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linux/arch/cris/arch-v10/drivers/ds1302.c
Arjan van de Ven 5dfe4c964a [PATCH] mark struct file_operations const 2 
Many struct file_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.

[akpm@osdl.org: sparc64 fix]
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:44 -08:00

630 lines
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/*!***************************************************************************
*!
*! FILE NAME : ds1302.c
*!
*! DESCRIPTION: Implements an interface for the DS1302 RTC through Etrax I/O
*!
*! Functions exported: ds1302_readreg, ds1302_writereg, ds1302_init
*!
*! $Log: ds1302.c,v $
*! Revision 1.18 2005/01/24 09:11:26 mikaelam
*! Minor changes to get DS1302 RTC chip driver to work
*!
*! Revision 1.17 2005/01/05 06:11:22 starvik
*! No need to do local_irq_disable after local_irq_save.
*!
*! Revision 1.16 2004/12/13 12:21:52 starvik
*! Added I/O and DMA allocators from Linux 2.4
*!
*! Revision 1.14 2004/08/24 06:48:43 starvik
*! Whitespace cleanup
*!
*! Revision 1.13 2004/05/28 09:26:59 starvik
*! Modified I2C initialization to work in 2.6.
*!
*! Revision 1.12 2004/05/14 07:58:03 starvik
*! Merge of changes from 2.4
*!
*! Revision 1.10 2004/02/04 09:25:12 starvik
*! Merge of Linux 2.6.2
*!
*! Revision 1.9 2003/07/04 08:27:37 starvik
*! Merge of Linux 2.5.74
*!
*! Revision 1.8 2003/04/09 05:20:47 starvik
*! Merge of Linux 2.5.67
*!
*! Revision 1.6 2003/01/09 14:42:51 starvik
*! Merge of Linux 2.5.55
*!
*! Revision 1.4 2002/12/11 13:13:57 starvik
*! Added arch/ to v10 specific includes
*! Added fix from Linux 2.4 in serial.c (flush_to_flip_buffer)
*!
*! Revision 1.3 2002/11/20 11:56:10 starvik
*! Merge of Linux 2.5.48
*!
*! Revision 1.2 2002/11/18 13:16:06 starvik
*! Linux 2.5 port of latest 2.4 drivers
*!
*! Revision 1.15 2002/10/11 16:14:33 johana
*! Added CONFIG_ETRAX_DS1302_TRICKLE_CHARGE and initial setting of the
*! trcklecharge register.
*!
*! Revision 1.14 2002/10/10 12:15:38 magnusmn
*! Added support for having the RST signal on bit g0
*!
*! Revision 1.13 2002/05/29 15:16:08 johana
*! Removed unused variables.
*!
*! Revision 1.12 2002/04/10 15:35:25 johana
*! Moved probe function closer to init function and marked it __init.
*!
*! Revision 1.11 2001/06/14 12:35:52 jonashg
*! The ATA hack is back. It is unfortunately the only way to set g27 to output.
*!
*! Revision 1.9 2001/06/14 10:00:14 jonashg
*! No need for tempudelay to be inline anymore (had to adjust the usec to
*! loops conversion because of this to make it slow enough to be a udelay).
*!
*! Revision 1.8 2001/06/14 08:06:32 jonashg
*! Made tempudelay delay usecs (well, just a tad more).
*!
*! Revision 1.7 2001/06/13 14:18:11 jonashg
*! Only allow processes with SYS_TIME capability to set time and charge.
*!
*! Revision 1.6 2001/06/12 15:22:07 jonashg
*! * Made init function __init.
*! * Parameter to out_byte() is unsigned char.
*! * The magic number 42 has got a name.
*! * Removed comment about /proc (nothing is exported there).
*!
*! Revision 1.5 2001/06/12 14:35:13 jonashg
*! Gave the module a name and added it to printk's.
*!
*! Revision 1.4 2001/05/31 14:53:40 jonashg
*! Made tempudelay() inline so that the watchdog doesn't reset (see
*! function comment).
*!
*! Revision 1.3 2001/03/26 16:03:06 bjornw
*! Needs linux/config.h
*!
*! Revision 1.2 2001/03/20 19:42:00 bjornw
*! Use the ETRAX prefix on the DS1302 options
*!
*! Revision 1.1 2001/03/20 09:13:50 magnusmn
*! Linux 2.4 port
*!
*! Revision 1.10 2000/07/05 15:38:23 bjornw
*! Dont update kernel time when a RTC_SET_TIME is done
*!
*! Revision 1.9 2000/03/02 15:42:59 macce
*! * Hack to make RTC work on all 2100/2400
*!
*! Revision 1.8 2000/02/23 16:59:18 torbjore
*! added setup of R_GEN_CONFIG when RTC is connected to the generic port.
*!
