On Thu, Oct 30, 2014 at 02:16:04PM +0100, Matthias Brugger wrote:

2014-10-29 6:37 GMT+01:00 Xudong Chen [off-list ref]:

quoted

+static int mt_i2c_do_transfer(struct mt_i2c *i2c)
+{
+       u16 addr_reg;
+       u16 control_reg;
+       int tmo = i2c->adap.timeout;
+
+       i2c->trans_stop = false;
+       i2c->irq_stat = 0;
+
+       /* If use i2c pin from PMIC mt6397 side, need set PATH_DIR first */
+       if (i2c->have_pmic)
+               i2c_writew(I2C_CONTROL_WRAPPER, i2c, OFFSET_PATH_DIR);

So this is some sort of multiplexer bit, right?
I think in this case we need to build a multi function device (mfd)
where the pmic driver will set this bit.

This bit is in the i2c controller register space, so it shouldn't be
controlled by some other driver. I think the configuration of this
register is already in the correct place. What I could think of is that
the PMIC could implement a pinctrl driver and the i2c controller driver
gets the pins from the PMIC. Anyway, the controlling of this bit would
still be in the i2c driver.

Sascha

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |