From: Corey Minyard <cminyard@xxxxxxxxxx>
The timer is too slow and significantly reduces performance. Use an
hrtimer to get things working faster.
Signed-off-by: Corey Minyard <minyard@xxxxxxx>
Tested-by: Andrew Manley <andrew.manley@xxxxxxxxxxxxxxx>
Reviewed-by: Andrew Manley <andrew.manley@xxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-imx.c | 23 +++++++++++++++--------
1 file changed, 15 insertions(+), 8 deletions(-)
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 26a04dc0590b..4b0e9d1784dd 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -38,7 +38,7 @@
#include <linux/iopoll.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
-#include <linux/timer.h>
+#include <linux/hrtimer.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
@@ -53,6 +53,8 @@
/* This will be the driver name the kernel reports */
#define DRIVER_NAME "imx-i2c"
+#define I2C_IMX_CHECK_DELAY 30000 /* Time to check for bus idle, in NS */
+
/*
* Enable DMA if transfer byte size is bigger than this threshold.
* As the hardware request, it must bigger than 4 bytes.\
@@ -214,8 +216,8 @@ struct imx_i2c_struct {
enum i2c_slave_event last_slave_event;
/* For checking slave events. */
- spinlock_t slave_lock;
- struct timer_list slave_timer;
+ spinlock_t slave_lock;
+ struct hrtimer slave_timer;
};
static const struct imx_i2c_hwdata imx1_i2c_hwdata = {
@@ -783,13 +785,16 @@ static irqreturn_t i2c_imx_slave_handle(struct imx_i2c_struct *i2c_imx,
}
out:
- mod_timer(&i2c_imx->slave_timer, jiffies + 1);
+ hrtimer_try_to_cancel(&i2c_imx->slave_timer);
+ hrtimer_forward_now(&i2c_imx->slave_timer, I2C_IMX_CHECK_DELAY);
+ hrtimer_restart(&i2c_imx->slave_timer);
return IRQ_HANDLED;
}
-static void i2c_imx_slave_timeout(struct timer_list *t)
+static enum hrtimer_restart i2c_imx_slave_timeout(struct hrtimer *t)
{
- struct imx_i2c_struct *i2c_imx = from_timer(i2c_imx, t, slave_timer);
+ struct imx_i2c_struct *i2c_imx = container_of(t, struct imx_i2c_struct,
+ slave_timer);
unsigned int ctl, status;
unsigned long flags;
@@ -798,6 +803,7 @@ static void i2c_imx_slave_timeout(struct timer_list *t)
ctl = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
i2c_imx_slave_handle(i2c_imx, status, ctl);
spin_unlock_irqrestore(&i2c_imx->slave_lock, flags);
+ return HRTIMER_NORESTART;
}
static void i2c_imx_slave_init(struct imx_i2c_struct *i2c_imx)
@@ -1423,7 +1429,8 @@ static int i2c_imx_probe(struct platform_device *pdev)
return -ENOMEM;
spin_lock_init(&i2c_imx->slave_lock);
- timer_setup(&i2c_imx->slave_timer, i2c_imx_slave_timeout, 0);
+ hrtimer_init(&i2c_imx->slave_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+ i2c_imx->slave_timer.function = i2c_imx_slave_timeout;
match = device_get_match_data(&pdev->dev);
if (match)
@@ -1538,7 +1545,7 @@ static int i2c_imx_remove(struct platform_device *pdev)
if (ret < 0)
return ret;
- del_timer_sync(&i2c_imx->slave_timer);
+ hrtimer_cancel(&i2c_imx->slave_timer);
/* remove adapter */
dev_dbg(&i2c_imx->adapter.dev, "adapter removed\n");
--
2.25.1
