| Message ID | 1725192519-3867920-3-git-send-email-radhey.shyam.pandey@amd.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | usb: misc: onboard_usb_dev: add Microchip usb5744 SMBus support | expand |
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@amd.com> > --- > 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
> -----Original Message----- > From: Greg KH <gregkh@linuxfoundation.org> > Sent: Tuesday, September 3, 2024 12:10 PM > To: Pandey, Radhey Shyam <radhey.shyam.pandey@amd.com> > Cc: mka@chromium.org; sakari.ailus@linux.intel.com; > wentong.wu@intel.com; javier.carrasco@wolfvision.net; > stefan.eichenberger@toradex.com; francesco.dolcini@toradex.com; > jbrunet@baylibre.com; macpaul.lin@mediatek.com; > frieder.schrempf@kontron.de; linux-usb@vger.kernel.org; linux- > kernel@vger.kernel.org; git (AMD-Xilinx) <git@amd.com> > Subject: Re: [PATCH v4 2/2] usb: misc: onboard_usb_dev: add Microchip > usb5744 SMBus programming support > > 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@amd.com> > > --- > > 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?) In onboard driver I am calling onboard_dev_5744_i2c_init() by detecting at runtime if "i2c-bus" phandle is present. But the problem is i2c_smbus_* APIs are declared and defined only for #if IS_ENABLED(CONFIG_I2C). Do you think we should implement no-ops for I2C smbus APIs (in linux/i2c.h)? OR a simpler alternative would be to add #if IS_ENABLED(CONFIG_I2C) check in the onboard_*_i2c_init() and return error code if CONFIG_I2C is not defined ? Did a grep on #if IS_ENABLED(CONFIG_I2C) and find couple of drivers using this approach. Thanks, Radhey
On Tue, Sep 03, 2024 at 07:19:09AM +0000, Pandey, Radhey Shyam wrote: > > -----Original Message----- > > From: Greg KH <gregkh@linuxfoundation.org> > > Sent: Tuesday, September 3, 2024 12:10 PM > > To: Pandey, Radhey Shyam <radhey.shyam.pandey@amd.com> > > Cc: mka@chromium.org; sakari.ailus@linux.intel.com; > > wentong.wu@intel.com; javier.carrasco@wolfvision.net; > > stefan.eichenberger@toradex.com; francesco.dolcini@toradex.com; > > jbrunet@baylibre.com; macpaul.lin@mediatek.com; > > frieder.schrempf@kontron.de; linux-usb@vger.kernel.org; linux- > > kernel@vger.kernel.org; git (AMD-Xilinx) <git@amd.com> > > Subject: Re: [PATCH v4 2/2] usb: misc: onboard_usb_dev: add Microchip > > usb5744 SMBus programming support > > > > 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@amd.com> > > > --- > > > 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?) > > In onboard driver I am calling onboard_dev_5744_i2c_init() by > detecting at runtime if "i2c-bus" phandle is present. But the > problem is i2c_smbus_* APIs are declared and defined only for > #if IS_ENABLED(CONFIG_I2C). > > Do you think we should implement no-ops for I2C smbus APIs > (in linux/i2c.h)? OR a simpler alternative would be to > add #if IS_ENABLED(CONFIG_I2C) check in the onboard_*_i2c_init() > and return error code if CONFIG_I2C is not defined ? > Did a grep on #if IS_ENABLED(CONFIG_I2C) and find couple of > drivers using this approach. Yes, try doing this with simpler way first and see what that looks like. thanks, greg k-h
