diff mbox series

[v6,1/4] mfd: ch341: add core driver for the WCH CH341 in I2C/SPI/GPIO mode

Message ID 20220616013747.126051-2-frank@zago.net
State New
Headers show
Series add driver for the WCH CH341 in I2C/GPIO mode | expand

Commit Message

Frank Zago June 16, 2022, 1:37 a.m. UTC
The CH341 is a multifunction chip, presenting 3 different USB PID. One
of these functions is for I2C/SPI/GPIO. This new set of drivers will
manage I2C and GPIO.

Signed-off-by: frank zago <frank@zago.net>
---
 MAINTAINERS               |  7 +++
 drivers/mfd/Kconfig       | 10 +++++
 drivers/mfd/Makefile      |  1 +
 drivers/mfd/ch341-core.c  | 90 +++++++++++++++++++++++++++++++++++++++
 include/linux/mfd/ch341.h | 18 ++++++++
 5 files changed, 126 insertions(+)
 create mode 100644 drivers/mfd/ch341-core.c
 create mode 100644 include/linux/mfd/ch341.h

Comments

Lee Jones June 27, 2022, 2:04 p.m. UTC | #1
USB review please.

> The CH341 is a multifunction chip, presenting 3 different USB PID. One
> 
> of these functions is for I2C/SPI/GPIO. This new set of drivers will
> manage I2C and GPIO.
> 
> Signed-off-by: frank zago <frank@zago.net>
> ---
>  MAINTAINERS               |  7 +++
>  drivers/mfd/Kconfig       | 10 +++++
>  drivers/mfd/Makefile      |  1 +
>  drivers/mfd/ch341-core.c  | 90 +++++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/ch341.h | 18 ++++++++
>  5 files changed, 126 insertions(+)
>  create mode 100644 drivers/mfd/ch341-core.c
>  create mode 100644 include/linux/mfd/ch341.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 43d3d07afccd..628eeaa9bf68 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -21475,6 +21475,13 @@ M:	David Härdeman <david@hardeman.nu>
>  S:	Maintained
>  F:	drivers/media/rc/winbond-cir.c
>  
> +WINCHIPHEAD CH341 I2C/GPIO MFD DRIVER
> +M:	Frank Zago <frank@zago.net>
> +L:	linux-usb@vger.kernel.org
> +S:	Maintained
> +F:	drivers/mfd/ch341-core.c
> +F:	include/linux/mfd/ch341.h
> +
>  WINSYSTEMS EBC-C384 WATCHDOG DRIVER
>  M:	William Breathitt Gray <vilhelm.gray@gmail.com>
>  L:	linux-watchdog@vger.kernel.org
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 3b59456f5545..893acc821a42 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -1784,6 +1784,16 @@ config MFD_LOCHNAGAR
>  	help
>  	  Support for Cirrus Logic Lochnagar audio development board.
>  
> +config MFD_CH341
> +	tristate "WinChipHead CH341 in I2C/SPI/GPIO mode"
> +	depends on USB
> +	help
> +	  If you say yes to this option, support for the CH341 series
> +	  of chips, running in I2C/SPI/GPIO mode will be included.
> +
> +	  This driver can also be built as a module.  If so, the
> +	  module will be called ch341-core.
> +
>  config MFD_ARIZONA
>  	select REGMAP
>  	select REGMAP_IRQ
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 858cacf659d6..fd615ab3929f 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -13,6 +13,7 @@ obj-$(CONFIG_MFD_ASIC3)		+= asic3.o tmio_core.o
>  obj-$(CONFIG_ARCH_BCM2835)	+= bcm2835-pm.o
>  obj-$(CONFIG_MFD_BCM590XX)	+= bcm590xx.o
>  obj-$(CONFIG_MFD_BD9571MWV)	+= bd9571mwv.o
> +obj-$(CONFIG_MFD_CH341)		+= ch341-core.o
>  obj-$(CONFIG_MFD_CROS_EC_DEV)	+= cros_ec_dev.o
>  obj-$(CONFIG_MFD_ENE_KB3930)	+= ene-kb3930.o
>  obj-$(CONFIG_MFD_EXYNOS_LPASS)	+= exynos-lpass.o
> diff --git a/drivers/mfd/ch341-core.c b/drivers/mfd/ch341-core.c
> new file mode 100644
> index 000000000000..f08a67dd6074
> --- /dev/null
> +++ b/drivers/mfd/ch341-core.c
> @@ -0,0 +1,90 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Core driver for the CH341A, CH341B and CH341T in I2C/SPI/GPIO
> + * mode. There are cell drivers available for I2C and GPIO. SPI is not
> + * yet supported.
> + *
> + * Copyright 2022, Frank Zago
> + * Copyright (c) 2017 Gunar Schorcht (gunar@schorcht.net)
> + * Copyright (c) 2016 Tse Lun Bien
> + * Copyright (c) 2014 Marco Gittler
> + * Copyright (c) 2006-2007 Till Harbaum (Till@Harbaum.org)
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/mfd/ch341.h>
> +#include <linux/mfd/core.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/usb.h>
> +
> +static const struct mfd_cell ch341_devs[] = {
> +	{
> +		.name = "ch341-gpio",
> +	},
> +	{
> +		.name = "ch341-i2c",
> +	},
> +};
> +
> +static int ch341_usb_probe(struct usb_interface *iface,
> +			   const struct usb_device_id *usb_id)
