* [PATCH] gpio: menz127: use the new open drain callback
@ 2016-04-09 19:56 Linus Walleij
2016-05-11 17:39 ` Andreas Werner
0 siblings, 1 reply; 2+ messages in thread
From: Linus Walleij @ 2016-04-09 19:56 UTC (permalink / raw)
To: linux-gpio, Alexandre Courbot; +Cc: Linus Walleij, Andreas Werner
The menz127 driver tries to support open drain by detecting it
at request time. However: without the new callbacks from the
gpiolib it is not really working: the core will still just emulate
the open drain mode by switching the line to an input.
By adding a hook into the new .set_single_ended() call rather than
trying to autodetect at request() time, proper open drain can be
supported.
Cc: Andreas Werner <andy@wernerandy.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
drivers/gpio/gpio-menz127.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
diff --git a/drivers/gpio/gpio-menz127.c b/drivers/gpio/gpio-menz127.c
index 8c1ab8e1974f..334fe270dcf1 100644
--- a/drivers/gpio/gpio-menz127.c
+++ b/drivers/gpio/gpio-menz127.c
@@ -88,21 +88,25 @@ static int men_z127_debounce(struct gpio_chip *gc, unsigned gpio,
return 0;
}
-static int men_z127_request(struct gpio_chip *gc, unsigned gpio_pin)
+static int men_z127_set_single_ended(struct gpio_chip *gc,
+ unsigned offset,
+ enum single_ended_mode mode)
{
struct men_z127_gpio *priv = gpiochip_get_data(gc);
u32 od_en;
- if (gpio_pin >= gc->ngpio)
- return -EINVAL;
+ if (mode != LINE_MODE_OPEN_DRAIN &&
+ mode != LINE_MODE_PUSH_PULL)
+ return -ENOTSUPP;
spin_lock(&priv->lock);
od_en = readl(priv->reg_base + MEN_Z127_ODER);
- if (gpiochip_line_is_open_drain(gc, gpio_pin))
- od_en |= BIT(gpio_pin);
+ if (mode == LINE_MODE_OPEN_DRAIN)
+ od_en |= BIT(offset);
else
- od_en &= ~BIT(gpio_pin);
+ /* Implicitly LINE_MODE_PUSH_PULL */
+ od_en &= ~BIT(offset);
writel(od_en, priv->reg_base + MEN_Z127_ODER);
spin_unlock(&priv->lock);
@@ -147,7 +151,7 @@ static int men_z127_probe(struct mcb_device *mdev,
goto err_unmap;
men_z127_gpio->gc.set_debounce = men_z127_debounce;
- men_z127_gpio->gc.request = men_z127_request;
+ men_z127_gpio->gc.set_single_ended = men_z127_set_single_ended;
ret = gpiochip_add_data(&men_z127_gpio->gc, men_z127_gpio);
if (ret) {
--
2.4.3
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] gpio: menz127: use the new open drain callback
2016-04-09 19:56 [PATCH] gpio: menz127: use the new open drain callback Linus Walleij
@ 2016-05-11 17:39 ` Andreas Werner
0 siblings, 0 replies; 2+ messages in thread
From: Andreas Werner @ 2016-05-11 17:39 UTC (permalink / raw)
To: Linus Walleij; +Cc: linux-gpio, Alexandre Courbot
On Sat, Apr 09, 2016 at 09:56:55PM +0200, Linus Walleij wrote:
> The menz127 driver tries to support open drain by detecting it
> at request time. However: without the new callbacks from the
> gpiolib it is not really working: the core will still just emulate
> the open drain mode by switching the line to an input.
>
> By adding a hook into the new .set_single_ended() call rather than
> trying to autodetect at request() time, proper open drain can be
> supported.
>
> Cc: Andreas Werner <andy@wernerandy.de>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> drivers/gpio/gpio-menz127.c | 18 +++++++++++-------
> 1 file changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpio/gpio-menz127.c b/drivers/gpio/gpio-menz127.c
> index 8c1ab8e1974f..334fe270dcf1 100644
> --- a/drivers/gpio/gpio-menz127.c
> +++ b/drivers/gpio/gpio-menz127.c
> @@ -88,21 +88,25 @@ static int men_z127_debounce(struct gpio_chip *gc, unsigned gpio,
> return 0;
> }
>
> -static int men_z127_request(struct gpio_chip *gc, unsigned gpio_pin)
> +static int men_z127_set_single_ended(struct gpio_chip *gc,
> + unsigned offset,
> + enum single_ended_mode mode)
> {
> struct men_z127_gpio *priv = gpiochip_get_data(gc);
> u32 od_en;
>
> - if (gpio_pin >= gc->ngpio)
> - return -EINVAL;
> + if (mode != LINE_MODE_OPEN_DRAIN &&
> + mode != LINE_MODE_PUSH_PULL)
> + return -ENOTSUPP;
>
> spin_lock(&priv->lock);
> od_en = readl(priv->reg_base + MEN_Z127_ODER);
>
> - if (gpiochip_line_is_open_drain(gc, gpio_pin))
> - od_en |= BIT(gpio_pin);
> + if (mode == LINE_MODE_OPEN_DRAIN)
> + od_en |= BIT(offset);
> else
> - od_en &= ~BIT(gpio_pin);
> + /* Implicitly LINE_MODE_PUSH_PULL */
> + od_en &= ~BIT(offset);
>
> writel(od_en, priv->reg_base + MEN_Z127_ODER);
> spin_unlock(&priv->lock);
> @@ -147,7 +151,7 @@ static int men_z127_probe(struct mcb_device *mdev,
> goto err_unmap;
>
> men_z127_gpio->gc.set_debounce = men_z127_debounce;
> - men_z127_gpio->gc.request = men_z127_request;
> + men_z127_gpio->gc.set_single_ended = men_z127_set_single_ended;
>
> ret = gpiochip_add_data(&men_z127_gpio->gc, men_z127_gpio);
> if (ret) {
> --
> 2.4.3
>
Hi Linus,
sorry for the late answer.
I will try to get the hardware and will test the patch.
I think this is exactly what I need to support the "real" open drain
mode.
Regards
Andy
^ permalink raw reply [flat|nested] 2+ messages in thread
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