Hello Sekhar,
On 02/08/2010 04:05 PM, Nori, Sekhar wrote:
Hi Philby,
On Fri, Feb 05, 2010 at 19:23:43, Philby John wrote:
Hello Sekhar,
[...]
+/* Generate a pulse on the i2c clock pin. */
+static void generic_i2c_clock_pulse(unsigned int scl_pin)
+{
+ u16 i;
+
+ if (scl_pin) {
+ /* Send high and low on the SCL line */
+ for (i = 0; i< 9; i++) {
+ gpio_set_value(scl_pin, 0);
+ udelay(20);
+ gpio_set_value(scl_pin, 1);
+ udelay(20);
+ }
Before using the pins as GPIO, you would have to set the
functionality of these pins as GPIO. You had this code in
previous incarnations of this patch - not sure why it is
dropped now.
Don't seem to remember having the code in the old versions at least
not in generic_i2c_clock_pulse(). The functions disable_i2c_pins() and
enable_i2c_pins() were discarded as the i2c protocol spec. did not
specify the need. Moreover bus recovered without it. (Tested on DM355
and Dm6446).
Yes, I was referring to the davinci_cfg_reg() calls in
{disable|enable}_i2c_pins() functions. Per the specification
of the DaVinci devices, a pin needs to be muxed as 'GPIO' if
it is to be used as GPIO controlled by GPIO module. It may
have worked on couple of devices but cannot be guaranteed to
work on all DaVinci devices (esp. DA8XX ones).
Couple of good to haves:
[...]
The I2C peripheral on da8xx itself contains a mode where its
pins could be used as GPIO - so no need for SoC level muxing
and need for the platform data. This seems to be missing from
DM355 though. Thankfully there is a revision id within the I2C
memory map which will help you differentiate the two cases
(revision 0x5 vs 0x6)
I did not entirely follow your above statement. Will usage of
gpio_request() solve the problem for da8xx and DM355 or does it
require a if else condition?
You require special casing for I2C version 0x6.
Have a look here: http://focus.ti.com/lit/ug/sprufl9a/sprufl9a.pdf
I was referring to registers described in sections
3.15-3.20
A reminder that the present code will
only work for DM6446 and DM355. I do not have a DA8xx to test specific
functionality if it were to be added.
Right. It is only an enhancement (and only good
to have at that). This should not stop the current
patch from getting in.
Thanks for clarifying this. I will get a patch out for this in a day or two.
Regards,
Philby
--
To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