El Tue, Sep 03, 2024 at 07:19:09AM GMT Pandey, Radhey Shyam ha dit: > > -----Original Message----- > > From: Greg KH <gregkh@linuxfoundation.org> > > Sent: Tuesday, September 3, 2024 12:10 PM > > To: Pandey, Radhey Shyam <radhey.shyam.pandey@amd.com> > > Cc: mka@chromium.org; sakari.ailus@linux.intel.com; > > wentong.wu@intel.com; javier.carrasco@wolfvision.net; > > stefan.eichenberger@toradex.com; francesco.dolcini@toradex.com; > > jbrunet@baylibre.com; macpaul.lin@mediatek.com; > > frieder.schrempf@kontron.de; linux-usb@vger.kernel.org; linux- > > kernel@vger.kernel.org; git (AMD-Xilinx) <git@amd.com> > > Subject: Re: [PATCH v4 2/2] usb: misc: onboard_usb_dev: add Microchip > > usb5744 SMBus programming support > > > > 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@amd.com> > > > --- > > > 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?) > > In onboard driver I am calling onboard_dev_5744_i2c_init() by > detecting at runtime if "i2c-bus" phandle is present. But the > problem is i2c_smbus_* APIs are declared and defined only for > #if IS_ENABLED(CONFIG_I2C). > > Do you think we should implement no-ops for I2C smbus APIs > (in linux/i2c.h)? OR a simpler alternative would be to > add #if IS_ENABLED(CONFIG_I2C) check in the onboard_*_i2c_init() > and return error code if CONFIG_I2C is not defined ? > Did a grep on #if IS_ENABLED(CONFIG_I2C) and find couple of > drivers using this approach. I expect using IS_ENABLED(CONFIG_I2C) would cause issues when USB_ONBOARD_DEV=y and CONFIG_I2C=m. Another option could be adding an option USB_ONBOARD_DEV_USB5744 (or similar) and make that dependent on CONFIG_I2C.
El Sun, Sep 01, 2024 at 05:38:39PM GMT Radhey Shyam Pandey ha dit: > 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@amd.com> > --- > 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 > help > Say Y here if you want to support discrete onboard USB devices > that don't require an additional control bus for initialization, > diff --git a/drivers/usb/misc/onboard_usb_dev.c b/drivers/usb/misc/onboard_usb_dev.c > index da27c48fc11d..247600015bca 100644 > --- a/drivers/usb/misc/onboard_usb_dev.c > +++ b/drivers/usb/misc/onboard_usb_dev.c > @@ -11,6 +11,7 @@ > #include <linux/err.h> > #include <linux/gpio/consumer.h> > #include <linux/init.h> > +#include <linux/i2c.h> > #include <linux/kernel.h> > #include <linux/list.h> > #include <linux/module.h> > @@ -29,6 +30,17 @@ > > #include "onboard_usb_dev.h" > > +/* USB5744 register offset and mask */ > +#define USB5744_CMD_ATTACH 0xAA > +#define USB5744_CMD_ATTACH_LSB 0x56 > +#define USB5744_CMD_CREG_ACCESS 0x99 > +#define USB5744_CMD_CREG_ACCESS_LSB 0x37 > +#define USB5744_CREG_MEM_ADDR 0x00 > +#define USB5744_CREG_WRITE 0x00 > +#define USB5744_CREG_RUNTIMEFLAGS2 0x41 > +#define USB5744_CREG_RUNTIMEFLAGS2_LSB 0x1D > +#define USB5744_CREG_BYPASS_UDC_SUSPEND BIT(3) > + > static void onboard_dev_attach_usb_driver(struct work_struct *work); > > static struct usb_device_driver onboard_dev_usbdev_driver; > @@ -297,10 +309,46 @@ static void onboard_dev_attach_usb_driver(struct work_struct *work) > pr_err("Failed to attach USB driver: %pe\n", ERR_PTR(err)); > } > > +static int onboard_dev_5744_i2c_init(struct i2c_client *client) > +{ > + struct device *dev = &client->dev; > + int ret; > + > + /* > + * Set BYPASS_UDC_SUSPEND bit to ensure MCU is always enabled > + * and ready to respond to SMBus runtime commands. > + * The command writes 5 bytes to memory and single data byte in nit: s/in/to the/ > + * configuration register. > + */ > + char wr_buf[7] = {USB5744_CREG_MEM_ADDR, 5, > + USB5744_CREG_WRITE, 1, > + USB5744_CREG_RUNTIMEFLAGS2, > + USB5744_CREG_RUNTIMEFLAGS2_LSB, > + USB5744_CREG_BYPASS_UDC_SUSPEND}; > + > + ret = i2c_smbus_write_block_data(client, 0, sizeof(wr_buf), wr_buf); > + if (ret) > + return dev_err_probe(dev, ret, "BYPASS_UDC_SUSPEND bit configuration failed\n"); > + > + ret = i2c_smbus_write_word_data(client, USB5744_CMD_CREG_ACCESS, > + USB5744_CMD_CREG_ACCESS_LSB); > + if (ret) > + return dev_err_probe(dev, ret, "Configuration Register Access Command failed\n"); nit: s/Command/command/ Uppercase for the register name is ok, but command isn't a name. > + > + /* Send SMBus command to boot hub. */ nit: from the code it's obvious that an SMBus command is sent, no need to spell that out. I suggest to change the comment to "Attach/boot the hub". > + ret = i2c_smbus_write_word_data(client, USB5744_CMD_ATTACH, > + USB5744_CMD_ATTACH_LSB); > + if (ret < 0) > + return dev_err_probe(dev, ret, "USB Attach with SMBus command failed\n"); nit: s/.../USB Attach command failed/ > + > + return ret; return 0; > +}
> -----Original Message----- > From: Matthias Kaehlcke <matthias@kaehlcke.net> > Sent: Wednesday, September 18, 2024 10:37 PM > To: Pandey, Radhey Shyam <radhey.shyam.pandey@amd.com> > Cc: Greg KH <gregkh@linuxfoundation.org>; mka@chromium.org; > sakari.ailus@linux.intel.com; wentong.wu@intel.com; > javier.carrasco@wolfvision.net; stefan.eichenberger@toradex.com; > francesco.dolcini@toradex.com; jbrunet@baylibre.com; macpaul.lin@mediatek.com; > frieder.schrempf@kontron.de; linux-usb@vger.kernel.org; linux- > kernel@vger.kernel.org; git (AMD-Xilinx) <git@amd.com> > Subject: Re: [PATCH v4 2/2] usb: misc: onboard_usb_dev: add Microchip usb5744 > SMBus programming support > > El Tue, Sep 03, 2024 at 07:19:09AM GMT Pandey, Radhey Shyam ha dit: > > > > -----Original Message----- > > > From: Greg KH <gregkh@linuxfoundation.org> > > > Sent: Tuesday, September 3, 2024 12:10 PM > > > To: Pandey, Radhey Shyam <radhey.shyam.pandey@amd.com> > > > Cc: mka@chromium.org; sakari.ailus@linux.intel.com; > > > wentong.wu@intel.com; javier.carrasco@wolfvision.net; > > > stefan.eichenberger@toradex.com; francesco.dolcini@toradex.com; > > > jbrunet@baylibre.com; macpaul.lin@mediatek.com; > > > frieder.schrempf@kontron.de; linux-usb@vger.kernel.org; linux- > > > kernel@vger.kernel.org; git (AMD-Xilinx) <git@amd.com> > > > Subject: Re: [PATCH v4 2/2] usb: misc: onboard_usb_dev: add > > > Microchip > > > usb5744 SMBus programming support > > > > > > 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@amd.com> > > > > --- > > > > 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?) > > > > In onboard driver I am calling onboard_dev_5744_i2c_init() by > > detecting at runtime if "i2c-bus" phandle is present. But the problem > > is i2c_smbus_* APIs are declared and