Re: [PATCH] w1: w1-gpio: Convert to use GPIO descriptors
On Tue, Dec 5, 2017 at 11:40 PM, Evgeniy Polyakov wrote: > Sorry for late reply It's cool. Much to do. > 20.11.2017, 11:47, "Linus Walleij" : >> The w1 master driver includes a complete open drain emulation >> reimplementation among other things. >> >> This converts the driver and all board files using it to use >> GPIO descriptors associated with the device to look up the >> GPIO wire, as well ass the optional pull-up GPIO line. > > I'm not familiar with gpio platform drivers, but these changes looks good. > Did it find its way into the tree yet? No but I interpret this as an Acked-by so I will add that and add it to the GPIO tree so we get some rotation in linux-next, OK? :) > If not, please add appropriate maintainers, I've added Ville Syrjala to copy. OK let's see if he has something to add. Yours, Linus Walleij
Re: [PATCH] w1: w1-gpio: Convert to use GPIO descriptors
Hi Linus
Sorry for late reply
20.11.2017, 11:47, "Linus Walleij" :
> The w1 master driver includes a complete open drain emulation
> reimplementation among other things.
>
> This converts the driver and all board files using it to use
> GPIO descriptors associated with the device to look up the
> GPIO wire, as well ass the optional pull-up GPIO line.
I'm not familiar with gpio platform drivers, but these changes looks good.
Did it find its way into the tree yet?
If not, please add appropriate maintainers, I've added Ville Syrjala to copy.
> When probed from the device tree, the driver will just pick
> descriptors and use them right off. For the two board files
> in the kernel, we add descriptor lookups so we do not need
> to keep any old platform data handling around for the GPIO
> lines.
>
> As the platform data is also a state container for this driver,
> we augment it to contain the GPIO descriptors.
>
> w1_gpio_write_bit_dir() and w1_gpio_write_bit_val() are gone
> since this pair was a reimplementation of open drain emulation
> which is now handled by gpiolib.
>
> The special "linux,open-drain" flag is a bit of mishap here:
> it has the same semantic as the same flags in I2C: it means
> that something in the platform is setting up the line as
> open drain behind our back. We handle this the same way as
> in I2C.
>
> To drive the pull-up, we need to bypass open drain emulation
> in gpiolib for the line, and this is done by driving it high
> using gpiod_set_raw_value() which has been augmented to have
> the semantic of overriding the open drain emulation.
>
> We also augment the documentation to reflect the way to pass
> GPIO descriptors from the machine.
>
> Signed-off-by: Linus Walleij
> ---
> I don't have a W1-capable system myself so testing would be
> appreciated. This needs to be applied to Torvald's HEAD
> or v4.15-rc1 when it is tagged to work, as it is using the new
> infrastructure updates I merged in the v4.15 merge window.
> ---
> Documentation/w1/masters/w1-gpio | 17 +++-
> arch/arm/mach-ixp4xx/vulcan-setup.c | 13 +++-
> arch/arm/mach-pxa/raumfeld.c | 16 ++--
> drivers/w1/masters/w1-gpio.c | 149 +++-
> include/linux/w1-gpio.h | 9 +--
> 5 files changed, 101 insertions(+), 103 deletions(-)
>
> diff --git a/Documentation/w1/masters/w1-gpio
> b/Documentation/w1/masters/w1-gpio
> index af5d3b4aa851..623961d9e83f 100644
> --- a/Documentation/w1/masters/w1-gpio
> +++ b/Documentation/w1/masters/w1-gpio
> @@ -8,17 +8,27 @@ Description
> ---
>
> GPIO 1-wire bus master driver. The driver uses the GPIO API to control the
> -wire and the GPIO pin can be specified using platform data.
> +wire and the GPIO pin can be specified using GPIO machine descriptor tables.
