mfd: Clean up after WM83xx AUXADC interrupt if it arrives late (5051d411) · Commits · e / devices / android_kernel_teracube_2e

In certain circumstances, especially under heavy load, the AUXADC completion interrupt may be detected after we've timed out waiting for it. That conversion would still succeed but the next conversion will see the completion that was signalled by the interrupt for the previous conversion and therefore not wait for the AUXADC conversion to run, causing it to report failure. Provide a simple, non-invasive cleanup by using try_wait_for_completion() to ensure that the completion is not signalled before we wait. Since the AUXADC is run within a mutex we know there can only have been at most one AUXADC interrupt outstanding. A more involved change should follow for the next merge window. Signed-off-by:

Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by:

Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/wm831x-core.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -349,6 +349,9 @@ int wm831x_auxadc_read(struct wm831x *wm831x, enum wm831x_auxadc input)
		goto disable;
		}

		/* If an interrupt arrived late clean up after it */
		try_wait_for_completion(&wm831x->auxadc_done);

		/* Ignore the result to allow us to soldier on without IRQ hookup */
		wait_for_completion_timeout(&wm831x->auxadc_done, msecs_to_jiffies(5));

drivers/mfd/wm8350-core.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -363,6 +363,10 @@ int wm8350_read_auxadc(struct wm8350 *wm8350, int channel, int scale, int vref)
		reg \|= 1 << channel \| WM8350_AUXADC_POLL;
		wm8350_reg_write(wm8350, WM8350_DIGITISER_CONTROL_1, reg);

		/* If a late IRQ left the completion signalled then consume
		* the completion. */
		try_wait_for_completion(&wm8350->auxadc_done);

		/* We ignore the result of the completion and just check for a
		* conversion result, allowing us to soldier on if the IRQ
		* infrastructure is not set up for the chip. */