On Tue, Feb 2, 2021 at 6:01 PM Sean Anderson <seanga2@xxxxxxxxx> wrote: > > On 2/2/21 2:02 PM, Rob Herring wrote: > > On Tue, Feb 2, 2021 at 4:36 AM Damien Le Moal <damien.lemoal@xxxxxxx> wrote: > >> > >> The sifive gpio IP block supports up to 32 GPIOs. Reflect that in the > >> interrupts property description and maxItems. Also add the standard > >> ngpios property to describe the number of GPIOs available on the > >> implementation. > >> > >> Also add the "canaan,k210-gpiohs" compatible string to indicate the use > >> of this gpio controller in the Canaan Kendryte K210 SoC. If this > >> compatible string is used, do not define the clocks property as > >> required as the K210 SoC does not have a software controllable clock > >> for the Sifive gpio IP block. > >> > >> Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx> > >> Cc: Rob Herring <robh@xxxxxxxxxx> > >> Cc: devicetree@xxxxxxxxxxxxxxx > >> Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxx> > >> --- > >> .../devicetree/bindings/gpio/sifive,gpio.yaml | 21 ++++++++++++++++--- > >> 1 file changed, 18 insertions(+), 3 deletions(-) > >> > >> diff --git a/Documentation/devicetree/bindings/gpio/sifive,gpio.yaml b/Documentation/devicetree/bindings/gpio/sifive,gpio.yaml > >> index ab22056f8b44..2cef18ca737c 100644 > >> --- a/Documentation/devicetree/bindings/gpio/sifive,gpio.yaml > >> +++ b/Documentation/devicetree/bindings/gpio/sifive,gpio.yaml > >> @@ -16,6 +16,7 @@ properties: > >> - enum: > >> - sifive,fu540-c000-gpio > >> - sifive,fu740-c000-gpio > >> + - canaan,k210-gpiohs > >> - const: sifive,gpio0 > >> > >> reg: > >> @@ -23,9 +24,9 @@ properties: > >> > >> interrupts: > >> description: > >> - interrupt mapping one per GPIO. Maximum 16 GPIOs. > >> + interrupt mapping one per GPIO. Maximum 32 GPIOs. > >> minItems: 1 > >> - maxItems: 16 > >> + maxItems: 32 > >> > >> interrupt-controller: true > >> > >> @@ -38,6 +39,10 @@ properties: > >> "#gpio-cells": > >> const: 2 > >> > >> + ngpios: > >> + minimum: 1 > >> + maximum: 32 > > > > What's the default as obviously drivers already assume something. > > The driver currently assumes 16. However, as noted in reply to Atish, > the number of GPIOs is configurable. So you need a 'default: 16' here. > > Does a driver actually need to know this? For example, does the > > register stride change or something? > > No. I believe that the number of GPIOs sets which bits in the control > registers are valid. So the maximum number of GPIOs is the word width of > the bus. So like register access size (e.g. readw vs readl)? If so, we have 'reg-io-width' for that purpose. > > Please don't add it if the only purpose is error check your DT (IOW, > > if it just checks the max cell value in gpios phandles). > > Why not? This seems like exactly the situation this property was > designed for. Because it is redundant. All the GPIO lines you want to use should be connected to something with a *-gpios property. If not, then that's a failure to describe part of the h/w. For comparison, we generally don't define how many interrupts an interrupt controller has. Or how many power-domains a power domain provider has. I can go on with every provider/consumer binding... Rob
