1 files changed, 190 insertions, 0 deletions
diff --git a/arch/mips/lasat/ds1603.c b/arch/mips/lasat/ds1603.c
new file mode 100644
index 000000000..e6ce39fef
--- /dev/null
+++ b/arch/mips/lasat/ds1603.c
@@ -0,0 +1,190 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Dallas Semiconductors 1603 RTC driver
+ *
+ * Brian Murphy <brian@murphy.dk>
+ *
+ */
+#include <linux/kernel.h>
+#include <asm/lasat/lasat.h>
+#include <linux/delay.h>
+#include <asm/lasat/ds1603.h>
+#include <asm/time.h>
+
+#include "ds1603.h"
+
+#define READ_TIME_CMD 0x81
+#define SET_TIME_CMD 0x80
+#define TRIMMER_SET_CMD 0xC0
+#define TRIMMER_VALUE_MASK 0x38
+#define TRIMMER_SHIFT 3
+
+struct ds_defs *ds1603;
+
+/* HW specific register functions */
+static void rtc_reg_write(unsigned long val)
+{
+	*ds1603->reg = val;
+}
+
+static unsigned long rtc_reg_read(void)
+{
+	unsigned long tmp = *ds1603->reg;
+	return tmp;
+}
+
+static unsigned long rtc_datareg_read(void)
+{
+	unsigned long tmp = *ds1603->data_reg;
+	return tmp;
+}
+
+static void rtc_nrst_high(void)
+{
+	rtc_reg_write(rtc_reg_read() | ds1603->rst);
+}
+
+static void rtc_nrst_low(void)
+{
+	rtc_reg_write(rtc_reg_read() & ~ds1603->rst);
+}
+
+static void rtc_cycle_clock(unsigned long data)
+{
+	data |= ds1603->clk;
+	rtc_reg_write(data);
+	lasat_ndelay(250);
+	if (ds1603->data_reversed)
+		data &= ~ds1603->data;
+	else
+		data |= ds1603->data;
+	data &= ~ds1603->clk;
+	rtc_reg_write(data);
+	lasat_ndelay(250 + ds1603->huge_delay);
+}
+
+static void rtc_write_databit(unsigned int bit)
+{
+	unsigned long data = rtc_reg_read();
+	if (ds1603->data_reversed)
+		bit = !bit;
+	if (bit)
+		data |= ds1603->data;
+	else
+		data &= ~ds1603->data;
+
+	rtc_reg_write(data);
+	lasat_ndelay(50 + ds1603->huge_delay);
+	rtc_cycle_clock(data);
+}
+
+static unsigned int rtc_read_databit(void)
+{
+	unsigned int data;
+
+	data = (rtc_datareg_read() & (1 << ds1603->data_read_shift))
+		>> ds1603->data_read_shift;
+	rtc_cycle_clock(rtc_reg_read());
+	return data;
+}
+
+static void rtc_write_byte(unsigned int byte)
+{
+	int i;
+
+	for (i = 0; i <= 7; i++) {
+		rtc_write_databit(byte & 1L);
+		byte >>= 1;
+	}
+}
+
+static void rtc_write_word(unsigned long word)
+{
+	int i;
+
+	for (i = 0; i <= 31; i++) {
+		rtc_write_databit(word & 1L);
+		word >>= 1;
+	}
+}
+
+static unsigned long rtc_read_word(void)
+{
+	int i;
+	unsigned long word = 0;
+	unsigned long shift = 0;
+
+	for (i = 0; i <= 31; i++) {
+		word |= rtc_read_databit() << shift;
+		shift++;
+	}
+	return word;
+}
+
+static void rtc_init_op(void)
+{
+	rtc_nrst_high();
+
+	rtc_reg_write(rtc_reg_read() & ~ds1603->clk);
+
+	lasat_ndelay(50);
+}
+
+static void rtc_end_op(void)
+{
+	rtc_nrst_low();
+	lasat_ndelay(1000);
+}
+
+void read_persistent_clock64(struct timespec64 *ts)
+{
+	unsigned long word;
+	unsigned long flags;
+
+	spin_lock_irqsave(&rtc_lock, flags);
+	rtc_init_op();
+	rtc_write_byte(READ_TIME_CMD);
+	word = rtc_read_word();
+	rtc_end_op();
+	spin_unlock_irqrestore(&rtc_lock, flags);
+
+	ts->tv_sec = word;
+	ts->tv_nsec = 0;
+}
+
+int update_persistent_clock64(struct timespec64 now)
+{
+	time64_t time = now.tv_sec;
+	unsigned long flags;
+
+	spin_lock_irqsave(&rtc_lock, flags);
+	rtc_init_op();
+	rtc_write_byte(SET_TIME_CMD);
+	/*
+	 * Due to the hardware limitation, we cast to 'unsigned long' type,
+	 * so it will overflow in year 2106 on 32-bit machine.
+	 */
+	rtc_write_word((unsigned long)time);
+	rtc_end_op();
+	spin_unlock_irqrestore(&rtc_lock, flags);
+
+	return 0;
+}
+
+void ds1603_set_trimmer(unsigned int trimval)
+{
+	rtc_init_op();
+	rtc_write_byte(((trimval << TRIMMER_SHIFT) & TRIMMER_VALUE_MASK)
+			| (TRIMMER_SET_CMD));
+	rtc_end_op();
+}
+
+void ds1603_disable(void)
+{
+	ds1603_set_trimmer(TRIMMER_DISABLE_RTC);
+}
+
+void ds1603_enable(void)
+{
+	ds1603_set_trimmer(TRIMMER_DEFAULT);
+}