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Date:   Tue, 26 Jun 2018 11:38:24 +0900
From:   Wolfram Sang <wsa@the-dreams.de>
To:     Eddie James <eajames@linux.vnet.ibm.com>
Cc:     linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org, robh+dt@kernel.org,
        benh@kernel.crashing.org, joel@jms.id.au, mark.rutland@arm.com,
        gregkh@linuxfoundation.org, rdunlap@infradead.org,
        andy.shevchenko@gmail.com, peda@axentia.se
Subject: Re: [PATCH v10 5/7] i2c: fsi: Add transfer implementation
Message-ID: <20180626023823.i3fmdegn2sric5kx@ninjato>
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On Wed, Jun 13, 2018 at 02:36:17PM -0500, Eddie James wrote:
> Execute I2C transfers from the FSI-attached I2C master. Use polling
> instead of interrupts as we have no hardware IRQ over FSI.
> 
> Signed-off-by: Eddie James <eajames@linux.vnet.ibm.com>
> ---
>  drivers/i2c/busses/i2c-fsi.c | 195 ++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 193 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c
> index 4611a0b..8c0a6cb 100644
> --- a/drivers/i2c/busses/i2c-fsi.c
> +++ b/drivers/i2c/busses/i2c-fsi.c
> @@ -155,6 +155,7 @@ struct fsi_i2c_port {
>  	struct i2c_adapter	adapter;
>  	struct fsi_i2c_master	*master;
>  	u16			port;
> +	u16			xfrd;
>  };
>  
>  static int fsi_i2c_read_reg(struct fsi_device *fsi, unsigned int reg,
> @@ -230,6 +231,99 @@ static int fsi_i2c_set_port(struct fsi_i2c_port *port)
>  	return fsi_i2c_write_reg(fsi, I2C_FSI_RESET_ERR, &dummy);
>  }
>  
> +static int fsi_i2c_start(struct fsi_i2c_port *port, struct i2c_msg *msg,
> +			 bool stop)
> +{
> +	struct fsi_i2c_master *i2c = port->master;
> +	u32 cmd = I2C_CMD_WITH_START | I2C_CMD_WITH_ADDR;
> +
> +	port->xfrd = 0;
> +
> +	if (msg->flags & I2C_M_RD)
> +		cmd |= I2C_CMD_READ;

Since you support MANGLING, I'd think you can easily support
I2C_M_REV_DIR_ADDR here, too?