defined only for #if > > IS_ENABLED(CONFIG_I2C). > > > > Do you think we should implement no-ops for I2C smbus APIs (in > > linux/i2c.h)? OR a simpler alternative would be to add #if > > IS_ENABLED(CONFIG_I2C) check in the onboard_*_i2c_init() and return > > error code if CONFIG_I2C is not defined ? > > Did a grep on #if IS_ENABLED(CONFIG_I2C) and find couple of drivers > > using this approach. > > I expect using IS_ENABLED(CONFIG_I2C) would cause issues when > USB_ONBOARD_DEV=y and CONFIG_I2C=m. > > Another option could be adding an option USB_ONBOARD_DEV_USB5744 (or > similar) and make that dependent on CONFIG_I2C. Yes, theoretically this can also be valid build configuration. I assume your suggestion is something like below: +config USB_ONBOARD_DEV_USB5744 + tristate "Onboard USB Microchip usb5744 hub with SMBus support" + depends on USB_ONBOARD_DEV && I2C + help + Say Y here if you want to support onboard USB Microchip usb5744 + hub that requires SMBus initialization. diff --git a/drivers/usb/misc/onboard_usb_dev.c b/drivers/usb/misc/onboard_usb_dev.c index 560591e02d6a..6169780a18d9 100644 --- a/drivers/usb/misc/onboard_usb_dev.c +++ b/drivers/usb/misc/onboard_usb_dev.c @@ -311,7 +311,7 @@ static void onboard_dev_attach_usb_driver(struct work_struct *work) static int onboard_dev_5744_i2c_init(struct i2c_client *client) { -#if IS_ENABLED(CONFIG_I2C) +#if IS_ENABLED(CONFIG_USB_ONBOARD_DEV_USB5744) <*> Onboard USB device support <M> Onboard USB Microchip usb5744 hub with SMBus support Here IS_ENABLED will report true either onboard usb5744 is module/in-built. So, we hit same issue as USB_ONBOARD_DEV=y and I2C=m. FYI, as this series merged to -next based on our discussion I will send another series fixing this particular build configuration and other coding style changes based on v4 review comments. Thanks, Radhey
El Wed, Sep 18, 2024 at 07:22:42PM GMT Pandey, Radhey Shyam ha dit: > > -----Original Message----- > > From: Matthias Kaehlcke <matthias@kaehlcke.net> > > Sent: Wednesday, September 18, 2024 10:37 PM > > To: Pandey, Radhey Shyam <radhey.shyam.pandey@amd.com> > > Cc: Greg KH <gregkh@linuxfoundation.org>; mka@chromium.org; > > sakari.ailus@linux.intel.com; wentong.wu@intel.com; > > javier.carrasco@wolfvision.net; stefan.eichenberger@toradex.com; > > francesco.dolcini@toradex.com; jbrunet@baylibre.com; macpaul.lin@mediatek.com; > > frieder.schrempf@kontron.de; linux-usb@vger.kernel.org; linux- > > kernel@vger.kernel.org; git (AMD-Xilinx) <git@amd.com> > > Subject: Re: [PATCH v4 2/2] usb: misc: onboard_usb_dev: add Microchip usb5744 > > SMBus programming support > > > > El Tue, Sep 03, 2024 at 07:19:09AM GMT Pandey, Radhey Shyam ha dit: > > > > > > -----Original Message----- > > > > From: Greg KH <gregkh@linuxfoundation.org> > > > > Sent: Tuesday, September 3, 2024 12:10 PM > > > > To: Pandey, Radhey Shyam <radhey.shyam.pandey@amd.com> > > > > Cc: mka@chromium.org; sakari.ailus@linux.intel.com; > > > > wentong.wu@intel.com; javier.carrasco@wolfvision.net; > > > > stefan.eichenberger@toradex.com; francesco.dolcini@toradex.com; > > > > jbrunet@baylibre.com; macpaul.lin@mediatek.com; > > > > frieder.schrempf@kontron.de; linux-usb@vger.kernel.org; linux- > > > > kernel@vger.kernel.org; git (AMD-Xilinx) <git@amd.com> > > > > Subject: Re: [PATCH v4 2/2] usb: misc: onboard_usb_dev: add > > > > Microchip > > > > usb5744 SMBus programming support > > > > > > > > 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@amd.com> > > > > > --- > > > > > 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?) > > > > > > In onboard driver I am calling onboard_dev_5744_i2c_init() by > > > detecting at runtime if "i2c-bus" phandle is present. But the problem > > > is i2c_smbus_* APIs are declared and defined only for #if > > > IS_ENABLED(CONFIG_I2C). > > > > > > Do you think we should implement no-ops for I2C smbus APIs (in > > > linux/i2c.h)? OR a simpler alternative would be to add #if > > > IS_ENABLED(CONFIG_I2C) check in the onboard_*_i2c_init() and return > > > error code if CONFIG_I2C is not defined ? > > > Did a grep on #if IS_ENABLED(CONFIG_I2C) and find couple of drivers > > > using this approach. > > > > I expect using IS_ENABLED(CONFIG_I2C) would cause issues when > > USB_ONBOARD_DEV=y and CONFIG_I2C=m. > > > > Another option could be adding an option USB_ONBOARD_DEV_USB5744 (or > > similar) and make that dependent on CONFIG_I2C. > > Yes, theoretically this can also be valid build configuration. > > I assume your suggestion is something like below: > > +config USB_ONBOARD_DEV_USB5744 > + tristate "Onboard USB Microchip usb5744 hub with SMBus support" > + depends on USB_ONBOARD_DEV && I2C > + help > + Say Y here if you want to support onboard USB Microchip usb5744 > + hub that requires SMBus initialization. > diff --git a/drivers/usb/misc/onboard_usb_dev.c b/drivers/usb/misc/onboard_usb_dev.c > index 560591e02d6a..6169780a18d9 100644 > --- a/drivers/usb/misc/onboard_usb_dev.c > +++ b/drivers/usb/misc/onboard_usb_dev.c > @@ -311,7 +311,7 @@ static void onboard_dev_attach_usb_driver(struct work_struct *work) > > static int onboard_dev_5744_i2c_init(struct i2c_client *client) > { > -#if IS_ENABLED(CONFIG_I2C) > +#if IS_ENABLED(CONFIG_USB_ONBOARD_DEV_USB5744) > > > <*> Onboard USB device support > <M> Onboard USB Microchip usb5744 hub with SMBus support Yes, something along these lines > Here IS_ENABLED will report true either onboard usb5744 is module/in-built. > > So, we hit same issue as USB_ONBOARD_DEV=y and I2C=m. Right, the problem is that USB_ONBOARD_DEV_USB5744 isn't an actual module, otherwise Kconfig would prevent it from being builtin when I2C=m. I think CONFIG_USB_ONBOARD_DEV_USB5744 should be boolean. It should only be selectable when CONFIG_I2C=y or CONFIG_USB_ONBOARD_DEV=m and CONFIG_I2C=m. That can be achieved with: depends on USB_ONBOARD_DEV && (I2C=y || I2C=USB_ONBOARD_DEV) or depends on (USB_ONBOARD_DEV && I2C=y) || (USB_ONBOARD_DEV=m && I2C=m) This doesn't look particularly elegant but should do the trick. > FYI, as this series merged to -next based on our discussion Ah, thanks for letting me know. Sorry for the delayed reply, I went through an intercontinental relocation and it took some time to get things settled. > I will send another series fixing this particular build configuration and > other coding style changes based on v4 review comments. Thanks!
