[PATCH 06/12] USB: serial: xr: add type abstraction

Johan Hovold
2021-03-30T14:40:28Z

There are at least four types of Maxlinear/Exar USB UARTs which differ
in various ways such as in their register layouts:

XR21V141X
XR21B142X
XR21B1411
XR22804

It is not clear whether the device type can be inferred from the
descriptors so encode it in the device-id table for now.

Add a type structure that can be used to abstract the register layout
and other features, and use it when accessing the XR21V141X UART
registers that are shared by all types.

Note that the currently supported XR21V141X type is the only type that
has a set of UART Manager registers and that these will need to be
handled specifically.

Similarly, XR21V141X is the only type which has the divisor registers
and that needs to use the format register when configuring the line
settings.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/usb/serial/xr_serial.c | 128 ++++++++++++++++++++++-----------
1 file changed, 85 insertions(+), 43 deletions(-)

diff --git a/drivers/usb/serial/xr_serial.c b/drivers/usb/serial/xr_serial.c
index bbfe92fcabc0..003aa1e04c85 100644
--- a/drivers/usb/serial/xr_serial.c
+++ b/drivers/usb/serial/xr_serial.c
@@ -29,10 +29,16 @@ struct xr_txrx_clk_mask {
#define XR21V141X_MIN_SPEED 46U
#define XR21V141X_MAX_SPEED XR_INT_OSC_HZ

-/* USB Requests */
+/* USB requests */
#define XR21V141X_SET_REQ 0
#define XR21V141X_GET_REQ 1

+/* XR21V141X register blocks */
+#define XR21V141X_UART_REG_BLOCK 0
+#define XR21V141X_UM_REG_BLOCK 4
+#define XR21V141X_UART_CUSTOM_BLOCK 0x66
+
+/* XR21V141X UART registers */
#define XR21V141X_CLOCK_DIVISOR_0 0x04
#define XR21V141X_CLOCK_DIVISOR_1 0x05
#define XR21V141X_CLOCK_DIVISOR_2 0x06
@@ -40,13 +46,9 @@ struct xr_txrx_clk_mask {
#define XR21V141X_TX_CLOCK_MASK_1 0x08
#define XR21V141X_RX_CLOCK_MASK_0 0x09
#define XR21V141X_RX_CLOCK_MASK_1 0x0a
+#define XR21V141X_REG_FORMAT 0x0b

-/* XR21V141X register blocks */
-#define XR21V141X_UART_REG_BLOCK 0
-#define XR21V141X_UM_REG_BLOCK 4
-#define XR21V141X_UART_CUSTOM_BLOCK 0x66
-
-/* XR21V141X UART Manager Registers */
+/* XR21V141X UART Manager registers */
#define XR21V141X_UM_FIFO_ENABLE_REG 0x10
#define XR21V141X_UM_ENABLE_TX_FIFO 0x01
#define XR21V141X_UM_ENABLE_RX_FIFO 0x02
@@ -94,23 +96,42 @@ struct xr_txrx_clk_mask {
#define XR_GPIO_MODE_RS485 0x3
#define XR_GPIO_MODE_RS485_ADDR 0x4

-#define XR21V141X_REG_ENABLE 0x03
-#define XR21V141X_REG_FORMAT 0x0b
-#define XR21V141X_REG_FLOW_CTRL 0x0c
-#define XR21V141X_REG_XON_CHAR 0x10
-#define XR21V141X_REG_XOFF_CHAR 0x11
-#define XR21V141X_REG_LOOPBACK 0x12
-#define XR21V141X_REG_TX_BREAK 0x14
-#define XR21V141X_REG_RS845_DELAY 0x15
-#define XR21V141X_REG_GPIO_MODE 0x1a
-#define XR21V141X_REG_GPIO_DIR 0x1b
-#define XR21V141X_REG_GPIO_INT_MASK 0x1c
-#define XR21V141X_REG_GPIO_SET 0x1d
-#define XR21V141X_REG_GPIO_CLR 0x1e
-#define XR21V141X_REG_GPIO_STATUS 0x1f
+struct xr_type {
+ u8 uart_enable;
+ u8 flow_control;
+ u8 xon_char;
+ u8 xoff_char;
+ u8 tx_break;
+ u8 gpio_mode;
+ u8 gpio_direction;
+ u8 gpio_set;
+ u8 gpio_clear;
+ u8 gpio_status;
+};
+
+enum xr_type_id {
+ XR21V141X,
+ XR_TYPE_COUNT,
+};
+
+static const struct xr_type xr_types[] = {
+ [XR21V141X] = {
+ .uart_enable = 0x03,
+ .flow_control = 0x0c,
+ .xon_char = 0x10,
+ .xoff_char = 0x11,
+ .tx_break = 0x14,
+ .gpio_mode = 0x1a,
+ .gpio_direction = 0x1b,
+ .gpio_set = 0x1d,
+ .gpio_clear = 0x1e,
+ .gpio_status = 0x1f,
+ },
+};