*! Revision 1.7 2000/01/17 15:51:43 johana
*! Added RTC_SET_CHARGE ioctl to enable trickle charger.
*!
*! Revision 1.6 1999/10/27 13:19:47 bjornw
*! Added update_xtime_from_cmos which reads back the updated RTC into the kernel.
*! /dev/rtc calls it now.
*!
*! Revision 1.5 1999/10/27 12:39:37 bjornw
*! Disabled superuser check. Anyone can now set the time.
*!
*! Revision 1.4 1999/09/02 13:27:46 pkj
*! Added shadow for R_PORT_PB_CONFIG.
*! Renamed port_g_shadow to port_g_data_shadow.
*!
*! Revision 1.3 1999/09/02 08:28:06 pkj
*! Made it possible to select either port PB or the generic port for the RST
*! signal line to the DS1302 RTC.
*! Also make sure the RST bit is configured as output on Port PB (if used).
*!
*! Revision 1.2 1999/09/01 14:47:20 bjornw
*! Added support for /dev/rtc operations with ioctl RD_TIME and SET_TIME to read
*! and set the date. Register as major 121.
*!
*! Revision 1.1 1999/09/01 09:45:29 bjornw
*! Implemented a DS1302 RTC driver.
*!
*!
*! ---------------------------------------------------------------------------
*!
*! (C) Copyright 1999, 2000, 2001, 2002, 2003, 2004 Axis Communications AB, LUND, SWEDEN
*!
*! $Id: ds1302.c,v 1.18 2005/01/24 09:11:26 mikaelam Exp $
*!
*!***************************************************************************/
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/miscdevice.h>
#include <linux/delay.h>
#include <linux/bcd.h>
#include <linux/capability.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/arch/svinto.h>
#include <asm/io.h>
#include <asm/rtc.h>
#include <asm/arch/io_interface_mux.h>
#define RTC_MAJOR_NR 121 /* local major, change later */
static const char ds1302_name[] = "ds1302";
/* The DS1302 might be connected to different bits on different products.
* It has three signals - SDA, SCL and RST. RST and SCL are always outputs,
* but SDA can have a selected direction.
* For now, only PORT_PB is hardcoded.
*/
/* The RST bit may be on either the Generic Port or Port PB. */
#ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
#define TK_RST_OUT(x) REG_SHADOW_SET(R_PORT_G_DATA, port_g_data_shadow, CONFIG_ETRAX_DS1302_RSTBIT, x)
#define TK_RST_DIR(x)
#else
#define TK_RST_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_RSTBIT, x)
#define TK_RST_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR, port_pb_dir_shadow, CONFIG_ETRAX_DS1302_RSTBIT, x)
#endif
#define TK_SDA_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SDABIT, x)
#define TK_SCL_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SCLBIT, x)
#define TK_SDA_IN() ((*R_PORT_PB_READ >> CONFIG_ETRAX_DS1302_SDABIT) & 1)
/* 1 is out, 0 is in */
#define TK_SDA_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR, port_pb_dir_shadow, CONFIG_ETRAX_DS1302_SDABIT, x)
#define TK_SCL_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR, port_pb_dir_shadow, CONFIG_ETRAX_DS1302_SCLBIT, x)
/*
* The reason for tempudelay and not udelay is that loops_per_usec
* (used in udelay) is not set when functions here are called from time.c
*/
static void tempudelay(int usecs)
{
volatile int loops;
for(loops = usecs * 12; loops > 0; loops--)
/* nothing */;
}
/* Send 8 bits. */
static void
out_byte(unsigned char x)
{
int i;
TK_SDA_DIR(1);
for (i = 8; i--;) {
/* The chip latches incoming bits on the rising edge of SCL. */
TK_SCL_OUT(0);
TK_SDA_OUT(x & 1);
tempudelay(1);
TK_SCL_OUT(1);
tempudelay(1);
x >>= 1;
}
TK_SDA_DIR(0);
}
static unsigned char
in_byte(void)
{
unsigned char x = 0;
int i;
/* Read byte. Bits come LSB first, on the falling edge of SCL.
* Assume SDA is in input direction already.
