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

[Lee Jones]

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;
> +};

-- 
Lee Jones [李琼斯]
Principal Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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