diff options
Diffstat (limited to 'rtc/ds1306.c')
| -rw-r--r-- | rtc/ds1306.c | 274 |
1 files changed, 274 insertions, 0 deletions
diff --git a/rtc/ds1306.c b/rtc/ds1306.c new file mode 100644 index 0000000000..9c11c600d6 --- /dev/null +++ b/rtc/ds1306.c @@ -0,0 +1,274 @@ +/* + * (C) Copyright 2002 SIXNET, dge@sixnetio.com. + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +/* + * Date & Time support for DS1306 RTC using software SPI + */ + +#include <common.h> +#include <command.h> +#include <rtc.h> + +#if defined(CONFIG_RTC_DS1306) && (CONFIG_COMMANDS & CFG_CMD_DATE) + +static unsigned int bin2bcd(unsigned int n); +static unsigned char bcd2bin(unsigned char c); +static void soft_spi_send(unsigned char n); +static unsigned char soft_spi_read(void); +static void init_spi(void); + +/*----------------------------------------------------------------------- + * Definitions + */ + +#define PB_SPISCK 0x00000002 /* PB 30 */ +#define PB_SPIMOSI 0x00000004 /* PB 29 */ +#define PB_SPIMISO 0x00000008 /* PB 28 */ +#define PB_SPI_CE 0x00010000 /* PB 15 */ + +/* ------------------------------------------------------------------------- */ + +/* read clock time from DS1306 and return it in *tmp */ +void rtc_get(struct rtc_time *tmp) +{ + volatile immap_t *immap = (immap_t *)CFG_IMMR; + unsigned char spi_byte; /* Data Byte */ + + init_spi(); /* set port B for software SPI */ + + /* Now we can enable the DS1306 RTC */ + immap->im_cpm.cp_pbdat |= PB_SPI_CE; + udelay(10); + + /* Shift out the address (0) of the time in the Clock Chip */ + soft_spi_send(0); + + /* Put the clock readings into the rtc_time structure */ + tmp->tm_sec = bcd2bin(soft_spi_read()); /* Read seconds */ + tmp->tm_min = bcd2bin(soft_spi_read()); /* Read minutes */ + + /* Hours are trickier */ + spi_byte = soft_spi_read(); /* Read Hours into temporary value */ + if (spi_byte & 0x40) { + /* 12 hour mode bit is set (time is in 1-12 format) */ + if (spi_byte & 0x20) { + /* since PM we add 11 to get 0-23 for hours */ + tmp->tm_hour = (bcd2bin(spi_byte & 0x1F)) + 11; + } + else { + /* since AM we subtract 1 to get 0-23 for hours */ + tmp->tm_hour = (bcd2bin(spi_byte & 0x1F)) - 1; + } + } + else { + /* Otherwise, 0-23 hour format */ + tmp->tm_hour = (bcd2bin(spi_byte & 0x3F)); + } + + soft_spi_read(); /* Read and discard Day of week */ + tmp->tm_mday = bcd2bin(soft_spi_read()); /* Read Day of the Month */ + tmp->tm_mon = bcd2bin(soft_spi_read()); /* Read Month */ + + /* Read Year and convert to this century */ + tmp->tm_year = bcd2bin(soft_spi_read()) + 2000; + + /* Now we can disable the DS1306 RTC */ + immap->im_cpm.cp_pbdat &= ~PB_SPI_CE; /* Disable DS1306 Chip */ + udelay(10); + + GregorianDay(tmp); /* Determine the day of week */ + + debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", + tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, + tmp->tm_hour, tmp->tm_min, tmp->tm_sec); +} + +/* ------------------------------------------------------------------------- */ + +/* set clock time in DS1306 RTC and in MPC8xx RTC */ +void rtc_set(struct rtc_time *tmp) +{ + volatile immap_t *immap = (immap_t *)CFG_IMMR; + + init_spi(); /* set port B for software SPI */ + + /* Now we can enable the DS1306 RTC */ + immap->im_cpm.cp_pbdat |= PB_SPI_CE; /* Enable DS1306 Chip */ + udelay(10); + + /* First disable write protect in the clock chip control register */ + soft_spi_send(0x8F); /* send address of the control register */ + soft_spi_send(0x00); /* send control register contents */ + + /* Now disable the DS1306 to terminate the write */ + immap->im_cpm.cp_pbdat &= ~PB_SPI_CE; + udelay(10); + + /* Now enable the DS1306 to initiate a new write */ + immap->im_cpm.cp_pbdat |= PB_SPI_CE; + udelay(10); + + /* Next, send the address of the clock time write registers */ + soft_spi_send(0x80); /* send address of the first time register */ + + /* Use Burst Mode to send all of the time data to the clock */ + bin2bcd(tmp->tm_sec); + soft_spi_send(bin2bcd(tmp->tm_sec)); /* Send Seconds */ + soft_spi_send(bin2bcd(tmp->tm_min)); /* Send Minutes */ + soft_spi_send(bin2bcd(tmp->tm_hour)); /* Send Hour */ + soft_spi_send(bin2bcd(tmp->tm_wday)); /* Send Day of the Week */ + soft_spi_send(bin2bcd(tmp->tm_mday)); /* Send