Hi,
We use the i2c-pnx.c driver on our device (NXP LPC3xxx devices), but have had
some
issues with compilation and general use. I hope these changes can be of use and
can
get back into the mainline. I'm happy to test any changes for the driver here on
our boards.
The i2c-pnx.c file doesn't seem to compile (even with the pnx4008 platform
selected).
It looks like several important header files are not included in the driver
(mach/i2c.h and asm/io.h). We have another board that uses this same IP, but
with a
slight reordering of the registers, so the i2c.h file in the mach area (which
defines
register offsets) is important where it is now.
For systems with a tick rate of 100Hz, the I2C_PNX_TIMEOUT value of 10mS give
only
1 jiffie before the transfer times out. We've noticed on some transfers that the
jiffie may tick immediately after the expire count is set, causing the transfer
in
progress to timeout before 10mS is up. A small test to make sure jiffies was at
least 2 fixed this.
We have multiple I2C busses on our system. The bus id value in the platform
definition
area (in the arm/mach- area) wasn't being correctly matched to the specific I2C
bus. This would cause some devices to not match to the correct I2C bus.
The 'buf' field in the I2C transfer descriptor was typed as a char. In the I2C
driver, data values in the buffer pointer to by buf were being sign extended
into
the stop and start bit positions (8 and 9). For I2C transfers where a data byte
had
bit 7 set, both the start and stop bits were also getting set in the hardware.
The complete patch is listed below:
diff -Naur -X linux-2.6.32-rc6-ref/Documentation/dontdiff
linux-2.6.32-rc6-ref/drivers/i2c/busses/i2c-pnx.c
linux-2.6.32-rc6/drivers/i2c/busses/i2c-pnx.c
--- linux-2.6.32-rc6-ref/drivers/i2c/busses/i2c-pnx.c 2009-11-03
11:37:49.000000000 -0800
+++ linux-2.6.32-rc6/drivers/i2c/busses/i2c-pnx.c 2009-11-10
14:09:11.000000000 -0800
@@ -20,8 +20,10 @@
#include <linux/platform_device.h>
#include <linux/i2c-pnx.h>
#include <mach/hardware.h>
+#include <mach/i2c.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
+#include <asm/io.h>
#define I2C_PNX_TIMEOUT 10 /* msec */
#define I2C_PNX_SPEED_KHZ 100
@@ -54,6 +56,9 @@
struct timer_list *timer = &data->mif.timer;
int expires = I2C_PNX_TIMEOUT / (1000 / HZ);
+ if (expires <= 1)
+ expires = 2;
+
del_timer_sync(timer);
dev_dbg(&adap->dev, "Timer armed at %lu plus %u jiffies.\n",
@@ -633,7 +638,8 @@
/* Register this adapter with the I2C subsystem */
i2c_pnx->adapter->dev.parent = &pdev->dev;
- ret = i2c_add_adapter(i2c_pnx->adapter);
+ i2c_pnx->adapter->nr = pdev->id;
+ ret = i2c_add_numbered_adapter(i2c_pnx->adapter);
if (ret < 0) {
dev_err(&pdev->dev, "I2C: Failed to add bus\n");
goto out_irq;
diff -Naur -X linux-2.6.32-rc6-ref/Documentation/dontdiff
linux-2.6.32-rc6-ref/include/linux/i2c-pnx.h
linux-2.6.32-rc6/include/linux/i2c-pnx.h
--- linux-2.6.32-rc6-ref/include/linux/i2c-pnx.h 2009-11-03
11:37:49.000000000 -0800
+++ linux-2.6.32-rc6/include/linux/i2c-pnx.h 2009-11-10 14:16:55.000000000
-0800
@@ -21,7 +21,7 @@
int mode; /* Interface mode */
struct completion complete; /* I/O completion */
struct timer_list timer; /* Timeout */
- char * buf; /* Data buffer */
+ u8 * buf; /* Data buffer */
int len; /* Length of data buffer */
};
thanks,
Kevin Wells
NXP Semiconductors
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