[PATCH v2 net-next 2/3] ptp: idt82p33: use i2c_master_send for bus write

From: min.li.xe
Date: Wed Nov 04 2020 - 18:14:30 EST


From: Min Li <min.li.xe@xxxxxxxxxxx>

Refactor idt82p33_xfer and use i2c_master_send for write operation.
Because some I2C controllers are only working with single-burst write
transaction.

Changes since v1:
- Fix broken build.

Signed-off-by: Min Li <min.li.xe@xxxxxxxxxxx>
---
drivers/ptp/ptp_idt82p33.c | 52 +++++++++++++++++++++++++++++++++-------------
drivers/ptp/ptp_idt82p33.h | 1 +
2 files changed, 39 insertions(+), 14 deletions(-)

diff --git a/drivers/ptp/ptp_idt82p33.c b/drivers/ptp/ptp_idt82p33.c
index 0cc4953..b1528a0 100644
--- a/drivers/ptp/ptp_idt82p33.c
+++ b/drivers/ptp/ptp_idt82p33.c
@@ -78,11 +78,10 @@ static void idt82p33_timespec_to_byte_array(struct timespec64 const *ts,
}
}

-static int idt82p33_xfer(struct idt82p33 *idt82p33,
- unsigned char regaddr,
- unsigned char *buf,
- unsigned int count,
- int write)
+static int idt82p33_xfer_read(struct idt82p33 *idt82p33,
+ unsigned char regaddr,
+ unsigned char *buf,
+ unsigned int count)
{
struct i2c_client *client = idt82p33->client;
struct i2c_msg msg[2];
@@ -94,7 +93,7 @@ static int idt82p33_xfer(struct idt82p33 *idt82p33,
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;

@@ -110,6 +109,31 @@ static int idt82p33_xfer(struct idt82p33 *idt82p33,
return 0;
}

+static int idt82p33_xfer_write(struct idt82p33 *idt82p33,
+ u8 regaddr,
+ u8 *buf,
+ u16 count)
+{
+ struct i2c_client *client = idt82p33->client;
+ /* we add 1 byte for device register */
+ u8 msg[IDT82P33_MAX_WRITE_COUNT + 1];
+ int err;
+
+ if (count > IDT82P33_MAX_WRITE_COUNT)
+ return -EINVAL;
+
+ msg[0] = regaddr;
+ memcpy(&msg[1], buf, count);
+
+ err = i2c_master_send(client, msg, count + 1);
+ if (err < 0) {
+ dev_err(&client->dev, "i2c_master_send returned %d\n", err);
+ return err;
+ }
+
+ return 0;
+}
+
static int idt82p33_page_offset(struct idt82p33 *idt82p33, unsigned char val)
{
int err;
@@ -117,7 +141,7 @@ static int idt82p33_page_offset(struct idt82p33 *idt82p33, unsigned char val)
if (idt82p33->page_offset == val)
return 0;

- err = idt82p33_xfer(idt82p33, PAGE_ADDR, &val, sizeof(val), 1);
+ err = idt82p33_xfer_write(idt82p33, PAGE_ADDR, &val, sizeof(val));
if (err)
dev_err(&idt82p33->client->dev,
"failed to set page offset %d\n", val);
@@ -130,20 +154,20 @@ static int idt82p33_page_offset(struct idt82p33 *idt82p33, unsigned char val)
static int idt82p33_rdwr(struct idt82p33 *idt82p33, unsigned int regaddr,
unsigned char *buf, unsigned int count, bool write)
{
+ u8 offset, page;
int err;
- u8 page;
- u8 offset;

page = _PAGE(regaddr);
- offset = _OFFSET(regaddr);
+ offset = _OFFSET(regaddr);

err = idt82p33_page_offset(idt82p33, page);
if (err)
- goto out;
+ return err;

- err = idt82p33_xfer(idt82p33, offset, buf, count, write);
-out:
- return err;
+ if (write)
+ return idt82p33_xfer_write(idt82p33, offset, buf, count);
+
+ return idt82p33_xfer_read(idt82p33, offset, buf, count);
}

static int idt82p33_read(struct idt82p33 *idt82p33, unsigned int regaddr,
diff --git a/drivers/ptp/ptp_idt82p33.h b/drivers/ptp/ptp_idt82p33.h
index 3a0e001..1c7a0f0 100644
--- a/drivers/ptp/ptp_idt82p33.h
+++ b/drivers/ptp/ptp_idt82p33.h
@@ -95,6 +95,7 @@ enum hw_tod_trig_sel {
#define MAX_MEASURMENT_COUNT (5)
#define SNAP_THRESHOLD_NS (150000)
#define SYNC_TOD_TIMEOUT_SEC (5)
+#define IDT82P33_MAX_WRITE_COUNT (512)

#define PLLMASK_ADDR_HI 0xFF
#define PLLMASK_ADDR_LO 0xA5
--
2.7.4