Day of Month */ + soft_spi_send(bin2bcd(tmp->tm_mon)); /* Send Month */ + soft_spi_send(bin2bcd(tmp->tm_year - 2000)); /* Send Year */ + + /* Now we can disable the Clock chip to terminate the burst write */ + immap->im_cpm.cp_pbdat &= ~PB_SPI_CE; /* Disable DS1306 Chip */ + udelay(10); + + /* Now we can enable the Clock chip to initiate a new write */ + immap->im_cpm.cp_pbdat |= PB_SPI_CE; /* Enable DS1306 Chip */ + udelay(10); + + /* First we Enable write protect in the clock chip control register */ + soft_spi_send(0x8F); /* send address of the control register */ + soft_spi_send(0x40); /* send out Control Register contents */ + + /* Now disable the DS1306 */ + immap->im_cpm.cp_pbdat &= ~PB_SPI_CE; /* Disable DS1306 Chip */ + udelay(10); + + /* Set standard MPC8xx clock to the same time so Linux will + * see the time even if it doesn't have a DS1306 clock driver. + * This helps with experimenting with standard kernels. + */ + { + ulong tim; + + tim = mktime(tmp->tm_year, tmp->tm_mon, tmp->tm_mday, + tmp->tm_hour, tmp->tm_min, tmp->tm_sec); + + immap->im_sitk.sitk_rtck = KAPWR_KEY; + immap->im_sit.sit_rtc = tim; + } + + debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", + tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, + tmp->tm_hour, tmp->tm_min, tmp->tm_sec); +} + +/* ------------------------------------------------------------------------- */ + +void rtc_reset(void) +{ + return; /* nothing to do */ +} + +/* ------------------------------------------------------------------------- */ + +static unsigned char bcd2bin(unsigned char n) +{ + return ((((n >> 4) & 0x0F) * 10) + (n & 0x0F)); +} + +/* ------------------------------------------------------------------------- */ + +static unsigned int bin2bcd(unsigned int n) +{ + return (((n / 10) << 4) | (n % 10)); +} + +/* ------------------------------------------------------------------------- */ + +/* Initialize Port B for software SPI */ +static void init_spi(void) { + volatile immap_t *immap = (immap_t *)CFG_IMMR; + + /* Force output pins to begin at logic 0 */ + immap->im_cpm.cp_pbdat &= ~(PB_SPI_CE | PB_SPIMOSI | PB_SPISCK); + + /* Set these 3 signals as outputs */ + immap->im_cpm.cp_pbdir |= (PB_SPIMOSI | PB_SPI_CE | PB_SPISCK); + + immap->im_cpm.cp_pbdir &= ~PB_SPIMISO; /* Make MISO pin an input */ + udelay(10); +} + +/* ------------------------------------------------------------------------- */ + +/* NOTE: soft_spi_send() assumes that the I/O lines are configured already */ +static void soft_spi_send(unsigned char n) +{ + volatile immap_t *immap = (immap_t *)CFG_IMMR; + unsigned char bitpos; /* bit position to receive */ + unsigned char i; /* Loop Control */ + + /* bit position to send, start with most significant bit */ + bitpos = 0x80; + + /* Send 8 bits to software SPI */ + for (i = 0; i < 8; i++) { /* Loop for 8 bits */ + immap->im_cpm.cp_pbdat |= PB_SPISCK; /* Raise SCK */ + + if (n & bitpos) + immap->im_cpm.cp_pbdat |= PB_SPIMOSI; /* Set MOSI to 1 */ + else + immap->im_cpm.cp_pbdat &= ~PB_SPIMOSI; /* Set MOSI to 0 */ + udelay(10); + + immap->im_cpm.cp_pbdat &= ~PB_SPISCK; /* Lower SCK */ + udelay(10); + + bitpos >>= 1; /* Shift for next bit position */ + } +} + +/* ------------------------------------------------------------------------- */ + +/* NOTE: soft_spi_read() assumes that the I/O lines are configured already */ +static unsigned char soft_spi_read(void) +{ + volatile immap_t *immap = (immap_t *)CFG_IMMR; + + unsigned char spi_byte = 0; /* Return value, assume success */ + unsigned char bitpos; /* bit position to receive */ + unsigned char i; /* Loop Control */ + + /* bit position to receive, start with most significant bit */ + bitpos = 0x80; + + /* Read 8 bits here */ + for (i = 0; i < 8; i++) { /* Do 8 bits in loop */ + immap->im_cpm.cp_pbdat |= PB_SPISCK; /* Raise SCK */ + udelay(10); + if (immap->im_cpm.cp_pbdat & PB_SPIMISO) /* Get a bit of data */ + spi_byte |= bitpos; /* Set data accordingly */ + immap->im_cpm.cp_pbdat &= ~PB_SPISCK; /* Lower SCK */ + udelay(10); + bitpos >>= 1; /* Shift for next bit position */ + } + + return spi_byte; /* Return the byte read */ +} + +/* ------------------------------------------------------------------------- */ + +#endif |
