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Allow data-only i2c transfers 

Modified the i2c_imx driver to support data-only transfers, without
command byte.  This allows to construct more complex i2c transfers
and support non genuine devices like Atmel ATxx secure memory, where the
master reads data after a write command.

Signed-off-by: Rosen Kolev <rosen.kolev@amk-drives.bg>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
Rosen Kolev 2011-09-29 11:57:02 +03:00 committed by Sascha Hauer
parent c7efd11b38
commit 502ecda2d1
2 changed files with 29 additions and 24 deletions
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52
drivers/i2c/busses/i2c-imx.c
View File

@ -314,19 +314,21 @@ static int i2c_imx_write(struct i2c_adapter *adapter, struct i2c_msg *msgs)
void __iomem *base = i2c_imx->base;
int i, result;
dev_dbg(adapter->dev,
"<%s> write slave address: addr=0x%02x\n",
__func__, msgs->addr << 1);
if ( !(msgs->flags & I2C_M_DATA_ONLY) ) {
dev_dbg(adapter->dev,
"<%s> write slave address: addr=0x%02x\n",
__func__, msgs->addr << 1);
/* write slave address */
writeb(msgs->addr << 1, base + IMX_I2C_I2DR);
/* write slave address */
writeb(msgs->addr << 1, base + IMX_I2C_I2DR);
result = i2c_imx_trx_complete(adapter);
if (result)
return result;
result = i2c_imx_acked(adapter);
if (result)
return result;
result = i2c_imx_trx_complete(adapter);
if (result)
return result;
result = i2c_imx_acked(adapter);
if (result)
return result;
}
/* write data */
for (i = 0; i < msgs->len; i++) {
@ -352,22 +354,24 @@ static int i2c_imx_read(struct i2c_adapter *adapter, struct i2c_msg *msgs)
int i, result;
unsigned int temp;
dev_dbg(adapter->dev,
"<%s> write slave address: addr=0x%02x\n",
__func__, (msgs->addr << 1) | 0x01);
/* clear IIF */
writeb(0x0, base + IMX_I2C_I2SR);
/* write slave address */
writeb((msgs->addr << 1) | 0x01, base + IMX_I2C_I2DR);
if ( !(msgs->flags & I2C_M_DATA_ONLY) ) {
dev_dbg(adapter->dev,
"<%s> write slave address: addr=0x%02x\n",
__func__, (msgs->addr << 1) | 0x01);
result = i2c_imx_trx_complete(adapter);
if (result)
return result;
result = i2c_imx_acked(adapter);
if (result)
return result;
/* write slave address */
writeb((msgs->addr << 1) | 0x01, base + IMX_I2C_I2DR);
result = i2c_imx_trx_complete(adapter);
if (result)
return result;
result = i2c_imx_acked(adapter);
if (result)
return result;
}
/* setup bus to read data */
temp = readb(base + IMX_I2C_I2CR);
@ -428,7 +432,7 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter,
/* read/write data */
for (i = 0; i < num; i++) {
if (i) {
if (i && !(msgs[i].flags & I2C_M_DATA_ONLY)) {
temp = readb(base + IMX_I2C_I2CR);
temp |= I2CR_RSTA;
writeb(temp, base + IMX_I2C_I2CR);

1
include/i2c/i2c.h
View File

@ -30,6 +30,7 @@ struct i2c_platform_data {
#define I2C_NAME_SIZE 20
#define I2C_M_RD 0x0001 /* read data, from slave to master */
#define I2C_M_DATA_ONLY 0x0002 /* transfer data bytes only */
#define I2C_M_TEN 0x0010 /* this is a ten bit chip address */
#define I2C_M_IGNORE_NAK 0x1000 /* if I2C_FUNC_PROTOCOL_MANGLING */