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 void 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 } 84 85 static struct platform_driver serial8250_ioc3_driver = { 86 .probe = serial8250_ioc3_probe, 87 .remove_new = serial8250_ioc3_remove, 88 .driver = { 89 .name = "ioc3-serial8250", 90 } 91 }; 92 93 module_platform_driver(serial8250_ioc3_driver); 94 95 MODULE_AUTHOR("Thomas Bogendoerfer <tbogendoerfer@suse.de>"); 96 MODULE_DESCRIPTION("SGI IOC3 8250 UART driver"); 97 MODULE_LICENSE("GPL"); 98