serial: pl011: Add device tree support for RX DMA polling

Add equivalent attributes to those provided in the platform data
for use when RX DMA is enabled.

Signed-off-by: Andrew Jackson <Andrew.Jackson@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 31 insertions, 10 deletions

diff --git a/Documentation/devicetree/bindings/serial/pl011.txt b/Documentation/devicetree/bindings/serial/pl011.txt
index 5d2e840ae65c..0e05340055e1 100644
--- a/Documentation/devicetree/bindings/serial/pl011.txt
+++ b/Documentation/devicetree/bindings/serial/pl011.txt
@@ -6,12 +6,17 @@ Required properties:
 - interrupts: exactly one interrupt specifier
 
 Optional properties:
-- pinctrl: When present, must have one state named "sleep"
-           and one state named "default"
-- clocks:  When present, must refer to exactly one clock named
-           "apb_pclk"
-- dmas:    When present, may have one or two dma channels.
-           The first one must be named "rx", the second one
-           must be named "tx".
+- pinctrl:              When present, must have one state named "sleep"
+                        and one state named "default"
+- clocks:               When present, must refer to exactly one clock named
+                        "apb_pclk"
+- dmas:                 When present, may have one or two dma channels.
+                        The first one must be named "rx", the second one
+                        must be named "tx".
+- auto-poll:            Enables polling when using RX DMA.
+- poll-rate-ms:         Rate at which poll occurs when auto-poll is set,
+                        default 100ms.
+- poll-timeout-ms:      Poll timeout when auto-poll is set, default
+                        3000ms.
 
 See also bindings/arm/primecell.txt
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index d984a97043b3..8d94c194f090 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -341,6 +341,7 @@ static void pl011_dma_probe_initcall(struct device *dev, struct uart_amba_port *
                 dmaengine_slave_config(chan, &rx_conf);
                 uap->dmarx.chan = chan;
 
+                uap->dmarx.auto_poll_rate = false;
                 if (plat && plat->dma_rx_poll_enable) {
                         /* Set poll rate if specified. */
                         if (plat->dma_rx_poll_rate) {
@@ -361,9 +362,24 @@ static void pl011_dma_probe_initcall(struct device *dev, struct uart_amba_port *
                                         plat->dma_rx_poll_timeout;
                         else
                                 uap->dmarx.poll_timeout = 3000;
-                } else
-                        uap->dmarx.auto_poll_rate = false;
-
+                } else if (!plat && dev->of_node) {
+                        uap->dmarx.auto_poll_rate = of_property_read_bool(
+                                                dev->of_node, "auto-poll");
+                        if (uap->dmarx.auto_poll_rate) {
+                                u32 x;
+
+                                if (0 == of_property_read_u32(dev->of_node,
+                                                "poll-rate-ms", &x))
+                                        uap->dmarx.poll_rate = x;
+                                else
+                                        uap->dmarx.poll_rate = 100;
+                                if (0 == of_property_read_u32(dev->of_node,
+                                                "poll-timeout-ms", &x))
+                                        uap->dmarx.poll_timeout = x;
+                                else
+                                        uap->dmarx.poll_timeout = 3000;
+                        }
+                }
                 dev_info(uap->port.dev, "DMA channel RX %s\n",
                          dma_chan_name(uap->dmarx.chan));
         }