> +{
> +	struct usb_endpoint_descriptor *bulk_out;
> +	struct usb_endpoint_descriptor *bulk_in;
> +	struct usb_endpoint_descriptor *intr_in;
> +	struct ch341_ddata *ddata;
> +	int ret;
> +
> +	ddata = devm_kzalloc(&iface->dev, sizeof(*ddata), GFP_KERNEL);
> +	if (!ddata)
> +		return -ENOMEM;
> +
> +	ddata->usb_dev = interface_to_usbdev(iface);
> +	mutex_init(&ddata->usb_lock);
> +
> +	ret = usb_find_common_endpoints(iface->cur_altsetting, &bulk_in,
> +					&bulk_out, &intr_in, NULL);
> +	if (ret) {
> +		dev_err(&iface->dev, "Could not find all endpoints\n");
> +		return -ENODEV;
> +	}
> +
> +	ddata->ep_in = bulk_in->bEndpointAddress;
> +	ddata->ep_out = bulk_out->bEndpointAddress;
> +	ddata->ep_intr = intr_in->bEndpointAddress;
> +	ddata->ep_intr_interval = intr_in->bInterval;
> +
> +	usb_set_intfdata(iface, ddata);
> +
> +	ret = mfd_add_devices(&iface->dev, PLATFORM_DEVID_AUTO, ch341_devs,
> +			      ARRAY_SIZE(ch341_devs), NULL, 0, NULL);
> +	if (ret)
> +		return dev_err_probe(&iface->dev, ret,
> +				     "Failed to register child devices\n");
> +
> +	return 0;
> +}
> +
> +static void ch341_usb_disconnect(struct usb_interface *usb_if)
> +{
> +	mfd_remove_devices(&usb_if->dev);
> +}
> +
> +static const struct usb_device_id ch341_usb_table[] = {
> +	{ USB_DEVICE(0x1a86, 0x5512) },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(usb, ch341_usb_table);
> +
> +static struct usb_driver ch341_usb_driver = {
> +	.name       = "ch341-mfd",
> +	.id_table   = ch341_usb_table,
> +	.probe      = ch341_usb_probe,
> +	.disconnect = ch341_usb_disconnect,
> +};
> +module_usb_driver(ch341_usb_driver);
> +
> +MODULE_AUTHOR("Frank Zago <frank@zago.net>");
> +MODULE_DESCRIPTION("CH341 USB to I2C/SPI/GPIO adapter");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/mfd/ch341.h b/include/linux/mfd/ch341.h
> new file mode 100644
> index 000000000000..44f5da0720bd
> --- /dev/null
> +++ b/include/linux/mfd/ch341.h
> @@ -0,0 +1,18 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/* Definitions for the CH341 driver */
> +
> +#include <linux/mutex.h>
> +#include <linux/types.h>
> +
> +struct usb_device;
> +struct usb_interface;
> +
> +struct ch341_ddata {
> +	struct usb_device *usb_dev;
> +	struct mutex usb_lock;
> +
> +	int ep_in;
> +	int ep_out;
> +	int ep_intr;
> +	u8 ep_intr_interval;
> +};
Greg KH June 27, 2022, 2:28 p.m. UTC | #2
On Mon, Jun 27, 2022 at 03:04:32PM +0100, Lee Jones wrote:
> USB review please.
> 
> > The CH341 is a multifunction chip, presenting 3 different USB PID. One
> > 
> > of these functions is for I2C/SPI/GPIO. This new set of drivers will
> > manage I2C and GPIO.
> > 
> > Signed-off-by: frank zago <frank@zago.net>
> > ---
> >  MAINTAINERS               |  7 +++
> >  drivers/mfd/Kconfig       | 10 +++++
> >  drivers/mfd/Makefile      |  1 +
> >  drivers/mfd/ch341-core.c  | 90 +++++++++++++++++++++++++++++++++++++++
> >  include/linux/mfd/ch341.h | 18 ++++++++
> >  5 files changed, 126 insertions(+)
> >  create mode 100644 drivers/mfd/ch341-core.c
> >  create mode 100644 include/linux/mfd/ch341.h
> > 
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 43d3d07afccd..628eeaa9bf68 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -21475,6 +21475,13 @@ M:	David Härdeman <david@hardeman.nu>
> >  S:	Maintained
> >  F:	drivers/media/rc/winbond-cir.c
> >  
> > +WINCHIPHEAD CH341 I2C/GPIO MFD DRIVER
> > +M:	Frank Zago <frank@zago.net>
> > +L:	linux-usb@vger.kernel.org
> > +S:	Maintained
> > +F:	drivers/mfd/ch341-core.c
> > +F:	include/linux/mfd/ch341.h
> > +
> >  WINSYSTEMS EBC-C384 WATCHDOG DRIVER
> >  M:	William Breathitt Gray <vilhelm.gray@gmail.com>
> >  L:	linux-watchdog@vger.kernel.org
> > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> > index 3b59456f5545..893acc821a42 100644
> > --- a/drivers/mfd/Kconfig
> > +++ b/drivers/mfd/Kconfig
> > @@ -1784,6 +1784,16 @@ config MFD_LOCHNAGAR
> >  	help
> >  	  Support for Cirrus Logic Lochnagar audio development board.
> >  
> > +config MFD_CH341
> > +	tristate "WinChipHead CH341 in I2C/SPI/GPIO mode"
> > +	depends on USB
> > +	help
> > +	  If you say yes to this option, support for the CH341 series
> > +	  of chips, running in I2C/SPI/GPIO mode will be included.
> > +
> > +	  This driver can also be built as a module.  If so, the
