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Subject[PATCH V1 1/4] usb: serial: f81534: add high baud rate support
Date
The F81532/534 had 4 clocksource 1.846/18.46/14.77/24MHz and baud rates can
be up to 1.5Mbits with 24MHz.

F81532/534 Clock register (offset +08h)

Bit0: UART Enable (always on)
Bit2-1: Clock source selector
00: 1.846MHz.
01: 18.46MHz.
10: 24MHz.
11: 14.77MHz.

Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
---
drivers/usb/serial/f81534.c | 84 ++++++++++++++++++++++++++++++++++++---------
1 file changed, 68 insertions(+), 16 deletions(-)

diff --git a/drivers/usb/serial/f81534.c b/drivers/usb/serial/f81534.c
index cb8214860192..76c676ef5f0d 100644
--- a/drivers/usb/serial/f81534.c
+++ b/drivers/usb/serial/f81534.c
@@ -45,6 +45,7 @@
#define F81534_MODEM_CONTROL_REG (0x04 + F81534_UART_BASE_ADDRESS)
#define F81534_LINE_STATUS_REG (0x05 + F81534_UART_BASE_ADDRESS)
#define F81534_MODEM_STATUS_REG (0x06 + F81534_UART_BASE_ADDRESS)
+#define F81534_CLOCK_REG (0x08 + F81534_UART_BASE_ADDRESS)
#define F81534_CONFIG1_REG (0x09 + F81534_UART_BASE_ADDRESS)

#define F81534_DEF_CONF_ADDRESS_START 0x3000
@@ -61,7 +62,7 @@

/* Default URB timeout for USB operations */
#define F81534_USB_MAX_RETRY 10
-#define F81534_USB_TIMEOUT 1000
+#define F81534_USB_TIMEOUT 2000
#define F81534_SET_GET_REGISTER 0xA0

#define F81534_NUM_PORT 4
@@ -100,7 +101,6 @@
#define F81534_CMD_READ 0x03

#define F81534_DEFAULT_BAUD_RATE 9600
-#define F81534_MAX_BAUDRATE 115200

#define F81534_PORT_CONF_DISABLE_PORT BIT(3)
#define F81534_PORT_CONF_NOT_EXIST_PORT BIT(7)
@@ -110,6 +110,22 @@
#define F81534_1X_RXTRIGGER 0xc3
#define F81534_8X_RXTRIGGER 0xcf

+/*
+ * F81532/534 Clock registers (offset +08h)
+ *
+ * Bit0: UART Enable (always on)
+ * Bit2-1: Clock source selector
+ * 00: 1.846MHz.
+ * 01: 18.46MHz.
+ * 10: 24MHz.
+ * 11: 14.77MHz.
+ */
+
+#define F81534_CLK_1_846_MHZ BIT(0)
+#define F81534_CLK_18_46_MHZ (BIT(0) | BIT(1))
+#define F81534_CLK_24_MHZ (BIT(0) | BIT(2))
+#define F81534_CLK_14_77_MHZ (BIT(0) | BIT(1) | BIT(2))
+
static const struct usb_device_id f81534_id_table[] = {
{ USB_DEVICE(FINTEK_VENDOR_ID_1, FINTEK_DEVICE_ID) },
{ USB_DEVICE(FINTEK_VENDOR_ID_2, FINTEK_DEVICE_ID) },
@@ -133,6 +149,7 @@ struct f81534_port_private {
struct usb_serial_port *port;
unsigned long tx_empty;
spinlock_t msr_lock;
+ u32 baud_base;
u8 shadow_mcr;
u8 shadow_lcr;
u8 shadow_msr;
@@ -464,13 +481,51 @@ static u32 f81534_calc_baud_divisor(u32 baudrate, u32 clockrate)
return DIV_ROUND_CLOSEST(clockrate, baudrate);
}

