LXR linux/drivers/tty/serial/8250/8250

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 *  drivers/tty/serial/8250/8250_pxa.c -- driver for PXA on-board UARTS
   4 *  Copyright:  (C) 2013 Sergei Ianovich <ynvich@gmail.com>
   5 *
   6 *  replaces drivers/serial/pxa.c by Nicolas Pitre
   7 *  Created:    Feb 20, 2003
   8 *  Copyright:  (C) 2003 Monta Vista Software, Inc.
   9 *
  10 *  Based on drivers/serial/8250.c by Russell King.
  11 */
  12
  13#include <linux/device.h>
  14#include <linux/init.h>
  15#include <linux/io.h>
  16#include <linux/module.h>
  17#include <linux/serial_8250.h>
  18#include <linux/serial_core.h>
  19#include <linux/serial_reg.h>
  20#include <linux/of.h>
  21#include <linux/of_irq.h>
  22#include <linux/of_platform.h>
  23#include <linux/platform_device.h>
  24#include <linux/slab.h>
  25#include <linux/clk.h>
  26#include <linux/pm_runtime.h>
  27
  28#include "8250.h"
  29
  30struct pxa8250_data {
  31        int                     line;
  32        struct clk              *clk;
  33};
  34
  35static int __maybe_unused serial_pxa_suspend(struct device *dev)
  36{
  37        struct pxa8250_data *data = dev_get_drvdata(dev);
  38
  39        serial8250_suspend_port(data->line);
  40
  41        return 0;
  42}
  43
  44static int __maybe_unused serial_pxa_resume(struct device *dev)
  45{
  46        struct pxa8250_data *data = dev_get_drvdata(dev);
  47
  48        serial8250_resume_port(data->line);
  49
  50        return 0;
  51}
  52
  53static const struct dev_pm_ops serial_pxa_pm_ops = {
  54        SET_SYSTEM_SLEEP_PM_OPS(serial_pxa_suspend, serial_pxa_resume)
  55};
  56
  57static const struct of_device_id serial_pxa_dt_ids[] = {
  58        { .compatible = "mrvl,pxa-uart", },
  59        { .compatible = "mrvl,mmp-uart", },
  60        {}
  61};
  62MODULE_DEVICE_TABLE(of, serial_pxa_dt_ids);
  63
  64/* Uart divisor latch write */
  65static void serial_pxa_dl_write(struct uart_8250_port *up, int value)
  66{
  67        unsigned int dll;
  68
  69        serial_out(up, UART_DLL, value & 0xff);
  70        /*
  71         * work around Erratum #74 according to Marvel(R) PXA270M Processor
  72         * Specification Update (April 19, 2010)
  73         */
  74        dll = serial_in(up, UART_DLL);
  75        WARN_ON(dll != (value & 0xff));
  76
  77        serial_out(up, UART_DLM, value >> 8 & 0xff);
  78}
  79
  80
  81static void serial_pxa_pm(struct uart_port *port, unsigned int state,
  82              unsigned int oldstate)
  83{
  84        struct pxa8250_data *data = port->private_data;
  85
  86        if (!state)
  87                clk_prepare_enable(data->clk);
  88        else
  89                clk_disable_unprepare(data->clk);
  90}
  91
  92static int serial_pxa_probe(struct platform_device *pdev)
  93{
  94        struct uart_8250_port uart = {};
  95        struct pxa8250_data *data;
  96        struct resource *mmres, *irqres;
  97        int ret;
  98
  99        mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 100        irqres = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 101        if (!mmres || !irqres)
 102                return -ENODEV;
 103
 104        data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 105        if (!data)
 106                return -ENOMEM;
 107
 108        data->clk = devm_clk_get(&pdev->dev, NULL);
 109        if (IS_ERR(data->clk))
 110                return PTR_ERR(data->clk);
 111
 112        ret = clk_prepare(data->clk);
 113        if (ret)
 114                return ret;
 115
 116        uart.port.type = PORT_XSCALE;
 117        uart.port.iotype = UPIO_MEM32;
 118        uart.port.mapbase = mmres->start;
 119        uart.port.regshift = 2;
 120        uart.port.irq = irqres->start;
 121        uart.port.fifosize = 64;
 122        uart.port.flags = UPF_IOREMAP | UPF_SKIP_TEST;
 123        uart.port.dev = &pdev->dev;
 124        uart.port.uartclk = clk_get_rate(data->clk);
 125        uart.port.pm = serial_pxa_pm;
 126        uart.port.private_data = data;
 127        uart.dl_write = serial_pxa_dl_write;
 128
 129        ret = serial8250_register_8250_port(&uart);
 130        if (ret < 0)
 131                goto err_clk;
 132
 133        data->line = ret;
 134
 135        platform_set_drvdata(pdev, data);
 136
 137        return 0;
 138
 139 err_clk:
 140        clk_unprepare(data->clk);
 141        return ret;
 142}
 143
 144static int serial_pxa_remove(struct platform_device *pdev)
 145{
 146        struct pxa8250_data *data = platform_get_drvdata(pdev);
 147
 148        serial8250_unregister_port(data->line);
 149
 150        clk_unprepare(data->clk);
 151
 152        return 0;
 153}
 154
 155static struct platform_driver serial_pxa_driver = {
 156        .probe          = serial_pxa_probe,
 157        .remove         = serial_pxa_remove,
 158
 159        .driver         = {
 160                .name   = "pxa2xx-uart",
 161                .pm     = &serial_pxa_pm_ops,
 162                .of_match_table = serial_pxa_dt_ids,
 163        },
 164};
 165
 166module_platform_driver(serial_pxa_driver);
 167
 168#ifdef CONFIG_SERIAL_8250_CONSOLE
 169static int __init early_serial_pxa_setup(struct earlycon_device *device,
 170                                  const char *options)
 171{
 172        struct uart_port *port = &device->port;
 173
 174        if (!(device->port.membase || device->port.iobase))
 175                return -ENODEV;
 176
 177        port->regshift = 2;
 178        return early_serial8250_setup(device, NULL);
 179}
 180OF_EARLYCON_DECLARE(early_pxa, "mrvl,pxa-uart", early_serial_pxa_setup);
 181#endif
 182
 183MODULE_AUTHOR("Sergei Ianovich");
 184MODULE_LICENSE("GPL");
 185MODULE_ALIAS("platform:pxa2xx-uart");
 186