struct xr_data {
- u8 channel; /* zero-based index */
+ const struct xr_type *type;
+ u8 channel; /* zero-based index */
};

static int xr_set_reg(struct usb_serial_port *port, u8 block, u8 reg, u8 val)
@@ -202,6 +223,7 @@ static int xr_set_reg_um(struct usb_serial_port *port, u8 reg_base, u8 val)
*/
static int xr_uart_enable(struct usb_serial_port *port)
{
+ struct xr_data *data = usb_get_serial_port_data(port);
int ret;

ret = xr_set_reg_um(port, XR21V141X_UM_FIFO_ENABLE_REG,
@@ -209,25 +231,25 @@ static int xr_uart_enable(struct usb_serial_port *port)
if (ret)
return ret;

- ret = xr_set_reg_uart(port, XR21V141X_REG_ENABLE,
+ ret = xr_set_reg_uart(port, data->type->uart_enable,
XR_UART_ENABLE_TX | XR_UART_ENABLE_RX);
if (ret)
return ret;

ret = xr_set_reg_um(port, XR21V141X_UM_FIFO_ENABLE_REG,
XR21V141X_UM_ENABLE_TX_FIFO | XR21V141X_UM_ENABLE_RX_FIFO);
-
if (ret)
- xr_set_reg_uart(port, XR21V141X_REG_ENABLE, 0);
+ xr_set_reg_uart(port, data->type->uart_enable, 0);

return ret;
}

static int xr_uart_disable(struct usb_serial_port *port)
{
+ struct xr_data *data = usb_get_serial_port_data(port);
int ret;

- ret = xr_set_reg_uart(port, XR21V141X_REG_ENABLE, 0);
+ ret = xr_set_reg_uart(port, data->type->uart_enable, 0);
if (ret)
return ret;

@@ -239,10 +261,11 @@ static int xr_uart_disable(struct usb_serial_port *port)
static int xr_tiocmget(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
+ struct xr_data *data = usb_get_serial_port_data(port);
u8 status;
int ret;

- ret = xr_get_reg_uart(port, XR21V141X_REG_GPIO_STATUS, &status);
+ ret = xr_get_reg_uart(port, data->type->gpio_status, &status);
if (ret)
return ret;

@@ -263,6 +286,8 @@ static int xr_tiocmget(struct tty_struct *tty)
static int xr_tiocmset_port(struct usb_serial_port *port,
unsigned int set, unsigned int clear)
{
+ struct xr_data *data = usb_get_serial_port_data(port);
+ const struct xr_type *type = data->type;
u8 gpio_set = 0;
u8 gpio_clr = 0;
int ret = 0;
@@ -279,10 +304,10 @@ static int xr_tiocmset_port(struct usb_serial_port *port,

/* Writing '0' to gpio_{set/clr} bits has no effect, so no need to do */
if (gpio_clr)
- ret = xr_set_reg_uart(port, XR21V141X_REG_GPIO_CLR, gpio_clr);
+ ret = xr_set_reg_uart(port, type->gpio_clear, gpio_clr);

if (gpio_set)
- ret = xr_set_reg_uart(port, XR21V141X_REG_GPIO_SET, gpio_set);
+ ret = xr_set_reg_uart(port, type->gpio_set, gpio_set);

return ret;
}
@@ -306,6 +331,8 @@ static void xr_dtr_rts(struct usb_serial_port *port, int on)
static void xr_break_ctl(struct tty_struct *tty, int break_state)
{
struct usb_serial_port *port = tty->driver_data;
+ struct xr_data *data = usb_get_serial_port_data(port);
+ const struct xr_type *type = data->type;
u8 state;

if (break_state == 0)
@@ -315,7 +342,7 @@ static void xr_break_ctl(struct tty_struct *tty, int break_state)

dev_dbg(&port->dev, "Turning break %s\n",
state == XR21V141X_UART_BREAK_OFF ? "off" : "on");
- xr_set_reg_uart(port, XR21V141X_REG_TX_BREAK, state);
+ xr_set_reg_uart(port, type->tx_break, state);
}

/* Tx and Rx clock mask values obtained from section 3.3.4 of datasheet */
@@ -425,10 +452,12 @@ static void xr_set_flow_mode(struct tty_struct *tty,
struct usb_serial_port *port,
struct ktermios *old_termios)
{
+ struct xr_data *data = usb_get_serial_port_data(port);
+ const struct xr_type *type = data->type;
u8 flow, gpio_mode;
int ret;

