Hi Chuanhua,
This patch enables the i2c controller to generate a stop signal before reading the slave device's internal register after setting the register address (need to determine if the signal is needed according to the message flag).
Signed-off-by: Biwen Li biwen.li@nxp.com Signed-off-by: Chuanhua Han chuanhua.han@nxp.com
Changes in v2:
- Split the original patch into 3 patches
- Add detailed description information for each patch
drivers/i2c/mxc_i2c.c | 70
I must admit that I'm a bit puzzled - in the patch 1/3 you added the U-Boot wide I2C_M_RD_NEED_STOP_BIT flag to indicate the need to generate a stop bit.
Iin this patch you change the respective mxc_i2c.c driver (which is NXP SoC specific). Shouldn't those changes go in to a "generic" i2c code (or better to the pcf2127 driver) ?
What would happen if somebody use this device (pcf2127.c) on board running e.g. TI processor? (like Beagle Bone Black). Would the pcf2127 work properly in that case?
++++++++++++++++++++++++++++++++++++++----- 1 file changed, 62 insertions(+), 8 deletions(-)
diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c index 23119cce65..f3811eb0c5 100644 --- a/drivers/i2c/mxc_i2c.c +++ b/drivers/i2c/mxc_i2c.c @@ -961,6 +961,8 @@ static int mxc_i2c_xfer(struct udevice *bus, struct i2c_msg *msg, int nmsgs) int reg_shift = i2c_bus->driver_data & I2C_QUIRK_FLAG ? VF610_I2C_REGSHIFT : IMX_I2C_REGSHIFT; int read_mode;
- bool quirk = i2c_bus->driver_data & I2C_QUIRK_FLAG ? true :
false;
unsigned int temp;
/* Here address len is set to -1 to not send any address at
first. * Otherwise i2c_init_transfer will send the chip address with write @@ -975,6 +977,7 @@ static int mxc_i2c_xfer(struct udevice *bus, struct i2c_msg *msg, int nmsgs) read_mode = -1; /* So it's always different on the first message */ for (; nmsgs > 0; nmsgs--, msg++) { const int msg_is_read = !!(msg->flags & I2C_M_RD);
bool next_is_read = nmsgs > 1 && (msg[1].flags &I2C_M_RD); debug("i2c_xfer: chip=0x%x, len=0x%x, dir=%c\n", msg->addr, msg->len, msg_is_read ? 'R' : 'W'); @@ -982,13 +985,16 @@ static int mxc_i2c_xfer(struct udevice *bus, struct i2c_msg *msg, int nmsgs) if (msg_is_read != read_mode) { /* Send repeated start if not 1st message */ if (read_mode != -1) {
debug("i2c_xfer: [RSTART]\n");ret = readb(base + (I2CR <<reg_shift));
ret |= I2CR_RSTA;writeb(ret, base + (I2CR <<reg_shift));
if (!(msg[1].flags &I2C_M_RD_NEED_STOP_BIT)) {
debug("i2c_xfer:[RSTART]\n");
ret = readb(base + (I2CR <<reg_shift));
ret |= I2CR_RSTA;writeb(ret, base + (I2CR <<reg_shift));
} } debug("i2c_xfer: [ADDR %02x | %c]\n",msg->addr, msg_is_read ? 'R' : 'W');
ret = tx_byte(i2c_bus, (msg->addr << 1) |msg_is_read); if (ret < 0) { debug("i2c_xfer: [STOP]\n"); @@ -998,16 +1004,64 @@ static int mxc_i2c_xfer(struct udevice *bus, struct i2c_msg *msg, int nmsgs) read_mode = msg_is_read; }
if (msg->flags & I2C_M_RD)
if (msg->flags & I2C_M_RD) { ret = i2c_read_data(i2c_bus, msg->addr,msg->buf, msg->len, nmsgs == 1 || (msg->flags & I2C_M_STOP));
elseret = i2c_write_data(i2c_bus, msg->addr,msg->buf,
msg->len);
if (ret < 0)break;continue;}/* Write message */ret = i2c_write_data(i2c_bus, msg->addr, msg->buf,msg->len);if (ret < 0) break;
if (!next_is_read)continue;/* Read message following write message */if (msg[1].flags & I2C_M_RD_NEED_STOP_BIT) {/* Generate a stop bit */i2c_imx_stop(i2c_bus);/* Reset i2c slave */i2c_force_reset_slave();/* Enable I2C controller */if (quirk)ret = readb(base + (I2CR <<reg_shift))
& I2CR_IDIS;elseret = !(readb(base + (I2CR <<reg_shift))
& I2CR_IEN);if (ret) {writeb(I2CR_IEN, base + (I2CR <<reg_shift));
/* Wait for controller to be stable*/
udelay(50);}/* Clear interrupt bit */writeb(I2SR_IIF_CLEAR, base + (I2SR <<reg_shift));
ret = wait_for_sr_state(i2c_bus,ST_BUS_IDLE);
if (ret < 0)return ret;/* Start I2C transaction */temp = readb(base + (I2CR << reg_shift));temp |= I2CR_MSTA;writeb(temp, base + (I2CR << reg_shift));ret = wait_for_sr_state(i2c_bus,ST_BUS_BUSY);
if (ret < 0)return ret;/* Enter transfer mode */temp |= I2CR_MTX | I2CR_TX_NO_AK;writeb(temp, base + (I2CR << reg_shift));udelay(50);}}
if (ret)
Best regards,
Lukasz Majewski
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