#include <asm/io.h>
#include <linux/delay.h>
+#include <linux/ktime.h>
#include <linux/moduleparam.h>
#include <linux/module.h>
116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53
};
-static void w1_delay(unsigned long tm)
+static void w1_delay(struct w1_master *dev, unsigned long tm)
{
- udelay(tm * w1_delay_parm);
+ ktime_t start, delta;
+
+ if (!dev->bus_master->delay_needs_poll) {
+ udelay(tm * w1_delay_parm);
+ return;
+ }
+
+ start = ktime_get();
+ delta = ktime_add(start, ns_to_ktime(1000 * tm * w1_delay_parm));
+ do {
+ dev->bus_master->read_bit(dev->bus_master->data);
+ udelay(1);
+ } while (ktime_before(ktime_get(), delta));
}
static void w1_write_bit(struct w1_master *dev, int bit);
if (bit) {
dev->bus_master->write_bit(dev->bus_master->data, 0);
- w1_delay(6);
+ w1_delay(dev, 6);
dev->bus_master->write_bit(dev->bus_master->data, 1);
- w1_delay(64);
+ w1_delay(dev, 64);
} else {
dev->bus_master->write_bit(dev->bus_master->data, 0);
- w1_delay(60);
+ w1_delay(dev, 60);
dev->bus_master->write_bit(dev->bus_master->data, 1);
- w1_delay(10);
+ w1_delay(dev, 10);
}
if(w1_disable_irqs) local_irq_restore(flags);
/* sample timing is critical here */
local_irq_save(flags);
dev->bus_master->write_bit(dev->bus_master->data, 0);
- w1_delay(6);
+ w1_delay(dev, 6);
dev->bus_master->write_bit(dev->bus_master->data, 1);
- w1_delay(9);
+ w1_delay(dev, 9);
result = dev->bus_master->read_bit(dev->bus_master->data);
local_irq_restore(flags);
- w1_delay(55);
+ w1_delay(dev, 55);
return result & 0x1;
}
* cpu for such a short amount of time AND get it back in
* the maximum amount of time.
*/
- w1_delay(500);
+ w1_delay(dev, 500);
dev->bus_master->write_bit(dev->bus_master->data, 1);
- w1_delay(70);
+ w1_delay(dev, 70);
result = dev->bus_master->read_bit(dev->bus_master->data) & 0x1;
/* minimum 70 (above) + 430 = 500 us
* There aren't any timing requirements between a reset and
* the following transactions. Sleeping is safe here.
*/
- /* w1_delay(430); min required time */
+ /* w1_delay(dev, 430); min required time */
msleep(1);
}
* @dev_id: Optional device id string, which w1 slaves could use for
* creating names, which then give a connection to the w1 master
*
+ * @delay_needs_poll: work around jitter introduced with GPIO controllers
+ * accessed over PCIe (RP1)
+ *
* Note: read_bit and write_bit are very low level functions and should only
* be used with hardware that doesn't really support 1-wire operations,
* like a parallel/serial port.
u8, w1_slave_found_callback);
char *dev_id;
+
+ bool delay_needs_poll;
};
/**