dm: serial: Add clock member to struct serial_device_info

Some callers of serial_getinfo() would like to know the UART base
clock speed in order to make decision what to pass to OS in some
cases. In particular, ACPI SPCR table expects only certain base
clock speed and thus we have to act accordingly.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/drivers/serial/sandbox.c b/drivers/serial/sandbox.c
index 1af5cc1..545ff3f 100644
--- a/drivers/serial/sandbox.c
+++ b/drivers/serial/sandbox.c
@@ -198,6 +198,7 @@
 		.reg_width = 1,
 		.reg_offset = 0,
 		.reg_shift = 0,
+		.clock = SERIAL_DEFAULT_CLOCK,
 	};
 
 	if (!serial_info)
diff --git a/include/serial.h b/include/serial.h
index 104f34f..54b21a0 100644
--- a/include/serial.h
+++ b/include/serial.h
@@ -139,6 +139,7 @@
  * @reg_width:	size (in bytes) of the IO accesses to the registers
  * @reg_offset:	offset to apply to the @addr from the start of the registers
  * @reg_shift:	quantity to shift the register offsets by
+ * @clock:	UART base clock speed in Hz
  * @baudrate:	baud rate
  */
 struct serial_device_info {
@@ -148,10 +149,12 @@
 	u8 reg_width;
 	u8 reg_offset;
 	u8 reg_shift;
+	unsigned int clock;
 	unsigned int baudrate;
 };
 
 #define SERIAL_DEFAULT_ADDRESS	0xBADACCE5
+#define SERIAL_DEFAULT_CLOCK	(16 * 115200)
 
 /**
  * struct struct dm_serial_ops - Driver model serial operations
diff --git a/test/dm/serial.c b/test/dm/serial.c
index 3d741a8..c6be6ab 100644
--- a/test/dm/serial.c
+++ b/test/dm/serial.c
@@ -29,6 +29,7 @@
 	ut_assertok(serial_getinfo(dev_serial, &info_serial));
 	ut_assert(info_serial.type == SERIAL_CHIP_UNKNOWN);
 	ut_assert(info_serial.addr == SERIAL_DEFAULT_ADDRESS);
+	ut_assert(info_serial.clock == SERIAL_DEFAULT_CLOCK);
 	/*
 	 * test with a parameter which is NULL pointer
 	 */