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SubjectRe: [PATCH v2 1/4] gpio: mvebu: Add limited PWM support
On Sat, Mar 18, 2017 at 04:43:01PM +0100, Ralph Sennhauser wrote:
> From: Andrew Lunn <andrew@lunn.ch>
>
> Armada 370/XP devices can 'blink' gpio lines with a configurable on
> and off period. This can be modelled as a PWM.
>
> However, there are only two sets of PWM configuration registers for
> all the gpio lines. This driver simply allows a single gpio line per
> gpio chip of 32 lines to be used as a PWM. Attempts to use more return
> EBUSY.
>
> Due to the interleaving of registers it is not simple to separate the
> PWM driver from the gpio driver. Thus the gpio driver has been
> extended with a PWM driver.
>
> Signed-off-by: Andrew Lunn <andrew@lunn.ch>
> URL: https://patchwork.ozlabs.org/patch/427287/
> URL: https://patchwork.ozlabs.org/patch/427295/
> [Ralph Sennhauser:
> * port forward
> * merge pwm portion into gpio-mvebu.c
> * merge documentation patch
> * update MAINTAINERS]
> Signed-off-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>
> ---
> .../devicetree/bindings/gpio/gpio-mvebu.txt | 31 +++
> MAINTAINERS | 2 +
> drivers/gpio/gpio-mvebu.c | 291 +++++++++++++++++++--
> 3 files changed, 307 insertions(+), 17 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-mvebu.txt b/Documentation/devicetree/bindings/gpio/gpio-mvebu.txt
> index a6f3bec..86932e3 100644
> --- a/Documentation/devicetree/bindings/gpio/gpio-mvebu.txt
> +++ b/Documentation/devicetree/bindings/gpio/gpio-mvebu.txt
> @@ -38,6 +38,23 @@ Required properties:
> - #gpio-cells: Should be two. The first cell is the pin number. The
> second cell is reserved for flags, unused at the moment.
>
> +Optional properties:
> +
> +In order to use the gpio lines in PWM mode, some additional optional
> +properties are required. Only Armada 370 and XP support these properties.
> +
> +- reg: an additional register set is needed, for the GPIO Blink
> + Counter on/off registers.
> +
> +- reg-names: Must contain an entry "pwm" corresponding to the
> + additional register range needed for pwm operation.
> +
> +- #pwm-cells: Should be two. The first cell is the pin number. The

s/pin number/gpio line/ ?

> + second cell is reserved for flags and should be set to 0, so it has a
> + known value. It then becomes possible to use it in the future.
> +
> +- clocks: Must be a phandle to the clock for the gpio controller.
> +
> Example:
>
> gpio0: gpio@d0018100 {
> @@ -51,3 +68,17 @@ Example:
> #interrupt-cells = <2>;
> interrupts = <16>, <17>, <18>, <19>;
> };
> +
> + gpio1: gpio@18140 {
> + compatible = "marvell,orion-gpio";

If only 370 and XP support this, I'd expect a compatible string for one
of them here.

> + reg = <0x18140 0x40>, <0x181c8 0x08>;
> + reg-names = "gpio", "pwm";
> + ngpios = <17>;
> + gpio-controller;
> + #gpio-cells = <2>;
> + #pwm-cells = <2>;
> + interrupt-controller;
> + #interrupt-cells = <2>;
> + interrupts = <87>, <88>, <89>;
> + clocks = <&coreclk 0>;
> + };

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