Some FTDI devices like FTX or FT232R support CBUS Bit Bang mode on CBUS
pins, allowing host to control them via simple USB control transfers.
To make use of a CBUS pin in Bit Bang mode, the pin must be configured
to I/O mode in the FTDI EEPROM. This mode perfectly coexists with regular
USB to Serial function.
In this implementation, a GPIO controller is registered on FTDI probe
if at least one CBUS pin is configured for I/O mode. For now, only
FTX devices are supported.
This patch is based on previous Stefan Agner implementation tentative
on LKML ([PATCH 0/2] FTDI CBUS GPIO support).
Signed-off-by: Loic Poulain <loic.poul...@linaro.org>
---
drivers/usb/serial/Kconfig | 9 ++
drivers/usb/serial/ftdi_sio.c | 222 ++++++++++++++++++++++++++++++++++++++++++
drivers/usb/serial/ftdi_sio.h | 83 ++++++++++++++++
3 files changed, 314 insertions(+)
diff --git a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig
index 533f127..64c9f2e 100644
--- a/drivers/usb/serial/Kconfig
+++ b/drivers/usb/serial/Kconfig
@@ -181,6 +181,15 @@ config USB_SERIAL_FTDI_SIO
To compile this driver as a module, choose M here: the
module will be called ftdi_sio.
+config USB_SERIAL_FTDI_SIO_CBUS_GPIO
+ bool "USB FDTI CBUS GPIO support"
+ depends on USB_SERIAL_FTDI_SIO
+ depends on GPIOLIB
+ help
+ Say yes here to add support for the CBUS bit-bang mode, allowing CBUS
+ pins to act as GPIOs. Note that pins must first be configured for GPIO
+ in the device's EEPROM. The FT232R and FT-X series support this mode.
+
config USB_SERIAL_VISOR
tristate "USB Handspring Visor / Palm m50x / Sony Clie Driver"
help
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index b5cef32..3cfb5fd 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -33,6 +33,7 @@
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
+#include <linux/gpio/driver.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/mutex.h>
@@ -40,12 +41,19 @@
#include <linux/usb.h>
#include <linux/serial.h>
#include <linux/usb/serial.h>
+
#include "ftdi_sio.h"
#include "ftdi_sio_ids.h"
#define DRIVER_AUTHOR "Greg Kroah-Hartman <g...@kroah.com>, Bill Ryder
<bry...@sgi.com>, Kuba Ober <k...@mareimbrium.org>, Andreas Mohr, Johan Hovold
<jhov...@gmail.com>"
#define DRIVER_DESC "USB FTDI Serial Converters Driver"
+struct ftdi_gpiochip {
+ struct gpio_chip gc;
+ unsigned int cbus_map[4];
+ unsigned long cbus_mask;
+ struct usb_serial_port *port;
+};
struct ftdi_private {
enum ftdi_chip_type chip_type;
@@ -72,6 +80,8 @@ struct ftdi_private {
unsigned int latency; /* latency setting in use */
unsigned short max_packet_size;
struct mutex cfg_lock; /* Avoid mess by parallel calls of config
ioctl() and change_speed() */
+
+ struct ftdi_gpiochip *fgc;
};
/* struct ftdi_sio_quirk is used by devices requiring special attention. */
@@ -1528,6 +1538,211 @@ static int get_lsr_info(struct usb_serial_port *port,
return 0;
}
+#ifdef CONFIG_USB_SERIAL_FTDI_SIO_CBUS_GPIO
+
+static int ftdi_read_eeprom(struct usb_device *udev, unsigned int off,
+ void *val, size_t bytes)
+{
+ if (bytes % 2) /* 16-bit eeprom */
+ return -EINVAL;
+
+ while (bytes) {
+ int rv;
+
+ rv = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
+ FTDI_SIO_READ_EEPROM_REQUEST,
+ FTDI_SIO_READ_EEPROM_REQUEST_TYPE,
