Re: [PATCH] i2c: i2c-stm32f7: Add I2C_SMBUS_I2C_BLOCK_DATA support

From: Wolfram Sang <wsa@the-dreams.de>
To: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: alexandre.torgue@st.com, linux-kernel@vger.kernel.org,
	pierre-yves.mordret@st.com, linux-i2c@vger.kernel.org,
	mcoquelin.stm32@gmail.com,
	linux-stm32@st-md-mailman.stormreply.com,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] i2c: i2c-stm32f7: Add I2C_SMBUS_I2C_BLOCK_DATA support
Date: Wed, 26 Jun 2019 15:45:35 +0200	[thread overview]
Message-ID: <20190626134535.GN801@ninjato> (raw)
In-Reply-To: <1559654451-26612-1-git-send-email-fabrice.gasnier@st.com>

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On Tue, Jun 04, 2019 at 03:20:51PM +0200, Fabrice Gasnier wrote:
> This patch adds the support of I2C_SMBUS_I2C_BLOCK_DATA transaction type
> for the stm32f7 SMBUS Controller.
> Use emulated I2C_SMBUS_I2C_BLOCK_DATA transactions as there is no specific
> hardware in STM32 I2C to manage this (e.g. like no need for PEC here).
> Emulated transfer will fall back calling i2c transfer method where there's
> already support for DMAs for example.
> So, use the I2C_FUNC_SMBUS_I2C_BLOCK in stm32f7_i2c_func(), and rely on
> emulated transfer by returning -EOPNOTSUPP in the smbus_xfer() routine
> for such a case.
> 
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>

Maintainers?

> ---
>  drivers/i2c/busses/i2c-stm32f7.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
> index 48337be..68a751e 100644
> --- a/drivers/i2c/busses/i2c-stm32f7.c
> +++ b/drivers/i2c/busses/i2c-stm32f7.c
> @@ -953,6 +953,9 @@ static int stm32f7_i2c_smbus_xfer_msg(struct stm32f7_i2c_dev *i2c_dev,
>  		cr2 &= ~STM32F7_I2C_CR2_RD_WRN;
>  		f7_msg->read_write = I2C_SMBUS_READ;
>  		break;
> +	case I2C_SMBUS_I2C_BLOCK_DATA:
> +		/* Rely on emulated i2c transfer (through master_xfer) */
> +		return -EOPNOTSUPP;
>  	default:
>  		dev_err(dev, "Unsupported smbus protocol %d\n", f7_msg->size);
>  		return -EOPNOTSUPP;
> @@ -1803,7 +1806,8 @@ static u32 stm32f7_i2c_func(struct i2c_adapter *adap)
>  		I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
>  		I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
>  		I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
> -		I2C_FUNC_SMBUS_PROC_CALL | I2C_FUNC_SMBUS_PEC;
> +		I2C_FUNC_SMBUS_PROC_CALL | I2C_FUNC_SMBUS_PEC |
> +		I2C_FUNC_SMBUS_I2C_BLOCK;
>  }
>  
>  static struct i2c_algorithm stm32f7_i2c_algo = {
> -- 
> 2.7.4
> 

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