This commit adds a new lower-half driver implementation for I2C bit-bang
that uses IO expander pins as the GPIO backend, enabling I2C bit-bang
functionality on systems where direct GPIO access is not available or
when I2C needs to be implemented using IO expander pins.
Background:
The existing I2C bit-bang driver (i2c_bitbang.c) provides a generic
upper-half implementation that requires a platform-specific lower-half
to control the SDA and SCL GPIO lines. Previously, each platform had to
implement its own lower-half using direct GPIO access.
Usage Example:
FAR struct ioexpander_dev_s *ioe = /* get IO expander */;
FAR struct i2c_master_s *i2c;
/* Initialize I2C bit-bang using IO expander pins 10 (SCL) and 11 (SDA) */
i2c = i2c_bitbang_ioexpander_initialize(ioe, 10, 11, 0);
if (i2c)
{
/* Use i2c master device normally */
}
Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>
This commit does two things:
1. First, it reorganizes the driver Kconfig files so that each is self contained. Before, a part of the driver configuration was in drivers/Kconfig and the rest was in in drivers/xyz/Konfig. Now, all of the driver configuration is consolitated in the latter.
2. Second, this commit correct numerous serious errors introduced in a previous reorganization of the driver Kconfig files. This was first noted by Nicholas Chin in PR270 for the case of the drivers/i2c/Kconfig but some examination indicates that the error was introduced into several other Kconfig files as well.
The nature of the introduced error was basically this:
- Nothing must intervene between the menuconfig selection and the following conditional configuration otpions.
- A previous PR erroneously introduced unconditional options between the menuconfig and the following confditional logic, thus corrupting the driver menus.
This error was easy to make because the driver Kconfig files were not well modularized. Making them fully self-contained should eliminate this kind of error in the future.
Feature pca9540bdp i2cmultiplexer
* Implement common i2c multiplexer abstraction to be reused by i2c multiplexer devices. Provide common interface with transfer and reset calls to set up virtual i2c busses.
* Remove i2cmux_lower_half.c and headers, will be implemented by each mux driver
* Implement PCA9540BDP I2C multiplexer lower half which uses the common i2c mux abstraction
* Remove application interface and implement common i2c functions
* Remove application interface from pca driver and implement common i2c functions directly in the pca driver
* Use i2cerr
Approved-by: Gregory Nutt <gnutt@nuttx.org>
dongjiuzhu1
Shoukui Zhang
Nathan Hartman
Alan C. Assis
Petro Karashchenko
Matias N
Gregory Nutt
Xiang Xiao
Giorgio Groß