[U-Boot] [PATCH 1/3] drivers/smc911x: Add support for shifted register read/write

[Roy Spliet]

Required for (but potentially not limited to) the snowball board. Implementation
is inspired by the linux smsc911x implementation, but by using a (pre-compiler)
constant, things should be optimised by the compiler for a shift of 0.

Signed-off-by: Roy Spliet <rspliet at eclipso.eu>
---
 drivers/net/smc911x.h | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/net/smc911x.h b/drivers/net/smc911x.h
index acae0cf..7144722 100644
--- a/drivers/net/smc911x.h
+++ b/drivers/net/smc911x.h
@@ -19,6 +19,12 @@
 	CONFIG_SMC911X_16_BIT shall be set"
 #endif
 
+#ifndef CONFIG_SMC911X_SHIFT
+#define CONFIG_SMC911X_SHIFT 0
+#endif
+
+#define smc911x_shift(i) ((i) << CONFIG_SMC911X_SHIFT)
+
 #if defined (CONFIG_SMC911X_32_BIT)
 static inline u32 __smc911x_reg_read(struct eth_device *dev, u32 offset)
 {
@@ -37,14 +43,14 @@ void smc911x_reg_write(struct eth_device *dev, u32 offset, u32 val)
 #elif defined (CONFIG_SMC911X_16_BIT)
 static inline u32 smc911x_reg_read(struct eth_device *dev, u32 offset)
 {
-	volatile u16 *addr_16 = (u16 *)(dev->iobase + offset);
-	return ((*addr_16 & 0x0000ffff) | (*(addr_16 + 1) << 16));
+	volatile u16 *addr_16 = (u16 *)(dev->iobase + smc911x_shift(offset));
+	return (*addr_16 & 0x0000FFFF) | (*(addr_16 + smc911x_shift(1)) << 16);
 }
 static inline void smc911x_reg_write(struct eth_device *dev,
 					u32 offset, u32 val)
 {
-	*(volatile u16 *)(dev->iobase + offset) = (u16)val;
-	*(volatile u16 *)(dev->iobase + offset + 2) = (u16)(val >> 16);
+	*(volatile u16 *)(dev->iobase + smc911x_shift(offset)) = (u16)val;
+	*(volatile u16 *)(dev->iobase + smc911x_shift(offset + 2)) = (u16)val;
 }
 #else
 #error "SMC911X: undefined bus width"
-- 
1.8.1.2