drivers/serial/s3c6400.c

   1 /* linux/drivers/serial/s3c6400.c
   2  *
   3  * Driver for Samsung S3C6400 and S3C6410 SoC onboard UARTs.
   4  *
   5  * Copyright 2008 Openmoko,  Inc.
   6  * Copyright 2008 Simtec Electronics
   7  *      Ben Dooks <ben@simtec.co.uk>
   8  *      http://armlinux.simtec.co.uk/
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13 */
  14
  15 #include <linux/module.h>
  16 #include <linux/ioport.h>
  17 #include <linux/io.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/init.h>
  20 #include <linux/serial_core.h>
  21 #include <linux/serial.h>
  22
  23 #include <asm/irq.h>
  24 #include <mach/hardware.h>
  25
  26 #include <plat/regs-serial.h>
  27
  28 #include "samsung.h"
  29
  30 static int s3c6400_serial_setsource(struct uart_port *port,
  31                                     struct s3c24xx_uart_clksrc *clk)
  32 {
  33         unsigned long ucon = rd_regl(port, S3C2410_UCON);
  34
  35         if (strcmp(clk->name, "uclk0") == 0) {
  36                 ucon &= ~S3C6400_UCON_CLKMASK;
  37                 ucon |= S3C6400_UCON_UCLK0;
  38         } else if (strcmp(clk->name, "uclk1") == 0)
  39                 ucon |= S3C6400_UCON_UCLK1;
  40         else if (strcmp(clk->name, "pclk") == 0) {
  41                 /* See notes about transitioning from UCLK to PCLK */
  42                 ucon &= ~S3C6400_UCON_UCLK0;
  43         } else {
  44                 printk(KERN_ERR "unknown clock source %s\n", clk->name);
  45                 return -EINVAL;
  46         }
  47
  48         wr_regl(port, S3C2410_UCON, ucon);
  49         return 0;
  50 }
  51
  52
  53 static int s3c6400_serial_getsource(struct uart_port *port,
  54                                     struct s3c24xx_uart_clksrc *clk)
  55 {
  56         u32 ucon = rd_regl(port, S3C2410_UCON);
  57
  58         clk->divisor = 1;
  59
  60         switch (ucon & S3C6400_UCON_CLKMASK) {
  61         case S3C6400_UCON_UCLK0:
  62                 clk->name = "uclk0";
  63                 break;
  64
  65         case S3C6400_UCON_UCLK1:
  66                 clk->name = "uclk1";
  67                 break;
  68
  69         case S3C6400_UCON_PCLK:
  70         case S3C6400_UCON_PCLK2:
  71                 clk->name = "pclk";
  72                 break;
  73         }
  74
  75         return 0;
  76 }
  77
  78 static int s3c6400_serial_resetport(struct uart_port *port,
  79                                     struct s3c2410_uartcfg *cfg)
  80 {
  81         unsigned long ucon = rd_regl(port, S3C2410_UCON);
  82
  83         dbg("s3c6400_serial_resetport: port=%p (%08lx), cfg=%p\n",
  84             port, port->mapbase, cfg);
  85
  86         /* ensure we don't change the clock settings... */
  87
  88         ucon &= S3C6400_UCON_CLKMASK;
  89
  90         wr_regl(port, S3C2410_UCON,  ucon | cfg->ucon);
  91         wr_regl(port, S3C2410_ULCON, cfg->ulcon);
  92
  93         /* reset both fifos */
  94
  95         wr_regl(port, S3C2410_UFCON, cfg->ufcon | S3C2410_UFCON_RESETBOTH);
  96         wr_regl(port, S3C2410_UFCON, cfg->ufcon);
  97
  98         return 0;
  99 }
 100
 101 static struct s3c24xx_uart_info s3c6400_uart_inf = {
 102         .name           = "Samsung S3C6400 UART",
 103         .type           = PORT_S3C6400,
 104         .fifosize       = 64,
 105         .has_divslot    = 1,
 106         .rx_fifomask    = S3C2440_UFSTAT_RXMASK,
 107         .rx_fifoshift   = S3C2440_UFSTAT_RXSHIFT,
 108         .rx_fifofull    = S3C2440_UFSTAT_RXFULL,
 109         .tx_fifofull    = S3C2440_UFSTAT_TXFULL,
 110         .tx_fifomask    = S3C2440_UFSTAT_TXMASK,
 111         .tx_fifoshift   = S3C2440_UFSTAT_TXSHIFT,
 112         .get_clksrc     = s3c6400_serial_getsource,
 113         .set_clksrc     = s3c6400_serial_setsource,
 114         .reset_port     = s3c6400_serial_resetport,
 115 };
 116
 117 /* device management */
 118
 119 static int s3c6400_serial_probe(struct platform_device *dev)
 120 {
 121         dbg("s3c6400_serial_probe: dev=%p\n", dev);
 122         return s3c24xx_serial_probe(dev, &s3c6400_uart_inf);
 123 }
 124
 125 static struct platform_driver s3c6400_serial_drv = {
 126         .probe          = s3c6400_serial_probe,
 127         .remove         = s3c24xx_serial_remove,
 128         .driver         = {
 129                 .name   = "s3c6400-uart",
 130                 .owner  = THIS_MODULE,
 131         },
 132 };
 133
 134 s3c24xx_console_init(&s3c6400_serial_drv, &s3c6400_uart_inf);
 135
 136 static int __init s3c6400_serial_init(void)
 137 {
 138         return s3c24xx_serial_init(&s3c6400_serial_drv, &s3c6400_uart_inf);
 139 }
 140
 141 static void __exit s3c6400_serial_exit(void)
 142 {
 143         platform_driver_unregister(&s3c6400_serial_drv);
 144 }
 145
 146 module_init(s3c6400_serial_init);
 147 module_exit(s3c6400_serial_exit);
 148
 149 MODULE_DESCRIPTION("Samsung S3C6400,S3C6410 SoC Serial port driver");
 150 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 151 MODULE_LICENSE("GPL v2");
 152 MODULE_ALIAS("platform:s3c6400-uart");