[PATCH v2 net] ptp: ptp_clockmatrix: use i2c_master_send for i2c write

[min.li.xe]

From: Min Li <min.li...@renesas.com>

The old code for i2c write would break on some controllers, which fails
at handling Repeated Start Condition. So we will just use i2c_master_send
to handle write in one transanction.

Changes since v1:
- Remove indentation change

Signed-off-by: Min Li <min.li...@renesas.com>
---
 drivers/ptp/ptp_clockmatrix.c | 56 +++++++++++++++++++++++++++++++++----------
 drivers/ptp/ptp_clockmatrix.h |  2 ++
 2 files changed, 45 insertions(+), 13 deletions(-)

diff --git a/drivers/ptp/ptp_clockmatrix.c b/drivers/ptp/ptp_clockmatrix.c
index 73aaae5..e020faf 100644
--- a/drivers/ptp/ptp_clockmatrix.c
+++ b/drivers/ptp/ptp_clockmatrix.c
@@ -142,16 +142,15 @@ static int idtcm_strverscmp(const char *ver1, const char 
*ver2)
        return result;
 }
 
-static int idtcm_xfer(struct idtcm *idtcm,
-                     u8 regaddr,
-                     u8 *buf,
-                     u16 count,
-                     bool write)
+static int idtcm_xfer_read(struct idtcm *idtcm,
+                          u8 regaddr,
+                          u8 *buf,
+                          u16 count)
 {
        struct i2c_client *client = idtcm->client;
        struct i2c_msg msg[2];
        int cnt;
-       char *fmt = "i2c_transfer failed at %d in %s for %s, at addr: %04X!\n";
+       char *fmt = "i2c_transfer failed at %d in %s, at addr: %04X!\n";
 
        msg[0].addr = client->addr;
        msg[0].flags = 0;
@@ -159,7 +158,7 @@ static int idtcm_xfer(struct idtcm *idtcm,
        msg[0].buf = &regaddr;
 
        msg[1].addr = client->addr;
-       msg[1].flags = write ? 0 : I2C_M_RD;
+       msg[1].flags = I2C_M_RD;
        msg[1].len = count;
        msg[1].buf = buf;
 
@@ -170,7 +169,6 @@ static int idtcm_xfer(struct idtcm *idtcm,
                        fmt,
                        __LINE__,
                        __func__,
-                       write ? "write" : "read",
                        regaddr);
                return cnt;
        } else if (cnt != 2) {
@@ -182,6 +180,37 @@ static int idtcm_xfer(struct idtcm *idtcm,
        return 0;
 }
 
+static int idtcm_xfer_write(struct idtcm *idtcm,
+                           u8 regaddr,
+                           u8 *buf,
+                           u16 count)
+{
+       struct i2c_client *client = idtcm->client;
+       /* we add 1 byte for device register */
+       u8 msg[IDTCM_MAX_WRITE_COUNT + 1];
+       int cnt;
+       char *fmt = "i2c_master_send failed at %d in %s, at addr: %04X!\n";
+
+       if (count > IDTCM_MAX_WRITE_COUNT)
+               return -EINVAL;
+
+       msg[0] = regaddr;
+       memcpy(&msg[1], buf, count);
+
+       cnt = i2c_master_send(client, msg, count + 1);
+
+       if (cnt < 0) {
+               dev_err(&client->dev,
+                       fmt,
+                       __LINE__,
+                       __func__,
+                       regaddr);
+               return cnt;
+       }
+
+       return 0;
+}
+
 static int idtcm_page_offset(struct idtcm *idtcm, u8 val)
 {
        u8 buf[4];
@@ -195,7 +224,7 @@ static int idtcm_page_offset(struct idtcm *idtcm, u8 val)
        buf[2] = 0x10;
        buf[3] = 0x20;
 
-       err = idtcm_xfer(idtcm, PAGE_ADDR, buf, sizeof(buf), 1);
+       err = idtcm_xfer_write(idtcm, PAGE_ADDR, buf, sizeof(buf));
 
        if (err) {
                idtcm->page_offset = 0xff;
@@ -223,11 +252,12 @@ static int _idtcm_rdwr(struct idtcm *idtcm,
        err = idtcm_page_offset(idtcm, hi);
 
        if (err)
-               goto out;
+               return err;
 
-       err = idtcm_xfer(idtcm, lo, buf, count, write);
-out:
-       return err;
+       if (write)
+               return idtcm_xfer_write(idtcm, lo, buf, count);
+
+       return idtcm_xfer_read(idtcm, lo, buf, count);
 }
 
 static int idtcm_read(struct idtcm *idtcm,
diff --git a/drivers/ptp/ptp_clockmatrix.h b/drivers/ptp/ptp_clockmatrix.h
index ffae56c..82840d7 100644
--- a/drivers/ptp/ptp_clockmatrix.h
+++ b/drivers/ptp/ptp_clockmatrix.h
@@ -55,6 +55,8 @@
 
 #define PEROUT_ENABLE_OUTPUT_MASK              (0xdeadbeef)
 
+#define IDTCM_MAX_WRITE_COUNT                  (512)
+
 /* Values of DPLL_N.DPLL_MODE.PLL_MODE */
 enum pll_mode {
        PLL_MODE_MIN = 0,
-- 
2.7.4