From e643f91ccfa544b7e3153a7721fba66e0e494759 Mon Sep 17 00:00:00 2001
From: Jim Brennan <jbren...@impinj.com>
Date: Wed, 13 Dec 2017 13:44:02 -0800
Subject: [PATCH] i2c: imx: bus arbitration fix when reading block data
Fixes arbitration failure on imx platform due to incorrect
chip address use when reading a block of data. Add support
for both reading or writing a block of data or any combination.
Signed-off-by: Jim Brennan <jbren...@impinj.com>
---
drivers/i2c/mxc_i2c.c | 65 ++++++++++++++++++++++++++++++++-------------------
1 file changed, 41 insertions(+), 24 deletions(-)
diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c
index 205274e947..bd2a39ebe6 100644
--- a/drivers/i2c/mxc_i2c.c
+++ b/drivers/i2c/mxc_i2c.c
@@ -25,6 +25,7 @@
#include <dm.h>
#include <dm/pinctrl.h>
#include <fdtdec.h>
+#include <stdbool.h>
DECLARE_GLOBAL_DATA_PTR;
@@ -275,7 +276,7 @@ static void i2c_imx_stop(struct mxc_i2c_bus *i2c_bus)
* write register address
*/
static int i2c_init_transfer_(struct mxc_i2c_bus *i2c_bus, u8 chip,
- u32 addr, int alen)
+ u32 addr, int alen, bool read)
{
unsigned int temp;
int ret;
@@ -317,9 +318,17 @@ static int i2c_init_transfer_(struct mxc_i2c_bus *i2c_bus,
u8 chip,
temp |= I2CR_MTX | I2CR_TX_NO_AK;
writeb(temp, base + (I2CR << reg_shift));
- if (alen >= 0) {
- /* write slave address */
- ret = tx_byte(i2c_bus, chip << 1);
+ /* write slave address */
+ u8 slave_address = (chip << 1);
+
+ if (read)
+ slave_address |= 1;
+ ret = tx_byte(i2c_bus, slave_address);
+ if (ret < 0)
+ return ret;
+
+ while (alen--) {
+ ret = tx_byte(i2c_bus, (addr >> (alen * 8)) & 0xff);
if (ret < 0)
return ret;
@@ -413,7 +422,7 @@ exit:
#endif
static int i2c_init_transfer(struct mxc_i2c_bus *i2c_bus, u8 chip,
- u32 addr, int alen)
+ u32 addr, int alen, bool read)
{
int retry;
int ret;
@@ -424,7 +433,7 @@ static int i2c_init_transfer(struct mxc_i2c_bus *i2c_bus,
u8 chip,
return -EINVAL;
for (retry = 0; retry < 3; retry++) {
- ret = i2c_init_transfer_(i2c_bus, chip, addr, alen);
+ ret = i2c_init_transfer_(i2c_bus, chip, addr, alen, read);
if (ret >= 0)
return 0;
i2c_imx_stop(i2c_bus);
@@ -536,7 +545,7 @@ static int bus_i2c_read(struct mxc_i2c_bus *i2c_bus, u8
chip, u32 addr,
VF610_I2C_REGSHIFT : IMX_I2C_REGSHIFT;
ulong base = i2c_bus->base;
- ret = i2c_init_transfer(i2c_bus, chip, addr, alen);
+ ret = i2c_init_transfer(i2c_bus, chip, addr, alen, false);
if (ret < 0)
return ret;
@@ -566,7 +575,7 @@ static int bus_i2c_write(struct mxc_i2c_bus *i2c_bus, u8
chip, u32 addr,
{
int ret = 0;
- ret = i2c_init_transfer(i2c_bus, chip, addr, alen);
+ ret = i2c_init_transfer(i2c_bus, chip, addr, alen, false);
if (ret < 0)
return ret;
@@ -817,7 +826,7 @@ static int mxc_i2c_probe_chip(struct udevice *bus, u32
chip_addr,
int ret;
struct mxc_i2c_bus *i2c_bus = dev_get_priv(bus);
- ret = i2c_init_transfer(i2c_bus, chip_addr, 0, 0);
+ ret = i2c_init_transfer(i2c_bus, chip_addr, 0, 0, false);
if (ret < 0) {
debug("%s failed, ret = %d\n", __func__, ret);
return ret;
@@ -841,35 +850,43 @@ static int mxc_i2c_xfer(struct udevice *bus, struct
i2c_msg *msg, int nmsgs)
* because here we only want to send out chip address. The register
* address is wrapped in msg.
*/
- ret = i2c_init_transfer(i2c_bus, msg->addr, 0, 0);
+
+ bool read = (msg->flags & I2C_M_RD) ? true : false;
+
+ ret = i2c_init_transfer(i2c_bus, msg->addr, 0, 0, read);
if (ret < 0) {
debug("i2c_init_transfer error: %d\n", ret);
return ret;
}
for (; nmsgs > 0; nmsgs--, msg++) {
+ bool current_is_read = (msg->flags & I2C_M_RD) ? true : false;
bool next_is_read = nmsgs > 1 && (msg[1].flags & I2C_M_RD);
debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
- if (msg->flags & I2C_M_RD)
+ if (current_is_read)
ret = i2c_read_data(i2c_bus, msg->addr, msg->buf,
msg->len);
else {
ret = i2c_write_data(i2c_bus, msg->addr, msg->buf,
msg->len);
- if (ret)
+ }
+ if (ret)
+ break;
+
+ if (nmsgs > 1 && (current_is_read ^ next_is_read)) {
+ u8 addr = msg->addr << 1;
+
+ /* Reuse ret */
+ ret = readb(base + (I2CR << reg_shift));
+ ret |= I2CR_RSTA;
+ writeb(ret, base + (I2CR << reg_shift));
+
+ if (next_is_read)
+ addr |= 1;
+
+ ret = tx_byte(i2c_bus, addr);
+ if (ret < 0)
break;
- if (next_is_read) {
- /* Reuse ret */
- ret = readb(base + (I2CR << reg_shift));
- ret |= I2CR_RSTA;
- writeb(ret, base + (I2CR << reg_shift));
-
- ret = tx_byte(i2c_bus, (msg->addr << 1) | 1);
- if (ret < 0) {
- i2c_imx_stop(i2c_bus);
- break;
- }
- }
}
}
--
2.13.6
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