ARM/serial: at91: switch atmel serial to use gpiolib

This passes the errata fix using a GPIO to control the RTS pin
on one of the AT91 chips to use gpiolib instead of the
AT91-specific interfaces. Also remove the reliance on
compile-time #defines and the cpu_* check and rely on the
platform passing down the proper GPIO pin through platform
data.

This is a prerequisite for getting rid of the local GPIO
implementation in the AT91 platform and move toward
multiplatform.

The patch also adds device tree support for getting the
RTS GPIO pin from the device tree on DT boot paths.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

diff --git a/Documentation/devicetree/bindings/serial/atmel-usart.txt b/Documentation/devicetree/bindings/serial/atmel-usart.txt
index 2191dcb9f1da986d008a87688ea0af693ea3bf28..3adc61c2e4cafacd14ffb5610c0fae2b0c633e97 100644 (file)
--- a/Documentation/devicetree/bindings/serial/atmel-usart.txt
+++ b/Documentation/devicetree/bindings/serial/atmel-usart.txt
@@ -10,6 +10,8 @@ Required properties:
 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
+- rts-gpios: specify a GPIO for RTS line. It will use specified PIO instead of the peripheral
+  function pin for the USART RTS feature. If unsure, don't specify this property.
 - add dma bindings for dma transfer:
        - dmas: DMA specifier, consisting of a phandle to DMA controller node,
                memory peripheral interface and USART DMA channel ID, FIFO configuration.
@@ -28,6 +30,7 @@ Example:
                interrupts = <7>;
                atmel,use-dma-rx;
                atmel,use-dma-tx;
+               rts-gpios = <&pioD 15 0>;
        };
 
 - use DMA:

diff --git a/arch/arm/mach-at91/at91rm9200_devices.c b/arch/arm/mach-at91/at91rm9200_devices.c
index 3ebc9792560cebed75a53883e42e774742c5660c..605add05af7e56c41881b792f16a1f53394ca7e3 100644 (file)
--- a/arch/arm/mach-at91/at91rm9200_devices.c
+++ b/arch/arm/mach-at91/at91rm9200_devices.c
@@ -922,6 +922,7 @@ static struct resource dbgu_resources[] = {
 static struct atmel_uart_data dbgu_data = {
        .use_dma_tx     = 0,
        .use_dma_rx     = 0,            /* DBGU not capable of receive DMA */
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 dbgu_dmamask = DMA_BIT_MASK(32);
@@ -960,6 +961,7 @@ static struct resource uart0_resources[] = {
 static struct atmel_uart_data uart0_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart0_dmamask = DMA_BIT_MASK(32);
@@ -987,9 +989,10 @@ static inline void configure_usart0_pins(unsigned pins)
        if (pins & ATMEL_UART_RTS) {
                /*
                 * AT91RM9200 Errata #39 - RTS0 is not internally connected to PA21.
-                *  We need to drive the pin manually.  Default is off (RTS is active low).
+                * We need to drive the pin manually. The serial driver will driver
+                * this to high when initializing.
                 */
-               at91_set_gpio_output(AT91_PIN_PA21, 1);
+               uart0_data.rts_gpio = AT91_PIN_PA21;
        }
 }
 
@@ -1009,6 +1012,7 @@ static struct resource uart1_resources[] = {
 static struct atmel_uart_data uart1_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart1_dmamask = DMA_BIT_MASK(32);
@@ -1060,6 +1064,7 @@ static struct resource uart2_resources[] = {
 static struct atmel_uart_data uart2_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart2_dmamask = DMA_BIT_MASK(32);
@@ -1103,6 +1108,7 @@ static struct resource uart3_resources[] = {
 static struct atmel_uart_data uart3_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart3_dmamask = DMA_BIT_MASK(32);

