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serial: Make retrieval of rs485 properties platform-agnostic

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Commit ef838a81dd ("serial: Add common rs485 device tree parsing
function") consolidated retrieval of rs485 OF properties in a common
helper function but did not #ifdef it to CONFIG_OF.  The function is
therefore included on ACPI platforms as well even though it's not used.

On the other hand ACPI platforms with rs485 do exist (e.g. Siemens
IOT2040) and they may leverage _DSD to store rs485 properties.  Likewise,
UART platform devices instantiated from an MFD should be able to specify
rs485 properties.  In fact, the tty subsystem maintainer had asked for
a "generic" function during review of commit ef838a81dd:
https://marc.info/?l=linux-serial&m=150143441725194&w=4

Thus, instead of constraining the helper to OF platforms, make it
platform-agnostic by converting it to device_property_*() functions
and renaming it accordingly.

In imx.c, move the invocation of uart_get_rs485_mode() from
serial_imx_probe_dt() to serial_imx_probe() so that it also gets called
for non-OF devices.

In omap-serial.c, move its invocation further up within
serial_omap_probe_rs485() so that the RTS polarity can be overridden
with the driver-specific "rs485-rts-active-high" property once we
introduce a generic "rs485-rts-active-low" property.

Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Richard Genoud <richard.genoud@gmail.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Lukas Wunner
2017-11-24 23:26:40 +01:00
committed by Greg Kroah-Hartman
parent cda64188ca
commit 743f93f822
6 changed files with 15 additions and 18 deletions
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4
drivers/tty/serial/omap-serial.c
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@@ -1611,6 +1611,8 @@ static int serial_omap_probe_rs485(struct uart_omap_port *up,
if (!np)
return 0;
uart_get_rs485_mode(up->dev, rs485conf);
if (of_property_read_bool(np, "rs485-rts-active-high"))
rs485conf->flags |= SER_RS485_RTS_ON_SEND;
else
@@ -1632,8 +1634,6 @@ static int serial_omap_probe_rs485(struct uart_omap_port *up,
up->rts_gpio = -EINVAL;
}
of_get_rs485_mode(np, rs485conf);
return 0;
}