powerpc/mpc5200: add rts/cts handling in PSC UART driver

Add RTS/CTS-support for the PSC of the MPC5200B. Tested with a Phytec
MPC5200B-IO.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

2 files changed, 47 insertions, 5 deletions

diff --git a/arch/powerpc/include/asm/mpc52xx_psc.h b/arch/powerpc/include/asm/mpc52xx_psc.h
index 8917ed630565..a218da6bec7c 100644
--- a/arch/powerpc/include/asm/mpc52xx_psc.h
+++ b/arch/powerpc/include/asm/mpc52xx_psc.h
@@ -68,12 +68,20 @@
 #define MPC52xx_PSC_IMR_ORERR           0x1000
 #define MPC52xx_PSC_IMR_IPC             0x8000
 
-/* PSC input port change bit */
+/* PSC input port change bits */
 #define MPC52xx_PSC_CTS                 0x01
 #define MPC52xx_PSC_DCD                 0x02
 #define MPC52xx_PSC_D_CTS               0x10
 #define MPC52xx_PSC_D_DCD               0x20
 
+/* PSC acr bits */
+#define MPC52xx_PSC_IEC_CTS             0x01
+#define MPC52xx_PSC_IEC_DCD             0x02
+
+/* PSC output port bits */
+#define MPC52xx_PSC_OP_RTS              0x01
+#define MPC52xx_PSC_OP_RES              0x02
+
 /* PSC mode fields */
 #define MPC52xx_PSC_MODE_5_BITS                 0x00
 #define MPC52xx_PSC_MODE_6_BITS                 0x01
@@ -91,6 +99,7 @@
 #define MPC52xx_PSC_MODE_ONE_STOP_5_BITS        0x00
 #define MPC52xx_PSC_MODE_ONE_STOP               0x07
 #define MPC52xx_PSC_MODE_TWO_STOP               0x0f
+#define MPC52xx_PSC_MODE_TXCTS                  0x10
 
 #define MPC52xx_PSC_RFNUM_MASK  0x01ff
 
diff --git a/drivers/serial/mpc52xx_uart.c b/drivers/serial/mpc52xx_uart.c
index d82650d54391..d2a1fc29834e 100644
--- a/drivers/serial/mpc52xx_uart.c
+++ b/drivers/serial/mpc52xx_uart.c
@@ -429,14 +429,24 @@ mpc52xx_uart_tx_empty(struct uart_port *port)
 static void
 mpc52xx_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
-        /* Not implemented */
+        if (mctrl & TIOCM_RTS)
+                out_8(&PSC(port)->op1, MPC52xx_PSC_OP_RTS);
+        else
+                out_8(&PSC(port)->op0, MPC52xx_PSC_OP_RTS);
 }
 
 static unsigned int
 mpc52xx_uart_get_mctrl(struct uart_port *port)
 {
-        /* Not implemented */
-        return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
+        unsigned int ret = TIOCM_DSR;
+        u8 status = in_8(&PSC(port)->mpc52xx_psc_ipcr);
+
+        if (!(status & MPC52xx_PSC_CTS))
+                ret |= TIOCM_CTS;
+        if (!(status & MPC52xx_PSC_DCD))
+                ret |= TIOCM_CAR;
+
+        return ret;
 }
 
 static void
@@ -479,7 +489,15 @@ mpc52xx_uart_stop_rx(struct uart_port *port)
 static void
 mpc52xx_uart_enable_ms(struct uart_port *port)
 {
-        /* Not implemented */
+        struct mpc52xx_psc __iomem *psc = PSC(port);
+
+        /* clear D_*-bits by reading them */
+        in_8(&psc->mpc52xx_psc_ipcr);
+        /* enable CTS and DCD as IPC interrupts */
+        out_8(&psc->mpc52xx_psc_acr, MPC52xx_PSC_IEC_CTS | MPC52xx_PSC_IEC_DCD);
+
+        port->read_status_mask |= MPC52xx_PSC_IMR_IPC;
+        out_be16(&psc->mpc52xx_psc_imr, port->read_status_mask);
 }
 
 static void
@@ -580,6 +598,10 @@ mpc52xx_uart_set_termios(struct uart_port *port, struct ktermios *new,
                         MPC52xx_PSC_MODE_ONE_STOP_5_BITS :
                         MPC52xx_PSC_MODE_ONE_STOP;
 
+        if (new->c_cflag & CRTSCTS) {
+                mr1 |= MPC52xx_PSC_MODE_RXRTS;
+                mr2 |= MPC52xx_PSC_MODE_TXCTS;
+        }
 
         baud = uart_get_baud_rate(port, new, old, 0, port->uartclk/16);
         quot = uart_get_divisor(port, baud);
@@ -617,6 +639,9 @@ mpc52xx_uart_set_termios(struct uart_port *port, struct ktermios *new,
         out_8(&psc->ctur, ctr >> 8);
         out_8(&psc->ctlr, ctr & 0xff);
 
+        if (UART_ENABLE_MS(port, new->c_cflag))
+                mpc52xx_uart_enable_ms(port);
+
         /* Reenable TX & RX */
         out_8(&psc->command, MPC52xx_PSC_TX_ENABLE);
         out_8(&psc->command, MPC52xx_PSC_RX_ENABLE);
@@ -832,6 +857,7 @@ mpc52xx_uart_int(int irq, void *dev_id)
         struct uart_port *port = dev_id;
         unsigned long pass = ISR_PASS_LIMIT;
         unsigned int keepgoing;
+        u8 status;
 
         spin_lock(&port->lock);
 
@@ -848,6 +874,13 @@ mpc52xx_uart_int(int irq, void *dev_id)
                 if (psc_ops->tx_rdy(port))
                         keepgoing |= mpc52xx_uart_int_tx_chars(port);
 
+                status = in_8(&PSC(port)->mpc52xx_psc_ipcr);
+                if (status & MPC52xx_PSC_D_DCD)
+                        uart_handle_dcd_change(port, !(status & MPC52xx_PSC_DCD));
+
+                if (status & MPC52xx_PSC_D_CTS)
+                        uart_handle_cts_change(port, !(status & MPC52xx_PSC_CTS));
+
                 /* Limit number of iteration */
                 if (!(--pass))
                         keepgoing = 0;