Add I2C with PCA9665

Hi,

I am using the PCA9665 controller in my custom board because the internal I2C controller of my processor (AT91RM9200) is not robust. The following are my configs:

Hardware:

D0 - D7 --> D0 - D7
Write strobe --> NWR0/NWE/CFWE
Read strobe --> NRD/NOE/CFOE
Chip Enable --> NCS2
A0 --> A0/NBS0
A1 --> A1
Interrupt request --> PB29/IRQ0
Reset --> PB27

Software:

static struct resource i2c_resources[] = {
    [0] = {
        .start    = AT91_CHIPSELECT_2,    /* 0x30000000 */
        .end    = AT91_CHIPSELECT_2 + SZ_16K - 1,
        .flags    = IORESOURCE_MEM,
    },
    [1] = {
        .start    = AT91RM9200_ID_IRQ0,
        .end    = AT91RM9200_ID_IRQ0,
        .flags    = IORESOURCE_IRQ,
    },
};

static struct i2c_pca9564_pf_platform_data pca9665_platform_data = {
    .gpio        = AT91_PIN_PB27,
    .i2c_clock_speed= 0,
    .timeout    = HZ,        /* timeout in jiffies */
};

static struct platform_device pca9665_twi_device = {
    .name        = "i2c-pca-platform",
    .id        = -1,
    .dev        = {
                .platform_data = &pca9665_platform_data,
            },
    .num_resources    = ARRAY_SIZE(i2c_resources),
    .resource    = i2c_resources,
};

void __init at91_add_device_i2c(struct i2c_board_info *devices, int nr_devices)

{
    at91_set_A_periph(AT91_PIN_PB29, 1);        /* IRQ0 interrupt pin */
    i2c_register_board_info(0, devices, nr_devices);
    platform_device_register(&pca9665_twi_device);
}

But the board detects the wrong external I2C controller (PCA9564):

# dmesg | grep PCA
PCA9564/PCA9665 at 0x30000000: PCA9564 detected.
PCA9564/PCA9665 at 0x30000000: Choosing the clock frequency based on index is deprecated. Use the nominal frequency.
PCA9564/PCA9665 at 0x30000000: Clock frequency is 330kHz
PCA9564/PCA9665 at 0x30000000 registered.

And, the i2c controller is not functional at all. The i2cdetect command of i2c-tools package from lm-sensors, does not detect any devices on my i2c bus, while there must be two i2c devices (a RTC and a temperature sensor) on my board. There is no i2c clock or data signal either on the bus using the oscilloscope probe.

How can I fix this so the board detects the functional and correct controller (PCA9665)?

Best regards,
Elyas Razzaghi

Unless reading 0x30000000 does not return something like 0xf8, you have a problem with mapping in the register range. Make sure the, 8 bit bus width works.

Regards,

Wolfram

Hi,

Thanks a lot Wolfram for the hint. I have added the mapping configs:

#if defined (CONFIG_I2C_PCA_PLATFORM) || defined(CONFIG_I2C_ALGOPCA)

static struct resource i2c_resources[] = {
    [0] = {
        .start    = AT91_CHIPSELECT_2,    /* 0x30000000 */
        .end    = AT91_CHIPSELECT_2 + SZ_16K - 1,
        .flags    = IORESOURCE_MEM | IORESOURCE_MEM_8BIT,

    },
    [1] = {
        .start    = AT91RM9200_ID_IRQ0,
        .end    = AT91RM9200_ID_IRQ0,
        .flags    = IORESOURCE_IRQ,
    },
};

static struct i2c_pca9564_pf_platform_data pca9665_platform_data = {
    .gpio        = AT91_PIN_PB27,
    .i2c_clock_speed= 400000,

    .timeout    = HZ,        /* timeout in jiffies */
};

static struct platform_device pca9665_twi_device = {
    .name        = "i2c-pca-platform",
    .id        = -1,
    .dev        = {
                .platform_data = &pca9665_platform_data,
            },
    .num_resources    = ARRAY_SIZE(i2c_resources),
    .resource    = i2c_resources,
};

static struct i2c_board_info __initdata ek_i2c_devices[] = {
    {
        I2C_BOARD_INFO("lm75", 0x48),
    },
    {
        I2C_BOARD_INFO("pcf8523", 0x68),
    },
};

void __init at91_add_device_i2c_pca(struct i2c_board_info *devices, int nr_devices)

{
    at91_set_A_periph(AT91_PIN_PB29, 1);        /* IRQ0 interrupt pin */

    /* Initialization of the Static Memory Controller for Chip Select 2 */
    at91_ramc_write(0, AT91_SMC_CSR(2), AT91_SMC_ACSS_STD
        | AT91_SMC_DBW_8    /* 8 bit */
        | AT91_SMC_WSEN        /* Wait State Enable */
    );

    i2c_register_board_info(0, devices, nr_devices);
    platform_device_register(&pca9665_twi_device);
}

#endif

And now the correct controller is detected:

# dmesg | grep PCA
PCA9564/PCA9665 at 0x30000000: PCA9665 detected.
PCA9564/PCA9665 at 0x30000000: Clock frequency is 400000Hz
PCA9564/PCA9665 at 0x30000000 registered.

The i2c devices are also detected:

# i2cdetect -y 0
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

Best regards,
Elyas