> > +	  module will be called ch341-core.
> > +
> >  config MFD_ARIZONA
> >  	select REGMAP
> >  	select REGMAP_IRQ
> > diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> > index 858cacf659d6..fd615ab3929f 100644
> > --- a/drivers/mfd/Makefile
> > +++ b/drivers/mfd/Makefile
> > @@ -13,6 +13,7 @@ obj-$(CONFIG_MFD_ASIC3)		+= asic3.o tmio_core.o
> >  obj-$(CONFIG_ARCH_BCM2835)	+= bcm2835-pm.o
> >  obj-$(CONFIG_MFD_BCM590XX)	+= bcm590xx.o
> >  obj-$(CONFIG_MFD_BD9571MWV)	+= bd9571mwv.o
> > +obj-$(CONFIG_MFD_CH341)		+= ch341-core.o
> >  obj-$(CONFIG_MFD_CROS_EC_DEV)	+= cros_ec_dev.o
> >  obj-$(CONFIG_MFD_ENE_KB3930)	+= ene-kb3930.o
> >  obj-$(CONFIG_MFD_EXYNOS_LPASS)	+= exynos-lpass.o
> > diff --git a/drivers/mfd/ch341-core.c b/drivers/mfd/ch341-core.c
> > new file mode 100644
> > index 000000000000..f08a67dd6074
> > --- /dev/null
> > +++ b/drivers/mfd/ch341-core.c
> > @@ -0,0 +1,90 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Core driver for the CH341A, CH341B and CH341T in I2C/SPI/GPIO
> > + * mode. There are cell drivers available for I2C and GPIO. SPI is not
> > + * yet supported.
> > + *
> > + * Copyright 2022, Frank Zago
> > + * Copyright (c) 2017 Gunar Schorcht (gunar@schorcht.net)
> > + * Copyright (c) 2016 Tse Lun Bien
> > + * Copyright (c) 2014 Marco Gittler
> > + * Copyright (c) 2006-2007 Till Harbaum (Till@Harbaum.org)
> > + */
> > +
> > +#include <linux/kernel.h>
> > +#include <linux/mfd/ch341.h>
> > +#include <linux/mfd/core.h>
> > +#include <linux/module.h>
> > +#include <linux/slab.h>
> > +#include <linux/usb.h>
> > +
> > +static const struct mfd_cell ch341_devs[] = {
> > +	{
> > +		.name = "ch341-gpio",
> > +	},
> > +	{
> > +		.name = "ch341-i2c",
> > +	},
> > +};
> > +
> > +static int ch341_usb_probe(struct usb_interface *iface,
> > +			   const struct usb_device_id *usb_id)
> > +{
> > +	struct usb_endpoint_descriptor *bulk_out;
> > +	struct usb_endpoint_descriptor *bulk_in;
> > +	struct usb_endpoint_descriptor *intr_in;
> > +	struct ch341_ddata *ddata;
> > +	int ret;
> > +
> > +	ddata = devm_kzalloc(&iface->dev, sizeof(*ddata), GFP_KERNEL);
> > +	if (!ddata)
> > +		return -ENOMEM;
> > +
> > +	ddata->usb_dev = interface_to_usbdev(iface);
> > +	mutex_init(&ddata->usb_lock);
> > +
> > +	ret = usb_find_common_endpoints(iface->cur_altsetting, &bulk_in,
> > +					&bulk_out, &intr_in, NULL);
> > +	if (ret) {
> > +		dev_err(&iface->dev, "Could not find all endpoints\n");
> > +		return -ENODEV;
> > +	}
> > +
> > +	ddata->ep_in = bulk_in->bEndpointAddress;
> > +	ddata->ep_out = bulk_out->bEndpointAddress;
> > +	ddata->ep_intr = intr_in->bEndpointAddress;
> > +	ddata->ep_intr_interval = intr_in->bInterval;
> > +
> > +	usb_set_intfdata(iface, ddata);
> > +
> > +	ret = mfd_add_devices(&iface->dev, PLATFORM_DEVID_AUTO, ch341_devs,
> > +			      ARRAY_SIZE(ch341_devs), NULL, 0, NULL);
> > +	if (ret)
> > +		return dev_err_probe(&iface->dev, ret,
> > +				     "Failed to register child devices\n");
> > +
> > +	return 0;
> > +}
> > +
> > +static void ch341_usb_disconnect(struct usb_interface *usb_if)
> > +{
> > +	mfd_remove_devices(&usb_if->dev);
> > +}
> > +
> > +static const struct usb_device_id ch341_usb_table[] = {
> > +	{ USB_DEVICE(0x1a86, 0x5512) },
> > +	{ }
> > +};
> > +MODULE_DEVICE_TABLE(usb, ch341_usb_table);
> > +
> > +static struct usb_driver ch341_usb_driver = {
> > +	.name       = "ch341-mfd",
> > +	.id_table   = ch341_usb_table,
> > +	.probe      = ch341_usb_probe,
> > +	.disconnect = ch341_usb_disconnect,
> > +};
> > +module_usb_driver(ch341_usb_driver);
> > +
> > +MODULE_AUTHOR("Frank Zago <frank@zago.net>");
> > +MODULE_DESCRIPTION("CH341 USB to I2C/SPI/GPIO adapter");
> > +MODULE_LICENSE("GPL");
> > diff --git a/include/linux/mfd/ch341.h b/include/linux/mfd/ch341.h
> > new file mode 100644
> > index 000000000000..44f5da0720bd
> > --- /dev/null
> > +++ b/include/linux/mfd/ch341.h
> > @@ -0,0 +1,18 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/* Definitions for the CH341 driver */
> > +
> > +#include <linux/mutex.h>
> > +#include <linux/types.h>
> > +
> > +struct usb_device;
> > +struct usb_interface;
> > +
> > +struct ch341_ddata {
> > +	struct usb_device *usb_dev;
> > +	struct mutex usb_lock;
> > +
> > +	int ep_in;
> > +	int ep_out;
> > +	int ep_intr;
> > +	u8 ep_intr_interval;
> > +};


