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path: root/drivers/tty/serial/atmel_serial.c
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Diffstat (limited to 'drivers/tty/serial/atmel_serial.c')
-rw-r--r--drivers/tty/serial/atmel_serial.c58
1 files changed, 43 insertions, 15 deletions
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 2eaa18ddef61..fd8aa1f4ba78 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -166,6 +166,7 @@ struct atmel_uart_port {
u32 rts_low;
bool ms_irq_enabled;
u32 rtor; /* address of receiver timeout register if it exists */
+ bool has_frac_baudrate;
bool has_hw_timer;
struct timer_list uart_timer;
@@ -1634,8 +1635,8 @@ static void atmel_init_property(struct atmel_uart_port *atmel_port,
if (np) {
/* DMA/PDC usage specification */
- if (of_get_property(np, "atmel,use-dma-rx", NULL)) {
- if (of_get_property(np, "dmas", NULL)) {
+ if (of_property_read_bool(np, "atmel,use-dma-rx")) {
+ if (of_property_read_bool(np, "dmas")) {
atmel_port->use_dma_rx = true;
atmel_port->use_pdc_rx = false;
} else {
@@ -1647,8 +1648,8 @@ static void atmel_init_property(struct atmel_uart_port *atmel_port,
atmel_port->use_pdc_rx = false;
}
- if (of_get_property(np, "atmel,use-dma-tx", NULL)) {
- if (of_get_property(np, "dmas", NULL)) {
+ if (of_property_read_bool(np, "atmel,use-dma-tx")) {
+ if (of_property_read_bool(np, "dmas")) {
atmel_port->use_dma_tx = true;
atmel_port->use_pdc_tx = false;
} else {
@@ -1745,6 +1746,11 @@ static void atmel_get_ip_name(struct uart_port *port)
dbgu_uart = 0x44424755; /* DBGU */
new_uart = 0x55415254; /* UART */
+ /*
+ * Only USART devices from at91sam9260 SOC implement fractional
+ * baudrate.
+ */
+ atmel_port->has_frac_baudrate = false;
atmel_port->has_hw_timer = false;
if (name == new_uart) {
@@ -1753,6 +1759,7 @@ static void atmel_get_ip_name(struct uart_port *port)
atmel_port->rtor = ATMEL_UA_RTOR;
} else if (name == usart) {
dev_dbg(port->dev, "Usart\n");
+ atmel_port->has_frac_baudrate = true;
atmel_port->has_hw_timer = true;
atmel_port->rtor = ATMEL_US_RTOR;
} else if (name == dbgu_uart) {
@@ -1764,6 +1771,7 @@ static void atmel_get_ip_name(struct uart_port *port)
case 0x302:
case 0x10213:
dev_dbg(port->dev, "This version is usart\n");
+ atmel_port->has_frac_baudrate = true;
atmel_port->has_hw_timer = true;
atmel_port->rtor = ATMEL_US_RTOR;
break;
@@ -1929,6 +1937,9 @@ static void atmel_shutdown(struct uart_port *port)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+ /* Disable modem control lines interrupts */
+ atmel_disable_ms(port);
+
/* Disable interrupts at device level */
atmel_uart_writel(port, ATMEL_US_IDR, -1);
@@ -1979,8 +1990,6 @@ static void atmel_shutdown(struct uart_port *port)
*/
free_irq(port->irq, port);
- atmel_port->ms_irq_enabled = false;
-
atmel_flush_buffer(port);
}
@@ -2025,8 +2034,9 @@ static void atmel_serial_pm(struct uart_port *port, unsigned int state,
static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
struct ktermios *old)
{
+ struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
unsigned long flags;
- unsigned int old_mode, mode, imr, quot, baud;
+ unsigned int old_mode, mode, imr, quot, baud, div, cd, fp = 0;
/* save the current mode register */
mode = old_mode = atmel_uart_readl(port, ATMEL_US_MR);
@@ -2036,12 +2046,6 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
ATMEL_US_PAR | ATMEL_US_USMODE);
baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
- quot = uart_get_divisor(port, baud);
-
- if (quot > 65535) { /* BRGR is 16-bit, so switch to slower clock */
- quot /= 8;
- mode |= ATMEL_US_USCLKS_MCK_DIV8;
- }
/* byte size */
switch (termios->c_cflag & CSIZE) {
@@ -2160,7 +2164,31 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
atmel_uart_writel(port, ATMEL_US_CR, rts_state);
}
- /* set the baud rate */
+ /*
+ * Set the baud rate:
+ * Fractional baudrate allows to setup output frequency more
+ * accurately. This feature is enabled only when using normal mode.
+ * baudrate = selected clock / (8 * (2 - OVER) * (CD + FP / 8))
+ * Currently, OVER is always set to 0 so we get
+ * baudrate = selected clock / (16 * (CD + FP / 8))
+ * then
+ * 8 CD + FP = selected clock / (2 * baudrate)
+ */
+ if (atmel_port->has_frac_baudrate &&
+ (mode & ATMEL_US_USMODE) == ATMEL_US_USMODE_NORMAL) {
+ div = DIV_ROUND_CLOSEST(port->uartclk, baud * 2);
+ cd = div >> 3;
+ fp = div & ATMEL_US_FP_MASK;
+ } else {
+ cd = uart_get_divisor(port, baud);
+ }
+
+ if (cd > 65535) { /* BRGR is 16-bit, so switch to slower clock */
+ cd /= 8;
+ mode |= ATMEL_US_USCLKS_MCK_DIV8;
+ }
+ quot = cd | fp << ATMEL_US_FP_OFFSET;
+
atmel_uart_writel(port, ATMEL_US_BRGR, quot);
atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN);
@@ -2292,7 +2320,7 @@ static void atmel_poll_put_char(struct uart_port *port, unsigned char ch)
}
#endif
-static struct uart_ops atmel_pops = {
+static const struct uart_ops atmel_pops = {
.tx_empty = atmel_tx_empty,
.set_mctrl = atmel_set_mctrl,
.get_mctrl = atmel_get_mctrl,