From: Heiko Stuebner <heiko@sntech.de>
To: gregkh@linuxfoundation.org
Cc: jslaby@suse.com, andriy.shevchenko@linux.intel.com,
matwey.kornilov@gmail.com, linux-serial@vger.kernel.org,
linux-kernel@vger.kernel.org, heiko@sntech.de,
Giulio Benetti <giulio.benetti@micronovasrl.com>,
Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
Subject: [PATCH 6/7] serial: 8250_dw: add em485 support
Date: Wed, 18 Mar 2020 15:26:39 +0100 [thread overview]
Message-ID: <20200318142640.982763-7-heiko@sntech.de> (raw)
In-Reply-To: <20200318142640.982763-1-heiko@sntech.de>
From: Giulio Benetti <giulio.benetti@micronovasrl.com>
Need to use rs485 transceiver so let's use existing em485 485 emulation
layer on top of 8250.
Add rs485_config callback to port.
Signed-off-by: Giulio Benetti <giulio.benetti@micronovasrl.com>
Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
---
drivers/tty/serial/8250/8250_dw.c | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 1c72fdc2dd37..7023b656658d 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -320,6 +320,36 @@ static void dw8250_set_ldisc(struct uart_port *p, struct ktermios *termios)
serial8250_do_set_ldisc(p, termios);
}
+static int dw8250_rs485_config(struct uart_port *p,
+ struct serial_rs485 *rs485)
+{
+ struct uart_8250_port *up = up_to_u8250p(p);
+
+ /* Clamp the delays to [0, 100ms] */
+ rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U);
+ rs485->delay_rts_after_send = min(rs485->delay_rts_after_send, 100U);
+
+ p->rs485 = *rs485;
+
+ /*
+ * Both serial8250_em485_init and serial8250_em485_destroy
+ * are idempotent
+ */
+ if (rs485->flags & SER_RS485_ENABLED) {
+ int ret = serial8250_em485_init(up, false);
+
+ if (ret) {
+ rs485->flags &= ~SER_RS485_ENABLED;
+ p->rs485.flags &= ~SER_RS485_ENABLED;
+ }
+ return ret;
+ }
+
+ serial8250_em485_destroy(up);
+
+ return 0;
+}
+
/*
* dw8250_fallback_dma_filter will prevent the UART from getting just any free
* channel on platforms that have DMA engines, but don't have any channels
@@ -417,6 +447,7 @@ static int dw8250_probe(struct platform_device *pdev)
p->serial_out = dw8250_serial_out;
p->set_ldisc = dw8250_set_ldisc;
p->set_termios = dw8250_set_termios;
+ p->rs485_config = dw8250_rs485_config;
p->membase = devm_ioremap(dev, regs->start, resource_size(regs));
if (!p->membase)
--
2.24.1
next prev parent reply other threads:[~2020-03-18 14:27 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-18 14:26 [PATCH 0/7] serial: 8250: Add rs485 emulation to 8250_dw Heiko Stuebner
2020-03-18 14:26 ` [PATCH 1/7] serial: 8250: Make em485_rts_after_send() set mctrl according to rts state Heiko Stuebner
2020-03-18 14:26 ` [PATCH 2/7] serial: 8250: add serial_in_poll_timeout helper Heiko Stuebner
2020-03-18 15:09 ` Andy Shevchenko
2020-03-18 14:26 ` [PATCH 3/7] serial: 8250: Handle case port doesn't have TEMT interrupt using em485 Heiko Stuebner
2020-03-18 14:26 ` [PATCH 4/7] serial: 8250: Start rs485 after registering port if rs485 is enabled in probe Heiko Stuebner
2020-03-18 14:26 ` [PATCH 5/7] serial: 8250: handle DTR in rs485 emulation Heiko Stuebner
2020-03-18 14:26 ` Heiko Stuebner [this message]
2020-03-18 15:15 ` [PATCH 6/7] serial: 8250_dw: add em485 support Andy Shevchenko
2020-03-18 14:26 ` [PATCH 7/7] serial: 8250_dw: allow enable rs485 at boot time Heiko Stuebner
2020-03-18 15:16 ` Andy Shevchenko
2020-03-18 18:28 ` Heiko Stübner
2020-03-18 18:31 ` Heiko Stübner
2020-03-18 14:43 ` [PATCH 0/7] serial: 8250: Add rs485 emulation to 8250_dw Andy Shevchenko
2020-03-18 15:37 ` Lukas Wunner
2020-03-18 15:54 ` Andy Shevchenko
2020-03-18 18:49 ` Heiko Stübner
2020-03-19 5:40 ` Lukas Wunner
2020-03-23 8:25 ` Heiko Stübner
2020-03-23 13:17 ` Lukas Wunner
2020-03-23 13:41 ` Andy Shevchenko
2020-03-25 13:41 ` Heiko Stübner
2020-03-25 14:42 ` Andy Shevchenko
2020-03-18 15:13 ` Andy Shevchenko
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