linux/drivers/serial/s3c2440.c
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   1/* linux/drivers/serial/s3c2440.c
   2 *
   3 * Driver for Samsung S3C2440 and S3C2442 SoC onboard UARTs.
   4 *
   5 * Ben Dooks, Copyright (c) 2003-2005,2008 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
  30static 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
  55static 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
 108static 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
 131static 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
 148static 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
 154static struct platform_driver s3c2440_serial_drv = {
 155        .probe          = s3c2440_serial_probe,
 156        .remove         = s3c24xx_serial_remove,
 157        .driver         = {
 158                .name   = "s3c2440-uart",
 159                .owner  = THIS_MODULE,
 160        },
 161};
 162
 163s3c24xx_console_init(&s3c2440_serial_drv, &s3c2440_uart_inf);
 164
 165static int __init s3c2440_serial_init(void)
 166{
 167        return s3c24xx_serial_init(&s3c2440_serial_drv, &s3c2440_uart_inf);
 168}
 169
 170static void __exit s3c2440_serial_exit(void)
 171{
 172        platform_driver_unregister(&s3c2440_serial_drv);
 173}
 174
 175module_init(s3c2440_serial_init);
 176module_exit(s3c2440_serial_exit);
 177
 178MODULE_DESCRIPTION("Samsung S3C2440,S3C2442 SoC Serial port driver");
 179MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 180MODULE_LICENSE("GPL v2");
 181MODULE_ALIAS("platform:s3c2440-uart");
 182