From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Date: Thu, 17 Oct 2019 13:30:24 +0000 Subject: Re: [PATCH V7 6/6] backlight: qcom-wled: Add auto string detection logic Message-Id: <20191017133024.GQ4365@dell> List-Id: References: <1571220826-7740-1-git-send-email-kgunda@codeaurora.org> <1571220826-7740-7-git-send-email-kgunda@codeaurora.org> <20191017122653.GO4365@dell> <689831a9d7561f51cdb7ea0a1760d472@codeaurora.org> In-Reply-To: <689831a9d7561f51cdb7ea0a1760d472@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: kgunda@codeaurora.org Cc: bjorn.andersson@linaro.org, jingoohan1@gmail.com, b.zolnierkie@samsung.com, dri-devel@lists.freedesktop.org, daniel.thompson@linaro.org, jacek.anaszewski@gmail.com, pavel@ucw.cz, robh+dt@kernel.org, mark.rutland@arm.com, linux-leds@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Andy Gross , linux-arm-msm@vger.kernel.org, linux-fbdev@vger.kernel.org On Thu, 17 Oct 2019, kgunda@codeaurora.org wrote: > On 2019-10-17 17:56, Lee Jones wrote: > > On Wed, 16 Oct 2019, Kiran Gunda wrote: > > > > > The auto string detection algorithm checks if the current WLED > > > sink configuration is valid. It tries enabling every sink and > > > checks if the OVP fault is observed. Based on this information > > > it detects and enables the valid sink configuration. > > > Auto calibration will be triggered when the OVP fault interrupts > > > are seen frequently thereby it tries to fix the sink configuration. > > > > > > The auto-detection also kicks in when the connected LED string > > > of the display-backlight malfunctions (because of damage) and > > > requires the damaged string to be turned off to prevent the > > > complete panel and/or board from being damaged. > > > > > > Signed-off-by: Kiran Gunda > > > --- > > > drivers/video/backlight/qcom-wled.c | 410 > > > +++++++++++++++++++++++++++++++++++- > > > 1 file changed, 404 insertions(+), 6 deletions(-) > > > > > > diff --git a/drivers/video/backlight/qcom-wled.c > > > b/drivers/video/backlight/qcom-wled.c > > > index b5b125c..ff7c409 100644 > > > --- a/drivers/video/backlight/qcom-wled.c > > > +++ b/drivers/video/backlight/qcom-wled.c [...] > > > + if (int_sts & WLED3_CTRL_REG_OVP_FAULT_STATUS) > > > + dev_dbg(wled->dev, "WLED OVP fault detected with SINK %d\n", > > > + i + 1); > > > > I haven't reviewed the whole patch, but this caught my eye. > > > > I think this should be upgraded to dev_warn(). > > > Thought of keeping these messages silent, Because the string configuration > will be corrected in this > and informing it at end of the auto string detection. [...] > > > + } else { > > > + dev_warn(wled->dev, "New WLED string configuration found %x\n", > > > + sink_valid); > > > > Why would the user care about this? Is it not normal? > > > Actually, it comes here if the user provided string configuration in the > device tree is in-correct. > That's why just informing the user about the right string configuration, > after the auto string detection. Then I think we need to be more forthcoming. Tell the user the configuration is incorrect and what you've done to rectify it. "XXX is not a valid configuration - using YYY instead" [...] > > > +static int wled_configure_ovp_irq(struct wled *wled, > > > + struct platform_device *pdev) > > > +{ > > > + int rc; > > > + u32 val; > > > + > > > + wled->ovp_irq = platform_get_irq_byname(pdev, "ovp"); > > > + if (wled->ovp_irq < 0) { > > > + dev_dbg(&pdev->dev, "ovp irq is not used\n"); > > > > I assume this is optional. What happens if no IRQ is provided? > > > Here OVP IRQ is used to detect the wrong string detection. If it is not > provided the auto string detection logic won't work. "OVP IRQ not found - disabling automatic string detection" > > If, for instance, polling mode is enabled, maybe something like this > > would be better? > > > > dev_warn(&pdev->dev, "No IRQ found, falling back to polling > > mode\n"); -- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog