Re: [PATCH 4/8] ARM: at91: do not configure at91sam9g10 twi pio as open-drain
From: Warner Losh <hidden>
Date: 2012-09-06 04:57:36
Also in:
linux-devicetree
On Aug 31, 2012, at 3:21 AM, [off-list ref] [off-list ref] wrote:
quoted hunk
From: Ludovic Desroches <redacted> As indicated in the datasheet, TWD and TWCK must not be programmed as open-drain. Signed-off-by: Ludovic Desroches <redacted> --- arch/arm/mach-at91/at91sam9261_devices.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-)diff --git a/arch/arm/mach-at91/at91sam9261_devices.c b/arch/arm/mach-at91/at91sam9261_devices.c index c94495d..405f603 100644 --- a/arch/arm/mach-at91/at91sam9261_devices.c +++ b/arch/arm/mach-at91/at91sam9261_devices.c@@ -324,20 +324,22 @@ static struct platform_device at91sam9261_twi_device = {void __init at91_add_device_i2c(struct i2c_board_info *devices, int nr_devices) { - /* IP version is not the same on 9261 and g10 */ + /* + * IP version is not the same on 9261 and g10 and only 9261 one + * requires to configure PIO as open-drain.
"The IP version is not the same on the 9261 and g10. Only the 9261 requires PIO configured as open-drain." would be a better way to say this.
+ */
if (cpu_is_at91sam9g10()) {
at91sam9261_twi_device.name = "at91sam9g10_i2c";
+ at91_set_A_periph(AT91_PIN_PA7, 0); /* TWD */
+ at91_set_A_periph(AT91_PIN_PA8, 0); /* TWCK */
} else {
at91sam9261_twi_device.name = "at91sam9261_i2c";
+ at91_set_A_periph(AT91_PIN_PA7, 0); /* TWD */
+ at91_set_multi_drive(AT91_PIN_PA7, 1);
+ at91_set_A_periph(AT91_PIN_PA8, 0); /* TWCK */
+ at91_set_multi_drive(AT91_PIN_PA8, 1);
}
- /* pins used for TWI interface */
- at91_set_A_periph(AT91_PIN_PA7, 0); /* TWD */
- at91_set_multi_drive(AT91_PIN_PA7, 1);
-
- at91_set_A_periph(AT91_PIN_PA8, 0); /* TWCK */
- at91_set_multi_drive(AT91_PIN_PA8, 1);
-You could just move the two multi-drive lines up into the 9261 branch of the above if. That would make it clearer that it is a workaround just for the 9261.
i2c_register_board_info(0, devices, nr_devices); platform_device_register(&at91sam9261_twi_device); } -- 1.7.11.3 _______________________________________________ devicetree-discuss mailing list devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org https://lists.ozlabs.org/listinfo/devicetree-discuss