Hi Loic.
Thanks for fixing comments. Looks good to me now.
On 6/26/18, Loic Poulain <loic.poulain@xxxxxxxxxx> 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. For example, FT232R and FTX chips have 128-byte and 2048-byte
> internal EEPROM respectively.
>
> 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.
>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> Signed-off-by: Loic Poulain <loic.poulain@xxxxxxxxxx>
Reviewed-by: Ajay Gupta <ajaykuee@xxxxxxxxx>
> ---
> 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
> v4: Reword commit message
> Remove default-yes from Kconfig
> Change includes ordering
> Use default linux size defines
> Use get_unaligned_le16 helper
> Prepend EEPROM functions with ftdi_
> Error message in ftdi_eeprom_register()
> v5: Fix missing linux/sizes header
> v6: Ordering new headers insertion
> Remove unecessary additional buf pointer from read/write_eeprom
>
> drivers/usb/serial/Kconfig | 10 ++++
> drivers/usb/serial/ftdi_sio.c | 118
> ++++++++++++++++++++++++++++++++++++++++++
> drivers/usb/serial/ftdi_sio.h | 28 ++++++++++
> 3 files changed, 156 insertions(+)
>
> diff --git a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig
> index 533f127..5747562 100644
> --- a/drivers/usb/serial/Kconfig
> +++ b/drivers/usb/serial/Kconfig
> @@ -181,6 +181,16 @@ 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
> + 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..34daa8c 100644
> --- a/drivers/usb/serial/ftdi_sio.c
> +++ b/drivers/usb/serial/ftdi_sio.c
> @@ -34,12 +34,17 @@
> #include <linux/tty_driver.h>
> #include <linux/tty_flip.h>
> #include <linux/module.h>
> +#include <linux/nvmem-provider.h>
> +#include <linux/sizes.h>
> #include <linux/spinlock.h>
> #include <linux/mutex.h>
> #include <linux/uaccess.h>
> #include <linux/usb.h>
> #include <linux/serial.h>
> #include <linux/usb/serial.h>
> +
> +#include <asm/unaligned.h>
> +
> #include "ftdi_sio.h"
> #include "ftdi_sio_ids.h"
>
> @@ -73,6 +78,8 @@ 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 +1536,110 @@ static int get_lsr_info(struct usb_serial_port
> *port,
> return 0;
> }
>
> +#ifdef CONFIG_USB_SERIAL_FTDI_SIO_NVMEM
> +
> +static int ftdi_write_eeprom(void *priv, unsigned int off, void *val,
> + size_t bytes)
> +{
> + struct usb_serial_port *port = priv;
> + struct usb_device *udev = port->serial->dev;
> +
> + if (bytes % 2) /* 16-bit eeprom */
> + return -EINVAL;
> +
> + while (bytes) {
> + int rv;
> +
> + rv = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
> + FTDI_SIO_WRITE_EEPROM_REQUEST,
> + FTDI_SIO_WRITE_EEPROM_REQUEST_TYPE,
> + get_unaligned_le16(val), off / 2, NULL,
> + 0, WDR_TIMEOUT);
> + if (rv < 0)
> + return rv;
> +
> + off += 2;
> + val += 2;
> + bytes -= 2;
> + }
> +
> + return 0;
> +}
> +
> +static int ftdi_read_eeprom(void *priv, unsigned int off, void *val,
> + size_t bytes)
> +{
> + struct usb_serial_port *port = priv;
> + struct usb_device *udev = port->serial->dev;
> +
> + 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_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 = SZ_2K;
> + break;
> + case FT232RL:
> + nvmconf.size = SZ_128;
> + 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 = ftdi_read_eeprom;
> + nvmconf.reg_write = ftdi_write_eeprom;
> + nvmconf.owner = THIS_MODULE;
> +
> + priv->eeprom = nvmem_register(&nvmconf);
> + if (IS_ERR(priv->eeprom)) {
> + dev_err(&udev->dev, "Unable to register FTDI EEPROM\n");
> + priv->eeprom = NULL;
> + return -ENOMEM;
> + }
> +
> + dev_info(&udev->dev, "Registered %d-byte FTDI EEPROM\n", nvmconf.size);
> +
> + return 0;
> +}
> +
> +static void ftdi_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 +1925,10 @@ 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_NVMEM
> + ftdi_register_eeprom(port);
> +#endif
> +
> return 0;
> }
>
> @@ -1931,6 +2046,9 @@ 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
> + ftdi_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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