+ 0, off / 2, val, 2, WDR_TIMEOUT);
+ if (rv < 0)
+ return rv;
+
+ off += 2;
+ val += 2;
+ bytes -= 2;
+ }
+
+ return 0;
+}
+
+static int ftdi_set_bitmode(struct usb_serial_port *port, u8 bitmask,
+ u8 bitmode)
+{
+ struct ftdi_private *priv = usb_get_serial_port_data(port);
+ __u16 urb_value = 0;
+
+ urb_value = bitmode << 8 | bitmask;
+
+ if (usb_control_msg(port->serial->dev,
+ usb_sndctrlpipe(port->serial->dev, 0),
+ FTDI_SIO_SET_BITMODE_REQUEST,
+ FTDI_SIO_SET_BITMODE_REQUEST_TYPE,
+ urb_value, priv->interface,
+ NULL, 0, WDR_SHORT_TIMEOUT) < 0) {
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int ftdi_read_pins(struct usb_serial_port *port, u8 *val)
+{
+ struct ftdi_private *priv = usb_get_serial_port_data(port);
+ unsigned char *buf;
+
+ buf = kmalloc(1, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ if (usb_control_msg(port->serial->dev,
+ usb_rcvctrlpipe(port->serial->dev, 0),
+ FTDI_SIO_READ_PINS_REQUEST,
+ FTDI_SIO_READ_PINS_REQUEST_TYPE,
+ 0, priv->interface, buf, 1, WDR_TIMEOUT) < 0) {
+ kfree(buf);
+ return -EIO;
+ }
+
+ *val = buf[0];
+ kfree(buf);
+
+ return 0;
+}
+
+static int ftdi_cbus_gpio_dir_in(struct gpio_chip *gc, unsigned gpio)
+{
+ struct ftdi_gpiochip *fgc = gpiochip_get_data(gc);
+ unsigned int cbus_idx = fgc->cbus_map[gpio];
+
+ clear_bit(cbus_idx + 4, &fgc->cbus_mask);
+
+ return ftdi_set_bitmode(fgc->port, fgc->cbus_mask,
+ FTDI_SIO_BITMODE_CBUS);
+}
+
+static int ftdi_cbus_gpio_dir_out(struct gpio_chip *gc, unsigned gpio, int val)
+{
+ struct ftdi_gpiochip *fgc = gpiochip_get_data(gc);
+ unsigned int cbus_idx = fgc->cbus_map[gpio];
+
+ set_bit(cbus_idx + 4, &fgc->cbus_mask); /* direction */
+ set_bit(cbus_idx, &fgc->cbus_mask); /* value */
+
+ return ftdi_set_bitmode(fgc->port, fgc->cbus_mask,
+ FTDI_SIO_BITMODE_CBUS);
+}
+
+static int ftdi_cbus_gpio_get(struct gpio_chip *gc, unsigned gpio)
+{
+ struct ftdi_gpiochip *fgc = gpiochip_get_data(gc);
+ struct usb_device *udev = fgc->port->serial->dev;
+ unsigned int cbus_idx = fgc->cbus_map[gpio];
+ u8 val = 0;
+ int rv;
+
+ rv = ftdi_read_pins(fgc->port, &val);
+ if (rv)
+ dev_err(&udev->dev, "Unable to read CBUS GPIO pins, %d\n", rv);
+
+ return !!(val & BIT(cbus_idx));
+}
+
+static void ftdi_cbus_gpio_set(struct gpio_chip *gc, unsigned gpio, int val)
+{
+ struct ftdi_gpiochip *fgc = gpiochip_get_data(gc);
+ struct usb_device *udev = fgc->port->serial->dev;
+ int rv;
+
+ if (val)
+ set_bit(fgc->cbus_map[gpio], &fgc->cbus_mask);
+ else
+ clear_bit(fgc->cbus_map[gpio], &fgc->cbus_mask);
+
+ rv = ftdi_set_bitmode(fgc->port, fgc->cbus_mask, FTDI_SIO_BITMODE_CBUS);
+ if (rv)
+ dev_err(&udev->dev, "Unable set CBUS Bit-Bang mode, %d\n", rv);
+}
+
+static int ftdi_register_cbus_gpiochip(struct usb_serial_port *port)
+{
+ struct ftdi_private *priv = usb_get_serial_port_data(port);
+ struct usb_device *udev = port->serial->dev;
+ struct ftdi_gpiochip *fgc;
+ int rv;
+
+ fgc = kzalloc(sizeof(*fgc), GFP_KERNEL);
+ if (!fgc)
+ return -ENOMEM;
+
+ if (priv->chip_type == FTX) {
+ unsigned char *cbus_mux;
+ unsigned int i;
+
+ cbus_mux = kmalloc(4, GFP_KERNEL);
+ if (!cbus_mux)
+ return -ENOMEM;
+
+ /* CBUS pins are individually configurable via 8-bit MUX control
+ * value, living at 0x1a for CBUS0. cf application note AN_201.