-static int f81534_set_port_config(struct usb_serial_port *port, u32 baudrate,
- u8 lcr)
+static int f81534_set_port_config(struct usb_serial_port *port,
+ struct tty_struct *tty, u32 baudrate, u32 old_baudrate, u8 lcr)
{
struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
u32 divisor;
int status;
+ int idx;
u8 value;
+ static u32 const baudrate_table[] = {115200, 921600, 1152000,
+ 1500000};
+ static u8 const clock_table[] = {F81534_CLK_1_846_MHZ,
+ F81534_CLK_14_77_MHZ, F81534_CLK_18_46_MHZ,
+ F81534_CLK_24_MHZ};
+
+ do {
+ for (idx = 0; idx < ARRAY_SIZE(baudrate_table); ++idx) {
+ if (baudrate <= baudrate_table[idx] &&
+ baudrate_table[idx] % baudrate == 0)
+ break;
+ }
+
+ /* Found acceptable baud rate */
+ if (idx != ARRAY_SIZE(baudrate_table))
+ break;
+
+ if (baudrate == old_baudrate &&
+ old_baudrate != F81534_DEFAULT_BAUD_RATE)
+ old_baudrate = F81534_DEFAULT_BAUD_RATE;
+
+ dev_warn(&port->dev,
+ "baudrate: %d not supported, change to: %d\n",
+ baudrate, old_baudrate);
+
+ baudrate = old_baudrate;
+ tty_encode_baud_rate(tty, baudrate, baudrate);
+
+ } while (1);
+
+ port_priv->baud_base = baudrate_table[idx];
+ status = f81534_set_port_register(port, F81534_CLOCK_REG,
+ clock_table[idx]);
+ if (status) {
+ dev_err(&port->dev, "CLOCK_REG setting failed\n");
+ return status;
+ }

if (baudrate <= 1200)
value = F81534_1X_RXTRIGGER; /* 128 FIFO & TL: 1x */
@@ -486,7 +541,7 @@ static int f81534_set_port_config(struct usb_serial_port *port, u32 baudrate,
if (baudrate <= 1200)
value = UART_FCR_TRIGGER_1 | UART_FCR_ENABLE_FIFO; /* TL: 1 */
else
- value = UART_FCR_R_TRIG_11 | UART_FCR_ENABLE_FIFO; /* TL: 14 */
+ value = UART_FCR_TRIGGER_8 | UART_FCR_ENABLE_FIFO; /* TL: 8 */

status = f81534_set_port_register(port, F81534_FIFO_CONTROL_REG,
value);
@@ -495,7 +550,7 @@ static int f81534_set_port_config(struct usb_serial_port *port, u32 baudrate,
return status;
}

- divisor = f81534_calc_baud_divisor(baudrate, F81534_MAX_BAUDRATE);
+ divisor = f81534_calc_baud_divisor(baudrate, baudrate_table[idx]);

mutex_lock(&port_priv->lcr_mutex);

@@ -745,6 +800,7 @@ static void f81534_set_termios(struct tty_struct *tty,
u8 new_lcr = 0;
int status;
u32 baud;
+ u32 old_baud;

if (C_BAUD(tty) == B0)
f81534_update_mctrl(port, 0, TIOCM_DTR | TIOCM_RTS);
@@ -784,18 +840,14 @@ static void f81534_set_termios(struct tty_struct *tty,
if (!baud)
return;

- if (baud > F81534_MAX_BAUDRATE) {
- if (old_termios)
- baud = tty_termios_baud_rate(old_termios);
- else
- baud = F81534_DEFAULT_BAUD_RATE;
-
- tty_encode_baud_rate(tty, baud, baud);
- }
+ if (old_termios)
+ old_baud = tty_termios_baud_rate(old_termios);
+ else
+ old_baud = F81534_DEFAULT_BAUD_RATE;

dev_dbg(&port->dev, "%s: baud: %d\n", __func__, baud);

- status = f81534_set_port_config(port, baud, new_lcr);
+ status = f81534_set_port_config(port, tty, baud, old_baud, new_lcr);
if (status < 0) {
dev_err(&port->dev, "%s: set port config failed: %d\n",
__func__, status);
@@ -951,7 +1003,7 @@ static int f81534_get_serial_info(struct usb_serial_port *port,
tmp.type = PORT_16550A;
tmp.port = port->port_number;
tmp.line = port->minor;
- tmp.baud_base = F81534_MAX_BAUDRATE;
+ tmp.baud_base = port_priv->baud_base;

if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
return -EFAULT;
--
2.7.4
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