Commit e3896be2 authored by Manikanta Guntupalli's avatar Manikanta Guntupalli Committed by Greg Kroah-Hartman
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tty: serial: uartps: Add support for uartps controller reset 



Add support for an optional reset for the uartps controller using
the reset driver. If the uartps node contains the "resets" property,
then cdns_uart_startup performs uartps controller non-pulse out of reset
and reset in exit path.

Signed-off-by: default avatarManikanta Guntupalli <manikanta.guntupalli@amd.com>
Link: https://lore.kernel.org/r/20240425062358.1347684-4-manikanta.guntupalli@amd.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b4337685

drivers/tty/serial/xilinx_uartps.c

+15 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <linux/gpio.h>

#include <linux/gpio/consumer.h>

#include <linux/delay.h>

#include <linux/reset.h>



#define CDNS_UART_TTY_NAME	"ttyPS"

#define CDNS_UART_NAME		"xuartps"
@@ -198,6 +199,7 @@ MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255"); 
 * @gpiod_rts:		Pointer to the gpio descriptor

 * @rs485_tx_started:	RS485 tx state

 * @tx_timer:		Timer for tx

 * @rstc:		Pointer to the reset control

 */

struct cdns_uart {

	struct uart_port	*port;
@@ -211,6 +213,7 @@ struct cdns_uart { 
	struct gpio_desc	*gpiod_rts;

	bool			rs485_tx_started;

	struct hrtimer		tx_timer;

	struct reset_control	*rstc;

};

struct cdns_platform_data {

	u32 quirks;
@@ -948,6 +951,10 @@ static int cdns_uart_startup(struct uart_port *port) 


	is_brk_support = cdns_uart->quirks & CDNS_UART_RXBS_SUPPORT;



	ret = reset_control_deassert(cdns_uart->rstc);

	if (ret)

		return ret;



	uart_port_lock_irqsave(port, &flags);



	/* Disable the TX and RX */
@@ -1721,6 +1728,13 @@ static int cdns_uart_probe(struct platform_device *pdev) 
		dev_err(&pdev->dev, "clock name 'ref_clk' is deprecated.\n");

	}



	cdns_uart_data->rstc = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);

	if (IS_ERR(cdns_uart_data->rstc)) {

		rc = PTR_ERR(cdns_uart_data->rstc);

		dev_err_probe(&pdev->dev, rc, "Cannot get UART reset\n");

		goto err_out_unregister_driver;

	}



	rc = clk_prepare_enable(cdns_uart_data->pclk);

	if (rc) {

		dev_err(&pdev->dev, "Unable to enable pclk clock.\n");
@@ -1881,6 +1895,7 @@ static void cdns_uart_remove(struct platform_device *pdev) 
	if (console_port == port)

		console_port = NULL;

#endif

	reset_control_assert(cdns_uart_data->rstc);



	if (!--instances)

		uart_unregister_driver(cdns_uart_data->cdns_uart_driver);