linux-kernel - Re: [PATCH V2 4/7] i2c: sprd: Add I2C controller driver to support dynamic switching of 400K/1M/3.4M frequency

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Message-ID: <20231024212845.htjc2uwtg36mig5j@zenone.zhora.eu>
Date:   Tue, 24 Oct 2023 23:28:45 +0200
From:   Andi Shyti <andi.shyti@...nel.org>
To:     Huangzheng Lai <Huangzheng.Lai@...soc.com>
Cc:     Orson Zhai <orsonzhai@...il.com>,
        Baolin Wang <baolin.wang@...ux.alibaba.com>,
        Chunyan Zhang <zhang.lyra@...il.com>,
        linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
        huangzheng lai <laihuangzheng@...il.com>,
        Xiongpeng Wu <xiongpeng.wu@...soc.com>
Subject: Re: [PATCH V2 4/7] i2c: sprd: Add I2C controller driver to support
 dynamic switching of 400K/1M/3.4M frequency

Hi Huangzheng,

On Mon, Oct 23, 2023 at 04:11:55PM +0800, Huangzheng Lai wrote:
> When I2C-slaves supporting different frequencies use the same I2C
> controller, the I2C controller usually only operates at lower frequencies.
> In order to improve the performance of I2C-slaves transmission supporting
> faster frequencies, we dynamically configure the I2C operating frequency
> based on the value of the input parameter msg ->flag.
> 
> Signed-off-by: Huangzheng Lai <Huangzheng.Lai@...soc.com>
> ---
>  drivers/i2c/busses/i2c-sprd.c | 101 +++++++++++++++++++---------------
>  1 file changed, 57 insertions(+), 44 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-sprd.c b/drivers/i2c/busses/i2c-sprd.c
> index dec627ef408c..f1f7fad42ecd 100644
> --- a/drivers/i2c/busses/i2c-sprd.c
> +++ b/drivers/i2c/busses/i2c-sprd.c
> @@ -75,7 +75,14 @@
>  #define SPRD_I2C_PM_TIMEOUT	1000
>  /* timeout (ms) for transfer message */
>  #define I2C_XFER_TIMEOUT	1000
> -
> +/* dynamic modify clk_freq flag  */
> +#define I2C_3M4_FLAG		0x0100
> +#define I2C_1M_FLAG		0x0080
> +#define I2C_400K_FLAG		0x0040
> +
> +#define I2C_FREQ_400K		400000
> +#define I2C_FREQ_1M		1000000
> +#define I2C_FREQ_3_4M		3400000

Why are you redefining these values?

You could use the defines you already have or, if you really want
a different name you could do:

#define I2C_FREQ_3_4M		I2C_MAX_HIGH_SPEED_MODE_FREQ

Rest looks good.

Andi