On Mon, Nov 14, 2011 at 09:58:03PM -0500, Tang Yuantian-B29983 wrote:
>
>
> > -----Original Message-----
> > From: Guenter Roeck [mailto:guenter.roeck@xxxxxxxxxxxx]
> > Hmm ... looking into the code, I2C_FUNC_SMBUS_READ_BLOCK_DATA is missing
> > from I2C_FUNC_SMBUS_EMUL.
> > Now that is interesting.
> >
> > If you change mpc_functionality() to
> > return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
> > I2C_FUNC_SMBUS_READ_BLOCK_DATA; I bet your problem will disappear.
> >
> > Jean, any idea why I2C_FUNC_SMBUS_EMUL doesn't include
> > I2C_FUNC_SMBUS_READ_BLOCK_DATA ?
> >
> [Yuantian:] unfortunately no, Even I add I2C_FUNC_SMBUS_READ_BLOCK_DATA support,
> The return value is not correct.
>
Actually, you are right. The i2c-mpc driver would also have to handle the I2C_M_RECV_LEN
flag, where the 1st received byte indicates the receive length. That would probably require
a change in mpc_read(), telling it that the first byte to be received is the length.
Something like the attached. Completely untested, of course ...
Guenter
diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c
index 107397a..77aade7 100644
--- a/drivers/i2c/busses/i2c-mpc.c
+++ b/drivers/i2c/busses/i2c-mpc.c
@@ -454,7 +454,7 @@ static int mpc_write(struct mpc_i2c *i2c, int target,
}
static int mpc_read(struct mpc_i2c *i2c, int target,
- u8 *data, int length, int restart)
+ u8 *data, int length, int restart, bool block)
{
unsigned timeout = i2c->adap.timeout;
int i, result;
@@ -470,7 +470,7 @@ static int mpc_read(struct mpc_i2c *i2c, int target,
return result;
if (length) {
- if (length == 1)
+ if (length == 1 && !block)
writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
else
writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA);
@@ -479,17 +479,28 @@ static int mpc_read(struct mpc_i2c *i2c, int target,
}
for (i = 0; i < length; i++) {
+ u8 byte;
+
result = i2c_wait(i2c, timeout, 0);
if (result < 0)
return result;
+ byte = readb(i2c->base + MPC_I2C_DR);
+ /*
+ * Adjust length if first received byte is length
+ */
+ if (i == 0 && block) {
+ if (byte == 0 || byte > I2C_SMBUS_BLOCK_MAX)
+ return -EPROTO;
+ length += byte;
+ }
+ data[i] = byte;
/* Generate txack on next to last byte */
if (i == length - 2)
writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
/* Do not generate stop on last byte */
if (i == length - 1)
writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX);
- data[i] = readb(i2c->base + MPC_I2C_DR);
}
return length;
@@ -532,12 +543,17 @@ static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
"Doing %s %d bytes to 0x%02x - %d of %d messages\n",
pmsg->flags & I2C_M_RD ? "read" : "write",
pmsg->len, pmsg->addr, i + 1, num);
- if (pmsg->flags & I2C_M_RD)
- ret =
- mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
- else
+ if (pmsg->flags & I2C_M_RD) {
+ bool block = pmsg->flags & I2C_M_RECV_LEN;
+
+ ret = mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i,
+ block);
+ if (block && ret > 0)
+ pmsg->len = ret;
+ } else {
ret =
mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
+ }
}
mpc_i2c_stop(i2c);
return (ret < 0) ? ret : num;
@@ -545,7 +561,8 @@ static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
static u32 mpc_functionality(struct i2c_adapter *adap)
{
- return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL
+ | I2C_FUNC_SMBUS_READ_BLOCK_DATA;
}
static const struct i2c_algorithm mpc_algo = {
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