i2c: designware: allow IP specific sda_hold_time

Because some old designware IPs were not supporting setting an SDA hold
time, vendors developed their own solution. Add a way for the final driver
to provide its own SDA hold time handling.
Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: NJarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: NJarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-designware-common.c

@@ -201,6 +201,8 @@ int i2c_dw_set_sda_hold(struct dw_i2c_dev *dev)
 		dev_dbg(dev->dev, "SDA Hold Time TX:RX = %d:%d\n",
 			dev->sda_hold_time & ~(u32)DW_IC_SDA_HOLD_RX_MASK,
 			dev->sda_hold_time >> DW_IC_SDA_HOLD_RX_SHIFT);
+	} else if (dev->set_sda_hold_time) {
+		dev->set_sda_hold_time(dev);
 	} else if (dev->sda_hold_time) {
 		dev_warn(dev->dev,
 			"Hardware too old to adjust SDA hold time.\n");

drivers/i2c/busses/i2c-designware-core.h

@@ -269,6 +269,7 @@ struct dw_i2c_dev {
 	void			(*disable)(struct dw_i2c_dev *dev);
 	void			(*disable_int)(struct dw_i2c_dev *dev);
 	int			(*init)(struct dw_i2c_dev *dev);
+	int			(*set_sda_hold_time)(struct dw_i2c_dev *dev);
 	int			mode;
 	struct i2c_bus_recovery_info rinfo;
 };