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_platform.h>
  22#include <linux/platform_device.h>
  23#include <linux/slab.h>
  24#include <linux/clk.h>
  25#include <linux/pm_runtime.h>
  26
  27#include "8250.h"
  28
  29struct pxa8250_data {
  30        int                     line;
  31        struct clk              *clk;
  32};
  33
  34static int __maybe_unused serial_pxa_suspend(struct device *dev)
  35{
  36        struct pxa8250_data *data = dev_get_drvdata(dev);
  37
  38        serial8250_suspend_port(data->line);
  39
  40        return 0;
  41}
  42
  43static int __maybe_unused serial_pxa_resume(struct device *dev)
  44{
  45        struct pxa8250_data *data = dev_get_drvdata(dev);
  46
  47        serial8250_resume_port(data->line);
  48
  49        return 0;
  50}
  51
  52static const struct dev_pm_ops serial_pxa_pm_ops = {
  53        SET_SYSTEM_SLEEP_PM_OPS(serial_pxa_suspend, serial_pxa_resume)
  54};
  55
  56static const struct of_device_id serial_pxa_dt_ids[] = {
  57        { .compatible = "mrvl,pxa-uart", },
  58        { .compatible = "mrvl,mmp-uart", },
  59        {}
  60};
  61MODULE_DEVICE_TABLE(of, serial_pxa_dt_ids);
  62
  63/* Uart divisor latch write */
  64static void serial_pxa_dl_write(struct uart_8250_port *up, int value)
  65{
  66        unsigned int dll;
  67
  68        serial_out(up, UART_DLL, value & 0xff);
  69        /*
  70         * work around Erratum #74 according to Marvel(R) PXA270M Processor
  71         * Specification Update (April 19, 2010)
  72         */
  73        dll = serial_in(up, UART_DLL);
  74        WARN_ON(dll != (value & 0xff));
  75
  76        serial_out(up, UART_DLM, value >> 8 & 0xff);
  77}
  78
  79
  80static void serial_pxa_pm(struct uart_port *port, unsigned int state,
  81              unsigned int oldstate)
  82{
  83        struct pxa8250_data *data = port->private_data;
  84
  85        if (!state)
  86                clk_prepare_enable(data->clk);
  87        else
  88                clk_disable_unprepare(data->clk);
  89}
  90
  91static int serial_pxa_probe(struct platform_device *pdev)
  92{
  93        struct uart_8250_port uart = {};
  94        struct pxa8250_data *data;
  95        struct resource *mmres;
  96        int irq, ret;
  97
  98        irq = platform_get_irq(pdev, 0);
  99        if (irq < 0)
 100                return irq;
 101
 102        mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 103        if (!mmres)
 104                return -ENODEV;
 105
 106        data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 107        if (!data)
 108                return -ENOMEM;
 109
 110        data->clk = devm_clk_get(&pdev->dev, NULL);
 111        if (IS_ERR(data->clk))
 112                return PTR_ERR(data->clk);
 113
 114        ret = clk_prepare(data->clk);
 115        if (ret)
 116                return ret;
 117
 118        ret = of_alias_get_id(pdev->dev.of_node, "serial");
 119        if (ret >= 0)
 120                uart.port.line = ret;
 121
 122        uart.port.type = PORT_XSCALE;
 123        uart.port.iotype = UPIO_MEM32;
 124        uart.port.mapbase = mmres->start;
 125        uart.port.regshift = 2;
 126        uart.port.irq = irq;
 127        uart.port.fifosize = 64;
 128        uart.port.flags = UPF_IOREMAP | UPF_SKIP_TEST | UPF_FIXED_TYPE;
 129        uart.port.dev = &pdev->dev;
 130        uart.port.uartclk = clk_get_rate(data->clk);
 131        uart.port.pm = serial_pxa_pm;
 132        uart.port.private_data = data;
 133        uart.dl_write = serial_pxa_dl_write;
 134
 135        ret = serial8250_register_8250_port(&uart);
 136        if (ret < 0)
 137                goto err_clk;
 138
 139        data->line = ret;
 140
 141        platform_set_drvdata(pdev, data);
 142
 143        return 0;
 144
 145 err_clk:
 146        clk_unprepare(data->clk);
 147        return ret;
 148}
 149
 150static int serial_pxa_remove(struct platform_device *pdev)
 151{
 152        struct pxa8250_data *data = platform_get_drvdata(pdev);
 153
 154        serial8250_unregister_port(data->line);
 155
 156        clk_unprepare(data->clk);
 157
 158        return 0;
 159}
 160
 161static struct platform_driver serial_pxa_driver = {
 162        .probe          = serial_pxa_probe,
 163        .remove         = serial_pxa_remove,
 164
 165        .driver         = {
 166                .name   = "pxa2xx-uart",
 167                .pm     = &serial_pxa_pm_ops,
 168                .of_match_table = serial_pxa_dt_ids,
 169        },
 170};
 171
 172module_platform_driver(serial_pxa_driver);
 173
 174#ifdef CONFIG_SERIAL_8250_CONSOLE
 175static int __init early_serial_pxa_setup(struct earlycon_device *device,
 176                                  const char *options)
 177{
 178        struct uart_port *port = &device->port;
 179
 180        if (!(device->port.membase || device->port.iobase))
 181                return -ENODEV;
 182
 183        port->regshift = 2;
 184        return early_serial8250_setup(device, NULL);
 185}
 186OF_EARLYCON_DECLARE(early_pxa, "mrvl,pxa-uart", early_serial_pxa_setup);
 187#endif
 188
 189MODULE_AUTHOR("Sergei Ianovich");
 190MODULE_LICENSE("GPL");
 191MODULE_ALIAS("platform:pxa2xx-uart");
 192