On 13:35 Tue 05 Nov , Linus Walleij wrote:
> 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.
>
> This also makes way for device tree conversion: the RTS
> GPIO pin can be passed by standard GPIO bindings.
>
> Signed-off-by: Linus Walleij <[email protected]>
> ---
> This is an alternative to the patch entitled
> "ARM/serial: at91: move machine quirk into machine"
> which needs testing to confirm this approach.
> Seeking ACKs on this if the approach seems OK to
> all parties.
> ---
> arch/arm/mach-at91/at91rm9200_devices.c | 1 +
> drivers/tty/serial/atmel_serial.c | 51
> +++++++++++++++++++++------------
> include/linux/platform_data/atmel.h | 1 +
> 3 files changed, 35 insertions(+), 18 deletions(-)
>
> diff --git a/arch/arm/mach-at91/at91rm9200_devices.c
> b/arch/arm/mach-at91/at91rm9200_devices.c
> index c721e9b08066..51d4c08962f6 100644
> --- a/arch/arm/mach-at91/at91rm9200_devices.c
> +++ b/arch/arm/mach-at91/at91rm9200_devices.c
> @@ -961,6 +961,7 @@ static struct resource uart0_resources[] = {
> static struct atmel_uart_data uart0_data = {
> .use_dma_tx = 1,
> .use_dma_rx = 1,
> + .rts_gpio = AT91_PIN_PA21,
> };
>
> static u64 uart0_dmamask = DMA_BIT_MASK(32);
> diff --git a/drivers/tty/serial/atmel_serial.c
> b/drivers/tty/serial/atmel_serial.c
> index d067285a2d20..3d5c848cdfe1 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -41,15 +41,11 @@
> #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 +163,7 @@ 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 +297,17 @@ 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) &&
> + port->mapbase == AT91RM9200_BASE_US0) {
not really a fon of this hack
if we use a uart for rs485 we need to use a gpio for rts too
so we may need to find a better way
> + 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 +2359,27 @@ static int atmel_serial_probe(struct platform_device
> *pdev)
> port = &atmel_ports[ret];
> port->backup_imr = 0;
> port->uart.line = ret;
> + port->rts_gpio = -1; /* Invalid, zero could be valid */
> + /*
> + * In theory the GPIO pin controlling RTS could be zero and
> + * this would be an improper check, but we know that the only
> + * existing case is != 0 and it's nice to use the zero-initialized
> + * structs to indicate "no RTS GPIO" instead of open-coding some
> + * invalid value everywhere.
> + */
> + if (pdata->rts_gpio > 0) {
this can not work 0 is a valid gpio if you do this you need to update
ALL the bard filee too to set it as -EINVAL;
> + ret = devm_gpio_request(&pdev->dev, pdata->rts_gpio, "RTS");
> + if (ret) {
> + dev_err(&pdev->dev, "error requesting RTS GPIO\n");
> + goto err;
> + }
> + port->rts_gpio = pdata->rts_gpio;
> + ret = gpio_direction_output(port->rts_gpio, 0);
> + 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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