修改GPIO导出默认初始值

hc

2024-10-16 50a212ec906f7524620675f0c57357691c26c81f

 kernel/arch/m68k/atari/time.c
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@@ -16,6 +16,7 @@
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 #include <linux/init.h>
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 #include <linux/rtc.h>
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 #include <linux/bcd.h>
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+#include <linux/clocksource.h>
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 #include <linux/delay.h>
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 #include <linux/export.h>
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@@ -24,12 +25,29 @@
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 DEFINE_SPINLOCK(rtc_lock);
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 EXPORT_SYMBOL_GPL(rtc_lock);
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+static u64 atari_read_clk(struct clocksource *cs);
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+
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+static struct clocksource atari_clk = {
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+	.name   = "mfp",
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+	.rating = 100,
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+	.read   = atari_read_clk,
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+	.mask   = CLOCKSOURCE_MASK(32),
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+	.flags  = CLOCK_SOURCE_IS_CONTINUOUS,
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+};
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+
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+static u32 clk_total;
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+static u8 last_timer_count;
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+
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 static irqreturn_t mfp_timer_c_handler(int irq, void *dev_id)
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 {
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 	irq_handler_t timer_routine = dev_id;
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 	unsigned long flags;
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 	local_irq_save(flags);
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+	do {
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+		last_timer_count = st_mfp.tim_dt_c;
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+	} while (last_timer_count == 1);
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+	clk_total += INT_TICKS;
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 	timer_routine(0, NULL);
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 	local_irq_restore(flags);
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@@ -44,32 +62,33 @@
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     /* start timer C, div = 1:100 */
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     st_mfp.tim_ct_cd = (st_mfp.tim_ct_cd & 15) | 0x60;
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     /* install interrupt service routine for MFP Timer C */
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-    if (request_irq(IRQ_MFP_TIMC, mfp_timer_c_handler, 0, "timer",
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+    if (request_irq(IRQ_MFP_TIMC, mfp_timer_c_handler, IRQF_TIMER, "timer",
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                     timer_routine))
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 	pr_err("Couldn't register timer interrupt\n");
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+
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+    clocksource_register_hz(&atari_clk, INT_CLK);
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 }
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 /* ++andreas: gettimeoffset fixed to check for pending interrupt */
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-#define TICK_SIZE 10000
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-
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-/* This is always executed with interrupts disabled.  */
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-u32 atari_gettimeoffset(void)
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+static u64 atari_read_clk(struct clocksource *cs)
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 {
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-  u32 ticks, offset = 0;
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+	unsigned long flags;
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+	u8 count;
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+	u32 ticks;
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-  /* read MFP timer C current value */
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-  ticks = st_mfp.tim_dt_c;
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-  /* The probability of underflow is less than 2% */
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-  if (ticks > INT_TICKS - INT_TICKS / 50)
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-    /* Check for pending timer interrupt */
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-    if (st_mfp.int_pn_b & (1 << 5))
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-      offset = TICK_SIZE;
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+	local_irq_save(flags);
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+	/* Ensure that the count is monotonically decreasing, even though
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+	 * the result may briefly stop changing after counter wrap-around.
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+	 */
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+	count = min(st_mfp.tim_dt_c, last_timer_count);
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+	last_timer_count = count;
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-  ticks = INT_TICKS - ticks;
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-  ticks = ticks * 10000L / INT_TICKS;
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+	ticks = INT_TICKS - count;
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+	ticks += clk_total;
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+	local_irq_restore(flags);
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-  return (ticks + offset) * 1000;
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+	return ticks;
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 }
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