On Mon, Oct 04, 2021 at 07:32:16PM -0500, minyard@xxxxxxx wrote:
> 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>
Do we need to keep this change history? If no, please merge it to the
first patch.
> ---
> 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
>
>
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