On Mon, Oct 6, 2014 at 5:39 PM, Yegor Yefremov
yegorsli...@googlemail.com wrote:
U-Boot 2014.07
I'm trying to use ping 44..47 as input. I've configured PINMUX and
invoked request, direction etc. I always get 0 from gpio_get_value()
int val;
gpio_request(44, dip_s1):
gpio_request(45, dip_s2);
gpio_request(46, dip_s3);
gpio_request(47, dip_s4);
gpio_direction_input(44);
gpio_direction_input(45);
gpio_direction_input(46);
gpio_direction_input(47);
val = gpio_get_value(44);
printf(DIP value: %d\n, val);
val = gpio_get_value(45);
printf(DIP value: %d\n, val);
val = gpio_get_value(46);
printf(DIP value: %d\n, val);
val = gpio_get_value(47);
printf(DIP value: %d\n, val);
After reading http://e2e.ti.com/support/arm/sitara_arm/f/791/t/248181.aspx
I've checked clock registers CM_PER_L4LS_CLKSTCTRL (bit 8 L4LS_GCLK
is set) and also CM_PER_GPIO1_CLKCTRL has value 2 - enabled. I can
also see, that arch/arm/cpu/armv7/am33xx/clock_am33xx.c-enable_basic_clocks()
enables clocks for GPIO1.
Then I checked GPIO1 specific registers and found out, that
GPIO_SYSSTATUS (0x4804C114) shows 0x i.e. GPIO is still in
reset. Any idea, what should be activated/setup in order to get the
second GPIO bank working?
Some more details. These pins are working in Linux. In U-boot I can
use them as output via gpio toggle 44 (I can measure the signal via
oscilloscope). So the requirements, that were mentioned in the thread
on TI forum are met. I still cannot understand from TRM, if debounce
clock is necessary or optional in order to get input working?
Yegor
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