Looks sane enough, but doesn't actually do any USB data transfers, maybe
that happens somewhere else...

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Lee Jones June 27, 2022, 2:43 p.m. UTC | #3
On Mon, 27 Jun 2022, Greg Kroah-Hartman wrote:

> On Mon, Jun 27, 2022 at 03:04:32PM +0100, Lee Jones wrote:
> > USB review please.
> > 
> > > The CH341 is a multifunction chip, presenting 3 different USB PID. One
> > > 
> > > of these functions is for I2C/SPI/GPIO. This new set of drivers will
> > > manage I2C and GPIO.
> > > 
> > > Signed-off-by: frank zago <frank@zago.net>
> > > ---
> > >  MAINTAINERS               |  7 +++
> > >  drivers/mfd/Kconfig       | 10 +++++
> > >  drivers/mfd/Makefile      |  1 +
> > >  drivers/mfd/ch341-core.c  | 90 +++++++++++++++++++++++++++++++++++++++
> > >  include/linux/mfd/ch341.h | 18 ++++++++
> > >  5 files changed, 126 insertions(+)
> > >  create mode 100644 drivers/mfd/ch341-core.c
> > >  create mode 100644 include/linux/mfd/ch341.h
> > > 
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index 43d3d07afccd..628eeaa9bf68 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -21475,6 +21475,13 @@ M:	David Härdeman <david@hardeman.nu>
> > >  S:	Maintained
> > >  F:	drivers/media/rc/winbond-cir.c
> > >  
> > > +WINCHIPHEAD CH341 I2C/GPIO MFD DRIVER
> > > +M:	Frank Zago <frank@zago.net>
> > > +L:	linux-usb@vger.kernel.org
> > > +S:	Maintained
> > > +F:	drivers/mfd/ch341-core.c
> > > +F:	include/linux/mfd/ch341.h
> > > +
> > >  WINSYSTEMS EBC-C384 WATCHDOG DRIVER
> > >  M:	William Breathitt Gray <vilhelm.gray@gmail.com>
> > >  L:	linux-watchdog@vger.kernel.org
> > > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> > > index 3b59456f5545..893acc821a42 100644
> > > --- a/drivers/mfd/Kconfig
> > > +++ b/drivers/mfd/Kconfig
> > > @@ -1784,6 +1784,16 @@ config MFD_LOCHNAGAR
> > >  	help
> > >  	  Support for Cirrus Logic Lochnagar audio development board.
> > >  
> > > +config MFD_CH341
> > > +	tristate "WinChipHead CH341 in I2C/SPI/GPIO mode"
> > > +	depends on USB
> > > +	help
> > > +	  If you say yes to this option, support for the CH341 series
> > > +	  of chips, running in I2C/SPI/GPIO mode will be included.
> > > +
> > > +	  This driver can also be built as a module.  If so, the
> > > +	  module will be called ch341-core.
> > > +
> > >  config MFD_ARIZONA
> > >  	select REGMAP
> > >  	select REGMAP_IRQ
> > > diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> > > index 858cacf659d6..fd615ab3929f 100644
> > > --- a/drivers/mfd/Makefile
> > > +++ b/drivers/mfd/Makefile
> > > @@ -13,6 +13,7 @@ obj-$(CONFIG_MFD_ASIC3)		+= asic3.o tmio_core.o
> > >  obj-$(CONFIG_ARCH_BCM2835)	+= bcm2835-pm.o
> > >  obj-$(CONFIG_MFD_BCM590XX)	+= bcm590xx.o
> > >  obj-$(CONFIG_MFD_BD9571MWV)	+= bd9571mwv.o
> > > +obj-$(CONFIG_MFD_CH341)		+= ch341-core.o
> > >  obj-$(CONFIG_MFD_CROS_EC_DEV)	+= cros_ec_dev.o
> > >  obj-$(CONFIG_MFD_ENE_KB3930)	+= ene-kb3930.o
> > >  obj-$(CONFIG_MFD_EXYNOS_LPASS)	+= exynos-lpass.o
> > > diff --git a/drivers/mfd/ch341-core.c b/drivers/mfd/ch341-core.c
> > > new file mode 100644
> > > index 000000000000..f08a67dd6074
> > > --- /dev/null
> > > +++ b/drivers/mfd/ch341-core.c
> > > @@ -0,0 +1,90 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * Core driver for the CH341A, CH341B and CH341T in I2C/SPI/GPIO
> > > + * mode. There are cell drivers available for I2C and GPIO. SPI is not
> > > + * yet supported.
> > > + *
> > > + * Copyright 2022, Frank Zago
> > > + * Copyright (c) 2017 Gunar Schorcht (gunar@schorcht.net)
> > > + * Copyright (c) 2016 Tse Lun Bien
> > > + * Copyright (c) 2014 Marco Gittler
> > > + * Copyright (c) 2006-2007 Till Harbaum (Till@Harbaum.org)
> > > + */
> > > +
> > > +#include <linux/kernel.h>
> > > +#include <linux/mfd/ch341.h>
> > > +#include <linux/mfd/core.h>
> > > +#include <linux/module.h>
> > > +#include <linux/slab.h>
> > > +#include <linux/usb.h>
> > > +
> > > +static const struct mfd_cell ch341_devs[] = {
> > > +	{
> > > +		.name = "ch341-gpio",
> > > +	},
> > > +	{
> > > +		.name = "ch341-i2c",
> > > +	},
> > > +};
> > > +
> > > +static int ch341_usb_probe(struct usb_interface *iface,
> > > +			   const struct usb_device_id *usb_id)
> > > +{
> > > +	struct usb_endpoint_descriptor *bulk_out;
> > > +	struct usb_endpoint_descriptor *bulk_in;
> > > +	struct usb_endpoint_descriptor *intr_in;
> > > +	struct ch341_ddata *ddata;
> > > +	int ret;
> > > +
> > > +	ddata = devm_kzalloc(&iface->dev, sizeof(*ddata), GFP_KERNEL);
> > > +	if (!ddata)
> > > +		return -ENOMEM;
> > > +
> > > +	ddata->usb_dev = interface_to_usbdev(iface);
> > > +	mutex_init(&ddata->usb_lock);
> > > +
> > > +	ret = usb_find_common_endpoints(iface->cur_altsetting, &bulk_in,
> > > +					&bulk_out, &intr_in, NULL);
> > > +	if (ret) {
> > > +		dev_err(&iface->dev, "Could not find all endpoints\n");
> > > +		return -ENODEV;
> > > +	}
> > > +
> > > +	ddata->ep_in = bulk_in->bEndpointAddress;
> > > +	ddata->ep_out = bulk_out->bEndpointAddress;
> > > +	ddata->ep_intr = intr_in->bEndpointAddress;
> > > +	ddata->ep_intr_interval = intr_in->bInterval;
> > > +
> > > +	usb_set_intfdata(iface, ddata);
> > > +
> > > +	ret = mfd_add_devices(&iface->dev, PLATFORM_DEVID_AUTO, ch341_devs,
> > > +			      ARRAY_SIZE(ch341_devs), NULL, 0, NULL);
> > > +	if (ret)
> > > +		return dev_err_probe(&iface->dev, ret,
> > > +				     "Failed to register child devices\n");
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static void ch341_usb_disconnect(struct usb_interface *usb_if)
> > > +{
> > > +	mfd_remove_devices(&usb_if->dev);
> > > +}
> > > +
> > > +static const struct usb_device_id ch341_usb_table[] = {
> > > +	{ USB_DEVICE(0x1a86, 0x5512) },
> > > +	{ }
> > > +};
> > > +MODULE_DEVICE_TABLE(usb, ch341_usb_table);
> > > +
> > > +static struct usb_driver ch341_usb_driver = {
> > > +	.name       = "ch341-mfd",
> > > +	.id_table   = ch341_usb_table,
> > > +	.probe      = ch341_usb_probe,
> > > +	.disconnect = ch341_usb_disconnect,
> > > +};
> > > +module_usb_driver(ch341_usb_driver);
> > > +
> > > +MODULE_AUTHOR("Frank Zago <frank@zago.net>");
> > > +MODULE_DESCRIPTION("CH341 USB to I2C/SPI/GPIO adapter");
> > > +MODULE_LICENSE("GPL");
> > > diff --git a/include/linux/mfd/ch341.h b/include/linux/mfd/ch341.h
> > > new file mode 100644
> > > index 000000000000..44f5da0720bd
> > > --- /dev/null
> > > +++ b/include/linux/mfd/ch341.h
> > > @@ -0,0 +1,18 @@
> > > +/* SPDX-License-Identifier: GPL-2.0 */
> > > +/* Definitions for the CH341 driver */
> > > +
> > > +#include <linux/mutex.h>
> > > +#include <linux/types.h>
> > > +
> > > +struct usb_device;
> > > +struct usb_interface;
> > > +
> > > +struct ch341_ddata {
> > > +	struct usb_device *usb_dev;
> > > +	struct mutex usb_lock;
> > > +
> > > +	int ep_in;
> > > +	int ep_out;
> > > +	int ep_intr;
> > > +	u8 ep_intr_interval;
> > > +};
> 
> 
> Looks sane enough, but doesn't actually do any USB data transfers, maybe
> that happens somewhere else...