+ */
+ rv = ftdi_read_eeprom(udev, 0x1a, cbus_mux, 4);
+ if (rv) {
+ dev_err(&udev->dev, "Unable to read CBUS config\n");
+ kfree(cbus_mux);
+ return -EIO;
+ }
+
+ for (i = 0; i < 4; i++) {
+ if (cbus_mux[i] == FTX_CBUS_MUX_IO)
+ fgc->cbus_map[fgc->gc.ngpio++] = i;
+ }
+
+ kfree(cbus_mux);
+ }
+
+ if (!fgc->gc.ngpio) {
+ kfree(fgc);
+ return 0;
+ }
+
+ fgc->gc.label = "ftdi-cbus-gpio";
+ fgc->gc.direction_input = ftdi_cbus_gpio_dir_in;
+ fgc->gc.direction_output = ftdi_cbus_gpio_dir_out;
+ fgc->gc.set = ftdi_cbus_gpio_set;
+ fgc->gc.get = ftdi_cbus_gpio_get;
+ fgc->gc.can_sleep = true;
+ fgc->gc.parent = &udev->dev;
+ fgc->gc.base = -1;
+ fgc->gc.owner = THIS_MODULE;
+ fgc->port = port;
+
+ rv = gpiochip_add_data(&fgc->gc, fgc);
+ if (rv) {
+ dev_err(&udev->dev, "Unable to add gpiochip\n");
+ kfree(fgc);
+ return rv;
+ }
+
+ priv->fgc = fgc;
+
+ dev_info(&udev->dev,
+ "FTDI USB GPIO controller Registered, base=%d, ngpio=%u\n",
+ fgc->gc.base, fgc->gc.ngpio);
+
+ return 0;
+}
+
+static void ftdi_unregister_cbus_gpiochip(struct usb_serial_port *port)
+{
+ struct ftdi_private *priv = usb_get_serial_port_data(port);
+ struct ftdi_gpiochip *fgc = priv->fgc;
+
+ if (fgc) {
+ gpiochip_remove(&fgc->gc);
+ kfree(fgc);
+ }
+}
+
+#endif /* CONFIG_USB_SERIAL_FTDI_SIO_CBUS_GPIO */
/* Determine type of FTDI chip based on USB config and descriptor. */
static void ftdi_determine_type(struct usb_serial_port *port)
@@ -1813,6 +2028,10 @@ static int ftdi_sio_port_probe(struct usb_serial_port
*port)
priv->latency = 16;
write_latency_timer(port);
create_sysfs_attrs(port);
+#ifdef CONFIG_USB_SERIAL_FTDI_SIO_CBUS_GPIO
+ ftdi_register_cbus_gpiochip(port);
+#endif
+
return 0;
}
@@ -1930,6 +2149,9 @@ static int ftdi_sio_port_remove(struct usb_serial_port
*port)
{
struct ftdi_private *priv = usb_get_serial_port_data(port);
+#ifdef CONFIG_USB_SERIAL_FTDI_SIO_CBUS_GPIO
+ ftdi_unregister_cbus_gpiochip(port);
+#endif
remove_sysfs_attrs(port);
kfree(priv);
diff --git a/drivers/usb/serial/ftdi_sio.h b/drivers/usb/serial/ftdi_sio.h
index dcd0b6e..3bd248f 100644
--- a/drivers/usb/serial/ftdi_sio.h
+++ b/drivers/usb/serial/ftdi_sio.h
@@ -36,6 +36,10 @@
#define FTDI_SIO_SET_ERROR_CHAR 7 /* Set the error character */
#define FTDI_SIO_SET_LATENCY_TIMER 9 /* Set the latency timer */
#define FTDI_SIO_GET_LATENCY_TIMER 10 /* Get the latency timer */
+#define FTDI_SIO_SET_BITMODE 11 /* Set the bitmode */
