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Subject[PATCH V1 2/2] usb: serial: f81534: Implement break control
Date
Implement Fintek f81534 break on/off with LCR register.
It's the same with 16550A LCR register layout.

Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
---
drivers/usb/serial/f81534.c | 46 +++++++++++++++++++++++++++++++++++++++------
1 file changed, 40 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/serial/f81534.c b/drivers/usb/serial/f81534.c
index 3f47afa..9ea407d 100644
--- a/drivers/usb/serial/f81534.c
+++ b/drivers/usb/serial/f81534.c
@@ -128,11 +128,13 @@ struct f81534_serial_private {

struct f81534_port_private {
struct mutex mcr_mutex;
+ struct mutex lcr_mutex;
struct work_struct lsr_work;
struct usb_serial_port *port;
unsigned long tx_empty;
spinlock_t msr_lock;
u8 shadow_mcr;
+ u8 shadow_lcr;
u8 shadow_msr;
u8 phy_num;
};
@@ -465,6 +467,7 @@ static u32 f81534_calc_baud_divisor(u32 baudrate, u32 clockrate)
static int f81534_set_port_config(struct usb_serial_port *port, u32 baudrate,
u8 lcr)
{
+ struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
u32 divisor;
int status;
u8 value;
@@ -493,35 +496,64 @@ static int f81534_set_port_config(struct usb_serial_port *port, u32 baudrate,
}

divisor = f81534_calc_baud_divisor(baudrate, F81534_MAX_BAUDRATE);
+
+ mutex_lock(&port_priv->lcr_mutex);
+
value = UART_LCR_DLAB;
status = f81534_set_port_register(port, F81534_LINE_CONTROL_REG,
value);
if (status) {
dev_err(&port->dev, "%s: set LCR failed\n", __func__);
- return status;
+ goto final;
}

value = divisor & 0xff;
status = f81534_set_port_register(port, F81534_DIVISOR_LSB_REG, value);
if (status) {
dev_err(&port->dev, "%s: set DLAB LSB failed\n", __func__);
- return status;
+ goto final;
}

value = (divisor >> 8) & 0xff;
status = f81534_set_port_register(port, F81534_DIVISOR_MSB_REG, value);
if (status) {
dev_err(&port->dev, "%s: set DLAB MSB failed\n", __func__);
- return status;
+ goto final;
}

- status = f81534_set_port_register(port, F81534_LINE_CONTROL_REG, lcr);
+ value = lcr | (port_priv->shadow_lcr & UART_LCR_SBC);
+ status = f81534_set_port_register(port, F81534_LINE_CONTROL_REG,
+ value);
if (status) {
dev_err(&port->dev, "%s: set LCR failed\n", __func__);
- return status;
+ goto final;
}

- return 0;
+ port_priv->shadow_lcr = value;
+final:
+ mutex_unlock(&port_priv->lcr_mutex);
+ return status;
+}
+
+static void f81534_break_ctl(struct tty_struct *tty, int break_state)
+{
+ struct usb_serial_port *port = tty->driver_data;
+ struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
+ int status;
+
+ mutex_lock(&port_priv->lcr_mutex);
+
+ if (break_state)
+ port_priv->shadow_lcr |= UART_LCR_SBC;
+ else
+ port_priv->shadow_lcr &= ~UART_LCR_SBC;
+
+ status = f81534_set_port_register(port, F81534_LINE_CONTROL_REG,
+ port_priv->shadow_lcr);
+ if (status)
+ dev_err(&port->dev, "set break failed: %x\n", status);
+
+ mutex_unlock(&port_priv->lcr_mutex);
}

static int f81534_update_mctrl(struct usb_serial_port *port, unsigned int set,
@@ -1193,6 +1225,7 @@ static int f81534_port_probe(struct usb_serial_port *port)

spin_lock_init(&port_priv->msr_lock);
mutex_init(&port_priv->mcr_mutex);
+ mutex_init(&port_priv->lcr_mutex);
INIT_WORK(&port_priv->lsr_work, f81534_lsr_worker);

/* Assign logic-to-phy mapping */
@@ -1359,6 +1392,7 @@ static struct usb_serial_driver f81534_device = {
.attach = f81534_attach,
.port_probe = f81534_port_probe,
.port_remove = f81534_port_remove,
+ .break_ctl = f81534_break_ctl,
.dtr_rts = f81534_dtr_rts,
.process_read_urb = f81534_process_read_urb,
.ioctl = f81534_ioctl,
--
2.7.4
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