* [PATCH] Allow data-only i2c transfers
@ 2011-09-29 8:57 Rosen Kolev
2011-10-07 13:46 ` Sascha Hauer
0 siblings, 1 reply; 2+ messages in thread
From: Rosen Kolev @ 2011-09-29 8:57 UTC (permalink / raw)
To: barebox
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>
---
drivers/i2c/busses/i2c-imx.c | 52 ++++++++++++++++++++++-------------------
include/i2c/i2c.h | 1 +
2 files changed, 29 insertions(+), 24 deletions(-)
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 2d075f7..d928839 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -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);
diff --git a/include/i2c/i2c.h b/include/i2c/i2c.h
index 2507d68..ccbf518 100644
--- a/include/i2c/i2c.h
+++ b/include/i2c/i2c.h
@@ -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 */
--
1.7.2.3
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^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [PATCH] Allow data-only i2c transfers
2011-09-29 8:57 [PATCH] Allow data-only i2c transfers Rosen Kolev
@ 2011-10-07 13:46 ` Sascha Hauer
0 siblings, 0 replies; 2+ messages in thread
From: Sascha Hauer @ 2011-10-07 13:46 UTC (permalink / raw)
To: Rosen Kolev; +Cc: barebox
Hi Rosen,
On Thu, Sep 29, 2011 at 11:57:02AM +0300, Rosen Kolev wrote:
> 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.
I must say that I don't really like this patch and hardware guys
making such changes necessary.
Anyway, this is probably the best way around this issue, so I applied
this one to next.
Sascha
>
> Signed-off-by: Rosen Kolev <rosen.kolev@amk-drives.bg>
> ---
> drivers/i2c/busses/i2c-imx.c | 52 ++++++++++++++++++++++-------------------
> include/i2c/i2c.h | 1 +
> 2 files changed, 29 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index 2d075f7..d928839 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -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);
> diff --git a/include/i2c/i2c.h b/include/i2c/i2c.h
> index 2507d68..ccbf518 100644
> --- a/include/i2c/i2c.h
> +++ b/include/i2c/i2c.h
> @@ -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 */
>
> --
> 1.7.2.3
>
>
> _______________________________________________
> barebox mailing list
> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox
>
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