Re: [PATCH v2 1/5] dt-bindings: add bindings for i2c-pca-platform
On Thu, Jun 22, 2017 at 09:20:59PM +, Chris Packham wrote: > On 22/06/17 20:23, Wolfram Sang wrote: > > > >> + - reset-gpios : gpio specifier for gpio connected to RESET_N pin. > > > > What about the 'active' state that Rob mentioned in his last review? > > > > My intention was that by saying it is connected to the RESET_N bin the > active state is covered. I would say okay, but based on below it's not. > I personally always get a little confused when talking about reset > lines. The _N denotes that the line is active low but because it is a > reset line writing 1 releases the reset so from a what-the-user-wants > perspective it's active high. > > dt-binding-wise what we want here is GPIO_ACTIVE_HIGH, as in the driver > writes 1 to release reset so don't do any polarity inversion. I'd be > happy do add something to that effect in a v3 but I actually felt saying > the gpio is connected to RESET_N was less ambiguous. No, the driver is wrong. The binding should say GPIO_ACTIVE_LOW because that is how the pin is defined. The driver needs to set it to inactive. Rob
Re: [PATCH v2 1/5] dt-bindings: add bindings for i2c-pca-platform
On Thu, Jun 22, 2017 at 09:20:59PM +, Chris Packham wrote: > On 22/06/17 20:23, Wolfram Sang wrote: > > > >> + - reset-gpios : gpio specifier for gpio connected to RESET_N pin. > > > > What about the 'active' state that Rob mentioned in his last review? > > > > My intention was that by saying it is connected to the RESET_N bin the > active state is covered. I would say okay, but based on below it's not. > I personally always get a little confused when talking about reset > lines. The _N denotes that the line is active low but because it is a > reset line writing 1 releases the reset so from a what-the-user-wants > perspective it's active high. > > dt-binding-wise what we want here is GPIO_ACTIVE_HIGH, as in the driver > writes 1 to release reset so don't do any polarity inversion. I'd be > happy do add something to that effect in a v3 but I actually felt saying > the gpio is connected to RESET_N was less ambiguous. No, the driver is wrong. The binding should say GPIO_ACTIVE_LOW because that is how the pin is defined. The driver needs to set it to inactive. Rob
Re: [PATCH v2 1/5] dt-bindings: add bindings for i2c-pca-platform
On Thu, Jun 22, 2017 at 09:20:59PM +, Chris Packham wrote: > On 22/06/17 20:23, Wolfram Sang wrote: > > > >> + - reset-gpios : gpio specifier for gpio connected to RESET_N pin. > > > > What about the 'active' state that Rob mentioned in his last review? > > > > My intention was that by saying it is connected to the RESET_N bin the > active state is covered. > > I personally always get a little confused when talking about reset > lines. The _N denotes that the line is active low but because it is a > reset line writing 1 releases the reset so from a what-the-user-wants > perspective it's active high. > > dt-binding-wise what we want here is GPIO_ACTIVE_HIGH, as in the driver > writes 1 to release reset so don't do any polarity inversion. I'd be > happy do add something to that effect in a v3 but I actually felt saying > the gpio is connected to RESET_N was less ambiguous. Okay. Thanks for the explanation. I am fine with it but I'll leave the final decision to Rob. signature.asc Description: PGP signature
Re: [PATCH v2 1/5] dt-bindings: add bindings for i2c-pca-platform
On Thu, Jun 22, 2017 at 09:20:59PM +, Chris Packham wrote: > On 22/06/17 20:23, Wolfram Sang wrote: > > > >> + - reset-gpios : gpio specifier for gpio connected to RESET_N pin. > > > > What about the 'active' state that Rob mentioned in his last review? > > > > My intention was that by saying it is connected to the RESET_N bin the > active state is covered. > > I personally always get a little confused when talking about reset > lines. The _N denotes that the line is active low but because it is a > reset line writing 1 releases the reset so from a what-the-user-wants > perspective it's active high. > > dt-binding-wise what we want here is GPIO_ACTIVE_HIGH, as in the driver > writes 1 to release reset so don't do any polarity inversion. I'd be > happy do add something to that effect in a v3 but I actually felt saying > the gpio is connected to RESET_N was less ambiguous. Okay. Thanks for the explanation. I am fine with it but I'll leave the final decision to Rob. signature.asc Description: PGP signature
Re: [PATCH v2 1/5] dt-bindings: add bindings for i2c-pca-platform
On 22/06/17 20:23, Wolfram Sang wrote: > >> + - reset-gpios : gpio specifier for gpio connected to RESET_N pin. > > What about the 'active' state that Rob mentioned in his last review? > My intention was that by saying it is connected to the RESET_N bin the active state is covered. I personally always get a little confused when talking about reset lines. The _N denotes that the line is active low but because it is a reset line writing 1 releases the reset so from a what-the-user-wants perspective it's active high. dt-binding-wise what we want here is GPIO_ACTIVE_HIGH, as in the driver writes 1 to release reset so don't do any polarity inversion. I'd be happy do add something to that effect in a v3 but I actually felt saying the gpio is connected to RESET_N was less ambiguous.
Re: [PATCH v2 1/5] dt-bindings: add bindings for i2c-pca-platform
On 22/06/17 20:23, Wolfram Sang wrote: > >> + - reset-gpios : gpio specifier for gpio connected to RESET_N pin. > > What about the 'active' state that Rob mentioned in his last review? > My intention was that by saying it is connected to the RESET_N bin the active state is covered. I personally always get a little confused when talking about reset lines. The _N denotes that the line is active low but because it is a reset line writing 1 releases the reset so from a what-the-user-wants perspective it's active high. dt-binding-wise what we want here is GPIO_ACTIVE_HIGH, as in the driver writes 1 to release reset so don't do any polarity inversion. I'd be happy do add something to that effect in a v3 but I actually felt saying the gpio is connected to RESET_N was less ambiguous.
Re: [PATCH v2 1/5] dt-bindings: add bindings for i2c-pca-platform
> + - reset-gpios : gpio specifier for gpio connected to RESET_N pin. What about the 'active' state that Rob mentioned in his last review? signature.asc Description: PGP signature
Re: [PATCH v2 1/5] dt-bindings: add bindings for i2c-pca-platform
> + - reset-gpios : gpio specifier for gpio connected to RESET_N pin. What about the 'active' state that Rob mentioned in his last review? signature.asc Description: PGP signature
