drivers/tty/serial/8250/8250_ioc3.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * SGI IOC3 8250 UART driver
   4  *
   5  * Copyright (C) 2019 Thomas Bogendoerfer <tbogendoerfer@suse.de>
   6  *
   7  * based on code Copyright (C) 2005 Stanislaw Skowronek <skylark@unaligned.org>
   8  *               Copyright (C) 2014 Joshua Kinard <kumba@gentoo.org>
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/errno.h>
  13 #include <linux/io.h>
  14 #include <linux/platform_device.h>
  15
  16 #include "8250.h"
  17
  18 #define IOC3_UARTCLK (22000000 / 3)
  19
  20 struct ioc3_8250_data {
  21         int line;
  22 };
  23
  24 static unsigned int ioc3_serial_in(struct uart_port *p, int offset)
  25 {
  26         return readb(p->membase + (offset ^ 3));
  27 }
  28
  29 static void ioc3_serial_out(struct uart_port *p, int offset, int value)
  30 {
  31         writeb(value, p->membase + (offset ^ 3));
  32 }
  33
  34 static int serial8250_ioc3_probe(struct platform_device *pdev)
  35 {
  36         struct ioc3_8250_data *data;
  37         struct uart_8250_port up;
  38         struct resource *r;
  39         void __iomem *membase;
  40         int irq, line;
  41
  42         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  43         if (!r)
  44                 return -ENODEV;
  45
  46         data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
  47         if (!data)
  48                 return -ENOMEM;
  49
  50         membase = devm_ioremap(&pdev->dev, r->start, resource_size(r));
  51         if (!membase)
  52                 return -ENOMEM;
  53
  54         irq = platform_get_irq(pdev, 0);
  55         if (irq < 0)
  56                 irq = 0; /* no interrupt -> use polling */
  57
  58         /* Register serial ports with 8250.c */
  59         memset(&up, 0, sizeof(struct uart_8250_port));
  60         up.port.iotype = UPIO_MEM;
  61         up.port.uartclk = IOC3_UARTCLK;
  62         up.port.type = PORT_16550A;
  63         up.port.irq = irq;
  64         up.port.flags = (UPF_BOOT_AUTOCONF | UPF_SHARE_IRQ);
  65         up.port.dev = &pdev->dev;
  66         up.port.membase = membase;
  67         up.port.mapbase = r->start;
  68         up.port.serial_in = ioc3_serial_in;
  69         up.port.serial_out = ioc3_serial_out;
  70         line = serial8250_register_8250_port(&up);
  71         if (line < 0)
  72                 return line;
  73
  74         platform_set_drvdata(pdev, data);
  75         return 0;
  76 }
  77
  78 static int serial8250_ioc3_remove(struct platform_device *pdev)
  79 {
  80         struct ioc3_8250_data *data = platform_get_drvdata(pdev);
  81
  82         serial8250_unregister_port(data->line);
  83         return 0;
  84 }
  85
  86 static struct platform_driver serial8250_ioc3_driver = {
  87         .probe  = serial8250_ioc3_probe,
  88         .remove = serial8250_ioc3_remove,
  89         .driver = {
  90                 .name = "ioc3-serial8250",
  91         }
  92 };
  93
  94 module_platform_driver(serial8250_ioc3_driver);
  95
  96 MODULE_AUTHOR("Thomas Bogendoerfer <tbogendoerfer@suse.de>");
  97 MODULE_DESCRIPTION("SGI IOC3 8250 UART driver");
  98 MODULE_LICENSE("GPL");