From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Shevchenko Subject: Re: [PATCH] mmc: sdhci-pci: Try "cd" for card-detect lookup before using NULL Date: Wed, 24 Oct 2018 13:02:30 +0300 Message-ID: <20181024100230.GQ10650@smile.fi.intel.com> References: <20181018215101.169847-1-rajatja@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Rajat Jain Cc: "Hunter, Adrian" , Ulf Hansson , linux-mmc@vger.kernel.org, Linus Walleij , Rajat Jain , Linux Kernel Mailing List , Mika Westerberg , Dmitry Torokhov , linux-gpio@vger.kernel.org, linux-acpi@vger.kernel.org List-Id: linux-gpio@vger.kernel.org On Mon, Oct 22, 2018 at 04:34:55PM -0700, Rajat Jain wrote: > On Fri, Oct 19, 2018 at 2:13 AM Andy Shevchenko > wrote: > > On Fri, Oct 19, 2018 at 12:53 AM Rajat Jain wrote: > > > across other users of this API (other MMC host controller drivers). > > > > > if (slot->cd_idx >= 0) { > > > - ret = mmc_gpiod_request_cd(host->mmc, NULL, slot->cd_idx, > > > + ret = mmc_gpiod_request_cd(host->mmc, "cd", slot->cd_idx, > > > slot->cd_override_level, 0, NULL); > > > > Yes. > > > > > + if (ret && ret != -EPROBE_DEFER) > > > + ret = mmc_gpiod_request_cd(host->mmc, NULL, > > > + slot->cd_idx, > > > + slot->cd_override_level, > > > + 0, NULL); > > > > And no. Instead of this part you need to provide an ACPI GPIO mapping table. > > Sure, I am willing to do so, and I tried earlier too. However, certain > doubts arose in my mind when I tried that and I posted my questions > earlier (https://lkml.org/lkml/2018/9/28/507) but couldn't elicit any > response. Unfortunately I still do not have answers. My primary > questions are: > > 1) - It seems that 1 SDHCI device may support multiple slots (looking > at the code). It is not clear to me if they could share card detect > interrupts, or should have separate ones? This is more likely question to HW engineers of your platform with a caveat that there should be a way to distinguish exact slot in which card is being inserted. > Also, the driver may not > really know? I think in such case the bug in HW design and / or driver. > So should I add 1 or two pins using the > devm_acpi_dev_add_driver_gpios(). This depends on the above, e.g. HW design, ACPI tables. > Is some one familiar with SDHC > driver can answer these questions, it shall be great. Actually above questions better to ask in linux-mmc mailing list, which by the fact is in Cc list already. So, wait for someone to clarify. > 2) I'm not really sure what should I set "active_low" to? Isn't this > something that should be specified by platform / ACPI too, and driver > should just be able to say say choose whatever the ACPI says? > > struct acpi_gpio_params { > unsigned int crs_entry_index; > unsigned int line_index; > bool active_low; > }; ACPI specification misses this property, that's why we have it in the structure. In your case it should be provided by _DSD and thus be consistent with the hardcoded values. > Since I do not understand the above two issues, and thus I chose the > safest path and not disturb the current code so as not to cause any > regressions. As far as I can see in the above it is disturbing the current code more than needed. > > Please let me know, and I'm happy to re-spin my patch. -- With Best Regards, Andy Shevchenko