the driver. Use bitfield to store the > >GPIO > >> direction and if the pin is configured as output store the status > >also in a > >> bitfiled. > >> In this way we can just look at these bitfields when we need > >information > >> about the pin status and only reach out to the chip when it is > >needed. > >> > >> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> > > > >Applied, thanks > > > >g. > > > >> @@ -279,64 +276,98 @@ static void twl_free(struct gpio_chip *chip, > >unsigned offset) > >> { > >> struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip); > >> > >> + mutex_lock(&priv->mutex); > >> if (offset >= TWL4030_GPIO_MAX) { > >> twl4030_led_set_value(offset - TWL4030_GPIO_MAX, 1); > > I have the mobile but where is the unlock here? Good catch. I've dropped the patch. Peter, please resend a fixed-up version. g. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" 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-twl4030.c b/drivers/gpio/gpio-twl4030.c index c092739..a38e6e9c 100644 --- a/drivers/gpio/gpio-twl4030.c +++ b/drivers/gpio/gpio-twl4030.c @@ -64,14 +64,15 @@ /* Mask for GPIO registers when aggregated into a 32-bit integer */ #define GPIO_32_MASK 0x0003ffff -/* Data structures */ -static DEFINE_MUTEX(gpio_lock); - struct gpio_twl4030_priv { struct gpio_chip gpio_chip; + struct mutex mutex; int irq_base; + /* Bitfields for state caching */ unsigned int usage_count; + unsigned int direction; + unsigned int out_state; }; /*----------------------------------------------------------------------*/ @@ -130,7 +131,7 @@ static inline int gpio_twl4030_read(u8 address) /*----------------------------------------------------------------------*/ -static u8 cached_leden; /* protected by gpio_lock */ +static u8 cached_leden; /* The LED lines are open drain outputs ... a FET pulls to GND, so an * external pullup is needed. We could also expose the integrated PWM @@ -144,14 +145,12 @@ static void twl4030_led_set_value(int led, int value) if (led) mask <<= 1; - mutex_lock(&gpio_lock); if (value) cached_leden &= ~mask; else cached_leden |= mask; status = twl_i2c_write_u8(TWL4030_MODULE_LED, cached_leden, TWL4030_LED_LEDEN_REG); - mutex_unlock(&gpio_lock); } static int twl4030_set_gpio_direction(int gpio, int is_input) @@ -162,7 +161,6 @@ static int twl4030_set_gpio_direction(int gpio, int is_input) u8 base = REG_GPIODATADIR1 + d_bnk; int ret = 0; - mutex_lock(&gpio_lock); ret = gpio_twl4030_read(base); if (ret >= 0) { if (is_input) @@ -172,7 +170,6 @@ static int twl4030_set_gpio_direction(int gpio, int is_input) ret = gpio_twl4030_write(base, reg); } - mutex_unlock(&gpio_lock); return ret; } @@ -212,7 +209,7 @@ static int twl_request(struct gpio_chip *chip, unsigned offset) struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip); int status = 0; - mutex_lock(&gpio_lock); + mutex_lock(&priv->mutex); /* Support the two LED outputs as output-only GPIOs. */ if (offset >= TWL4030_GPIO_MAX) { @@ -271,7 +268,7 @@ done: if (!status) priv->usage_count |= BIT(offset); - mutex_unlock(&gpio_lock); + mutex_unlock(&priv->mutex); return status; } @@ -279,64 +276,98 @@ static void twl_free(struct gpio_chip *chip, unsigned offset) { struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip); + mutex_lock(&priv->mutex); if (offset >= TWL4030_GPIO_MAX) { twl4030_led_set_value(offset - TWL4030_GPIO_MAX, 1); return; } - mutex_lock(&gpio_lock); - priv->usage_count &= ~BIT(offset); /* on last use, switch off GPIO module */ if (!priv->usage_count) gpio_twl4030_write(REG_GPIO_CTRL, 0x0); - mutex_unlock(&gpio_lock); + mutex_unlock(&priv->mutex); } static int twl_direction_in(struct gpio_chip *chip, unsigned offset) { - return (offset < TWL4030_GPIO_MAX) - ? twl4030_set_gpio_direction(offset, 1) - : -EINVAL; + struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip); + int ret; + + mutex_lock(&priv->mutex); + if (offset < TWL4030_GPIO_MAX) + ret = twl4030_set_gpio_direction(offset, 1); + else + ret = -EINVAL; + + if (!ret) + priv->direction &= ~BIT(offset); + + mutex_unlock(&priv->mutex); + + return ret; } static int twl_get(struct gpio_chip *chip, unsigned offset) { struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip); + int ret; int status = 0; - if (!(priv->usage_count & BIT(offset))) - return -EPERM; + mutex_lock(&priv->mutex); + if (!(priv->usage_count & BIT(offset))) { + ret = -EPERM; + goto out; + } - if (offset < TWL4030_GPIO_MAX) - status = twl4030_get_gpio_datain(offset); - else if (offset == TWL4030_GPIO_MAX) - status = cached_leden & LEDEN_LEDAON; + if (priv->direction & BIT(offset)) + status = priv->out_state & BIT(offset); else - status = cached_leden & LEDEN_LEDBON; + status = twl4030_get_gpio_datain(offset); - return (status < 0) ? 0 : status; + ret = (status <= 0) ? 0 : 1; +out: + mutex_unlock(&priv->mutex); + dev_err(chip->dev, "%s: offset %d value %d\n", __func__, offset, ret); + return ret; } -static int twl_direction_out(struct gpio_chip *chip, unsigned offset, int value) +static void twl_set(struct gpio_chip *chip, unsigned offset, int value) { - if (offset < TWL4030_GPIO_MAX) { + struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip); + + dev_err(chip->dev, "%s: offset %d value %d\n", __func__, offset, value); + mutex_lock(&priv->mutex); + if (offset < TWL4030_GPIO_MAX) twl4030_set_gpio_dataout(offset, value); - return twl4030_set_gpio_direction(offset, 0); - } else { + else twl4030_led_set_value(offset - TWL4030_GPIO_MAX, value); - return 0; - } + + if (value) + priv->out_state |= BIT(offset); + else + priv->out_state &= ~BIT(offset); + + mutex_unlock(&priv->mutex); } -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); + + dev_err(chip->dev, "%s: offset %d value %d\n", __func__, offset, value); + mutex_lock(&priv->mutex); if (offset < TWL4030_GPIO_MAX) twl4030_set_gpio_dataout(offset, value); - else - twl4030_led_set_value(offset - TWL4030_GPIO_MAX, value); + + priv->direction |= BIT(offset); + mutex_unlock(&priv->mutex); + + twl_set(chip, offset, value); + + return 0; } static int twl_to_irq(struct gpio_chip *chip, unsigned offset) @@ -469,6 +500,8 @@ no_irqs: priv->gpio_chip.ngpio = TWL4030_GPIO_MAX; priv->gpio_chip.dev = &pdev->dev; + mutex_init(&priv->mutex); + if (node) pdata = of_gpio_twl4030(&pdev->dev);
Use more coherent locking in the driver. Use bitfield to store the GPIO direction and if the pin is configured as output store the status also in a bitfiled. In this way we can just look at these bitfields when we need information about the pin status and only reach out to the chip when it is needed. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> --- drivers/gpio/gpio-twl4030.c | 99 ++++++++++++++++++++++++++++++--------------- 1 file changed, 66 insertions(+), 33 deletions(-)