Re: [PATCH v4 1/3] i2c: tegra: calculate timeout for config load when needed

From: Jon Hunter
Date: Mon Apr 25 2016 - 05:38:05 EST



On 23/04/16 12:03, Shardar Shariff Md wrote:
> Instead of calculating timeout for the config load during init,
> calculate it after config load register is written by using
> readx_poll_timeout().
>
> Signed-off-by: Shardar Shariff Md <smohammed@xxxxxxxxxx>
>
> Changes since v1:
> - Split timeout calculation to seperate patch
> ---
> drivers/i2c/busses/i2c-tegra.c | 25 +++++++++++++++----------
> 1 file changed, 15 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
> index d764d64..c1b02c7 100644
> --- a/drivers/i2c/busses/i2c-tegra.c
> +++ b/drivers/i2c/busses/i2c-tegra.c
> @@ -28,6 +28,7 @@
> #include <linux/of_device.h>
> #include <linux/module.h>
> #include <linux/reset.h>
> +#include <linux/iopoll.h>
>
> #include <asm/unaligned.h>
>
> @@ -110,6 +111,8 @@
> #define I2C_CLKEN_OVERRIDE 0x090
> #define I2C_MST_CORE_CLKEN_OVR (1 << 0)
>
> +#define I2C_CONFIG_LOAD_TIMEOUT 1000000
> +
> /*
> * msg_end_type: The bus control which need to be send at end of transfer.
> * @MSG_END_STOP: Send stop pulse at end of transfer.
> @@ -428,7 +431,6 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
> u32 val;
> int err = 0;
> u32 clk_divisor;
> - unsigned long timeout = jiffies + HZ;
>
> err = tegra_i2c_clock_enable(i2c_dev);
> if (err < 0) {
> @@ -478,24 +480,27 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
> i2c_writel(i2c_dev, I2C_MST_CORE_CLKEN_OVR, I2C_CLKEN_OVERRIDE);
>
> if (i2c_dev->hw->has_config_load_reg) {
> + u32 val;
> +
> i2c_writel(i2c_dev, I2C_MSTR_CONFIG_LOAD, I2C_CONFIG_LOAD);
> - while (i2c_readl(i2c_dev, I2C_CONFIG_LOAD) != 0) {
> - if (time_after(jiffies, timeout)) {
> - dev_warn(i2c_dev->dev,
> - "timeout waiting for config load\n");
> - return -ETIMEDOUT;
> - }
> - msleep(1);
> + err = readx_poll_timeout(readl, i2c_dev->base +
> + tegra_i2c_reg_addr(i2c_dev,
> + I2C_CONFIG_LOAD), val, val == 0,
> + 1000, I2C_CONFIG_LOAD_TIMEOUT);
> + if (err) {
> + dev_warn(i2c_dev->dev,
> + "timeout waiting for config load\n");
> + goto err;
> }
> }
>
> - tegra_i2c_clock_disable(i2c_dev);
> -
> if (i2c_dev->irq_disabled) {
> i2c_dev->irq_disabled = 0;
> enable_irq(i2c_dev->irq);
> }
>
> +err:
> + tegra_i2c_clock_disable(i2c_dev);
> return err;

Minor comment ... moving the clock disable here looks like the right
thing to do, but this is not mentioned in the changelog and it seems
that if this is a fix, then it should be a separate patch?

Cheers
Jon