*/
TK_SDA_DIR(0);
for (i = 8; i--;) {
TK_SCL_OUT(0);
tempudelay(1);
x >>= 1;
x |= (TK_SDA_IN() << 7);
TK_SCL_OUT(1);
tempudelay(1);
}
return x;
}
/* Prepares for a transaction by de-activating RST (active-low). */
static void
start(void)
{
TK_SCL_OUT(0);
tempudelay(1);
TK_RST_OUT(0);
tempudelay(5);
TK_RST_OUT(1);
}
/* Ends a transaction by taking RST active again. */
static void
stop(void)
{
tempudelay(2);
TK_RST_OUT(0);
}
/* Enable writing. */
static void
ds1302_wenable(void)
{
start();
out_byte(0x8e); /* Write control register */
out_byte(0x00); /* Disable write protect bit 7 = 0 */
stop();
}
/* Disable writing. */
static void
ds1302_wdisable(void)
{
start();
out_byte(0x8e); /* Write control register */
out_byte(0x80); /* Disable write protect bit 7 = 0 */
stop();
}
/* Read a byte from the selected register in the DS1302. */
unsigned char
ds1302_readreg(int reg)
{
unsigned char x;
start();
out_byte(0x81 | (reg << 1)); /* read register */
x = in_byte();
stop();
return x;
}
/* Write a byte to the selected register. */
void
ds1302_writereg(int reg, unsigned char val)
{
#ifndef CONFIG_ETRAX_RTC_READONLY
int do_writereg = 1;
#else
int do_writereg = 0;
if (reg == RTC_TRICKLECHARGER)
do_writereg = 1;
#endif
if (do_writereg) {
ds1302_wenable();
start();
out_byte(0x80 | (reg << 1)); /* write register */
out_byte(val);
stop();
ds1302_wdisable();
}
}
void
get_rtc_time(struct rtc_time *rtc_tm)
{
unsigned long flags;
local_irq_save(flags);
rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
local_irq_restore(flags);
BCD_TO_BIN(rtc_tm->tm_sec);
BCD_TO_BIN(rtc_tm->tm_min);
BCD_TO_BIN(rtc_tm->tm_hour);
BCD_TO_BIN(rtc_tm->tm_mday);
BCD_TO_BIN(rtc_tm->tm_mon);
BCD_TO_BIN(rtc_tm->tm_year);
/*
* Account for differences between how the RTC uses the values
* and how they are defined in a struct rtc_time;
*/
if (rtc_tm->tm_year <= 69)
rtc_tm->tm_year += 100;
rtc_tm->tm_mon--;
}
static unsigned char days_in_mo[] =
{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
/* ioctl that supports RTC_RD_TIME and RTC_SET_TIME (read and set time/date). */
static int
rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
unsigned long arg)
{
unsigned long flags;
switch(cmd) {
case RTC_RD_TIME: /* read the time/date from RTC */
{
struct rtc_time rtc_tm;
memset(&rtc_tm, 0, sizeof (struct rtc_time));
get_rtc_time(&rtc_tm);
if (copy_to_user((struct rtc_time*)arg, &rtc_tm, sizeof(struct rtc_time)))
return -EFAULT;
return 0;
}
case RTC_SET_TIME: /* set the RTC */
{
struct rtc_time rtc_tm;
unsigned char mon, day, hrs, min, sec, leap_yr;
unsigned int yrs;
if (!capable(CAP_SYS_TIME))
return -EPERM;
if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time)))
return -EFAULT;
yrs = rtc_tm.tm_year + 1900;
mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
day = rtc_tm.tm_mday;
hrs = rtc_tm.tm_hour;
min = rtc_tm.tm_min;
sec = rtc_tm.tm_sec;
if ((yrs < 1970) || (yrs > 2069))
return -EINVAL;
leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
if ((mon > 12) || (day == 0))
return -EINVAL;
if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
return -EINVAL;
if ((hrs >= 24) || (min >= 60) || (sec >= 60))
return -EINVAL;
if (yrs >= 2000)
yrs -= 2000; /* RTC (0, 1, ... 69) */
else
yrs -= 1900; /* RTC (70, 71, ... 99) */
BIN_TO_BCD(sec);
BIN_TO_BCD(min);
BIN_TO_BCD(hrs);
BIN_TO_BCD(day);
BIN_TO_BCD(mon);
BIN_TO_BCD(yrs);
local_irq_save(flags);
CMOS_WRITE(yrs, RTC_YEAR);
CMOS_WRITE(mon, RTC_MONTH);
CMOS_WRITE(day, RTC_DAY_OF_MONTH);
CMOS_WRITE(hrs, RTC_HOURS);
CMOS_WRITE(min, RTC_MINUTES);
CMOS_WRITE(sec, RTC_SECONDS);
local_irq_restore(flags);
/* Notice that at this point, the RTC is updated but
* the kernel is still running with the old time.
* You need to set that separately with settimeofday
* or adjtimex.
*/
return 0;
}
case RTC_SET_CHARGE: /* set the RTC TRICKLE CHARGE register */
{
int tcs_val;
if (!capable(CAP_SYS_TIME))
return -EPERM;
if(copy_from_user(&tcs_val, (int*)arg, sizeof(int)))
return -EFAULT;
tcs_val = RTC_TCR_PATTERN | (tcs_val & 0x0F);
ds1302_writereg(RTC_TRICKLECHARGER, tcs_val);
return 0;
}
case RTC_VLOW_RD:
{
/* TODO:
* Implement voltage low detection support
*/
printk(KERN_WARNING "DS1302: RTC Voltage Low detection"
" is not supported\n");
return 0;
}
case RTC_VLOW_SET:
{
/* TODO:
* Nothing to do since Voltage Low detection is not supported
*/
return 0;
}
default:
return -ENOIOCTLCMD;
}
}
static void
print_rtc_status(void)
{
struct rtc_time tm;
get_rtc_time(&tm);
/*
* There is no way to tell if the luser has the RTC set for local
* time or for Universal Standard Time (GMT). Probably local though.
