On Sun, Sep 01, 2024 at 05:38:39PM +0530, Radhey Shyam Pandey wrote: > usb5744 supports SMBus Configuration and it may be configured via the > SMBus slave interface during the hub start-up configuration stage. > > To program it driver uses i2c-bus phandle (added in commit '02be19e914b8 > dt-bindings: usb: Add support for Microchip usb5744 hub controller') to > get i2c client device and then based on usb5744 compatible check calls > usb5744 i2c default initialization sequence. > > Apart from the USB command attach, prevent the hub from suspend. > when the USB Attach with SMBus (0xAA56) command is issued to the hub, > the hub is getting enumerated and then it puts in a suspend mode. > This causes the hub to NAK any SMBus access made by the SMBus Master > during this period and not able to see the hub's slave address while > running the "i2c probe" command. > > Prevent the MCU from putting the HUB in suspend mode through register > write. The BYPASS_UDC_SUSPEND bit (Bit 3) of the RuntimeFlags2 > register at address 0x411D controls this aspect of the hub. The > BYPASS_UDC_SUSPEND bit in register 0x411Dh must be set to ensure that the > MCU is always enabled and ready to respond to SMBus runtime commands. > This register needs to be written before the USB attach command is issued. > > The byte sequence is as follows: > Slave addr: 0x2d 00 00 05 00 01 41 1D 08 > Slave addr: 0x2d 99 37 00 > Slave addr: 0x2d AA 56 00 > > Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxx> > --- > Changes for v4: > - Fix error: implicit declaration of function 'i2c_smbus_*' APIs by > introducing a dependency on I2C_CONFIG. This error is reported > by kernel test on v3 series and usb:usb-testing 20/25 branch. > https://lore.kernel.org/all/2024082503-uncoated-chaperone-7f70@gregkh > > Changes for v3: > - Add comment for UDC suspend sequence. > - Drop USB5744_CREG_MEM_NBYTES and USB5744_CREG_NBYTES and replace > it with literal + comment. > - Move microchip defines to source file. > > Changes for v2: > - Move power on reset delay to separate patch. > - Switch to compatible based check for calling usb5755 > onboard_dev_5744_i2c_init(). This is done to make > onboard_dev_5744_i2c_init() as static. > - Fix subsystem "usb: misc: onboard_usb_dev:..." > - Use #define for different register bits instead of magic values. > - Use err_power_off label name. > - Modified commit description to be in sync with v2 changes. > --- > drivers/usb/misc/Kconfig | 2 +- > drivers/usb/misc/onboard_usb_dev.c | 73 ++++++++++++++++++++++++++++++ > 2 files changed, 74 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig > index 50b86d531701..cb5e47d439ab 100644 > --- a/drivers/usb/misc/Kconfig > +++ b/drivers/usb/misc/Kconfig > @@ -318,7 +318,7 @@ config BRCM_USB_PINMAP > > config USB_ONBOARD_DEV > tristate "Onboard USB device support" > - depends on OF > + depends on OF && I2C This feels wrong. While a single device that this driver supports might need i2c, not all of the devices do, so you have the potential to drag in a bunch of code here for devices that do not have/need i2c at all, right? Any way to "split this out" into a smaller chunk? Or better yet, just detect at runtime if you need/want to call those i2c functions (and they should have no-ops for when i2c is not enabled, right?) thanks, greg k-h
