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Subject[RFC PATCH] tty/serial: atmel_serial: add device tree support
Date
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
---
Hi,

Here is a first attempt to add device tree support to atmel_serial driver.
RS485 data are not handled for the moment. My feeling is that they should be
added as a generic DT biding set.


.../devicetree/bindings/tty/serial/atmel-usart.txt | 27 +++++++++
drivers/tty/serial/atmel_serial.c | 56 +++++++++++++++++---
2 files changed, 75 insertions(+), 8 deletions(-)
create mode 100644 Documentation/devicetree/bindings/tty/serial/atmel-usart.txt

diff --git a/Documentation/devicetree/bindings/tty/serial/atmel-usart.txt b/Documentation/devicetree/bindings/tty/serial/atmel-usart.txt
new file mode 100644
index 0000000..a49d9a1
--- /dev/null
+++ b/Documentation/devicetree/bindings/tty/serial/atmel-usart.txt
@@ -0,0 +1,27 @@
+* Atmel Universal Synchronous Asynchronous Receiver/Transmitter (USART)
+
+Required properties:
+- compatible: Should be "atmel,<chip>-usart"
+ The compatible <chip> indicated will be the first SoC to support an
+ additional mode or an USART new feature.
+- reg: Should contain registers location and length
+- interrupts: Should contain interrupt
+
+Optional properties:
+- atmel,use-dma-rx: use of PDC or DMA for receiving data
+- atmel,use-dma-tx: use of PDC or DMA for transmitting data
+
+<chip> compatible description:
+- at91rm9200: legacy USART support
+- at91sam9260: generic USART implementation for SAM9 SoCs
+
+Example:
+
+ usart0: serial@fff8c000 {
+ compatible = "atmel,at91sam9260-usart";
+ reg = <0xfff8c000 0x4000>;
+ interrupts = <7>;
+ atmel,use-dma-rx;
+ atmel,use-dma-tx;
+ };
+
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 453cdb5..65f56c3 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -33,6 +33,8 @@
#include <linux/sysrq.h>
#include <linux/tty_flip.h>
#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
#include <linux/dma-mapping.h>
#include <linux/atmel_pdc.h>
#include <linux/atmel_serial.h>
@@ -162,6 +164,16 @@ static struct atmel_uart_port atmel_ports[ATMEL_MAX_UART];
static struct console atmel_console;
#endif

+#if defined(CONFIG_OF)
+static const struct of_device_id atmel_serial_dt_ids[] = {
+ { .compatible = "atmel,at91rm9200-usart" },
+ { .compatible = "atmel,at91sam9260-usart" },
+ { /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, atmel_serial_dt_ids);
+#endif
+
static inline struct atmel_uart_port *
to_atmel_uart_port(struct uart_port *uart)
{
@@ -1413,14 +1425,31 @@ static struct uart_ops atmel_pops = {
static void __devinit atmel_init_port(struct atmel_uart_port *atmel_port,
struct platform_device *pdev)
{
+ struct device_node *np = pdev->dev.of_node;
struct uart_port *port = &atmel_port->uart;
struct atmel_uart_data *pdata = pdev->dev.platform_data;
+ int ret;
+
+ if (np) {
+ ret = of_alias_get_id(np, "serial");
+ if (ret >= 0)
+ port->line = ret;
+ if (of_get_property(np, "atmel,use-dma-rx", NULL))
+ atmel_port->use_dma_rx = 1;
+ if (of_get_property(np, "atmel,use-dma-tx", NULL))
+ atmel_port->use_dma_tx = 1;
+ } else {
+ port->line = pdata->num;
+
+ atmel_port->use_dma_rx = pdata->use_dma_rx;
+ atmel_port->use_dma_tx = pdata->use_dma_tx;
+ atmel_port->rs485 = pdata->rs485;
+ }

port->iotype = UPIO_MEM;
port->flags = UPF_BOOT_AUTOCONF;
port->ops = &atmel_pops;
port->fifosize = 1;
- port->line = pdata->num;
port->dev = &pdev->dev;
port->mapbase = pdev->resource[0].start;
port->irq = pdev->resource[1].start;
@@ -1430,7 +1459,7 @@ static void __devinit atmel_init_port(struct atmel_uart_port *atmel_port,

memset(&atmel_port->rx_ring, 0, sizeof(atmel_port->rx_ring));

- if (pdata->regs) {
+ if (pdata && pdata->regs) {
/* Already mapped by setup code */
port->membase = pdata->regs;
} else {
@@ -1447,10 +1476,6 @@ static void __devinit atmel_init_port(struct atmel_uart_port *atmel_port,
/* only enable clock when USART is in use */
}

- atmel_port->use_dma_rx = pdata->use_dma_rx;
- atmel_port->use_dma_tx = pdata->use_dma_tx;
- atmel_port->rs485 = pdata->rs485;
-
/* Use TXEMPTY for interrupt when rs485 else TXRDY or ENDTX|TXBUFE */
if (atmel_port->rs485.flags & SER_RS485_ENABLED)
atmel_port->tx_done_mask = ATMEL_US_TXEMPTY;
@@ -1710,13 +1735,27 @@ static int atmel_serial_resume(struct platform_device *pdev)
static int __devinit atmel_serial_probe(struct platform_device *pdev)
{
struct atmel_uart_port *port;
+ struct device_node *np = pdev->dev.of_node;
struct atmel_uart_data *pdata = pdev->dev.platform_data;
void *data;
int ret;

BUILD_BUG_ON(ATMEL_SERIAL_RINGSIZE & (ATMEL_SERIAL_RINGSIZE - 1));

- port = &atmel_ports[pdata->num];
+ if (np) {
+ ret = of_alias_get_id(np, "serial");
+ if (ret < 0)
+ goto err;
+ } else {
+ if (pdata) {
+ ret = pdata->num;
+ } else {
+ ret = -ENODEV;
+ goto err;
+ }
+ }
+
+ port = &atmel_ports[ret];
port->backup_imr = 0;

atmel_init_port(port, pdev);
@@ -1763,7 +1802,7 @@ err_alloc_ring:
clk_put(port->clk);
port->clk = NULL;
}
-
+err:
return ret;
}

@@ -1796,6 +1835,7 @@ static struct platform_driver atmel_serial_driver = {
.driver = {
.name = "atmel_usart",
.owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(atmel_serial_dt_ids),
},
};

--
1.7.3


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