I expect those to happen in *both* of these:

  static const struct mfd_cell ch341_devs[] = {
	{
		.name = "ch341-gpio",
	},
	{
		.name = "ch341-i2c",
	},
  };

Is that correct Frank?

> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Thanks.
Frank Zago June 27, 2022, 11:30 p.m. UTC | #4
On 6/27/22 09:43, Lee Jones wrote:
> On Mon, 27 Jun 2022, Greg Kroah-Hartman wrote:
> 
>> On Mon, Jun 27, 2022 at 03:04:32PM +0100, Lee Jones wrote:
>>> USB review please.
>>>
>>>> The CH341 is a multifunction chip, presenting 3 different USB PID. One
>>>>
>>>> of these functions is for I2C/SPI/GPIO. This new set of drivers will
>>>> manage I2C and GPIO.
>>>>
>>>> Signed-off-by: frank zago <frank@zago.net>
>>>> ---
>>>>  MAINTAINERS               |  7 +++
>>>>  drivers/mfd/Kconfig       | 10 +++++
>>>>  drivers/mfd/Makefile      |  1 +
>>>>  drivers/mfd/ch341-core.c  | 90 +++++++++++++++++++++++++++++++++++++++
>>>>  include/linux/mfd/ch341.h | 18 ++++++++
>>>>  5 files changed, 126 insertions(+)
>>>>  create mode 100644 drivers/mfd/ch341-core.c
>>>>  create mode 100644 include/linux/mfd/ch341.h
>>>>
>>>> diff --git a/MAINTAINERS b/MAINTAINERS
>>>> index 43d3d07afccd..628eeaa9bf68 100644
>>>> --- a/MAINTAINERS
>>>> +++ b/MAINTAINERS
>>>> @@ -21475,6 +21475,13 @@ M:	David Härdeman <david@hardeman.nu>
>>>>  S:	Maintained
>>>>  F:	drivers/media/rc/winbond-cir.c
>>>>  
>>>> +WINCHIPHEAD CH341 I2C/GPIO MFD DRIVER
>>>> +M:	Frank Zago <frank@zago.net>
>>>> +L:	linux-usb@vger.kernel.org
>>>> +S:	Maintained
>>>> +F:	drivers/mfd/ch341-core.c
>>>> +F:	include/linux/mfd/ch341.h
>>>> +
>>>>  WINSYSTEMS EBC-C384 WATCHDOG DRIVER
>>>>  M:	William Breathitt Gray <vilhelm.gray@gmail.com>
>>>>  L:	linux-watchdog@vger.kernel.org
>>>> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
>>>> index 3b59456f5545..893acc821a42 100644
>>>> --- a/drivers/mfd/Kconfig
>>>> +++ b/drivers/mfd/Kconfig
>>>> @@ -1784,6 +1784,16 @@ config MFD_LOCHNAGAR
>>>>  	help
>>>>  	  Support for Cirrus Logic Lochnagar audio development board.
>>>>  
>>>> +config MFD_CH341
>>>> +	tristate "WinChipHead CH341 in I2C/SPI/GPIO mode"
>>>> +	depends on USB
>>>> +	help
>>>> +	  If you say yes to this option, support for the CH341 series
>>>> +	  of chips, running in I2C/SPI/GPIO mode will be included.
>>>> +
>>>> +	  This driver can also be built as a module.  If so, the
>>>> +	  module will be called ch341-core.
>>>> +
>>>>  config MFD_ARIZONA
>>>>  	select REGMAP
>>>>  	select REGMAP_IRQ
>>>> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
>>>> index 858cacf659d6..fd615ab3929f 100644
>>>> --- a/drivers/mfd/Makefile
>>>> +++ b/drivers/mfd/Makefile
>>>> @@ -13,6 +13,7 @@ obj-$(CONFIG_MFD_ASIC3)		+= asic3.o tmio_core.o
>>>>  obj-$(CONFIG_ARCH_BCM2835)	+= bcm2835-pm.o
>>>>  obj-$(CONFIG_MFD_BCM590XX)	+= bcm590xx.o
>>>>  obj-$(CONFIG_MFD_BD9571MWV)	+= bd9571mwv.o
>>>> +obj-$(CONFIG_MFD_CH341)		+= ch341-core.o
>>>>  obj-$(CONFIG_MFD_CROS_EC_DEV)	+= cros_ec_dev.o
>>>>  obj-$(CONFIG_MFD_ENE_KB3930)	+= ene-kb3930.o
>>>>  obj-$(CONFIG_MFD_EXYNOS_LPASS)	+= exynos-lpass.o
>>>> diff --git a/drivers/mfd/ch341-core.c b/drivers/mfd/ch341-core.c
>>>> new file mode 100644
>>>> index 000000000000..f08a67dd6074
>>>> --- /dev/null
>>>> +++ b/drivers/mfd/ch341-core.c
>>>> @@ -0,0 +1,90 @@
>>>> +// SPDX-License-Identifier: GPL-2.0
>>>> +/*
>>>> + * Core driver for the CH341A, CH341B and CH341T in I2C/SPI/GPIO
>>>> + * mode. There are cell drivers available for I2C and GPIO. SPI is not
>>>> + * yet supported.
>>>> + *
>>>> + * Copyright 2022, Frank Zago
