drivers/tty/serial/8250/8250_pxa.c

   1 /*
   2  *  drivers/tty/serial/8250/8250_pxa.c -- driver for PXA on-board UARTS
   3  *  Copyright:  (C) 2013 Sergei Ianovich <ynvich@gmail.com>
   4  *
   5  *  replaces drivers/serial/pxa.c by Nicolas Pitre
   6  *  Created:    Feb 20, 2003
   7  *  Copyright:  (C) 2003 Monta Vista Software, Inc.
   8  *
   9  *  Based on drivers/serial/8250.c by Russell King.
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  */
  17
  18 #include <linux/device.h>
  19 #include <linux/init.h>
  20 #include <linux/io.h>
  21 #include <linux/module.h>
  22 #include <linux/serial_8250.h>
  23 #include <linux/serial_core.h>
  24 #include <linux/serial_reg.h>
  25 #include <linux/of.h>
  26 #include <linux/of_irq.h>
  27 #include <linux/of_platform.h>
  28 #include <linux/platform_device.h>
  29 #include <linux/slab.h>
  30 #include <linux/clk.h>
  31 #include <linux/pm_runtime.h>
  32
  33 #include "8250.h"
  34
  35 struct pxa8250_data {
  36         int                     line;
  37         struct clk              *clk;
  38 };
  39
  40 static int __maybe_unused serial_pxa_suspend(struct device *dev)
  41 {
  42         struct pxa8250_data *data = dev_get_drvdata(dev);
  43
  44         serial8250_suspend_port(data->line);
  45
  46         return 0;
  47 }
  48
  49 static int __maybe_unused serial_pxa_resume(struct device *dev)
  50 {
  51         struct pxa8250_data *data = dev_get_drvdata(dev);
  52
  53         serial8250_resume_port(data->line);
  54
  55         return 0;
  56 }
  57
  58 static const struct dev_pm_ops serial_pxa_pm_ops = {
  59         SET_SYSTEM_SLEEP_PM_OPS(serial_pxa_suspend, serial_pxa_resume)
  60 };
  61
  62 static const struct of_device_id serial_pxa_dt_ids[] = {
  63         { .compatible = "mrvl,pxa-uart", },
  64         { .compatible = "mrvl,mmp-uart", },
  65         {}
  66 };
  67 MODULE_DEVICE_TABLE(of, serial_pxa_dt_ids);
  68
  69 /* Uart divisor latch write */
  70 static void serial_pxa_dl_write(struct uart_8250_port *up, int value)
  71 {
  72         unsigned int dll;
  73
  74         serial_out(up, UART_DLL, value & 0xff);
  75         /*
  76          * work around Erratum #74 according to Marvel(R) PXA270M Processor
  77          * Specification Update (April 19, 2010)
  78          */
  79         dll = serial_in(up, UART_DLL);
  80         WARN_ON(dll != (value & 0xff));
  81
  82         serial_out(up, UART_DLM, value >> 8 & 0xff);
  83 }
  84
  85
  86 static void serial_pxa_pm(struct uart_port *port, unsigned int state,
  87               unsigned int oldstate)
  88 {
  89         struct pxa8250_data *data = port->private_data;
  90
  91         if (!state)
  92                 clk_prepare_enable(data->clk);
  93         else
  94                 clk_disable_unprepare(data->clk);
  95 }
  96
  97 static int serial_pxa_probe(struct platform_device *pdev)
  98 {
  99         struct uart_8250_port uart = {};
 100         struct pxa8250_data *data;
 101         struct resource *mmres, *irqres;
 102         int ret;
 103
 104         mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 105         irqres = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 106         if (!mmres || !irqres)
 107                 return -ENODEV;
 108
 109         data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 110         if (!data)
 111                 return -ENOMEM;
 112
 113         data->clk = devm_clk_get(&pdev->dev, NULL);
 114         if (IS_ERR(data->clk))
 115                 return PTR_ERR(data->clk);
 116
 117         ret = clk_prepare(data->clk);
 118         if (ret)
 119                 return ret;
 120
 121         uart.port.type = PORT_XSCALE;
 122         uart.port.iotype = UPIO_MEM32;
 123         uart.port.mapbase = mmres->start;
 124         uart.port.regshift = 2;
 125         uart.port.irq = irqres->start;
 126         uart.port.fifosize = 64;
 127         uart.port.flags = UPF_IOREMAP | UPF_SKIP_TEST;
 128         uart.port.dev = &pdev->dev;
 129         uart.port.uartclk = clk_get_rate(data->clk);
 130         uart.port.pm = serial_pxa_pm;
 131         uart.port.private_data = data;
 132         uart.dl_write = serial_pxa_dl_write;
 133
 134         ret = serial8250_register_8250_port(&uart);
 135         if (ret < 0)
 136                 goto err_clk;
 137
 138         data->line = ret;
 139
 140         platform_set_drvdata(pdev, data);
 141
 142         return 0;
 143
 144  err_clk:
 145         clk_unprepare(data->clk);
 146         return ret;
 147 }
 148
 149 static int serial_pxa_remove(struct platform_device *pdev)
 150 {
 151         struct pxa8250_data *data = platform_get_drvdata(pdev);
 152
 153         serial8250_unregister_port(data->line);
 154
 155         clk_unprepare(data->clk);
 156
 157         return 0;
 158 }
 159
 160 static struct platform_driver serial_pxa_driver = {
 161         .probe          = serial_pxa_probe,
 162         .remove         = serial_pxa_remove,
 163
 164         .driver         = {
 165                 .name   = "pxa2xx-uart",
 166                 .pm     = &serial_pxa_pm_ops,
 167                 .of_match_table = serial_pxa_dt_ids,
 168         },
 169 };
 170
 171 module_platform_driver(serial_pxa_driver);
 172
 173 #ifdef CONFIG_SERIAL_8250_CONSOLE
 174 static int __init early_serial_pxa_setup(struct earlycon_device *device,
 175                                   const char *options)
 176 {
 177         struct uart_port *port = &device->port;
 178
 179         if (!(device->port.membase || device->port.iobase))
 180                 return -ENODEV;
 181
 182         port->regshift = 2;
 183         return early_serial8250_setup(device, NULL);
 184 }
 185 OF_EARLYCON_DECLARE(early_pxa, "mrvl,pxa-uart", early_serial_pxa_setup);
 186 #endif
 187
 188 MODULE_AUTHOR("Sergei Ianovich");
 189 MODULE_LICENSE("GPL");
 190 MODULE_ALIAS("platform:pxa2xx-uart");