+#define FTDI_SIO_READ_PINS 12 /* Read pins in bitmode */
+#define FTDI_SIO_READ_EEPROM 0x90 /* Read eeprom */
+#define FTDI_SIO_WRITE_EEPROM 0x91 /* Write eeprom */
/* Interface indices for FT2232, FT2232H and FT4232H devices */
#define INTERFACE_A 1
@@ -400,6 +404,60 @@ enum ftdi_sio_baudrate {
*
*/
+ /* FTDI_SIO_READ_EEPROM */
+#define FTDI_SIO_READ_EEPROM_REQUEST_TYPE 0xc0
+#define FTDI_SIO_READ_EEPROM_REQUEST FTDI_SIO_READ_EEPROM
+/*
+ * BmRequestType: 1100 0000b
+ * bRequest: FTDI_SIO_READ_EEPROM
+ * wValue: 0
+ * wIndex: Word Index
+ * wLength: 2
+ * Data: return data (a word)
+ *
+ */
+
+/* FTDI_SIO_WRITE_EEPROM */
+#define FTDI_SIO_WRITE_EEPROM_REQUEST_TYPE 0x40
+#define FTDI_SIO_WRITE_EEPROM_REQUEST FTDI_SIO_WRITE_EEPROM
+/*
+ * BmRequestType: 0100 0000b
+ * bRequest: FTDI_SIO_WRITE_EEPROM
+ * wValue: Data (word)
+ * wIndex: Word Index
+ * wLength: 0
+ * Data: None
+ *
+ */
+
+ /* FTDI_SIO_SET_BITMODE */
+#define FTDI_SIO_SET_BITMODE_REQUEST_TYPE 0x40
+#define FTDI_SIO_SET_BITMODE_REQUEST FTDI_SIO_SET_BITMODE
+#define FTDI_SIO_BITMODE_RESET 0x00
+#define FTDI_SIO_BITMODE_CBUS 0x20
+/*
+ * BmRequestType: 0100 0000b
+ * bRequest: FTDI_SIO_SET_BITMODE
+ * wValue: [0-7] bitmask, [8-15] bitmode
+ * wIndex: Port
+ * wLength: 0
+ * Data: None
+ *
+ */
+
+/* FTDI_SIO_READ_PINS */
+#define FTDI_SIO_READ_PINS_REQUEST_TYPE 0xC0
+#define FTDI_SIO_READ_PINS_REQUEST FTDI_SIO_READ_PINS
+/*
+ * BmRequestType: 1100 0000b
+ * bRequest: FTDI_SIO_READ_PINS
+ * wValue: 0
+ * wIndex: Port
+ * wLength: 2
+ * Data: return data (a word)
+ *
+ */
+
/* FTDI_SIO_GET_MODEM_STATUS */
/* Retrieve the current value of the modem status register */
@@ -563,3 +621,28 @@ enum ftdi_sio_baudrate {
* B2..7 Length of message - (not including Byte 0)
*
*/
+
+enum ftdi_ftx_cbus_mux {
+ FTX_CBUS_MUX_TRISTATE,
+ FTX_CBUS_MUX_RXLED,
+ FTX_CBUS_MUX_TXLED,
+ FTX_CBUS_MUX_TXRXLED,
+ FTX_CBUS_MUX_PWREN,
+ FTX_CBUS_MUX_SLEEP,
+ FTX_CBUS_MUX_DRIVE0,
+ FTX_CBUS_MUX_DRIVE1,
+ FTX_CBUS_MUX_IO,
+ FTX_CBUS_MUX_TXDEN,
+ FTX_CBUS_MUX_CLK24,
+ FTX_CBUS_MUX_CLK12,
+ FTX_CBUS_MUX_CLK6,
+ FTX_CBUS_MUX_BCD_CHARGER,
+ FTX_CBUS_MUX_BCD_CHARGER_N,
+ FTX_CBUS_MUX_I2C_TXE,
+ FTX_CBUS_MUX_I2C_RXF,
+ FTX_CBUS_MUX_VBUS_SENSE,
+ FTX_CBUS_MUX_BITBANG_WR,
+ FTX_CBUS_MUX_BITBANG_RD,
+ FTX_CBUS_MUX_TIMESTAMP,
+ FTX_CBUS_MUX_KEEP_AWAKE
+};
--
2.7.4
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