>>>> + * Copyright (c) 2017 Gunar Schorcht (gunar@schorcht.net)
>>>> + * Copyright (c) 2016 Tse Lun Bien
>>>> + * Copyright (c) 2014 Marco Gittler
>>>> + * Copyright (c) 2006-2007 Till Harbaum (Till@Harbaum.org)
>>>> + */
>>>> +
>>>> +#include <linux/kernel.h>
>>>> +#include <linux/mfd/ch341.h>
>>>> +#include <linux/mfd/core.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/slab.h>
>>>> +#include <linux/usb.h>
>>>> +
>>>> +static const struct mfd_cell ch341_devs[] = {
>>>> +	{
>>>> +		.name = "ch341-gpio",
>>>> +	},
>>>> +	{
>>>> +		.name = "ch341-i2c",
>>>> +	},
>>>> +};
>>>> +
>>>> +static int ch341_usb_probe(struct usb_interface *iface,
>>>> +			   const struct usb_device_id *usb_id)
>>>> +{
>>>> +	struct usb_endpoint_descriptor *bulk_out;
>>>> +	struct usb_endpoint_descriptor *bulk_in;
>>>> +	struct usb_endpoint_descriptor *intr_in;
>>>> +	struct ch341_ddata *ddata;
>>>> +	int ret;
>>>> +
>>>> +	ddata = devm_kzalloc(&iface->dev, sizeof(*ddata), GFP_KERNEL);
>>>> +	if (!ddata)
>>>> +		return -ENOMEM;
>>>> +
>>>> +	ddata->usb_dev = interface_to_usbdev(iface);
>>>> +	mutex_init(&ddata->usb_lock);
>>>> +
>>>> +	ret = usb_find_common_endpoints(iface->cur_altsetting, &bulk_in,
>>>> +					&bulk_out, &intr_in, NULL);
>>>> +	if (ret) {
>>>> +		dev_err(&iface->dev, "Could not find all endpoints\n");
>>>> +		return -ENODEV;
>>>> +	}
>>>> +
>>>> +	ddata->ep_in = bulk_in->bEndpointAddress;
>>>> +	ddata->ep_out = bulk_out->bEndpointAddress;
>>>> +	ddata->ep_intr = intr_in->bEndpointAddress;
>>>> +	ddata->ep_intr_interval = intr_in->bInterval;
>>>> +
>>>> +	usb_set_intfdata(iface, ddata);
>>>> +
>>>> +	ret = mfd_add_devices(&iface->dev, PLATFORM_DEVID_AUTO, ch341_devs,
>>>> +			      ARRAY_SIZE(ch341_devs), NULL, 0, NULL);
>>>> +	if (ret)
>>>> +		return dev_err_probe(&iface->dev, ret,
>>>> +				     "Failed to register child devices\n");
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static void ch341_usb_disconnect(struct usb_interface *usb_if)
>>>> +{
>>>> +	mfd_remove_devices(&usb_if->dev);
>>>> +}
>>>> +
>>>> +static const struct usb_device_id ch341_usb_table[] = {
>>>> +	{ USB_DEVICE(0x1a86, 0x5512) },
>>>> +	{ }
>>>> +};
>>>> +MODULE_DEVICE_TABLE(usb, ch341_usb_table);
>>>> +
>>>> +static struct usb_driver ch341_usb_driver = {
>>>> +	.name       = "ch341-mfd",
>>>> +	.id_table   = ch341_usb_table,
>>>> +	.probe      = ch341_usb_probe,
>>>> +	.disconnect = ch341_usb_disconnect,
>>>> +};
>>>> +module_usb_driver(ch341_usb_driver);
>>>> +
>>>> +MODULE_AUTHOR("Frank Zago <frank@zago.net>");
>>>> +MODULE_DESCRIPTION("CH341 USB to I2C/SPI/GPIO adapter");
>>>> +MODULE_LICENSE("GPL");
>>>> diff --git a/include/linux/mfd/ch341.h b/include/linux/mfd/ch341.h
>>>> new file mode 100644
>>>> index 000000000000..44f5da0720bd
>>>> --- /dev/null
>>>> +++ b/include/linux/mfd/ch341.h
>>>> @@ -0,0 +1,18 @@
>>>> +/* SPDX-License-Identifier: GPL-2.0 */
>>>> +/* Definitions for the CH341 driver */
>>>> +
>>>> +#include <linux/mutex.h>
>>>> +#include <linux/types.h>
>>>> +
>>>> +struct usb_device;
>>>> +struct usb_interface;
>>>> +
>>>> +struct ch341_ddata {
>>>> +	struct usb_device *usb_dev;
>>>> +	struct mutex usb_lock;
>>>> +
>>>> +	int ep_in;
>>>> +	int ep_out;
>>>> +	int ep_intr;
>>>> +	u8 ep_intr_interval;
>>>> +};
>>
>>
>> Looks sane enough, but doesn't actually do any USB data transfers, maybe
>> that happens somewhere else...
> 
> I expect those to happen in *both* of these:
> 
>   static const struct mfd_cell ch341_devs[] = {
> 	{
> 		.name = "ch341-gpio",
> 	},
> 	{
> 		.name = "ch341-i2c",
> 	},
>   };
> 
> Is that correct Frank?