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 help Say Y here if you want to support discrete onboard USB devices that don't require an additional control bus for initialization, diff --git a/drivers/usb/misc/onboard_usb_dev.c b/drivers/usb/misc/onboard_usb_dev.c index da27c48fc11d..247600015bca 100644 --- a/drivers/usb/misc/onboard_usb_dev.c +++ b/drivers/usb/misc/onboard_usb_dev.c @@ -11,6 +11,7 @@ #include <linux/err.h> #include <linux/gpio/consumer.h> #include <linux/init.h> +#include <linux/i2c.h> #include <linux/kernel.h> #include <linux/list.h> #include <linux/module.h> @@ -29,6 +30,17 @@ #include "onboard_usb_dev.h" +/* USB5744 register offset and mask */ +#define USB5744_CMD_ATTACH 0xAA +#define USB5744_CMD_ATTACH_LSB 0x56 +#define USB5744_CMD_CREG_ACCESS 0x99 +#define USB5744_CMD_CREG_ACCESS_LSB 0x37 +#define USB5744_CREG_MEM_ADDR 0x00 +#define USB5744_CREG_WRITE 0x00 +#define USB5744_CREG_RUNTIMEFLAGS2 0x41 +#define USB5744_CREG_RUNTIMEFLAGS2_LSB 0x1D +#define USB5744_CREG_BYPASS_UDC_SUSPEND BIT(3) + static void onboard_dev_attach_usb_driver(struct work_struct *work); static struct usb_device_driver onboard_dev_usbdev_driver; @@ -297,10 +309,46 @@ static void onboard_dev_attach_usb_driver(struct work_struct *work) pr_err("Failed to attach USB driver: %pe\n", ERR_PTR(err)); } +static int onboard_dev_5744_i2c_init(struct i2c_client *client) +{ + struct device *dev = &client->dev; + int ret; + + /* + * Set BYPASS_UDC_SUSPEND bit to ensure MCU is always enabled + * and ready to respond to SMBus runtime commands. + * The command writes 5 bytes to memory and single data byte in + * configuration register. + */ + char wr_buf[7] = {USB5744_CREG_MEM_ADDR, 5, + USB5744_CREG_WRITE, 1, + USB5744_CREG_RUNTIMEFLAGS2, + USB5744_CREG_RUNTIMEFLAGS2_LSB, + USB5744_CREG_BYPASS_UDC_SUSPEND}; + + ret = i2c_smbus_write_block_data(client, 0, sizeof(wr_buf), wr_buf); + if (ret) + return dev_err_probe(dev, ret, "BYPASS_UDC_SUSPEND bit configuration failed\n"); + + ret = i2c_smbus_write_word_data(client, USB5744_CMD_CREG_ACCESS, + USB5744_CMD_CREG_ACCESS_LSB); + if (ret) + return dev_err_probe(dev, ret, "Configuration Register Access Command failed\n"); + + /* Send SMBus command to boot hub. */ + ret = i2c_smbus_write_word_data(client, USB5744_CMD_ATTACH, + USB5744_CMD_ATTACH_LSB); + if (ret < 0) + return dev_err_probe(dev, ret, "USB Attach with SMBus command failed\n"); + + return ret; +} + static int onboard_dev_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct onboard_dev *onboard_dev; + struct device_node *i2c_node; int err; onboard_dev = devm_kzalloc(dev, sizeof(*onboard_dev), GFP_KERNEL); @@ -340,6 +388,27 @@ static int onboard_dev_probe(struct platform_device *pdev) if (err) return err; + i2c_node = of_parse_phandle(pdev->dev.of_node, "i2c-bus", 0); + if (i2c_node) { + struct i2c_client *client; + + client = of_find_i2c_device_by_node(i2c_node); + of_node_put(i2c_node); + + if (!client) { + err = -EPROBE_DEFER; + goto err_power_off; + } + + if (of_device_is_compatible(pdev->dev.of_node, "usb424,2744") || + of_device_is_compatible(pdev->dev.of_node, "usb424,5744")) + err = onboard_dev_5744_i2c_init(client); + + put_device(&client->dev); + if (err < 0) + goto err_power_off; + } + /* * The USB driver might have been detached from the USB devices by * onboard_dev_remove() (e.g. through an 'unbind' by userspace), @@ -351,6 +420,10 @@ static int onboard_dev_probe(struct platform_device *pdev) schedule_work(&attach_usb_driver_work); return 0; + +err_power_off: + onboard_dev_power_off(onboard_dev); + return err; } static void onboard_dev_remove(struct platform_device *pdev)
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@amd.com> --- 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(-)