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

[Greg Kroah-Hartman]

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@xxxxxxxx>
> > ---
> >  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@xxxxxxxxxxx>
> >  S:	Maintained
> >  F:	drivers/media/rc/winbond-cir.c
> >  
> > +WINCHIPHEAD CH341 I2C/GPIO MFD DRIVER
> > +M:	Frank Zago <frank@xxxxxxxx>
> > +L:	linux-usb@xxxxxxxxxxxxxxx
> > +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@xxxxxxxxx>
> >  L:	linux-watchdog@xxxxxxxxxxxxxxx
> > 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@xxxxxxxxxxxx)
> > + * Copyright (c) 2016 Tse Lun Bien
> > + * Copyright (c) 2014 Marco Gittler
> > + * Copyright (c) 2006-2007 Till Harbaum (Till@xxxxxxxxxxx)
> > + */
> > +
> > +#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@xxxxxxxx>");
> > +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@xxxxxxxxxxxxxxxxxxx>