drivers/tty/serial/s3c2440.c

   1 /* linux/drivers/serial/s3c2440.c
   2  *
   3  * Driver for Samsung S3C2440 and S3C2442 SoC onboard UARTs.
   4  *
   5  * Ben Dooks, Copyright (c) 2003-2008 Simtec Electronics
   6  *      http://armlinux.simtec.co.uk/
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11 */
  12
  13 #include <linux/module.h>
  14 #include <linux/ioport.h>
  15 #include <linux/io.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/init.h>
  18 #include <linux/serial_core.h>
  19 #include <linux/serial.h>
  20
  21 #include <asm/irq.h>
  22 #include <mach/hardware.h>
  23
  24 #include <plat/regs-serial.h>
  25 #include <mach/regs-gpio.h>
  26
  27 #include "samsung.h"
  28
  29
  30 static int s3c2440_serial_setsource(struct uart_port *port,
  31                                      struct s3c24xx_uart_clksrc *clk)
  32 {
  33         unsigned long ucon = rd_regl(port, S3C2410_UCON);
  34
  35         /* todo - proper fclk<>nonfclk switch. */
  36
  37         ucon &= ~S3C2440_UCON_CLKMASK;
  38
  39         if (strcmp(clk->name, "uclk") == 0)
  40                 ucon |= S3C2440_UCON_UCLK;
  41         else if (strcmp(clk->name, "pclk") == 0)
  42                 ucon |= S3C2440_UCON_PCLK;
  43         else if (strcmp(clk->name, "fclk") == 0)
  44                 ucon |= S3C2440_UCON_FCLK;
  45         else {
  46                 printk(KERN_ERR "unknown clock source %s\n", clk->name);
  47                 return -EINVAL;
  48         }
  49
  50         wr_regl(port, S3C2410_UCON, ucon);
  51         return 0;
  52 }
  53
  54
  55 static int s3c2440_serial_getsource(struct uart_port *port,
  56                                     struct s3c24xx_uart_clksrc *clk)
  57 {
  58         unsigned long ucon = rd_regl(port, S3C2410_UCON);
  59         unsigned long ucon0, ucon1, ucon2;
  60
  61         switch (ucon & S3C2440_UCON_CLKMASK) {
  62         case S3C2440_UCON_UCLK:
  63                 clk->divisor = 1;
  64                 clk->name = "uclk";
  65                 break;
  66
  67         case S3C2440_UCON_PCLK:
  68         case S3C2440_UCON_PCLK2:
  69                 clk->divisor = 1;
  70                 clk->name = "pclk";
  71                 break;
  72
  73         case S3C2440_UCON_FCLK:
  74                 /* the fun of calculating the uart divisors on
  75                  * the s3c2440 */
  76
  77                 ucon0 = __raw_readl(S3C24XX_VA_UART0 + S3C2410_UCON);
  78                 ucon1 = __raw_readl(S3C24XX_VA_UART1 + S3C2410_UCON);
  79                 ucon2 = __raw_readl(S3C24XX_VA_UART2 + S3C2410_UCON);
  80
  81                 printk("ucons: %08lx, %08lx, %08lx\n", ucon0, ucon1, ucon2);
  82
  83                 ucon0 &= S3C2440_UCON0_DIVMASK;
  84                 ucon1 &= S3C2440_UCON1_DIVMASK;
  85                 ucon2 &= S3C2440_UCON2_DIVMASK;
  86
  87                 if (ucon0 != 0) {
  88                         clk->divisor = ucon0 >> S3C2440_UCON_DIVSHIFT;
  89                         clk->divisor += 6;
  90                 } else if (ucon1 != 0) {
  91                         clk->divisor = ucon1 >> S3C2440_UCON_DIVSHIFT;
  92                         clk->divisor += 21;
  93                 } else if (ucon2 != 0) {
  94                         clk->divisor = ucon2 >> S3C2440_UCON_DIVSHIFT;
  95                         clk->divisor += 36;
  96                 } else {
  97                         /* manual calims 44, seems to be 9 */
  98                         clk->divisor = 9;
  99                 }
 100
 101                 clk->name = "fclk";
 102                 break;
 103         }
 104
 105         return 0;
 106 }
 107
 108 static int s3c2440_serial_resetport(struct uart_port *port,
 109                                     struct s3c2410_uartcfg *cfg)
 110 {
 111         unsigned long ucon = rd_regl(port, S3C2410_UCON);
 112
 113         dbg("s3c2440_serial_resetport: port=%p (%08lx), cfg=%p\n",
 114             port, port->mapbase, cfg);
 115
 116         /* ensure we don't change the clock settings... */
 117
 118         ucon &= (S3C2440_UCON0_DIVMASK | (3<<10));
 119
 120         wr_regl(port, S3C2410_UCON,  ucon | cfg->ucon);
 121         wr_regl(port, S3C2410_ULCON, cfg->ulcon);
 122
 123         /* reset both fifos */
 124
 125         wr_regl(port, S3C2410_UFCON, cfg->ufcon | S3C2410_UFCON_RESETBOTH);
 126         wr_regl(port, S3C2410_UFCON, cfg->ufcon);
 127
 128         return 0;
 129 }
 130
 131 static struct s3c24xx_uart_info s3c2440_uart_inf = {
 132         .name           = "Samsung S3C2440 UART",
 133         .type           = PORT_S3C2440,
 134         .fifosize       = 64,
 135         .rx_fifomask    = S3C2440_UFSTAT_RXMASK,
 136         .rx_fifoshift   = S3C2440_UFSTAT_RXSHIFT,
 137         .rx_fifofull    = S3C2440_UFSTAT_RXFULL,
 138         .tx_fifofull    = S3C2440_UFSTAT_TXFULL,
 139         .tx_fifomask    = S3C2440_UFSTAT_TXMASK,
 140         .tx_fifoshift   = S3C2440_UFSTAT_TXSHIFT,
 141         .get_clksrc     = s3c2440_serial_getsource,
 142         .set_clksrc     = s3c2440_serial_setsource,
 143         .reset_port     = s3c2440_serial_resetport,
 144 };
 145
 146 /* device management */
 147
 148 static int s3c2440_serial_probe(struct platform_device *dev)
 149 {
 150         dbg("s3c2440_serial_probe: dev=%p\n", dev);
 151         return s3c24xx_serial_probe(dev, &s3c2440_uart_inf);
 152 }
 153
 154 static struct platform_driver s3c2440_serial_driver = {
 155         .probe          = s3c2440_serial_probe,
 156         .remove         = __devexit_p(s3c24xx_serial_remove),
 157         .driver         = {
 158                 .name   = "s3c2440-uart",
 159                 .owner  = THIS_MODULE,
 160         },
 161 };
 162
 163 s3c24xx_console_init(&s3c2440_serial_driver, &s3c2440_uart_inf);
 164
 165 static int __init s3c2440_serial_init(void)
 166 {
 167         return s3c24xx_serial_init(&s3c2440_serial_driver, &s3c2440_uart_inf);
 168 }
 169
 170 static void __exit s3c2440_serial_exit(void)
 171 {
 172         platform_driver_unregister(&s3c2440_serial_driver);
 173 }
 174
 175 module_init(s3c2440_serial_init);
 176 module_exit(s3c2440_serial_exit);
 177
 178 MODULE_DESCRIPTION("Samsung S3C2440,S3C2442 SoC Serial port driver");
 179 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 180 MODULE_LICENSE("GPL v2");
 181 MODULE_ALIAS("platform:s3c2440-uart");