[PATCH v4] ARM/serial: at91: switch atmel serial to use gpiolib
Linus Walleij
linus.walleij at linaro.org
Thu Nov 7 04:25:55 EST 2013
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 at atmel.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
---
ChangeLog v3->v4:
- Assign RTS pin setup at runtime for the applicable
platforms. Drive it to 1 rather than 0 by default as
RTS is active low. Thanks to Jean-Christophe for noticing
the fine details... sorry for the fuzz :-/
ChangeLog v2->v3:
- Instead of disallowing GPIO 0 to be used for the RTS
signal to allow null-initialized platform data to mean
"no RTS GPIO", be more generic and actually allow it,
and patch every instance of atmel_uart_data to set
.rts_gpio to -EINVAL except for the one case where we
actually use pin 21 for RTS over GPIO.
ChangeLog v1->v2:
- Skip check for UART base address from leftover hack,
if we have an RTS GPIO we just use it.
- Set default error value on GPIO pin to -EINVAL
- Fold in a device tree support patch from Nicolas Ferre
---
.../devicetree/bindings/serial/atmel-usart.txt | 3 ++
arch/arm/mach-at91/at91rm9200_devices.c | 10 ++++-
arch/arm/mach-at91/at91sam9260_devices.c | 7 ++++
arch/arm/mach-at91/at91sam9261_devices.c | 4 ++
arch/arm/mach-at91/at91sam9263_devices.c | 4 ++
arch/arm/mach-at91/at91sam9g45_devices.c | 5 +++
arch/arm/mach-at91/at91sam9rl_devices.c | 5 +++
drivers/tty/serial/atmel_serial.c | 49 ++++++++++++++--------
include/linux/platform_data/atmel.h | 1 +
9 files changed, 68 insertions(+), 20 deletions(-)
diff --git a/Documentation/devicetree/bindings/serial/atmel-usart.txt b/Documentation/devicetree/bindings/serial/atmel-usart.txt
index 2191dcb9f1da..3adc61c2e4ca 100644
--- 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 c721e9b08066..08ac5e2ff97d 100644
--- a/arch/arm/mach-at91/at91rm9200_devices.c
+++ b/arch/arm/mach-at91/at91rm9200_devices.c
@@ -923,6 +923,7 @@ 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);
@@ -961,6 +962,7 @@ 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);
@@ -988,9 +990,10 @@ 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;
}
}
@@ -1010,6 +1013,7 @@ 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);
@@ -1061,6 +1065,7 @@ 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);
@@ -1104,6 +1109,7 @@ 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 428abfc14848..bcf4a161a3d8 100644
--- 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 4e02e9271ac9..d5b08ef9e848 100644
--- 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 3a384ef27cf6..22b13c6226cb 100644
--- a/arch/arm/mach-at91/at91sam9263_devices.c
+++ b/arch/arm/mach-at91/at91sam9263_devices.c
@@ -1325,6 +1325,7 @@ 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);
@@ -1363,6 +1364,7 @@ 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);
@@ -1406,6 +1408,7 @@ 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);
@@ -1449,6 +1452,7 @@ 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 6b8effbffc28..89f95ed711c6 100644
--- a/arch/arm/mach-at91/at91sam9g45_devices.c
+++ b/arch/arm/mach-at91/at91sam9g45_devices.c
@@ -1588,6 +1588,7 @@ 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);
@@ -1626,6 +1627,7 @@ 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);
@@ -1669,6 +1671,7 @@ 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);
@@ -1712,6 +1715,7 @@ 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);
@@ -1755,6 +1759,7 @@ 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 6cf441cadf94..3c2462b15b8b 100644
--- a/arch/arm/mach-at91/at91sam9rl_devices.c
+++ b/arch/arm/mach-at91/at91sam9rl_devices.c
@@ -957,6 +957,7 @@ 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);
@@ -995,6 +996,7 @@ 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);
@@ -1046,6 +1048,7 @@ 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);
@@ -1089,6 +1092,7 @@ 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);
@@ -1132,6 +1136,7 @@ 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 d067285a2d20..af6765d3aedb 100644
--- 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 */
@@ -167,6 +164,7 @@ 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 */
@@ -300,20 +298,16 @@ 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;
@@ -2365,6 +2359,25 @@ 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 cea9f70133c5..e26b0c14edea 100644
--- 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 */
--
1.8.3.1
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