i2c: designware: add SLAVE mode functions

- Changes in Kconfig to enable I2C_DESIGNWARE_SLAVE support
- Slave functions added to core library file
- Slave abort sources added to common source file
- New driver: i2c-designware-slave added
- Changes in the Makefile to compile the I2C_DESIGNWARE_SLAVE module
  when supported by the architecture.

All the SLAVE flow is added but it is not enabled via platform
driver.
Signed-off-by: Luis Oliveira <lolivei@synopsys.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
[wsa: made a function static and one-lined a message]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/Kconfig

@@ -483,14 +483,26 @@ config I2C_DESIGNWARE_CORE
 config I2C_DESIGNWARE_PLATFORM
 	tristate "Synopsys DesignWare Platform"
 	select I2C_DESIGNWARE_CORE
+	select I2C_DESIGNWARE_SLAVE
 	depends on (ACPI && COMMON_CLK) || !ACPI
 	help
 	  If you say yes to this option, support will be included for the
-	  Synopsys DesignWare I2C adapter. Only master mode is supported.
+	  Synopsys DesignWare I2C adapter.
 
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-designware-platform.
 
+config I2C_DESIGNWARE_SLAVE
+	bool "Synopsys DesignWare Slave"
+	select I2C_SLAVE
+	depends on I2C_DESIGNWARE_PLATFORM
+	help
+	  If you say yes to this option, support will be included for the
+	  Synopsys DesignWare I2C slave adapter.
+
+	  This is not a standalone module, this module compiles together with
+	  i2c-designware-core.
+
 config I2C_DESIGNWARE_PCI
 	tristate "Synopsys DesignWare PCI"
 	depends on PCI

drivers/i2c/busses/Makefile

@@ -42,6 +42,9 @@ obj-$(CONFIG_I2C_CPM)		+= i2c-cpm.o
 obj-$(CONFIG_I2C_DAVINCI)	+= i2c-davinci.o
 obj-$(CONFIG_I2C_DESIGNWARE_CORE)	+= i2c-designware-core.o
 i2c-designware-core-objs := i2c-designware-common.o i2c-designware-master.o
+ifeq ($(CONFIG_I2C_DESIGNWARE_SLAVE),y)
+i2c-designware-core-objs += i2c-designware-slave.o
+endif
 obj-$(CONFIG_I2C_DESIGNWARE_PLATFORM)	+= i2c-designware-platform.o
 i2c-designware-platform-objs := i2c-designware-platdrv.o
 i2c-designware-platform-$(CONFIG_I2C_DESIGNWARE_BAYTRAIL) += i2c-designware-baytrail.o

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

@@ -56,6 +56,12 @@ static char *abort_sources[] = {
 		"trying to use disabled adapter",
 	[ARB_LOST] =
 		"lost arbitration",
+	[ABRT_SLAVE_FLUSH_TXFIFO] =
+		"read command so flush old data in the TX FIFO",
+	[ABRT_SLAVE_ARBLOST] =
+		"slave lost the bus while transmitting data to a remote master",
+	[ABRT_SLAVE_RD_INTX] =
+		"incorrect slave-transmitter mode configuration",
 };
 
 u32 dw_readl(struct dw_i2c_dev *dev, int offset)

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

@@ -305,9 +305,11 @@ u32 i2c_dw_func(struct i2c_adapter *adap);
 void i2c_dw_disable(struct dw_i2c_dev *dev);
 void i2c_dw_disable_int(struct dw_i2c_dev *dev);
 int i2c_dw_init(struct dw_i2c_dev *dev);
+int i2c_dw_init_slave(struct dw_i2c_dev *dev);
 
 extern u32 i2c_dw_read_comp_param(struct dw_i2c_dev *dev);
 extern int i2c_dw_probe(struct dw_i2c_dev *dev);
+extern int i2c_dw_probe_slave(struct dw_i2c_dev *dev);
 
 #if IS_ENABLED(CONFIG_I2C_DESIGNWARE_BAYTRAIL)
 extern int i2c_dw_probe_lock_support(struct dw_i2c_dev *dev);