diff --git a/arch/arm/mach-at91/at91sam9260_devices.c b/arch/arm/mach-at91/at91sam9260_devices.c
index eda8d1679d404ef3a75ad999fabd333c23296b58..b52527c78b12c7433b7268f6458a142051319a58 100644 (file)
--- a/arch/arm/mach-at91/at91sam9260_devices.c
+++ b/arch/arm/mach-at91/at91sam9260_devices.c
@@ -819,6 +819,7 @@ static struct resource dbgu_resources[] = {
 static struct atmel_uart_data dbgu_data = {
        .use_dma_tx     = 0,
        .use_dma_rx     = 0,            /* DBGU not capable of receive DMA */
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 dbgu_dmamask = DMA_BIT_MASK(32);
@@ -857,6 +858,7 @@ static struct resource uart0_resources[] = {
 static struct atmel_uart_data uart0_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart0_dmamask = DMA_BIT_MASK(32);
@@ -908,6 +910,7 @@ static struct resource uart1_resources[] = {
 static struct atmel_uart_data uart1_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart1_dmamask = DMA_BIT_MASK(32);
@@ -951,6 +954,7 @@ static struct resource uart2_resources[] = {
 static struct atmel_uart_data uart2_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart2_dmamask = DMA_BIT_MASK(32);
@@ -994,6 +998,7 @@ static struct resource uart3_resources[] = {
 static struct atmel_uart_data uart3_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart3_dmamask = DMA_BIT_MASK(32);
@@ -1037,6 +1042,7 @@ static struct resource uart4_resources[] = {
 static struct atmel_uart_data uart4_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart4_dmamask = DMA_BIT_MASK(32);
@@ -1075,6 +1081,7 @@ static struct resource uart5_resources[] = {
 static struct atmel_uart_data uart5_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart5_dmamask = DMA_BIT_MASK(32);

diff --git a/arch/arm/mach-at91/at91sam9261_devices.c b/arch/arm/mach-at91/at91sam9261_devices.c
index b2a34740146aaab4d3af99b741979c670be6402e..6c1a2ecc306fcca09b1336c706015787f336b594 100644 (file)
--- a/arch/arm/mach-at91/at91sam9261_devices.c
+++ b/arch/arm/mach-at91/at91sam9261_devices.c
@@ -880,6 +880,7 @@ static struct resource dbgu_resources[] = {
 static struct atmel_uart_data dbgu_data = {
        .use_dma_tx     = 0,
        .use_dma_rx     = 0,            /* DBGU not capable of receive DMA */
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 dbgu_dmamask = DMA_BIT_MASK(32);
@@ -918,6 +919,7 @@ static struct resource uart0_resources[] = {
 static struct atmel_uart_data uart0_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart0_dmamask = DMA_BIT_MASK(32);
@@ -961,6 +963,7 @@ static struct resource uart1_resources[] = {
 static struct atmel_uart_data uart1_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart1_dmamask = DMA_BIT_MASK(32);
@@ -1004,6 +1007,7 @@ static struct resource uart2_resources[] = {
 static struct atmel_uart_data uart2_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart2_dmamask = DMA_BIT_MASK(32);

diff --git a/arch/arm/mach-at91/at91sam9263_devices.c b/arch/arm/mach-at91/at91sam9263_devices.c
index 4aeadddbc18108918b883150bef49b3a770eeb42..97cc2a0d6f90178476edcf7d3008f54bd836b905 100644 (file)
--- a/arch/arm/mach-at91/at91sam9263_devices.c
+++ b/arch/arm/mach-at91/at91sam9263_devices.c
@@ -1324,6 +1324,7 @@ static struct resource dbgu_resources[] = {
 static struct atmel_uart_data dbgu_data = {
        .use_dma_tx     = 0,
        .use_dma_rx     = 0,            /* DBGU not capable of receive DMA */
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 dbgu_dmamask = DMA_BIT_MASK(32);
@@ -1362,6 +1363,7 @@ static struct resource uart0_resources[] = {
 static struct atmel_uart_data uart0_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart0_dmamask = DMA_BIT_MASK(32);
@@ -1405,6 +1407,7 @@ static struct resource uart1_resources[] = {
 static struct atmel_uart_data uart1_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart1_dmamask = DMA_BIT_MASK(32);
@@ -1448,6 +1451,7 @@ static struct resource uart2_resources[] = {
 static struct atmel_uart_data uart2_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart2_dmamask = DMA_BIT_MASK(32);

