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> --- Documentation/misc-devices/ch341.rst | 114 +++++++++++++++++++++++++++ Documentation/misc-devices/index.rst | 1 + MAINTAINERS | 7 ++ drivers/mfd/Kconfig | 12 +++ drivers/mfd/Makefile | 1 + drivers/mfd/ch341-core.c | 103 ++++++++++++++++++++++++ include/linux/mfd/ch341.h | 25 ++++++ 7 files changed, 263 insertions(+) create mode 100644 Documentation/misc-devices/ch341.rst create mode 100644 drivers/mfd/ch341-core.c create mode 100644 include/linux/mfd/ch341.h diff --git a/Documentation/misc-devices/ch341.rst b/Documentation/misc-devices/ch341.rst new file mode 100644 index 000000000000..a4884918cd32 --- /dev/null +++ b/Documentation/misc-devices/ch341.rst @@ -0,0 +1,114 @@ +.. SPDX-License-Identifier: GPL-2.0-or-later + +=========================================================== +WinChipHead (沁恒) CH341 linux driver for I2C and GPIO mode +=========================================================== + +The CH341 is declined in several flavors, and may support one or more +of UART, SPI, I2C and GPIO, but not always simultaneously: + + - CH341 A/B/F: UART, Printer, SPI, I2C and GPIO + - CH341 C/T: UART and I2C + - CH341 H: SPI + +They work in 3 different modes, with only one being presented +depending on the USB PID: + + - 0x5523: UART mode, covered by the USB `ch341` serial driver + - 0x5512: SPI/I2C/GPIO mode, covered by the MFD `ch341-mfd` driver + - 0x5584: Parallel printer mode, covered by the USB `usblp` driver + +Mode selection is done at the hardware level by tying some +pins. Breakout boards with one of the CH341 chip usually have one or +more jumpers to select which mode they work on. At least one model +(CJMCU-341) appears to need bridging some solder pads to select a +different default. Breakout boards also don't usually offer an option +to configure the chip into printer mode; for that case, connect the +SCL and SDA lines directly together. + +The various CH341 appear to be indistinguishable from the +software. For instance the ch341 MFD driver will present a GPIO +interface for the CH341T although physical pins are not present, and +the device will accept GPIO commands. + +The ch341 MFD driver has been tested with a CH341A, CH341B and +CH341T. + +Some breakout boards work in 3.3V and 5V depending on some jumpers. + +The black chip programmer with a ZIF socket will power the CH341 at +3.3V if a jumper is set, but will only output 5V to the chips to be +programmed, which is not always desirable. A hardware hack to use 3.3V +everywhere, involving some soldering, is available at +https://eevblog.com/forum/repair/ch341a-serial-memory-programmer-power-supply-fix/ + +Some sample code for the CH341 is available at the manufacturer +website, at http://wch-ic.com/products/CH341.html + +The repository at https://github.com/boseji/CH341-Store contains a lot +of information on these chips, including datasheets. + +This driver is based on the pre-existing work at +https://github.com/gschorcht/i2c-ch341-usb + + +I2C Caveats +----------- + +The ch341 doesn't work with a Wii nunchuk, possibly because the +pull-up value is too low (1500 ohms). + +i2c AT24 eeproms can be read but not programmed properly because the +at24 linux driver tries to write a byte at a time, and doesn't wait at +all (or enough) between writes. Data corruption on writes does occur. + +The driver doesn't support detection of I2C device present on the +bus. Apparently when a device is not present at a given address, the +CH341 will return an extra byte of data, but the driver doesn't +support that. This may be addressed in the future. + + +The GPIOs +--------- + +16 GPIOs are available on the CH341 A/B/F. The first 6 are input/output, +and the last 10 are input only. + +Pinout and their names as they appear on some breakout boards:: + + CH341A/B/F GPIO Names Mode + pin line + + 15 0 D0, CS0 input/output + 16 1 D1, CS1 input/output + 17 2 D2, CS2 input/output + 18 3 D3, SCK, DCK input/output + 19 4 D4, DOUT2, CS3 input/output + 20 5 D5, MOSI, DOUT, SDO input/output + 21 6 D6, DIN2 input + 22 7 D7, MISO, DIN input + 5 8 ERR input + 6 9 PEMP input + 7 10 INT input + 8 11 SLCT (SELECT) input + 26 12 RST# (?) input + 27 13 WT (WAIT) input + 4 14 DS (Data Select?) input + 3 15 AS (Address Select?) input + + +GPIO interrupt +~~~~~~~~~~~~~~ + +The INT pin, corresponding to GPIO 10 is an input pin that can trigger +an interrupt on a rising edge. Only that pin is able to generate an +interrupt, and only on a rising edge. Trying to monitor events on +another GPIO, or that GPIO on something other than a rising edge, will +be rejected. + + +SPI +--- + +This driver doesn't offer an SPI interface (yet) due to the +impossibility of declaring an SPI device like I2C does. diff --git a/Documentation/misc-devices/index.rst b/Documentation/misc-devices/index.rst index 30ac58f81901..190f93b56ec6 100644 --- a/Documentation/misc-devices/index.rst +++ b/Documentation/misc-devices/index.rst @@ -29,3 +29,4 @@ fit into other categories. spear-pcie-gadget uacce xilinx_sdfec + ch341 diff --git a/MAINTAINERS b/MAINTAINERS index cd0f68d4a34a..a6b2805fd1a1 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -20845,6 +20845,13 @@ 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 ba0b3eb131f1..84067e454c90 100644 --- a/drivers/mfd/Kconfig +++ b/drivers/mfd/Kconfig @@ -1778,6 +1778,18 @@ 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. + + The chip's SPI mode is not supported. + + 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 df1ecc4a4c95..a0364a0d5e33 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..fbb2897cd956 --- /dev/null +++ b/drivers/mfd/ch341-core.c @@ -0,0 +1,103 @@ +// 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/module.h> +#include <linux/slab.h> +#include <linux/mfd/core.h> + +#include <linux/mfd/ch341.h> + +static const struct mfd_cell ch341_devs[] = { +}; + +static int ch341_usb_probe(struct usb_interface *iface, + const struct usb_device_id *usb_id) +{ + struct usb_host_endpoint *endpoints; + struct ch341_device *dev; + int rc; + + dev = kzalloc(sizeof(*dev), GFP_KERNEL); + if (!dev) + return -ENOMEM; + + dev->usb_dev = usb_get_dev(interface_to_usbdev(iface)); + dev->iface = iface; + mutex_init(&dev->usb_lock); + + if (iface->cur_altsetting->desc.bNumEndpoints != 3) { + rc = -ENODEV; + goto free_dev; + } + + endpoints = iface->cur_altsetting->endpoint; + if (!usb_endpoint_is_bulk_in(&endpoints[0].desc) || + !usb_endpoint_is_bulk_out(&endpoints[1].desc) || + !usb_endpoint_xfer_int(&endpoints[2].desc)) { + rc = -ENODEV; + goto free_dev; + } + + dev->ep_in = endpoints[0].desc.bEndpointAddress; + dev->ep_out = endpoints[1].desc.bEndpointAddress; + dev->ep_intr = endpoints[2].desc.bEndpointAddress; + dev->ep_intr_interval = endpoints[2].desc.bInterval; + + usb_set_intfdata(iface, dev); + + rc = mfd_add_hotplug_devices(&iface->dev, ch341_devs, + ARRAY_SIZE(ch341_devs)); + if (rc) { + dev_err(&iface->dev, "Failed to add mfd devices to core."); + goto free_dev; + } + + return 0; + +free_dev: + usb_put_dev(dev->usb_dev); + kfree(dev); + + return rc; +} + +static void ch341_usb_disconnect(struct usb_interface *usb_if) +{ + struct ch341_device *dev = usb_get_intfdata(usb_if); + + mfd_remove_devices(&usb_if->dev); + usb_set_intfdata(dev->iface, NULL); + usb_put_dev(dev->usb_dev); + kfree(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("Various"); +MODULE_DESCRIPTION("CH341 USB to I2C/SPI/GPIO adapter"); +MODULE_LICENSE("GPL v2"); diff --git a/include/linux/mfd/ch341.h b/include/linux/mfd/ch341.h new file mode 100644 index 000000000000..246159477cdf --- /dev/null +++ b/include/linux/mfd/ch341.h @@ -0,0 +1,25 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Definitions for CH341 MFD driver + */ + +#include <linux/usb.h> +#include <linux/mutex.h> + +#define DEFAULT_TIMEOUT 1000 /* 1s USB requests timeout */ + +/* All commands fit inside a 32-byte segment. There may be several + * of these segments in a USB command. + */ +#define SEG_SIZE 32 + +struct ch341_device { + struct usb_device *usb_dev; + struct usb_interface *iface; + struct mutex usb_lock; + + int ep_in; + int ep_out; + int ep_intr; + u8 ep_intr_interval; +}; -- 2.32.0
