[PATCH v4] ARM/serial: at91: switch atmel serial to use gpiolib
Nicolas Ferre
nicolas.ferre at atmel.com
Mon Dec 2 03:47:50 EST 2013
On 13/11/2013 17:28, Nicolas Ferre :
> On 07/11/2013 10:25, Linus Walleij :
>> 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>
>
> Hi Greg,
>
> You acknowledged a previous version of this patch which was taking a
> different approach with the subject:
> "[PATCH 1/4] ARM/serial: at91: move machine quirk into machine"
>
> In order to integrate the series build by Linus in our AT91/arm-soc
> flow, would you mind reviewing this v4 patch and eventually giving your
> blessing ;-)
> If it is okay on your side, I'll integrate it in a pull-request to
> arm-soc for 3.14.
Greg, ping?
>
> Thanks, bye,
>
>
>> ---
>> 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 */
>>
>
>
--
Nicolas Ferre
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