diff --git a/arch/arm/mach-at91/at91sam9g45_devices.c b/arch/arm/mach-at91/at91sam9g45_devices.c
index cb36fa872d305d6f22b9133d48d3bdaaa678789d..c10149588e214265cd1e55f6e994959d3e9dd270 100644 (file)
--- a/arch/arm/mach-at91/at91sam9g45_devices.c
+++ b/arch/arm/mach-at91/at91sam9g45_devices.c
@@ -1587,6 +1587,7 @@ static struct resource dbgu_resources[] = {
 static struct atmel_uart_data dbgu_data = {
        .use_dma_tx     = 0,
        .use_dma_rx     = 0,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 dbgu_dmamask = DMA_BIT_MASK(32);
@@ -1625,6 +1626,7 @@ static struct resource uart0_resources[] = {
 static struct atmel_uart_data uart0_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart0_dmamask = DMA_BIT_MASK(32);
@@ -1668,6 +1670,7 @@ static struct resource uart1_resources[] = {
 static struct atmel_uart_data uart1_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart1_dmamask = DMA_BIT_MASK(32);
@@ -1711,6 +1714,7 @@ static struct resource uart2_resources[] = {
 static struct atmel_uart_data uart2_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart2_dmamask = DMA_BIT_MASK(32);
@@ -1754,6 +1758,7 @@ static struct resource uart3_resources[] = {
 static struct atmel_uart_data uart3_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart3_dmamask = DMA_BIT_MASK(32);

diff --git a/arch/arm/mach-at91/at91sam9rl_devices.c b/arch/arm/mach-at91/at91sam9rl_devices.c
index a698bdab2cce682fee2983e0942d5bc2126139e4..4120af972b61a7d9e0b6e119c5b55c957d33cee8 100644 (file)
--- a/arch/arm/mach-at91/at91sam9rl_devices.c
+++ b/arch/arm/mach-at91/at91sam9rl_devices.c
@@ -956,6 +956,7 @@ static struct resource dbgu_resources[] = {
 static struct atmel_uart_data dbgu_data = {
        .use_dma_tx     = 0,
        .use_dma_rx     = 0,            /* DBGU not capable of receive DMA */
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 dbgu_dmamask = DMA_BIT_MASK(32);
@@ -994,6 +995,7 @@ static struct resource uart0_resources[] = {
 static struct atmel_uart_data uart0_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart0_dmamask = DMA_BIT_MASK(32);
@@ -1045,6 +1047,7 @@ static struct resource uart1_resources[] = {
 static struct atmel_uart_data uart1_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart1_dmamask = DMA_BIT_MASK(32);
@@ -1088,6 +1091,7 @@ static struct resource uart2_resources[] = {
 static struct atmel_uart_data uart2_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart2_dmamask = DMA_BIT_MASK(32);
@@ -1131,6 +1135,7 @@ static struct resource uart3_resources[] = {
 static struct atmel_uart_data uart3_data = {
        .use_dma_tx     = 1,
        .use_dma_rx     = 1,
+       .rts_gpio       = -EINVAL,
 };
 
 static u64 uart3_dmamask = DMA_BIT_MASK(32);

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index c7d99af46a966f1fdc9b9ebf0359756180e90b20..40d6c9b0d98b118ef31f74c151976cb71aaf333a 100644 (file)
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -35,21 +35,18 @@
 #include <linux/platform_device.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/of_gpio.h>
 #include <linux/dma-mapping.h>
 #include <linux/atmel_pdc.h>
 #include <linux/atmel_serial.h>
 #include <linux/uaccess.h>
 #include <linux/platform_data/atmel.h>
 #include <linux/timer.h>
+#include <linux/gpio.h>
 
