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Message-ID: <20240424112933.3528590-4-manikanta.guntupalli@amd.com>
Date: Wed, 24 Apr 2024 16:59:33 +0530
From: Manikanta Guntupalli <manikanta.guntupalli@....com>
To: <git@....com>, <gregkh@...uxfoundation.org>, <jirislaby@...nel.org>,
<robh@...nel.org>, <krzk+dt@...nel.org>, <conor+dt@...nel.org>,
<michal.simek@....com>, <p.zabel@...gutronix.de>,
<laurent.pinchart@...asonboard.com>, <radhey.shyam.pandey@....com>,
<parth.gajjar@....com>, <u.kleine-koenig@...gutronix.de>,
<tglx@...utronix.de>, <julien.malik@...eenlabs.fr>, <ruanjinjie@...wei.com>,
<linux-kernel@...r.kernel.org>, <linux-serial@...r.kernel.org>,
<devicetree@...r.kernel.org>, <linux-arm-kernel@...ts.infradead.org>
CC: <srinivas.goud@....com>, <shubhrajyoti.datta@....com>,
<manion05gk@...il.com>, Manikanta Guntupalli <manikanta.guntupalli@....com>
Subject: [PATCH V2 3/3] 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: Manikanta Guntupalli <manikanta.guntupalli@....com>
---
Changes for V2:
Remove check for reset_control_deassert, as reset_control_deassert
function internally has NULL check
---
drivers/tty/serial/xilinx_uartps.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index de3487206bcb..2acfcea403ce 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -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);
--
2.25.1
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