Most of FTDI's devices have an EEPROM which records FTDI devices
configuration setting (e.g. the VID, PID, I/O config...) and user
data. FT230R chip integrates a 128-byte eeprom, FT230X a 2048-byte
eeprom...
This patch adds support for FTDI EEPROM read/write via USB control
transfers and register a new nvm device to the nvmem core.
This permits to expose the eeprom as a sysfs file, allowing userspace
to read/modify FTDI configuration and its user data without having to
rely on a specific userspace USB driver.
Moreover, any upcoming new tentative to add CBUS GPIO support could
integrate CBUS EEPROM configuration reading in order to determine
which of the CBUS pins are available as GPIO.
Signed-off-by: Loic Poulain <loic.poulain@xxxxxxxxxx>
---
v2: Use ifdef instead of IS_ENABLED
error message in case of nvmem registering failure
Fix space/tab in Kconfig
v3: Make nvmem a child of the usb dev instead of the serial port
Add macros defining eeprom sizes
Check read/write size is a nultiple of the eeprom word-size
Remove useless change in Kconfig
drivers/usb/serial/Kconfig | 11 ++++
drivers/usb/serial/ftdi_sio.c | 123 ++++++++++++++++++++++++++++++++++++++++++
drivers/usb/serial/ftdi_sio.h | 28 ++++++++++
3 files changed, 162 insertions(+)
diff --git a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig
index 533f127..ee9230c 100644
--- a/drivers/usb/serial/Kconfig
+++ b/drivers/usb/serial/Kconfig
@@ -181,6 +181,17 @@ 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_NVMEM
+ bool "FTDI MTP non-volatile memory support"
+ depends on USB_SERIAL_FTDI_SIO
+ select NVMEM
+ default y
+ help
+ Say yes here to add support for the MTP non-volatile memory
+ present on FTDI. Most of FTDI's devices have an EEPROM which
+ records FTDI device's configuration setting as well as user
+ data.
+
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 7ea221d..8183b02 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -40,6 +40,7 @@
#include <linux/usb.h>
#include <linux/serial.h>
#include <linux/usb/serial.h>
+#include <linux/nvmem-provider.h>
#include "ftdi_sio.h"
#include "ftdi_sio_ids.h"
@@ -73,6 +74,8 @@ 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 nvmem_device *eeprom;
};
/* struct ftdi_sio_quirk is used by devices requiring special attention. */
@@ -1529,6 +1532,116 @@ static int get_lsr_info(struct usb_serial_port *port,
return 0;
}
+#ifdef CONFIG_USB_SERIAL_FTDI_SIO_NVMEM
+
+#define EEPROM_SZ_FTX 2048 /* cf FTDI AN_201 */
+#define EEPROM_SZ_FT232RL 128 /* cf FTDI AN_121 */
+
+static int write_eeprom(void *priv, unsigned int off, void *_val, size_t bytes)
+{
+ struct usb_serial_port *port = priv;
+ struct usb_serial *serial = port->serial;
+ struct usb_device *udev = serial->dev;
+ unsigned char *buf = _val;
+
+ if (bytes % 2) /* 16-bit eeprom */
+ return -EINVAL;
+
+ while (bytes) {
+ uint16_t val;
+ int rv;
+
+ val = buf[0] + (buf[1] << 8);
+
+ rv = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+ FTDI_SIO_WRITE_EEPROM_REQUEST,
+ FTDI_SIO_WRITE_EEPROM_REQUEST_TYPE,
+ val, off / 2, NULL, 0, WDR_TIMEOUT);
+ if (rv < 0)
+ return rv;
+
+ off += 2;
+ buf += 2;
+ bytes -= 2;
+ }
+
+ return 0;
+}
+
+static int read_eeprom(void *priv, unsigned int off, void *val, size_t bytes)
+{
+ struct usb_serial_port *port = priv;
+ struct usb_serial *serial = port->serial;
+ struct usb_device *udev = serial->dev;
+ unsigned char *buf = val;
+
+ 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, buf, 2, WDR_TIMEOUT);
+ if (rv < 0)
+ return rv;
+
+ off += 2;
+ buf += 2;
+ bytes -= 2;
+ }
+
+ return 0;
+}
+
+static int register_eeprom(struct usb_serial_port *port)
+{
+ struct ftdi_private *priv = usb_get_serial_port_data(port);
+ struct usb_device *udev = port->serial->dev;
+ struct nvmem_config nvmconf = {};
+
+ switch (priv->chip_type) {
+ case FTX:
+ nvmconf.size = EEPROM_SZ_FTX;
+ break;
+ case FT232RL:
+ nvmconf.size = EEPROM_SZ_FT232RL;
+ break;
+ default:
+ return 0;
+ }
+
+ nvmconf.word_size = 2;
+ nvmconf.stride = 2;
+ nvmconf.read_only = false;
+ nvmconf.priv = port;
+ nvmconf.dev = &udev->dev;
+ nvmconf.reg_read = read_eeprom;
+ nvmconf.reg_write = write_eeprom;
+ nvmconf.owner = THIS_MODULE;
+
+ priv->eeprom = nvmem_register(&nvmconf);
+ if (IS_ERR(priv->eeprom)) {
+ priv->eeprom = NULL;
+ return -ENOMEM;
+ }
+
+ dev_info(&udev->dev, "Registered %d-byte FTDI EEPROM\n", nvmconf.size);
+
+ return 0;
+}
+
+static void unregister_eeprom(struct usb_serial_port *port)
+{
+ struct ftdi_private *priv = usb_get_serial_port_data(port);
+
+ if (priv->eeprom)
+ nvmem_unregister(priv->eeprom);
+}
+
+#endif /* CONFIG_USB_SERIAL_FTDI_SIO_NVMEM */
/* Determine type of FTDI chip based on USB config and descriptor. */
static void ftdi_determine_type(struct usb_serial_port *port)
@@ -1814,6 +1927,13 @@ 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_NVMEM
+ if (register_eeprom(port)) {
+ dev_err(&port->dev, "Unable to register FTDI EEPROM\n");
+ /* non-fatal */
+ }
+#endif
+
return 0;
}
@@ -1931,6 +2051,9 @@ 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_NVMEM
+ unregister_eeprom(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..9eab961 100644
--- a/drivers/usb/serial/ftdi_sio.h
+++ b/drivers/usb/serial/ftdi_sio.h
@@ -36,6 +36,8 @@
#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_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 +402,32 @@ 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_GET_MODEM_STATUS */
/* Retrieve the current value of the modem status register */
--
2.7.4
--
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