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

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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>
This commit is contained in:
Linus Walleij
2013-11-07 10:25:55 +01:00
committed by Uwe Kleine-König
parent 6a79799d56
commit 354e57f3a0
9 changed files with 68 additions and 20 deletions
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49
drivers/tty/serial/atmel_serial.c
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@@ -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)