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,