I2C device driver error [TCA6408 I/O expander] - linux

Question

I want to connect TCA6408 IO Expander and get key input to my embedded system.
I am trying with SABRELite (iMX6Q) Boad and my development environment is LTIB (L3.0.35_4.1.0_130816_source.tar.gz)
I have done below modifications
1.) add an entry into "board-mx6q_sabrelite.c"
static struct i2c_board_info mxc_i2c2_board_info[] __initdata = {
{
I2C_BOARD_INFO("pca953x", 0x21),
.irq = gpio_to_irq(MX6Q_SABRELITE_CAP_TCH_INT1),
},
};
2.) Enable driver from menuconfig
--- GPIO Support
< * > PCA953x, PCA955x, TCA64xx, and MAX7310 I/O ports
[ * ] Interrupt controller support for PCA953x
When I boot the system, driver registration is OK.
But there is an error(pca953x: probe of 2-0020 failed with error -22) in Probe() function.
#Console Log
Freescale USB OTG Driver loaded, $Revision: 1.55 $
pca953x: probe of 2-0020 failed with error -22
imx-ipuv3 imx-ipuv3.0: IPU DMFC NORMAL mode: 1(0~1), 5B(4,5), 5F(6,7)
imx-ipuv3 imx-ipuv3.1: IPU DMFC NORMAL mode: 1(0~1), 5B(4,5), 5F(6,7)
mxc_mipi_csi2 mxc_mipi_csi2: i.MX MIPI CSI2 driver probed
mxc_mipi_csi2 mxc_mipi_csi2: i.MX MIPI CSI2 dphy version is 0x3130302a
MIPI CSI2 driver module loaded
Advanced Linux Sound Architecture Driver Version 1.0.24.
This error occured becauseof (pdata == NULL)
linux-3.0.35/drivers/gpio/pca953x.c
static int __devinit pca953x_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct pca953x_platform_data *pdata;
struct pca953x_chip *chip;
int ret = 0;
chip = kzalloc(sizeof(struct pca953x_chip), GFP_KERNEL);
if (chip == NULL)
return -ENOMEM;
pdata = client->dev.platform_data;
if (pdata == NULL) {
pdata = pca953x_get_alt_pdata(client);
/*
* Unlike normal platform_data, this is allocated
* dynamically and must be freed in the driver
*/
chip->dyn_pdata = pdata;
}
if (pdata == NULL) {
dev_dbg(&client->dev, "no platform data\n");
ret = -EINVAL;
goto out_failed;
}
I can not understand the problem. what kind of modification needs in "platform_data"?
anybody please support me.

Answer 1

You need to supply some platform data in the i2c_board_info structure.
From the code you supplied, the structure should be of type struct pca953x_platform_data and
referred to in the platform_data field.
i.e. (SABRE Lite Board)
static struct pca953x_platform_data my_pca953x_pdata = {
.gpio_base = MX6Q_PAD_GPIO_5__I2C3_SCL,
};
static struct i2c_board_info mxc_i2c2_board_info[] __initdata = {
{
I2C_BOARD_INFO("pca953x", 0x21),
.irq = gpio_to_irq(MX6Q_SABRELITE_CAP_TCH_INT1),
.platform_data = &my_pca953x_pdata
},
};

Answer 2

Here is an example for am3517 board and tca6416. platform_data specifies from what GPIO number new GPIO should be counted. For example OMAP_MAX_GPIO_LINES 128, then the first tca6416 GPIO would be 128 + 1 = 129.
static struct pca953x_platform_data sp860_gpio_expander_info_0 = {
.gpio_base = OMAP_MAX_GPIO_LINES,
};
static struct i2c_board_info __initdata am3517evm_i2c2_boardinfo[] = {
{
I2C_BOARD_INFO("tca6416", 0x20),
.platform_data = &sp860_gpio_expander_info_0,
},
};
You can set following parameters in this platform_data structure:
struct pca953x_platform_data {
/* number of the first GPIO */
unsigned gpio_base;
/* initial polarity inversion setting */
uint16_t invert;
/* interrupt base */
int irq_base;
void *context; /* param to setup/teardown */
int (*setup)(struct i2c_client *client,
unsigned gpio, unsigned ngpio,
void *context);
int (*teardown)(struct i2c_client *client,
unsigned gpio, unsigned ngpio,
void *context);
const char *const *names;
};