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

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