Re: [PATCH v11 2/2] i2c: ls2x: Add clocks property parsing and adjust bus speed

[Wolfram Sang <wsa+renesas@sang-engineering.com>]

On Fri, Nov 06, 2026 at 11:02:03AM +0800, Hongliang Wang wrote:
> The original driver uses a fixed PCLK frequency(LS2X_I2C_PCLK_FREQ) and
> fixed div(5) for I2C bus speed calculation. As PCLK frequency and div
> vary on different SoCs and ACPI platforms, this leads to inaccurate I2C
> bus speed calculation and poor adaptability across platforms.
> 
> Improve the accuracy of I2C bus speed calculation across different
> platforms by parsing the real I2C bus reference clock (PCLK) and div.
> Support both DTS and ACPI.
> 
> For DTS:
> - Retrieve I2C bus reference clock via the common clock framework
> - Fetch div from match data for LS2K/LS7A series
> - Fallback to default values if clock lookup fails or the obtained
>   pclk or div is zero
> 
> For ACPI:
> - Parse "clocks" property to get I2C bus reference clock
> - Parse "clock-div" property to get div
> - Fallback to the default values if property parsing fails or the
>   obtained pclk or div is zero
> 
> Calculate the I2C clock prescaler based on reference clock, div and
> target bus frequency with the formula:
> 
> prescale = (pclk * 10) / (div * bus_freq_hz) - 1
> 
> Dynamically acquiring PCLK and div per platform ensures accurate I2C bus
> speed calculation and reliable operation across different platforms.
> 
> Reviewed-by: Binbin Zhou <zhoubinbin@loongson.cn>
> Tested-by: Xi Ruoyao <xry111@xry111.site>
> Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
> Cc: stable@vger.kernel.org
> Signed-off-by: Hongliang Wang <wanghongliang@loongson.cn>

Applied to my for-andi branch, thanks!