Merge tag 'driver-core-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git...

[firefly-linux-kernel-4.4.55.git] / drivers / i2c / busses / i2c-xiic.c

diff --git a/drivers/i2c/busses/i2c-xiic.c b/drivers/i2c/busses/i2c-xiic.c
index e60e67a5fac6b73be05b87501be418ecc7103939..e8400042b358847e05a5d09cea11d178ab235c02 100644 (file)
--- a/drivers/i2c/busses/i2c-xiic.c
+++ b/drivers/i2c/busses/i2c-xiic.c
@@ -12,10 +12,6 @@
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- *
  *
  * This code was implemented by Mocean Laboratories AB when porting linux
  * to the automotive development board Russellville. The copyright holder
@@ -50,6 +46,11 @@ enum xilinx_i2c_state {
        STATE_START
 };
 
+enum xiic_endian {
+       LITTLE,
+       BIG
+};
+
 /**
  * struct xiic_i2c - Internal representation of the XIIC I2C bus
  * @base:      Memory base of the HW registers
@@ -74,6 +75,7 @@ struct xiic_i2c {
        enum xilinx_i2c_state   state;
        struct i2c_msg          *rx_msg;
        int                     rx_pos;
+       enum xiic_endian        endianness;
 };
 
 
@@ -174,29 +176,58 @@ struct xiic_i2c {
 static void xiic_start_xfer(struct xiic_i2c *i2c);
 static void __xiic_start_xfer(struct xiic_i2c *i2c);
 
+/*
+ * For the register read and write functions, a little-endian and big-endian
+ * version are necessary. Endianness is detected during the probe function.
+ * Only the least significant byte [doublet] of the register are ever
+ * accessed. This requires an offset of 3 [2] from the base address for
+ * big-endian systems.
+ */
+
 static inline void xiic_setreg8(struct xiic_i2c *i2c, int reg, u8 value)
 {
-       iowrite8(value, i2c->base + reg);
+       if (i2c->endianness == LITTLE)
+               iowrite8(value, i2c->base + reg);
+       else
+               iowrite8(value, i2c->base + reg + 3);
 }
 
 static inline u8 xiic_getreg8(struct xiic_i2c *i2c, int reg)
 {
-       return ioread8(i2c->base + reg);
+       u8 ret;
+
+       if (i2c->endianness == LITTLE)
+               ret = ioread8(i2c->base + reg);
+       else
+               ret = ioread8(i2c->base + reg + 3);
+       return ret;
 }
 
 static inline void xiic_setreg16(struct xiic_i2c *i2c, int reg, u16 value)
 {
-       iowrite16(value, i2c->base + reg);
+       if (i2c->endianness == LITTLE)
+               iowrite16(value, i2c->base + reg);
+       else
+               iowrite16be(value, i2c->base + reg + 2);
 }
 
 static inline void xiic_setreg32(struct xiic_i2c *i2c, int reg, int value)
 {
-       iowrite32(value, i2c->base + reg);
+       if (i2c->endianness == LITTLE)
+               iowrite32(value, i2c->base + reg);
+       else
+               iowrite32be(value, i2c->base + reg);
 }
 
 static inline int xiic_getreg32(struct xiic_i2c *i2c, int reg)
 {
-       return ioread32(i2c->base + reg);
+       u32 ret;
+
+       if (i2c->endianness == LITTLE)
+               ret = ioread32(i2c->base + reg);
+       else
+               ret = ioread32be(i2c->base + reg);
+       return ret;
 }
 
 static inline void xiic_irq_dis(struct xiic_i2c *i2c, u32 mask)
@@ -696,6 +727,7 @@ static int xiic_i2c_probe(struct platform_device *pdev)
        struct resource *res;
        int ret, irq;
        u8 i;
+       u32 sr;
 
        i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
        if (!i2c)
@@ -728,6 +760,18 @@ static int xiic_i2c_probe(struct platform_device *pdev)
                return ret;
        }
 
+       /*
+        * Detect endianness
+        * Try to reset the TX FIFO. Then check the EMPTY flag. If it is not
+        * set, assume that the endianness was wrong and swap.
+        */
+       i2c->endianness = LITTLE;
+       xiic_setreg32(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_TX_FIFO_RESET_MASK);
+       /* Reset is cleared in xiic_reinit */
+       sr = xiic_getreg32(i2c, XIIC_SR_REG_OFFSET);
+       if (!(sr & XIIC_SR_TX_FIFO_EMPTY_MASK))
+               i2c->endianness = BIG;
+
        xiic_reinit(i2c);
 
        /* add i2c adapter to i2c tree */