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yanovichgregkh
yanovich
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serial: rewrite pxa2xx-uart to use 8250_core
pxa2xx-uart was a separate uart platform driver. It was declaring the same device names and numbers as 8250 driver. As a result, it was impossible to use 8250 driver on PXA SoCs. Upon closer examination pxa2xx-uart turned out to be a clone of 8250_core driver. Workaround for Erratum torvalds#19 according to Marvel(R) PXA270M Processor Specification Update (April 19, 2010) is dropped. 8250_core reads from FIFO immediately after checking DR bit in LSR. The patch leaves the original SERIAL_PXA driver around. The original driver is just marked DEPRECATED in Kconfig and C source. When the original driver is considered safe to remove, no changes to SERIAL_8250 will be necessary. Compiling SERIAL_8250_CONSOLE and SERIAL_PXA_CONSOLE even without SERIAL_8250_PXA breaks console for SERIAL_PXA. For this reasons, the new and the original drivers are made mutually exclusive. Signed-off-by: Sergei Ianovich <ynvich@gmail.com> CC: Heikki Krogerus <heikki.krogerus@linux.intel.com> CC: James Cameron <quozl@laptop.org> CC: Robert Jarzmik <robert.jarzmik@free.fr> CC: Russell King <linux@arm.linux.org.uk> Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> [rebased on v4.8] Tested-by: Robert Jarzmik <robert.jarzmik@free.fr> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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‎drivers/tty/serial/8250/8250_pxa.c

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/*
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* drivers/tty/serial/8250/8250_pxa.c -- driver for PXA on-board UARTS
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* Copyright: (C) 2013 Sergei Ianovich <ynvich@gmail.com>
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*
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* replaces drivers/serial/pxa.c by Nicolas Pitre
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* Created: Feb 20, 2003
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* Copyright: (C) 2003 Monta Vista Software, Inc.
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*
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* Based on drivers/serial/8250.c by Russell King.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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*/
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#include <linux/device.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/serial_8250.h>
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#include <linux/serial_core.h>
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#include <linux/serial_reg.h>
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#include <linux/of.h>
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#include <linux/of_irq.h>
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#include <linux/of_platform.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/clk.h>
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#include <linux/pm_runtime.h>
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#include "8250.h"
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struct pxa8250_data {
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int line;
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struct clk *clk;
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};
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#ifdef CONFIG_PM
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static int serial_pxa_suspend(struct device *dev)
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{
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struct pxa8250_data *data = dev_get_drvdata(dev);
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serial8250_suspend_port(data->line);
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return 0;
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}
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static int serial_pxa_resume(struct device *dev)
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{
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struct pxa8250_data *data = dev_get_drvdata(dev);
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serial8250_resume_port(data->line);
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return 0;
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}
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#endif
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static const struct dev_pm_ops serial_pxa_pm_ops = {
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SET_SYSTEM_SLEEP_PM_OPS(serial_pxa_suspend, serial_pxa_resume)
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};
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static const struct of_device_id serial_pxa_dt_ids[] = {
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{ .compatible = "mrvl,pxa-uart", },
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{ .compatible = "mrvl,mmp-uart", },
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{}
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};
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MODULE_DEVICE_TABLE(of, serial_pxa_dt_ids);
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/* Uart divisor latch write */
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static void serial_pxa_dl_write(struct uart_8250_port *up, int value)
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{
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unsigned int dll;
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serial_out(up, UART_DLL, value & 0xff);
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/*
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* work around Erratum #74 according to Marvel(R) PXA270M Processor
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* Specification Update (April 19, 2010)
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*/
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dll = serial_in(up, UART_DLL);
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WARN_ON(dll != (value & 0xff));
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serial_out(up, UART_DLM, value >> 8 & 0xff);
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}
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static void serial_pxa_pm(struct uart_port *port, unsigned int state,
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unsigned int oldstate)
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{
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struct pxa8250_data *data = port->private_data;
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if (!state)
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clk_prepare_enable(data->clk);
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else
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clk_disable_unprepare(data->clk);
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}
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static int serial_pxa_probe(struct platform_device *pdev)
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{
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struct uart_8250_port uart = {};
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struct pxa8250_data *data;
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struct resource *mmres, *irqres;
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int ret;
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mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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irqres = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
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if (!mmres || !irqres)
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return -ENODEV;
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data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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data->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(data->clk))
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return PTR_ERR(data->clk);
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ret = clk_prepare(data->clk);
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if (ret)
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return ret;
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uart.port.type = PORT_XSCALE;
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uart.port.iotype = UPIO_MEM32;
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uart.port.mapbase = mmres->start;
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uart.port.regshift = 2;
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uart.port.irq = irqres->start;
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uart.port.fifosize = 64;
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uart.port.flags = UPF_IOREMAP | UPF_SKIP_TEST;
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uart.port.dev = &pdev->dev;
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uart.port.uartclk = clk_get_rate(data->clk);
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uart.port.pm = serial_pxa_pm;
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uart.port.private_data = data;
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uart.dl_write = serial_pxa_dl_write;
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ret = serial8250_register_8250_port(&uart);
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if (ret < 0)
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goto err_clk;
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data->line = ret;
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platform_set_drvdata(pdev, data);
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return 0;
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err_clk:
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clk_unprepare(data->clk);
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return ret;
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}
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static int serial_pxa_remove(struct platform_device *pdev)
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{
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struct pxa8250_data *data = platform_get_drvdata(pdev);
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serial8250_unregister_port(data->line);
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clk_unprepare(data->clk);
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return 0;
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}
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static struct platform_driver serial_pxa_driver = {
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.probe = serial_pxa_probe,
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.remove = serial_pxa_remove,
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.driver = {
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.name = "pxa2xx-uart",
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.pm = &serial_pxa_pm_ops,
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.of_match_table = serial_pxa_dt_ids,
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},
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};
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module_platform_driver(serial_pxa_driver);
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MODULE_AUTHOR("Sergei Ianovich");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:pxa2xx-uart");

‎drivers/tty/serial/8250/Kconfig

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@@ -439,6 +439,16 @@ config SERIAL_8250_MOXA
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This driver can also be built as a module. The module will be called
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8250_moxa. If you want to do that, say M here.
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config SERIAL_8250_PXA
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tristate "PXA serial port support"
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depends on SERIAL_8250
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depends on ARCH_PXA || ARCH_MMP
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help
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If you have a machine based on an Intel XScale PXA2xx CPU you can
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enable its onboard serial ports by enabling this option. The option is
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applicable to both devicetree and legacy boards, and early console is
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part of its support.
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config SERIAL_OF_PLATFORM
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tristate "Devicetree based probing for 8250 ports"
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depends on SERIAL_8250 && OF

‎drivers/tty/serial/8250/Makefile

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@@ -31,6 +31,7 @@ obj-$(CONFIG_SERIAL_8250_INGENIC) += 8250_ingenic.o
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obj-$(CONFIG_SERIAL_8250_LPSS) += 8250_lpss.o
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obj-$(CONFIG_SERIAL_8250_MID) += 8250_mid.o
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obj-$(CONFIG_SERIAL_8250_MOXA) += 8250_moxa.o
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obj-$(CONFIG_SERIAL_8250_PXA) += 8250_pxa.o
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obj-$(CONFIG_SERIAL_OF_PLATFORM) += 8250_of.o
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CFLAGS_8250_ingenic.o += -I$(srctree)/scripts/dtc/libfdt

‎drivers/tty/serial/Kconfig

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@@ -438,17 +438,27 @@ config SERIAL_MPSC_CONSOLE
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Say Y here if you want to support a serial console on a Marvell MPSC.
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config SERIAL_PXA
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bool "PXA serial port support"
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bool "PXA serial port support (DEPRECATED)"
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depends on ARCH_PXA || ARCH_MMP
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select SERIAL_CORE
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select SERIAL_8250_PXA if SERIAL_8250=y
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select SERIAL_PXA_NON8250 if !SERIAL_8250=y
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help
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If you have a machine based on an Intel XScale PXA2xx CPU you
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can enable its onboard serial ports by enabling this option.
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Unless you have a specific need, you should use SERIAL_8250_PXA
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instead of this.
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config SERIAL_PXA_NON8250
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bool
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depends on !SERIAL_8250
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config SERIAL_PXA_CONSOLE
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bool "Console on PXA serial port"
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bool "Console on PXA serial port (DEPRECATED)"
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depends on SERIAL_PXA
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select SERIAL_CORE_CONSOLE
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select SERIAL_8250_CONSOLE if SERIAL_8250=y
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help
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If you have enabled the serial port on the Intel XScale PXA
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CPU you can make it the console by answering Y to this option.
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your boot loader (lilo or loadlin) about how to pass options to the
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kernel at boot time.)
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Unless you have a specific need, you should use SERIAL_8250_PXA
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and SERIAL_8250_CONSOLE instead of this.
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config SERIAL_SA1100
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bool "SA1100 serial port support"
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depends on ARCH_SA1100

‎drivers/tty/serial/Makefile

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@@ -23,7 +23,7 @@ obj-$(CONFIG_SERIAL_8250) += 8250/
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obj-$(CONFIG_SERIAL_AMBA_PL010) += amba-pl010.o
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obj-$(CONFIG_SERIAL_AMBA_PL011) += amba-pl011.o
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obj-$(CONFIG_SERIAL_CLPS711X) += clps711x.o
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obj-$(CONFIG_SERIAL_PXA) += pxa.o
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obj-$(CONFIG_SERIAL_PXA_NON8250) += pxa.o
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obj-$(CONFIG_SERIAL_PNX8XXX) += pnx8xxx_uart.o
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obj-$(CONFIG_SERIAL_SA1100) += sa1100.o
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obj-$(CONFIG_SERIAL_BCM63XX) += bcm63xx_uart.o

‎drivers/tty/serial/pxa.c

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@@ -925,7 +925,9 @@ static struct platform_driver serial_pxa_driver = {
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},
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};
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static int __init serial_pxa_init(void)
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/* 8250 driver for PXA serial ports should be used */
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static int __deprecated __init serial_pxa_init(void)
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{
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int ret;
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