Re: [PATCH v3 2/2] i2c: qcom-target: Add driver for Qualcomm I2C target controller

[Andi Shyti <andi.shyti@kernel.org>]

Hi Viken,

On Thu, Aug 27, 2026 at 06:44:21PM +0530, Viken Dadhaniya wrote:
> On 8/26/2026 7:27 PM, Andi Shyti wrote:
> > ...
> > 
> >> +static void qcom_i2c_target_hw_reset(struct qcom_i2c_target *target)
> >> +{
> >> +	/* Clear error bits before SW_RESET; the reset may not be instantaneous */
> >> +	writel(BIT(ERR_CONDITION) | BIT(CLOCK_LOW_TIMEOUT),
> >> +	       target->base + I2C_S_IRQ_CLR);
> >> +	writel(SW_RESET, target->base + I2C_S_SW_RESET_REG);
> >> +	/*
> >> +	 * I2C_S_SW_RESET_REG is write-only so completion cannot be polled.
> >> +	 * Use a conservative delay to allow the reset to finish before
> >> +	 * reconfiguring the controller.
> >> +	 */
> >> +	usleep_range(10, 20);
> > 
> > This is also called in atomic context from the irq handler.
> > Please avoid using usleep_range(), perhaps you can put this in a
> > thread.
> > 
> 
> Thanks for the review. The delay is only 20 µs, so we were
> thinking of replacing usleep_range() with udelay() instead of
> converting to a threaded IRQ, to avoid the added complexity on
> all the normal fast paths.

perhaps before sleeping you could check the context you are
executing (with an explaining comment).

Thanks,
Andi