> +It is also possible to define the master using device tree, see
> +Documentation/devicetree/bindings/w1/w1-gpio.txt
>
> Example (mach-at91)
> ---
>
> +#include
> #include
>
> +static struct gpiod_lookup_table foo_w1_gpiod_table = {
> + .dev_id = "w1-gpio",
> + .table = {
> + GPIO_LOOKUP_IDX("at91-gpio", AT91_PIN_PB20, NULL, 0,
> + GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN),
> + },
> +};
> +
> static struct w1_gpio_platform_data foo_w1_gpio_pdata = {
> - .pin = AT91_PIN_PB20,
> - .is_open_drain = 1,
> + .ext_pullup_enable_pin = -EINVAL,
> };
>
> static struct platform_device foo_w1_device = {
> @@ -30,4 +40,5 @@ static struct platform_device foo_w1_device = {
> ...
> at91_set_GPIO_periph(foo_w1_gpio_pdata.pin, 1);
> at91_set_multi_drive(foo_w1_gpio_pdata.pin, 1);
> + gpiod_add_lookup_table(&foo_w1_gpiod_table);
> platform_device_register(&foo_w1_device);
> diff --git a/arch/arm/mach-ixp4xx/vulcan-setup.c
> b/arch/arm/mach-ixp4xx/vulcan-setup.c
> index 731fb2019ecb..2c03d2f6b647 100644
> --- a/arch/arm/mach-ixp4xx/vulcan-setup.c
> +++ b/arch/arm/mach-ixp4xx/vulcan-setup.c
> @@ -16,6 +16,7 @@
> #include
> #include
> #include
> +#include
> #include
> #include
> #include
> @@ -162,9 +163,16 @@ static struct platform_device vulcan_max6369 = {
> .num_resources = 1,
> };
>
> +static struct gpiod_lookup_table vulcan_w1_gpiod_table = {
> + .dev_id = "w1-gpio",
> + .table = {
> + GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", 14, NULL, 0,
> + GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
> + },
> +};
> +
> static struct w1_gpio_platform_data vulcan_w1_gpio_pdata = {
> - .pin = 14,
> - .ext_pullup_enable_pin = -EINVAL,
> + /* Intentionally left blank */
> };
>
> static struct platform_device vulcan_w1_gpio = {
> @@ -233,6 +241,7 @@ static void __init vulcan_init(void)
> IXP4XX_EXP_BUS_WR_EN |
> IXP4XX_EXP_BUS_BYTE_EN;
>
> + gpiod_add_lookup_table(&vulcan_w1_gpiod_table);
> platform_add_devices(vulcan_devices, ARRAY_SIZE(vulcan_devices));
> }
>
> diff --git a/arch/arm/mach-pxa/raumfeld.c b/arch/arm/mach-pxa/raumfeld.c
> index 9d662fed03ec..feddca7f3540 100644
> --- a/arch/arm/mach-pxa/raum
[PATCH] w1: w1-gpio: Convert to use GPIO descriptors
The w1 master driver includes a complete open drain emulation
reimplementation among other things.
This converts the driver and all board files using it to use
GPIO descriptors associated with the device to look up the
GPIO wire, as well ass the optional pull-up GPIO line.
When probed from the device tree, the driver will just pick
descriptors and use them right off. For the two board files
in the kernel, we add descriptor lookups so we do not need
to keep any old platform data handling around for the GPIO
lines.
As the platform data is also a state container for this driver,
we augment it to contain the GPIO descriptors.
w1_gpio_write_bit_dir() and w1_gpio_write_bit_val() are gone
since this pair was a reimplementation of open drain emulation
which is now handled by gpiolib.
The special "linux,open-drain" flag is a bit of mishap here:
it has the same semantic as the same flags in I2C: it means
that something in the platform is setting up the line as
open drain behind our back. We handle this the same way as
in I2C.
To drive the pull-up, we need to bypass open drain emulation
in gpiolib for the line, and this is done by driving it high
using gpiod_set_raw_value() which has been augmented to have
the semantic of overriding the open drain emulation.
We also augment the documentation to reflect the way to pass
GPIO descriptors from the machine.
Signed-off-by: Linus Walleij
---
I don't have a W1-capable system myself so testing would be
appreciated. This needs to be applied to Torvald's HEAD
or v4.15-rc1 when it is tagged to work, as it is using the new
infrastructure updates I merged in the v4.15 merge window.
---
Documentation/w1/masters/w1-gpio| 17 +++-
arch/arm/mach-ixp4xx/vulcan-setup.c | 13 +++-
arch/arm/mach-pxa/raumfeld.c| 16 ++--
drivers/w1/masters/w1-gpio.c| 149 +++-
include/linux/w1-gpio.h | 9 +--
5 files changed, 101 insertions(+), 103 deletions(-)
diff --git a/Documentation/w1/masters/w1-gpio b/Documentation/w1/masters/w1-gpio
index af5d3b4aa851..623961d9e83f 100644
--- a/Documentation/w1/masters/w1-gpio
+++ b/Documentation/w1/masters/w1-gpio
@@ -8,17 +8,27 @@ Description
---
GPIO 1-wire bus master driver. The driver uses the GPIO API to control the
-wire and the GPIO pin can be specified using platform data.
+wire and the GPIO pin can be specified using GPIO machine descriptor tables.
+It is also possible to define the master using device tree, see
+Documentation/devicetree/bindings/w1/w1-gpio.txt
Example (mach-at91)
---
+#include
#include
+static struct gpiod_lookup_table foo_w1_gpiod_table = {
+ .dev_id = "w1-gpio",
+ .table = {
+ GPIO_LOOKUP_IDX("at91-gpio", AT91_PIN_PB20, NULL, 0,
+ GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN),
+ },
+};
+
static struct w1_gpio_platform_data foo_w1_gpio_pdata = {
- .pin= AT91_PIN_PB20,
- .is_open_drain = 1,
+ .ext_pullup_enable_pin = -EINVAL,
};
static struct platform_device foo_w1_device = {
@@ -30,4 +40,5 @@ static struct platform_device foo_w1_device = {
...
at91_set_GPIO_periph(foo_w1_gpio_pdata.pin, 1);
at91_set_multi_drive(foo_w1_gpio_pdata.pin, 1);
+ gpiod_add_lookup_table(&foo_w1_gpiod_table);
platform_device_register(&foo_w1_device);
diff --git a/arch/arm/mach-ixp4xx/vulcan-setup.c
b/arch/arm/mach-ixp4xx/vulcan-setup.c
index 731fb2019ecb..2c03d2f6b647 100644
--- a/arch/arm/mach-ixp4xx/vulcan-setup.c
+++ b/arch/arm/mach-ixp4xx/vulcan-setup.c
@@ -16,6 +16,7 @@
#include
#include
#include
+#include
#include
#include
#include
@@ -162,9 +163,16 @@ static struct platform_device vulcan_max6369 = {
.num_resources = 1,
};
+static struct gpiod_lookup_table vulcan_w1_gpiod_table = {
+ .dev_id = "w1-gpio",
+ .table = {
+ GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", 14, NULL, 0,
+ GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
+ },
+};
+
static struct w1_gpio_platform_data vulcan_w1_gpio_pdata = {
- .pin= 14,
- .ext_pullup_enable_pin = -EINVAL,
+ /* Intentionally left blank */
};
static struct platform_device vulcan_w1_gpio = {
@@ -233,6 +241,7 @@ static void __init vulcan_init(void)
IXP4XX_EXP_BUS_WR_EN |
IXP4XX_EXP_BUS_BYTE_EN;
+ gpiod_add_lookup_table(&vulcan_w1_gpiod_table);
platform_add_devices(vulcan_devices, ARRAY_SIZE(vulcan_devices));
}
diff --git a/arch/arm/mach-pxa/raumfeld.c b/arch/arm/mach-pxa/raumfeld.c
index 9d662fed03ec..feddca7f3540 100644
--- a/arch/arm/mach-pxa/raumfeld.c
+++ b/arch/arm/mach-pxa/raumfeld.c
@@ -506,11 +506,16 @@ static void w1_enable_external_pullup(int enable)
msleep(100);
}
+static struct gpiod_lookup_table raumfeld_w1_gpiod_table = {
+ .dev_id = "w1-gpio",
+ .table = {
+
