i2c: core: Parse SDA hold time from firmware

There are two drivers already using the SDA hold time setting.
It might be more in the future, thus, make I2C core to parse the setting
for us if provided by firmware.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/i2c-core-base.c

@@ -1576,6 +1576,8 @@ void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_de
 	ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
 	if (ret && use_defaults)
 		t->sda_fall_ns = t->scl_fall_ns;
+
+	device_property_read_u32(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns);
 }
 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
 

include/linux/i2c.h

@@ -564,6 +564,7 @@ struct i2c_lock_operations {
  * @scl_fall_ns: time SCL signal takes to fall in ns; t(f) in the I2C specification
  * @scl_int_delay_ns: time IP core additionally needs to setup SCL in ns
  * @sda_fall_ns: time SDA signal takes to fall in ns; t(f) in the I2C specification
+ * @sda_hold_ns: time IP core additionally needs to hold SDA in ns
  */
 struct i2c_timings {
 	u32 bus_freq_hz;
@@ -571,6 +572,7 @@ struct i2c_timings {
 	u32 scl_fall_ns;
 	u32 scl_int_delay_ns;
 	u32 sda_fall_ns;
+	u32 sda_hold_ns;
 };
 
 /**