On Tue, Oct 01, 2024 at 04:29:33PM +0800, Michael Wu wrote:
> Since there are no registers controlling the hardware parameters
> IC_CAP_LOADING and IC_CLK_FREQ_OPTIMIZATION, their values can only be
> declared in the device tree.
>
> snps,bus-capacitance-pf indicates the bus capacitance in picofarads (pF).
> It affects the high and low pulse width of SCL line in high speed mode.
> The legal values for this property are 100 and 400 only, and default
> value is 100. This property corresponds to IC_CAP_LOADING.
>
> snps,clk-freq-optimized indicates whether the hardware input clock
> frequency is reduced by reducing the internal latency. This property
> corresponds to IC_CLK_FREQ_OPTIMIZATION.
>
> The driver can calculate hs_hcnt and hs_lcnt appropriate for the hardware
> based on these two properties.
>
> Signed-off-by: Michael Wu <michael.wu@xxxxxxxxx>
> ---
> .../bindings/i2c/snps,designware-i2c.yaml | 24 +++++++++++++++++++
> 1 file changed, 24 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/i2c/snps,designware-i2c.yaml b/Documentation/devicetree/bindings/i2c/snps,designware-i2c.yaml
> index 60035a787e5c..c373f3acd34b 100644
> --- a/Documentation/devicetree/bindings/i2c/snps,designware-i2c.yaml
> +++ b/Documentation/devicetree/bindings/i2c/snps,designware-i2c.yaml
> @@ -97,6 +97,21 @@ properties:
> - const: tx
> - const: rx
>
> + snps,bus-capacitance-pf:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + description: >
I asked to drop |, so you replaced it with something else? So drop >...
and then you are going to replace it with another one?
That's not a cat and mouse.
> + This property indicates the bus capacitance in picofarads (pF).
> + This value is used to compute the tHIGH and tLOW periods for high speed
> + mode.
> + default: 100
I asked for some constraints here. min/maximum. I think you never
replied to this.
> +
> + snps,clk-freq-optimized:
> + description: >
> + This property indicates whether the hardware input clock frequency is
> + reduced by reducing the internal latency. This value is used to compute
> + the tHIGH and tLOW periods for high speed mode.
> + type: boolean
> +
> unevaluatedProperties: false
>
> required:
> @@ -146,4 +161,13 @@ examples:
> interrupts = <8>;
> clocks = <&ahb_clk>;
> };
> + - |
> + i2c@c5000000 {
> + compatible = "snps,designware-i2c";
Extend EXISTING example. Not add new example.
Best regards,
Krzysztof
