Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754491AbbGCCug (ORCPT ); Thu, 2 Jul 2015 22:50:36 -0400 Received: from mail-oi0-f54.google.com ([209.85.218.54]:33722 "EHLO mail-oi0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754508AbbGCCuU (ORCPT ); Thu, 2 Jul 2015 22:50:20 -0400 MIME-Version: 1.0 In-Reply-To: References: <1435735399-15333-1-git-send-email-chunyan.zhang@spreadtrum.com> Date: Fri, 3 Jul 2015 10:50:19 +0800 Message-ID: Subject: Re: [RFC PATCH] mmc: sprd: add MMC host driver for Spreadtrum SoC From: Orson Zhai To: Rob Herring Cc: Chunyan Zhang , "chris@printf.net" , Ulf Hansson , Lee Jones , Shawn Guo , Grant Likely , Rob Herring , Arnd Bergmann , billows.wu@spreadtrum.com, =?UTF-8?B?V2VpIFFpYW8gKOS5lOS8nyk=?= , baolin.wang@spreadtrum.com, ning.yang@spreadtrum.com, =?UTF-8?B?T3Jzb24gWmhhaSjnv5/kuqwp?= , jason.wu@spreadtrum.com, "linux-mmc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3337 Lines: 77 On Thu, Jul 2, 2015 at 11:47 PM, Rob Herring wrote: > On Thu, Jul 2, 2015 at 4:26 AM, Orson Zhai wrote: >> Hi Rob, >> >> Thanks for your quick reply. >> I have one question to your last comment. >> >> On Thu, Jul 2, 2015 at 1:50 AM, Rob Herring wrote: >>> On Wed, Jul 1, 2015 at 2:23 AM, Chunyan Zhang >>> wrote: >>>> From: Billows Wu > > [...] > >>>> +const struct of_device_id sdhost_of_match[] = { >>>> + {.compatible = "sprd,sd-sdhost-3.0", .data = &sd_caps_info,}, >>>> + {.compatible = "sprd,wifi-sdhost-3.0", .data = &wifi_caps_info,}, >>>> + {.compatible = "sprd,emmc-sdhost-3.0", .data = &emmc_caps_info,}, >>> >>> What these are connected to is irrelevant to the driver and compatible >>> string. All these differences belong in the DT unless the IP blocks >>> are really different. >> >> It's my idea to let Billows do like this. >> I learn from SSP part in freescale "arch/arm/boot/dts/imx28-evk.dts" >> Their ssp0-ssp2 each have 2 roles, mmc or generic spi bus. >> And they may write one of their combo configuration like this: > > That is a bit different as the host controller is operating in > completely different modes. In your case, the host controller is the > same and functions the same way, but just has different cards > attached. > >> >> 43 ssp1: ssp@80012000 { >> 44 compatible = "fsl,imx28-mmc"; >> 45 bus-width = <8>; >> 46 wp-gpios = <&gpio0 28 0>; >> 47 }; >> 48 >> 49 ssp2: ssp@80014000 { >> 50 #address-cells = <1>; >> 51 #size-cells = <0>; >> 52 compatible = "fsl,imx28-spi"; >> 53 pinctrl-names = "default"; >> 54 pinctrl-0 = <&spi2_pins_a>; >> 55 status = "okay"; >> 56 >> 57 flash: m25p80@0 { >> 58 #address-cells = <1>; >> 59 #size-cells = <1>; >> 60 compatible = "sst,sst25vf016b"; >> 61 spi-max-frequency = <40000000>; >> 62 reg = <0>; >> 63 }; >> 64 }; >> >> Billows tell me they also have 3 roles in their sd host controller >> corresponding to 3 kinds of different operation. >> He used to create "sprd,name" property for this. Is it a good way or >> anything else better? > > Why do you need to know? You can define parameters which can't be > probed such as bus width, voltage, and clock freq. in DT for each > host. The MMC subsys core will figure out the type of device attached. I think you're right. Thanks! -orson > > Rob -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/