 #include <asm/io.h>
 #include <asm/ioctls.h>
 
-#ifdef CONFIG_ARM
-#include <mach/cpu.h>
-#include <asm/gpio.h>
-#endif
-
 #define PDC_BUFFER_SIZE                512
 /* Revisit: We should calculate this based on the actual port settings */
 #define PDC_RX_TIMEOUT         (3 * 10)                /* 3 bytes */
@@ -168,6 +165,7 @@ struct atmel_uart_port {
        struct circ_buf         rx_ring;
 
        struct serial_rs485     rs485;          /* rs485 settings */
+       int                     rts_gpio;       /* optional RTS GPIO */
        unsigned int            tx_done_mask;
        bool                    is_usart;       /* usart or uart */
        struct timer_list       uart_timer;     /* uart timer */
@@ -301,20 +299,16 @@ static void atmel_set_mctrl(struct uart_port *port, u_int mctrl)
        unsigned int mode;
        struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 
-#ifdef CONFIG_ARCH_AT91RM9200
-       if (cpu_is_at91rm9200()) {
-               /*
-                * AT91RM9200 Errata #39: RTS0 is not internally connected
-                * to PA21. We need to drive the pin manually.
-                */
-               if (port->mapbase == AT91RM9200_BASE_US0) {
-                       if (mctrl & TIOCM_RTS)
-                               at91_set_gpio_value(AT91_PIN_PA21, 0);
-                       else
-                               at91_set_gpio_value(AT91_PIN_PA21, 1);
-               }
+       /*
+        * AT91RM9200 Errata #39: RTS0 is not internally connected
+        * to PA21. We need to drive the pin as a GPIO.
+        */
+       if (gpio_is_valid(atmel_port->rts_gpio)) {
+               if (mctrl & TIOCM_RTS)
+                       gpio_set_value(atmel_port->rts_gpio, 0);
+               else
+                       gpio_set_value(atmel_port->rts_gpio, 1);
        }
-#endif
 
        if (mctrl & TIOCM_RTS)
                control |= ATMEL_US_RTSEN;
@@ -2379,6 +2373,25 @@ static int atmel_serial_probe(struct platform_device *pdev)
        port = &atmel_ports[ret];
        port->backup_imr = 0;
        port->uart.line = ret;
+       port->rts_gpio = -EINVAL; /* Invalid, zero could be valid */
+       if (pdata)
+               port->rts_gpio = pdata->rts_gpio;
+       else if (np)
+               port->rts_gpio = of_get_named_gpio(np, "rts-gpios", 0);
+
+       if (gpio_is_valid(port->rts_gpio)) {
+               ret = devm_gpio_request(&pdev->dev, port->rts_gpio, "RTS");
+               if (ret) {
+                       dev_err(&pdev->dev, "error requesting RTS GPIO\n");
+                       goto err;
+               }
+               /* Default to 1 as RTS is active low */
+               ret = gpio_direction_output(port->rts_gpio, 1);
+               if (ret) {
+                       dev_err(&pdev->dev, "error setting up RTS GPIO\n");
+                       goto err;
+               }
+       }
 
        ret = atmel_init_port(port, pdev);
        if (ret)

diff --git a/include/linux/platform_data/atmel.h b/include/linux/platform_data/atmel.h
index cea9f70133c521f1d5fb2a0d459f3e30ca3f9576..e26b0c14edea9c0864e6ebc4178537dc7a8eee75 100644 (file)
--- a/include/linux/platform_data/atmel.h
+++ b/include/linux/platform_data/atmel.h
@@ -84,6 +84,7 @@ struct atmel_uart_data {
        short                   use_dma_rx;     /* use receive DMA? */
        void __iomem            *regs;          /* virt. base address, if any */
        struct serial_rs485     rs485;          /* rs485 settings */
+       int                     rts_gpio;       /* optional RTS GPIO */
 };
 
  /* Touchscreen Controller */