Yes, that's correct.

Frank
Lee Jones July 4, 2022, 10:09 a.m. UTC | #5
On Wed, 15 Jun 2022, frank zago wrote:

> The CH341 is a multifunction chip, presenting 3 different USB PID. One
> of these functions is for I2C/SPI/GPIO. This new set of drivers will
> manage I2C and GPIO.
> 
> Signed-off-by: frank zago <frank@zago.net>
> ---
>  MAINTAINERS               |  7 +++
>  drivers/mfd/Kconfig       | 10 +++++
>  drivers/mfd/Makefile      |  1 +
>  drivers/mfd/ch341-core.c  | 90 +++++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/ch341.h | 18 ++++++++
>  5 files changed, 126 insertions(+)
>  create mode 100644 drivers/mfd/ch341-core.c
>  create mode 100644 include/linux/mfd/ch341.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 43d3d07afccd..628eeaa9bf68 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -21475,6 +21475,13 @@ M:	David Härdeman <david@hardeman.nu>
>  S:	Maintained
>  F:	drivers/media/rc/winbond-cir.c
>  
> +WINCHIPHEAD CH341 I2C/GPIO MFD DRIVER
> +M:	Frank Zago <frank@zago.net>
> +L:	linux-usb@vger.kernel.org
> +S:	Maintained
> +F:	drivers/mfd/ch341-core.c
> +F:	include/linux/mfd/ch341.h
> +
>  WINSYSTEMS EBC-C384 WATCHDOG DRIVER
>  M:	William Breathitt Gray <vilhelm.gray@gmail.com>
>  L:	linux-watchdog@vger.kernel.org
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 3b59456f5545..893acc821a42 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -1784,6 +1784,16 @@ config MFD_LOCHNAGAR
>  	help
>  	  Support for Cirrus Logic Lochnagar audio development board.
>  
> +config MFD_CH341
> +	tristate "WinChipHead CH341 in I2C/SPI/GPIO mode"
> +	depends on USB
> +	help
> +	  If you say yes to this option, support for the CH341 series
> +	  of chips, running in I2C/SPI/GPIO mode will be included.
> +
> +	  This driver can also be built as a module.  If so, the
> +	  module will be called ch341-core.
> +
>  config MFD_ARIZONA
>  	select REGMAP
>  	select REGMAP_IRQ
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 858cacf659d6..fd615ab3929f 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -13,6 +13,7 @@ obj-$(CONFIG_MFD_ASIC3)		+= asic3.o tmio_core.o
>  obj-$(CONFIG_ARCH_BCM2835)	+= bcm2835-pm.o
>  obj-$(CONFIG_MFD_BCM590XX)	+= bcm590xx.o
>  obj-$(CONFIG_MFD_BD9571MWV)	+= bd9571mwv.o
> +obj-$(CONFIG_MFD_CH341)		+= ch341-core.o
>  obj-$(CONFIG_MFD_CROS_EC_DEV)	+= cros_ec_dev.o
>  obj-$(CONFIG_MFD_ENE_KB3930)	+= ene-kb3930.o
>  obj-$(CONFIG_MFD_EXYNOS_LPASS)	+= exynos-lpass.o
> diff --git a/drivers/mfd/ch341-core.c b/drivers/mfd/ch341-core.c
> new file mode 100644
> index 000000000000..f08a67dd6074
> --- /dev/null
> +++ b/drivers/mfd/ch341-core.c
> @@ -0,0 +1,90 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Core driver for the CH341A, CH341B and CH341T in I2C/SPI/GPIO
> + * mode. There are cell drivers available for I2C and GPIO. SPI is not
> + * yet supported.
> + *
> + * Copyright 2022, Frank Zago
> + * Copyright (c) 2017 Gunar Schorcht (gunar@schorcht.net)
> + * Copyright (c) 2016 Tse Lun Bien
> + * Copyright (c) 2014 Marco Gittler
> + * Copyright (c) 2006-2007 Till Harbaum (Till@Harbaum.org)
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/mfd/ch341.h>
> +#include <linux/mfd/core.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/usb.h>
> +
> +static const struct mfd_cell ch341_devs[] = {
> +	{
> +		.name = "ch341-gpio",
> +	},
> +	{
> +		.name = "ch341-i2c",
> +	},
> +};

These should both be on one line each.

> +static int ch341_usb_probe(struct usb_interface *iface,
> +			   const struct usb_device_id *usb_id)
> +{
> +	struct usb_endpoint_descriptor *bulk_out;
> +	struct usb_endpoint_descriptor *bulk_in;
> +	struct usb_endpoint_descriptor *intr_in;
> +	struct ch341_ddata *ddata;
> +	int ret;
> +
> +	ddata = devm_kzalloc(&iface->dev, sizeof(*ddata), GFP_KERNEL);
> +	if (!ddata)
> +		return -ENOMEM;
> +
> +	ddata->usb_dev = interface_to_usbdev(iface);
> +	mutex_init(&ddata->usb_lock);
> +
> +	ret = usb_find_common_endpoints(iface->cur_altsetting, &bulk_in,
> +					&bulk_out, &intr_in, NULL);
> +	if (ret) {
> +		dev_err(&iface->dev, "Could not find all endpoints\n");
> +		return -ENODEV;
> +	}
> +
> +	ddata->ep_in = bulk_in->bEndpointAddress;
> +	ddata->ep_out = bulk_out->bEndpointAddress;
> +	ddata->ep_intr = intr_in->bEndpointAddress;
> +	ddata->ep_intr_interval = intr_in->bInterval;
> +
> +	usb_set_intfdata(iface, ddata);
> +
> +	ret = mfd_add_devices(&iface->dev, PLATFORM_DEVID_AUTO, ch341_devs,
> +			      ARRAY_SIZE(ch341_devs), NULL, 0, NULL);
> +	if (ret)
> +		return dev_err_probe(&iface->dev, ret,
> +				     "Failed to register child devices\n");
> +
> +	return 0;
> +}
> +
> +static void ch341_usb_disconnect(struct usb_interface *usb_if)
> +{
> +	mfd_remove_devices(&usb_if->dev);

Why not use the devm_* version?

> +}
> +
> +static const struct usb_device_id ch341_usb_table[] = {
> +	{ USB_DEVICE(0x1a86, 0x5512) },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(usb, ch341_usb_table);
> +
> +static struct usb_driver ch341_usb_driver = {
> +	.name       = "ch341-mfd",
> +	.id_table   = ch341_usb_table,
> +	.probe      = ch341_usb_probe,
> +	.disconnect = ch341_usb_disconnect,
> +};
> +module_usb_driver(ch341_usb_driver);
> +
> +MODULE_AUTHOR("Frank Zago <frank@zago.net>");
> +MODULE_DESCRIPTION("CH341 USB to I2C/SPI/GPIO adapter");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/mfd/ch341.h b/include/linux/mfd/ch341.h
> new file mode 100644
> index 000000000000..44f5da0720bd
> --- /dev/null
> +++ b/include/linux/mfd/ch341.h
> @@ -0,0 +1,18 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/* Definitions for the CH341 driver */

What definitions?