*/
printk(KERN_INFO "rtc_time\t: %02d:%02d:%02d\n",
tm.tm_hour, tm.tm_min, tm.tm_sec);
printk(KERN_INFO "rtc_date\t: %04d-%02d-%02d\n",
tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
}
/* The various file operations we support. */
static const struct file_operations rtc_fops = {
.owner = THIS_MODULE,
.ioctl = rtc_ioctl,
};
/* Probe for the chip by writing something to its RAM and try reading it back. */
#define MAGIC_PATTERN 0x42
static int __init
ds1302_probe(void)
{
int retval, res;
TK_RST_DIR(1);
TK_SCL_DIR(1);
TK_SDA_DIR(0);
/* Try to talk to timekeeper. */
ds1302_wenable();
start();
out_byte(0xc0); /* write RAM byte 0 */
out_byte(MAGIC_PATTERN); /* write something magic */
start();
out_byte(0xc1); /* read RAM byte 0 */
if((res = in_byte()) == MAGIC_PATTERN) {
stop();
ds1302_wdisable();
printk(KERN_INFO "%s: RTC found.\n", ds1302_name);
printk(KERN_INFO "%s: SDA, SCL, RST on PB%i, PB%i, %s%i\n",
ds1302_name,
CONFIG_ETRAX_DS1302_SDABIT,
CONFIG_ETRAX_DS1302_SCLBIT,
#ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
"GENIO",
#else
"PB",
#endif
CONFIG_ETRAX_DS1302_RSTBIT);
print_rtc_status();
retval = 1;
} else {
stop();
retval = 0;
}
return retval;
}
/* Just probe for the RTC and register the device to handle the ioctl needed. */
int __init
ds1302_init(void)
{
#ifdef CONFIG_ETRAX_I2C
i2c_init();
#endif
if (!ds1302_probe()) {
#ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
#if CONFIG_ETRAX_DS1302_RSTBIT == 27
/*
* The only way to set g27 to output is to enable ATA.
*
* Make sure that R_GEN_CONFIG is setup correct.
*/
/* Allocating the ATA interface will grab almost all
* pins in I/O groups a, b, c and d. A consequence of
* allocating the ATA interface is that the fixed
* interfaces shared RAM, parallel port 0, parallel
* port 1, parallel port W, SCSI-8 port 0, SCSI-8 port
* 1, SCSI-W, serial port 2, serial port 3,
* synchronous serial port 3 and USB port 2 and almost
* all GPIO pins on port g cannot be used.
*/
if (cris_request_io_interface(if_ata, "ds1302/ATA")) {
printk(KERN_WARNING "ds1302: Failed to get IO interface\n");
return -1;
}
#elif CONFIG_ETRAX_DS1302_RSTBIT == 0
if (cris_io_interface_allocate_pins(if_gpio_grp_a,
'g',
CONFIG_ETRAX_DS1302_RSTBIT,
CONFIG_ETRAX_DS1302_RSTBIT)) {
printk(KERN_WARNING "ds1302: Failed to get IO interface\n");
return -1;
}
/* Set the direction of this bit to out. */
genconfig_shadow = ((genconfig_shadow &
~IO_MASK(R_GEN_CONFIG, g0dir)) |
(IO_STATE(R_GEN_CONFIG, g0dir, out)));
*R_GEN_CONFIG = genconfig_shadow;
#endif
if (!ds1302_probe()) {
printk(KERN_WARNING "%s: RTC not found.\n", ds1302_name);
return -1;
}
#else
printk(KERN_WARNING "%s: RTC not found.\n", ds1302_name);
return -1;
#endif
}
/* Initialise trickle charger */
ds1302_writereg(RTC_TRICKLECHARGER,
RTC_TCR_PATTERN |(CONFIG_ETRAX_DS1302_TRICKLE_CHARGE & 0x0F));
/* Start clock by resetting CLOCK_HALT */
ds1302_writereg(RTC_SECONDS, (ds1302_readreg(RTC_SECONDS) & 0x7F));
return 0;
}
static int __init ds1302_register(void)
{
ds1302_init();
if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) {
printk(KERN_INFO "%s: unable to get major %d for rtc\n",
ds1302_name, RTC_MAJOR_NR);
return -1;
}
return 0;
}
module_init(ds1302_register);
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