i2c: ihs_i2c: Prepare DM conversion

Prepare the function interface of the ihs_i2c driver for DM conversion
in a future patch.

While we're at it, fix some style violations, and make the code more readable.

Signed-off-by: Mario Six <mario.six@gdsys.cc>

diff --git a/drivers/i2c/ihs_i2c.c b/drivers/i2c/ihs_i2c.c
index 29612e69fe1bee0c487fea88a31dd5039abd1798..6fd016339cfa7608b9cc7b6eba125a117b8a7c04 100644 (file)
--- a/drivers/i2c/ihs_i2c.c
+++ b/drivers/i2c/ihs_i2c.c
@@ -11,6 +11,7 @@
 #include <common.h>
 #include <i2c.h>
 #include <gdsys_fpga.h>
+#include <asm/unaligned.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -41,30 +42,38 @@ DECLARE_GLOBAL_DATA_PTR;
 #endif
 
 enum {
-       I2CINT_ERROR_EV = 1 << 13,
-       I2CINT_TRANSMIT_EV = 1 << 14,
-       I2CINT_RECEIVE_EV = 1 << 15,
+       I2CINT_ERROR_EV = BIT(13),
+       I2CINT_TRANSMIT_EV = BIT(14),
+       I2CINT_RECEIVE_EV = BIT(15),
 };
 
 enum {
+       I2CMB_READ = 0 << 10,
        I2CMB_WRITE = 1 << 10,
+       I2CMB_1BYTE = 0 << 11,
        I2CMB_2BYTE = 1 << 11,
+       I2CMB_DONT_HOLD_BUS = 0 << 13,
        I2CMB_HOLD_BUS = 1 << 13,
        I2CMB_NATIVE = 2 << 14,
 };
 
+enum {
+       I2COP_WRITE = 0,
+       I2COP_READ = 1,
+};
+
 static int wait_for_int(bool read)
 {
        u16 val;
-       unsigned int ctr = 0;
+       uint ctr = 0;
 
        I2C_GET_REG(interrupt_status, &val);
+       /* Wait until error or receive/transmit interrupt was raised */
        while (!(val & (I2CINT_ERROR_EV
               | (read ? I2CINT_RECEIVE_EV : I2CINT_TRANSMIT_EV)))) {
                udelay(10);
-               if (ctr++ > 5000) {
+               if (ctr++ > 5000)
                        return 1;
-               }
                I2C_GET_REG(interrupt_status, &val);
        }
 
@@ -76,10 +85,12 @@ static int ihs_i2c_transfer(uchar chip, uchar *buffer, int len, bool read,
 {
        u16 val;
 
+       /* Clear interrupt status */
        I2C_SET_REG(interrupt_status, I2CINT_ERROR_EV
                     | I2CINT_RECEIVE_EV | I2CINT_TRANSMIT_EV);
        I2C_GET_REG(interrupt_status, &val);
 
+       /* If we want to write and have data, write the bytes to the mailbox */
        if (!read && len) {
                val = buffer[0];
 
@@ -98,6 +109,7 @@ static int ihs_i2c_transfer(uchar chip, uchar *buffer, int len, bool read,
        if (wait_for_int(read))
                return 1;
 
+       /* If we want to read, get the bytes from the mailbox */
        if (read) {
                I2C_GET_REG(read_mailbox_ext, &val);
                buffer[0] = val & 0xff;
@@ -108,55 +120,44 @@ static int ihs_i2c_transfer(uchar chip, uchar *buffer, int len, bool read,
        return 0;
 }
 
-static int ihs_i2c_address(uchar chip, uint addr, int alen, bool hold_bus)
+static int ihs_i2c_address(uchar chip, u8 *addr, int alen, bool hold_bus)
 {
-       int shift = (alen-1) * 8;
-
        while (alen) {
                int transfer = min(alen, 2);
-               uchar buf[2];
                bool is_last = alen <= transfer;
 
-               buf[0] = addr >> shift;
-               if (alen > 1)
-                       buf[1] = addr >> (shift - 8);
-
-               if (ihs_i2c_transfer(chip, buf, transfer, false,
+               if (ihs_i2c_transfer(chip, addr, transfer, I2COP_WRITE,
                                     hold_bus ? false : is_last))
                        return 1;
 
-               shift -= 16;
                alen -= transfer;
        }
 
        return 0;
 }
 
-static int ihs_i2c_access(struct i2c_adapter *adap, uchar chip, uint addr,
-                         int alen, uchar *buffer, int len, bool read)
+static int ihs_i2c_access(struct i2c_adapter *adap, uchar chip, u8 *addr,
+                         int alen, uchar *buffer, int len, int read)
 {
-       if (len <= 0)
-               return 1;
-
-       if (ihs_i2c_address(chip, addr, alen, len))
+       /* Don't hold the bus if length of data to send/receive is zero */
+       if (len <= 0 || ihs_i2c_address(chip, addr, alen, len))
                return 1;
 
        while (len) {
                int transfer = min(len, 2);
+               bool is_last = len <= transfer;
 
                if (ihs_i2c_transfer(chip, buffer, transfer, read,
-                                    len <= transfer))
-                       return 1;
+                                    is_last))
+                       return 2;
 
                buffer += transfer;
-               addr += transfer;
                len -= transfer;
        }
 
        return 0;
 }
 
-
 static void ihs_i2c_init(struct i2c_adapter *adap, int speed, int slaveaddr)
 {
 #ifdef CONFIG_SYS_I2C_INIT_BOARD
@@ -173,7 +174,7 @@ static int ihs_i2c_probe(struct i2c_adapter *adap, uchar chip)
 {
        uchar buffer[2];
 
-       if (ihs_i2c_transfer(chip, buffer, 0, true, true))
+       if (ihs_i2c_transfer(chip, buffer, 0, I2COP_READ, true))
                return 1;
 
        return 0;
@@ -182,13 +183,23 @@ static int ihs_i2c_probe(struct i2c_adapter *adap, uchar chip)
 static int ihs_i2c_read(struct i2c_adapter *adap, uchar chip, uint addr,
                        int alen, uchar *buffer, int len)
 {
-       return ihs_i2c_access(adap, chip, addr, alen, buffer, len, true);
+       u8 addr_bytes[4];
+
+       put_unaligned_le32(addr, addr_bytes);
+
+       return ihs_i2c_access(adap, chip, addr_bytes, alen, buffer, len,
+                             I2COP_READ);
 }
 
 static int ihs_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr,
                         int alen, uchar *buffer, int len)
 {
-       return ihs_i2c_access(adap, chip, addr, alen, buffer, len, false);
+       u8 addr_bytes[4];
+
+       put_unaligned_le32(addr, addr_bytes);
+
+       return ihs_i2c_access(adap, chip, addr_bytes, alen, buffer, len,
+                             I2COP_WRITE);
 }
 
 static unsigned int ihs_i2c_set_bus_speed(struct i2c_adapter *adap,