Hi David,
I think you figure out Gustavo's mistake.
Gustavo, all you need to do is use the existing driver. In your code
you was trying to implement a low level driver to communicate with
your PCF8575. You don't need to do it.
Unfortunately there is not much boards examples using IOEXPANDER (shame on us).
But I think Mateusz (raiden00) created one here:
boards/arm/nrf52/thingy52/src/nrf52_sx1509.c
Just look this example and you will figure out everything.
Basically:
struct pcf8575_config_s g_pcf8575_cfg
{
.address = 0x71; /* the I2C address returned by i2ctool */
.frequency = 100000;
};
...
int stm32_pcf8575_initialize(void)
{
struct i2c_master_s *i2c = NULL;
struct ioexpander_dev_s *ioe = NULL;
int ret = OK;
i2c = stm32_i2c_register(I2C_BUS); /* I2C_BUS is your I2Cx bus
number (0, 1, etc) */
ioe = pcf8575_initialize(i2c, &g_pcf8575_cfg);
...
}
BR,
Alan
On 10/5/23, David S. Alessio <[email protected]> wrote:
> Hi, Gustavo,
>
> You might consider using the I2C IO expander driver I wrote some time ago to
> manage a multi-tiered tree of I2C bus expanders.
>
> The advantages are:
> * I2C sub buses are transparently available to application space through
> /dev/i2c*
> * transparently manages hierarch of I2C bus expanders
> * downstream I2C device drivers go through the I2C character driver (pro
> and con)
>
> The disadvantages are:
> * I2C drivers need to use the I2C character driver
> * many I2C HW drivers don’t properly handle multiple command packets in
> I2C_TRANSFER()
>
> Example: let’s say we have an 4-port I2C switch PCA9545A attached to
> /dev/i2c1 using an STM32F407 MCU. The board initialization would be:
>
>
> i2c = stm32_i2c_register(1);
>
> /*
> * support for I2C bus epander
> * /dev/i2c1.0 -- /dev/i2c1.3
> */
> ret = i2c_vbus_initialize("/dev/i2c1", 0x70, I2C_VBUS_PCA9545, 0x0f, 0,
> NULL);
> if (ret != OK)
> {
> syslog(LOG_ERR, "ERROR: Failed to initialize i2c_vbus %#x: %d\n",
> 0x70, ret);
> }
>
> Now the sub bus I2C segments are transparently available as /dev/i2c1.0
> through /dev/i2c1.3.
>
> You can add a second PCA9545A, let’s say connected to port 2 (/dev/i2c1.2)
> of the first PCA9545A. It would be registered as:
>
> ret = i2c_vbus_initialize("/dev/i2c1.2", 0x71, I2C_VBUS_PCA9545, 0x0f,
> 0,
> NULL);
>
> and its ports would be addressable as /dev/i2c1.2.0 through /dev/i2c1.2.3.
>
> Let me know if this is something of interest to you, I’ll help you get it
> working...
>
> Cheers,
> -david
>
>
>
>> On Oct 4, 2023, at 7:36 PM, Gregory Nutt <[email protected]> wrote:
>>
>>
>> On 10/4/2023 8:02 PM, Gustavo Soares wrote:
>>> Hi Greg!
>>>
>>> Yes, if I use #include <nuttx/ioexpander/pcf8575.h> this problem is
>>> solved, but then the code loses the reference to that specific struct
>>> causing another error.
>>>
>>> And how exactly "the file does not exist"? I can open it and it is at the
>>> nuttx repo, I shared it's link.
>> Because the compiler keeps a list of paths that it will include files
>> from. It will NOT include files from drivers/ioexpander because that is
>> not in that include path list. So "the file does not exists" in any
>> directory in the list of include paths. You could hack up the build
>> system (but no PRs for that please)or you could just copy the header file
>> (a lot easier). But you cannot include it from drivers/ioexpander. Since
>> this is necessarily throw-away code, the easier solution is recommended.
>
>
