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SubjectRe: [PATCH v10 5/7] i2c: fsi: Add transfer implementation
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On 06/25/2018 09:38 PM, Wolfram Sang wrote:
> 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?

Hm, I don't really understand the purpose of that flag. From the docs:

This toggles the Rd/Wr flag. That is, if you want to do a write, but
    need to emit an Rd instead of a Wr, or vice versa, you set this
    flag. For example:
S Addr Rd [A] Data [A] Data [A] ... [A] Data [A] P

I don't think our hardware supports this type of operation.

Thanks,
Eddie

>

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