Re: [PATCH v4 1/2] dt-bindings: i2c: snps,designware-i2c: declare bus capacitance and clk freq optimized

From: Krzysztof Kozlowski
Date: Thu Oct 03 2024 - 09:22:13 EST


On 03/10/2024 13:15, 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 reduce its
> internal clock frequency by reducing the internal latency required to
> generate the high period and low period of SCL line. This property
> corresponds to IC_CLK_FREQ_OPTIMIZATION.
>
> The driver can calculate the high period count and low period count of
> SCL line for high speed mode based on these two properties.
>
> Signed-off-by: Michael Wu <michael.wu@xxxxxxxxx>
> ---


Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>


---

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Krzysztof