Overall nvmem side looks good!
Minor nits below.
On 14/06/18 21:08, Loic Poulain wrote:
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>
---
drivers/usb/serial/Kconfig | 11 +++++
drivers/usb/serial/ftdi_sio.c | 108 ++++++++++++++++++++++++++++++++++++++++++
drivers/usb/serial/ftdi_sio.h | 28 +++++++++++
3 files changed, 147 insertions(+)
diff --git a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig
index 533f127..2dd2f5d 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
Looks inconsistent tab and spaces here.
+ select NVMEM
+ default y
??
Does that mean all the FTDIs have EEPROM?
+ 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..03c9c75 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 +1532,104 @@ static int get_lsr_info(struct usb_serial_port *port,
return 0;
}
+#if IS_ENABLED(CONFIG_USB_SERIAL_FTDI_SIO_NVMEM)
I think only ifdef should be Okay here as this Kconfig is just bool
+
...
+static int register_eeprom(struct usb_serial_port *port)
+{
+ struct ftdi_private *priv = usb_get_serial_port_data(port);
+ struct nvmem_config nvmconf = {};
+
+ switch (priv->chip_type) {
+ case FTX:
+ nvmconf.size = 2048;
+ break;
+ case FT232RL:
+ nvmconf.size = 128;
+ break;
+ default:
+ return 0;
+ }
+
+ nvmconf.word_size = 2;
+ nvmconf.stride = 2;
+ nvmconf.read_only = false;
+ nvmconf.priv = port;
+ nvmconf.dev = &port->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;
+ }
+
+ 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 +1915,10 @@ static int ftdi_sio_port_probe(struct usb_serial_port *port)
priv->latency = 16;
write_latency_timer(port);
create_sysfs_attrs(port);
+#if IS_ENABLED(CONFIG_USB_SERIAL_FTDI_SIO_NVMEM)
+ register_eeprom(port);
Users will be clueless if the register_eeprom fails here.
+#endif
+
return 0;
}
@@ -1931,6 +2036,9 @@ static int ftdi_sio_port_remove(struct usb_serial_port *port)
{
struct ftdi_private *priv = usb_get_serial_port_data(port);
+#if IS_ENABLED(CONFIG_USB_SERIAL_FTDI_SIO_NVMEM)
+ unregister_eeprom(port);
+#endif
remove_sysfs_attrs(port);
kfree(priv);
thanks,
srini
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