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-rw-r--r--rtc/ds1306.c274
1 files changed, 274 insertions, 0 deletions
diff --git a/rtc/ds1306.c b/rtc/ds1306.c
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+++ b/rtc/ds1306.c
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+/*
+ * (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
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