linux-kernel - Re: [PATCH 5/8] i2c: sprd: Configure the enable bit of the IIC controller before each transmission initiation

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Date:   Thu, 31 Aug 2023 16:09:08 +0800
From:   Chunyan Zhang <zhang.lyra@...il.com>
To:     Huangzheng Lai <Huangzheng.Lai@...soc.com>
Cc:     Andi Shyti <andi.shyti@...nel.org>,
        Orson Zhai <orsonzhai@...il.com>,
        Baolin Wang <baolin.wang@...ux.alibaba.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 5/8] i2c: sprd: Configure the enable bit of the IIC
 controller before each transmission initiation

On Thu, 17 Aug 2023 at 17:46, Huangzheng Lai <Huangzheng.Lai@...soc.com> wrote:
>
> When a timeout exception occurs in the IIC driver, the IIC controller
> will be reset, and after resetting, control bits such as I2C_EN and
> I2C_INT_EN will be reset to 0, and the IIC master cannot initiate
> Transmission unless sprd_i2c_enable() is executed. To address this issue,
> this patch places sprd_i2c_enable() before each transmission initiation
> to ensure that the necessary control bits of the IIC controller are
> configured.
>
> Signed-off-by: Huangzheng Lai <Huangzheng.Lai@...soc.com>
> ---
>  drivers/i2c/busses/i2c-sprd.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-sprd.c b/drivers/i2c/busses/i2c-sprd.c
> index 02c11a9ff2da..7314c897525d 100644
> --- a/drivers/i2c/busses/i2c-sprd.c
> +++ b/drivers/i2c/busses/i2c-sprd.c
> @@ -310,6 +310,8 @@ static int sprd_i2c_handle_msg(struct i2c_adapter *i2c_adap,
>         return i2c_dev->err;
>  }
>
> +static void sprd_i2c_enable(struct sprd_i2c *i2c_dev);

Can we move this whole function above its caller?

> +
>  static int sprd_i2c_master_xfer(struct i2c_adapter *i2c_adap,
>                                 struct i2c_msg *msgs, int num)
>  {
> @@ -320,6 +322,8 @@ static int sprd_i2c_master_xfer(struct i2c_adapter *i2c_adap,
>         if (ret < 0)
>                 return ret;
>
> +       sprd_i2c_enable(i2c_dev);
> +
>         for (im = 0; im < num - 1; im++) {
>                 ret = sprd_i2c_handle_msg(i2c_adap, &msgs[im], 0);
>                 if (ret)
> @@ -661,8 +665,6 @@ static int __maybe_unused sprd_i2c_runtime_resume(struct device *dev)
>         if (ret)
>                 return ret;
>
> -       sprd_i2c_enable(i2c_dev);
> -
>         return 0;
>  }
>
> --
> 2.17.1
>