From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Cameron Subject: Re: [PATCH] iio: adc: rockchip_saradc: Explicitly disable ADC on probe Date: Mon, 15 Aug 2016 19:04:31 +0100 Message-ID: <8ebf4c53-21e2-0220-1756-beb57af32304@kernel.org> References: <1469475540-26855-1-git-send-email-linux@roeck-us.net> <5796D036.1060101@rock-chips.com> <5796D792.4080407@roeck-us.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <5796D792.4080407-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org> Sender: linux-iio-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Guenter Roeck , Caesar Wang , Heiko Stuebner Cc: linux-iio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: linux-rockchip.vger.kernel.org On 26/07/16 04:22, Guenter Roeck wrote: > On 07/25/2016 07:51 PM, Caesar Wang wrote: >> Hi Guenter, >> >> Thanks for fixing it. >> >> On 2016年07月26日 03:39, Guenter Roeck wrote: >>> If the ADC is read for the first time, the caller gets a timeout error, >>> and the kernel log shows >>> >>> read channel() error: -110 >>> >>> The ADC may be enabled on boot, and needs to be explicitly disabled >>> for a read sequence to work (otherwise there is no completion interrupt). >>> Disaple it explicitly in the probe function. >>> >>> Fixes: 44d6f2ef94f9 ("iio: adc: add driver for Rockchip saradc") >>> Signed-off-by: Guenter Roeck >>> --- >>> drivers/iio/adc/rockchip_saradc.c | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/drivers/iio/adc/rockchip_saradc.c b/drivers/iio/adc/rockchip_saradc.c >>> index f9ad6c2d6821..6aa3271d86b5 100644 >>> --- a/drivers/iio/adc/rockchip_saradc.c >>> +++ b/drivers/iio/adc/rockchip_saradc.c >>> @@ -280,6 +280,9 @@ static int rockchip_saradc_probe(struct platform_device *pdev) >>> goto err_pclk; >>> } >>> + /* Make sure ADC is disabled */ >>> + writel_relaxed(0, info->regs + SARADC_CTRL); >> >> I think we should reset the saradc controller. >> Since make sure the reset value is 0 and loader-->kernel may even cause harm, as my experience on tsadc. (drivers/thermal/rockchip_thermal.c) >> >> >> e.g.: >> /** >> * Reset SARADC Controller, reset all saradc registers. >> */ >> static void rockchip_saradc_reset_controller(struct reset_control *reset) >> { >> reset_control_assert(reset); >> usleep_range(10, 20); >> reset_control_deassert(reset); >> } >> >> ..probe() >> { >> ... >> rockchip_saradc_reset_controller(); >> ... >> } >> > > Ok, I'll give it a try. > > Guenter Could you confirm if this patch is superseded by that change or not? > >> >> - >> Caesar >> >>> + >>> platform_set_drvdata(pdev, indio_dev); >>> indio_dev->name = dev_name(&pdev->dev); >> >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-iio" in > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > More majordomo info at http://vger.kernel.org/majordomo-info.html