Screwface 
Hi,
I try to make an ADXL345 accelerometer working with linux. I use
Pengutronix BSP. I have modified my mach-mini2440.c platform file to
activate SPI as follow :
added lines
#include <linux/spi/spi.h>
#include <mach/spi.h>
#include <linux/input/adxl34x.h>
/* ADXL345 Accelerometer support */
static const struct adxl34x_platform_data adxl34x_info = {
.x_axis_offset = 0,
.y_axis_offset = 0,
.z_axis_offset = 0,
.tap_threshold = 0x31,
.tap_duration = 0x10,
.tap_latency = 0x60,
.tap_window = 0xF0,
.tap_axis_control = ADXL_TAP_X_EN | ADXL_TAP_Y_EN | ADXL_TAP_Z_EN,
.act_axis_control = 0xFF,
.activity_threshold = 5,
.inactivity_threshold = 3,
.inactivity_time = 4,
.free_fall_threshold = 0x7,
.free_fall_time = 0x20,
.data_rate = 0x8,
.data_range = ADXL_FULL_RES,
.ev_type = EV_ABS,
.ev_code_x = ABS_X, /* EV_REL */
.ev_code_y = ABS_Y, /* EV_REL */
.ev_code_z = ABS_Z, /* EV_REL */
.ev_code_tap = {BTN_TOUCH, BTN_TOUCH, BTN_TOUCH}, /* EV_KEY x,y,z
*/
/* .ev_code_ff = KEY_F,*/ /* EV_KEY */
/* .ev_code_act_inactivity = KEY_A,*/ /* EV_KEY */
.power_mode = ADXL_AUTO_SLEEP | ADXL_LINK,
.fifo_mode = ADXL_FIFO_STREAM,
.orientation_enable = ADXL_EN_ORIENTATION_3D,
.deadzone_angle = ADXL_DEADZONE_ANGLE_10p8,
.divisor_length = ADXL_LP_FILTER_DIVISOR_16,
/* EV_KEY {+Z, +Y, +X, -X, -Y, -Z} */
.ev_codes_orient_3d = {BTN_Z, BTN_Y, BTN_X, BTN_A, BTN_B, BTN_C},
};
// First SPI slave
static struct s3c2410_spi_info mini2440_spi0_platdata = {
.num_cs = 1,
.bus_num = 0,
.pin_cs = S3C2410_GPG(2),
.gpio_setup = &s3c24xx_spi_gpiocfg_bus0_gpe11_12_13,
};
static struct spi_board_info mini2440_spi_devs[] __initdata = {
{ /* ADXL345 accelerometer */
.modalias = "adxl34x",
.platform_data = &adxl34x_info,
.irq = IRQ_EINT17,
.chip_select = 0,
.max_speed_hz = 5 * 1000 * 1000, /* max spi clock (SCK) speed in HZ
*/
.bus_num = 0,
.mode=SPI_MODE_3,
}
};
static struct platform_device *mini2440_devices[] __initdata = {
........
&s3c_device_spi0,
};
static void __init mini2440_init(void)
{
........
/* setup SPI */
s3c_device_spi0.dev.platform_data = &mini2440_spi0_platdata;
spi_register_board_info(mini2440_spi_devs,
ARRAY_SIZE(mini2440_spi_devs));
........
}
I have also added this line in the config MACH_MINI2440 section of the
Kconfig file. I don't know which option does it select in which menu, but
I've seen it was needed
select S3C24XX_SPI_BUS0_GPE11_GPE12_GPE13
I have connected the pins of the ADXL345 as follow :
ADXL345 MINI2440
CS nSS_SPI
INT1 EINT17 (not sure it is needed)
INT2 not connected
SDA SPIMOSI
SDO SPIMISO
SCL SPICLK
My problem is the ADXL345 is not detected: during boot, I get this message
:
adxl34x spi0.0 : failed to probe ADXL34X accelerometer.
An Analog Devices document mentions this is due to a failed initialization
and communication with the ADXL34x. The advice is to check bus_num and
chip_select in the platform file.
I think I'm right on those items.
The thing which is unclead for me is the interrupt.
If I don't mention irq in spi_board_info structure, I get an "irq ?"
during boot up. I have set it as it was mentionned for the CAN interface at
http://cor-net.org/2009/09/can-interface-for-the-mini2440-dev-board/ and
connected the line to EINT17 but without really understanding what I was
doing.
For me, the INT1 has to be configured in the ADXL345 to be rised up when
some particular movements are detected (tap, double tap, free fall). So
this pin is not mandatory.
On the other side, I'm not sure if there is something to do to tell the
EINT17 is an interrupt input pin.
I tried also in I2C mode, I got the device detected, but the board hangs if
I try an evtest on the corresponding event (event1)
The same Analog Devices document mentions something wrong with the
interrupt and advices to check the irq number in the platform file.
Can somebody :
- tell me which option is selected in kernel menuconfig when adding 'select
S3C24XX_SPI_BUS0_GPE11_GPE12_GPE13' in the Kconfig file ?
- help me with this irq story: how to determine the correct IRQ, set and
configure it?
Thanks a lot!