- ret = xr_get_reg_uart(port, XR21V141X_REG_GPIO_MODE, &gpio_mode);
+ ret = xr_get_reg_uart(port, type->gpio_mode, &gpio_mode);
if (ret)
return;

@@ -446,8 +475,8 @@ static void xr_set_flow_mode(struct tty_struct *tty,
dev_dbg(&port->dev, "Enabling sw flow ctrl\n");
flow = XR_UART_FLOW_MODE_SW;

- xr_set_reg_uart(port, XR21V141X_REG_XON_CHAR, start_char);
- xr_set_reg_uart(port, XR21V141X_REG_XOFF_CHAR, stop_char);
+ xr_set_reg_uart(port, type->xon_char, start_char);
+ xr_set_reg_uart(port, type->xoff_char, stop_char);
} else {
dev_dbg(&port->dev, "Disabling flow ctrl\n");
flow = XR_UART_FLOW_MODE_NONE;
@@ -458,10 +487,10 @@ static void xr_set_flow_mode(struct tty_struct *tty,
* FLOW_CONTROL register.
*/
xr_uart_disable(port);
- xr_set_reg_uart(port, XR21V141X_REG_FLOW_CTRL, flow);
+ xr_set_reg_uart(port, type->flow_control, flow);
xr_uart_enable(port);

- xr_set_reg_uart(port, XR21V141X_REG_GPIO_MODE, gpio_mode);
+ xr_set_reg_uart(port, type->gpio_mode, gpio_mode);

if (C_BAUD(tty) == B0)
xr_dtr_rts(port, 0);
@@ -585,17 +614,19 @@ static int xr_probe(struct usb_serial *serial, const struct usb_device_id *id)
if (ret)
return ret;

+ usb_set_serial_data(serial, (void *)id->driver_info);
+
return 0;
}

-static int xr_gpio_init(struct usb_serial_port *port)
+static int xr_gpio_init(struct usb_serial_port *port, const struct xr_type *type)
{
u8 mask, mode;
int ret;

/* Configure all pins as GPIO. */
mode = 0;
- ret = xr_set_reg_uart(port, XR21V141X_REG_GPIO_MODE, mode);
+ ret = xr_set_reg_uart(port, type->gpio_mode, mode);
if (ret)
return ret;

@@ -604,11 +635,11 @@ static int xr_gpio_init(struct usb_serial_port *port)
* (active low), and configure RI, CD, DSR and CTS as inputs.
*/
mask = XR_GPIO_DTR | XR_GPIO_RTS;
- ret = xr_set_reg_uart(port, XR21V141X_REG_GPIO_DIR, mask);
+ ret = xr_set_reg_uart(port, type->gpio_direction, mask);
if (ret)
return ret;

- ret = xr_set_reg_uart(port, XR21V141X_REG_GPIO_SET, mask);
+ ret = xr_set_reg_uart(port, type->gpio_set, mask);
if (ret)
return ret;

@@ -618,19 +649,26 @@ static int xr_gpio_init(struct usb_serial_port *port)
static int xr_port_probe(struct usb_serial_port *port)
{
struct usb_interface_descriptor *desc;
+ const struct xr_type *type;
struct xr_data *data;
+ enum xr_type_id type_id;
int ret;

+ type_id = (int)(unsigned long)usb_get_serial_data(port->serial);
+ type = &xr_types[type_id];
+
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;

+ data->type = type;
+
desc = &port->serial->interface->cur_altsetting->desc;
data->channel = desc->bInterfaceNumber / 2;

usb_set_serial_port_data(port, data);

- ret = xr_gpio_init(port);
+ ret = xr_gpio_init(port, type);
if (ret)
goto err_free;

@@ -649,10 +687,14 @@ static void xr_port_remove(struct usb_serial_port *port)
kfree(data);
}

+#define XR_DEVICE(vid, pid, type) \
+ USB_DEVICE_INTERFACE_CLASS((vid), (pid), USB_CLASS_COMM), \
+ .driver_info = (type)
+
static const struct usb_device_id id_table[] = {
- { USB_DEVICE_INTERFACE_CLASS(0x04e2, 0x1410, USB_CLASS_COMM) }, /* XR21V1410 */
- { USB_DEVICE_INTERFACE_CLASS(0x04e2, 0x1412, USB_CLASS_COMM) }, /* XR21V1412 */
- { USB_DEVICE_INTERFACE_CLASS(0x04e2, 0x1414, USB_CLASS_COMM) }, /* XR21V1414 */
+ { XR_DEVICE(0x04e2, 0x1410, XR21V141X) },
+ { XR_DEVICE(0x04e2, 0x1412, XR21V141X) },
+ { XR_DEVICE(0x04e2, 0x1414, XR21V141X) },
{ }
};
MODULE_DEVICE_TABLE(usb, id_table);
--
2.26.3