> +
> +#include <linux/mutex.h>
> +#include <linux/types.h>
> +
> +struct usb_device;
> +struct usb_interface;
> +
> +struct ch341_ddata {
> +	struct usb_device *usb_dev;
> +	struct mutex usb_lock;
> +
> +	int ep_in;
> +	int ep_out;
> +	int ep_intr;
> +	u8 ep_intr_interval;
> +};
diff mbox series

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 43d3d07afccd..628eeaa9bf68 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -21475,6 +21475,13 @@  M:	David Härdeman <david@hardeman.nu>
 S:	Maintained
 F:	drivers/media/rc/winbond-cir.c
 
+WINCHIPHEAD CH341 I2C/GPIO MFD DRIVER
+M:	Frank Zago <frank@zago.net>
+L:	linux-usb@vger.kernel.org
+S:	Maintained
+F:	drivers/mfd/ch341-core.c
+F:	include/linux/mfd/ch341.h
+
 WINSYSTEMS EBC-C384 WATCHDOG DRIVER
 M:	William Breathitt Gray <vilhelm.gray@gmail.com>
 L:	linux-watchdog@vger.kernel.org
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 3b59456f5545..893acc821a42 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -1784,6 +1784,16 @@  config MFD_LOCHNAGAR
 	help
 	  Support for Cirrus Logic Lochnagar audio development board.
 
+config MFD_CH341
+	tristate "WinChipHead CH341 in I2C/SPI/GPIO mode"
+	depends on USB
+	help
+	  If you say yes to this option, support for the CH341 series
+	  of chips, running in I2C/SPI/GPIO mode will be included.
+
+	  This driver can also be built as a module.  If so, the
+	  module will be called ch341-core.
+
 config MFD_ARIZONA
 	select REGMAP
 	select REGMAP_IRQ
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 858cacf659d6..fd615ab3929f 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -13,6 +13,7 @@  obj-$(CONFIG_MFD_ASIC3)		+= asic3.o tmio_core.o
 obj-$(CONFIG_ARCH_BCM2835)	+= bcm2835-pm.o
 obj-$(CONFIG_MFD_BCM590XX)	+= bcm590xx.o
 obj-$(CONFIG_MFD_BD9571MWV)	+= bd9571mwv.o
+obj-$(CONFIG_MFD_CH341)		+= ch341-core.o
 obj-$(CONFIG_MFD_CROS_EC_DEV)	+= cros_ec_dev.o
 obj-$(CONFIG_MFD_ENE_KB3930)	+= ene-kb3930.o
 obj-$(CONFIG_MFD_EXYNOS_LPASS)	+= exynos-lpass.o
diff --git a/drivers/mfd/ch341-core.c b/drivers/mfd/ch341-core.c
new file mode 100644
index 000000000000..f08a67dd6074
--- /dev/null
+++ b/drivers/mfd/ch341-core.c
@@ -0,0 +1,90 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Core driver for the CH341A, CH341B and CH341T in I2C/SPI/GPIO
+ * mode. There are cell drivers available for I2C and GPIO. SPI is not
+ * yet supported.
+ *
+ * Copyright 2022, Frank Zago
+ * Copyright (c) 2017 Gunar Schorcht (gunar@schorcht.net)
+ * Copyright (c) 2016 Tse Lun Bien
+ * Copyright (c) 2014 Marco Gittler
+ * Copyright (c) 2006-2007 Till Harbaum (Till@Harbaum.org)
+ */
+
+#include <linux/kernel.h>
+#include <linux/mfd/ch341.h>
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+
+static const struct mfd_cell ch341_devs[] = {
+	{
+		.name = "ch341-gpio",
+	},
+	{
+		.name = "ch341-i2c",
+	},
+};
+
+static int ch341_usb_probe(struct usb_interface *iface,
+			   const struct usb_device_id *usb_id)
+{
+	struct usb_endpoint_descriptor *bulk_out;
+	struct usb_endpoint_descriptor *bulk_in;
+	struct usb_endpoint_descriptor *intr_in;
+	struct ch341_ddata *ddata;
+	int ret;
+
+	ddata = devm_kzalloc(&iface->dev, sizeof(*ddata), GFP_KERNEL);
+	if (!ddata)
+		return -ENOMEM;
+
+	ddata->usb_dev = interface_to_usbdev(iface);
+	mutex_init(&ddata->usb_lock);
+
+	ret = usb_find_common_endpoints(iface->cur_altsetting, &bulk_in,
+					&bulk_out, &intr_in, NULL);
+	if (ret) {
+		dev_err(&iface->dev, "Could not find all endpoints\n");
+		return -ENODEV;
+	}
+
+	ddata->ep_in = bulk_in->bEndpointAddress;
+	ddata->ep_out = bulk_out->bEndpointAddress;
+	ddata->ep_intr = intr_in->bEndpointAddress;
+	ddata->ep_intr_interval = intr_in->bInterval;
+
+	usb_set_intfdata(iface, ddata);
+
+	ret = mfd_add_devices(&iface->dev, PLATFORM_DEVID_AUTO, ch341_devs,
+			      ARRAY_SIZE(ch341_devs), NULL, 0, NULL);
+	if (ret)
+		return dev_err_probe(&iface->dev, ret,
+				     "Failed to register child devices\n");
+
+	return 0;
+}
+
+static void ch341_usb_disconnect(struct usb_interface *usb_if)
+{
+	mfd_remove_devices(&usb_if->dev);
+}
+
+static const struct usb_device_id ch341_usb_table[] = {
+	{ USB_DEVICE(0x1a86, 0x5512) },
+	{ }
+};
+MODULE_DEVICE_TABLE(usb, ch341_usb_table);
+
+static struct usb_driver ch341_usb_driver = {
+	.name       = "ch341-mfd",
+	.id_table   = ch341_usb_table,
+	.probe      = ch341_usb_probe,
+	.disconnect = ch341_usb_disconnect,
+};
+module_usb_driver(ch341_usb_driver);
+
+MODULE_AUTHOR("Frank Zago <frank@zago.net>");
+MODULE_DESCRIPTION("CH341 USB to I2C/SPI/GPIO adapter");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/mfd/ch341.h b/include/linux/mfd/ch341.h
new file mode 100644
index 000000000000..44f5da0720bd
--- /dev/null
+++ b/include/linux/mfd/ch341.h
@@ -0,0 +1,18 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Definitions for the CH341 driver */
+
+#include <linux/mutex.h>
+#include <linux/types.h>
+
+struct usb_device;
+struct usb_interface;
+
+struct ch341_ddata {
+	struct usb_device *usb_dev;
+	struct mutex usb_lock;
+
+	int ep_in;
+	int ep_out;
+	int ep_intr;
+	u8 ep_intr_interval;
+};