From patchwork Wed Jun 12 15:48:30 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Conor Dooley X-Patchwork-Id: 13695243 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 04060C27C53 for ; Wed, 12 Jun 2024 15:49:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:Subject:Cc :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=7D189b5vEdTxRRsh77A4CWEWuAYksy5hCWxuUGdhK+M=; b=ECmW0IOOqMIRFf KziXsAs/sa8Okmv+7FL2B4xiVa7aB+GULmQaVglmE8ZK7WE7Q46xP1wFDJ0Zn1msOjc6g6JzZ3aBe UIj6uYGMXmWiA4n9hO8IzXwc7qjPQJUBUQRbEXd6iPEbVHIXNoV4Snh3HaGG1p5lt7P5jJx2c6QkL 2/3K4Qs8Vje5ozTXw5LidWFHCZncsSHBfI3xtt6iPilBXoBiE8C5G8JsN9F3v8iEN02skfYOJWeEw 2RmWXeFBKj3bw2lR0EV75bnStDFOOsXihzoZkJJ7S/fXfiexidAUVvCaRqkIsm7wLvmbEN8WHJjwo NsxLu5CC/ggsXjIE7qDQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sHQDX-0000000DEV8-2stq; Wed, 12 Jun 2024 15:48:55 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sHQDU-0000000DEUL-3ACe for linux-riscv@lists.infradead.org; Wed, 12 Jun 2024 15:48:54 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id A7033614D1; Wed, 12 Jun 2024 15:48:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E4F4C116B1; Wed, 12 Jun 2024 15:48:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1718207331; bh=Zv5RO+ev5GfuXBQM8OVvJacsGQmGXoAme99ziwuiEck=; h=From:To:Cc:Subject:Date:From; b=BX7YQziIjwMZfXU0YaZomh/upatYQYZUGXQ/gieuDsa9lHHH6IXuLe5CWwi8zvEiO 4MVnoIG7zXqf/0d24cWmZHPf3kTevU7tUBOj26/3MnuklimKVGk5huSRgKYwztRmu/ GgkcV19g3+RW982sqldDpHHAyHvbiGqO4/GwXUcplKhwhc1jhFSXMOFwjOAeS/uY2g UURuFkVVoi6LncNTPzj390R3bL4rqB7DQ5N9JiXHB2HBpnNkuAw2AP6yUK23Mddplw L+GDRo7hirnaWDCQs9G5tvMOJL78qu04pnRH/U7EWVNQWmfqsfvDi7Kk7dRbB9Dxri UMWjj3YilADrw== From: Conor Dooley To: linux-mmc@vger.kernel.org Cc: conor@kernel.org, Conor Dooley , Ulf Hansson , cyril.jean@microchip.com, Mark Brown , linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, linux-spi@vger.kernel.org Subject: [RFC v1 0/3] mmc-spi - support controllers incapable of getting as low as 400KHz Date: Wed, 12 Jun 2024 16:48:30 +0100 Message-ID: <20240612-brigade-shell-1f626e7e592f@spud> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1827; i=conor.dooley@microchip.com; h=from:subject:message-id; bh=jUBdCKFRhPbdoAZJHxpB1biK3nMfNT3Pp93RB7R03bE=; b=owGbwMvMwCFWscWwfUFT0iXG02pJDGmZh31+Pm/g6ohf0duw6nVeD9Per0uMtwtxV56d+SrMv b92nZBlRykLgxgHg6yYIkvi7b4WqfV/XHY497yFmcPKBDKEgYtTACbytpbhr8Bf9Si3ZXVFdZVd x49dWL3xPsN13mz1GY8DrmmEx8WwlTL8L+kS/R9c+YftQeCvP85rHr7O8L3xseH8jP878tVe9mf sZAMA X-Developer-Key: i=conor.dooley@microchip.com; a=openpgp; fpr=F9ECA03CF54F12CD01F1655722E2C55B37CF380C X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240612_084852_887349_218DB203 X-CRM114-Status: GOOD ( 11.62 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org From: Conor Dooley Yo, RFC for some stuff that I've got in-progress for a customer's board where they want to use mmc-spi-slot with a QSPI controller that is incapable of getting as low as 400KHz with the way clocks have been configured on the system. At the moment, if a controller cannot get that low, linux continuously reports that queuing a transfer fails. The first couple of transfers will complete on this system, until mmc_start_host() kicks in and clamps the frequency to the larger of host->f_min and 400 KHz. Doing something like patch 1 of this set would allow the mmc-spi-slot to function for some sd cards, an improvement on the current none. I don't have any sd cards on hand that don't support the 5 MHz minimum frequency that this controller is limited to, so I amn't sure at what point this will blow up if such a card was used. Is this sort of change something that would fly? Patches 2 & 3 are just here b/c without #3 the qspi driver for this platform doesn't support anything other than mem ops and #2 is required to set the minimum frequency for mmc_spi to pick up. Cheers, Conor. CC: Ulf Hansson CC: Conor Dooley CC: cyril.jean@microchip.com CC: Mark Brown CC: linux-mmc@vger.kernel.org CC: linux-kernel@vger.kernel.org CC: linux-riscv@lists.infradead.org CC: linux-spi@vger.kernel.org Conor Dooley (2): mmc: mmc_spi: allow for spi controllers incapable of getting as low as 400k spi: microchip-core-qspi: set min_speed_hz during probe Cyril Jean (1): spi: microchip-core-qspi: Add regular transfers drivers/mmc/host/mmc_spi.c | 5 +- drivers/spi/spi-microchip-core-qspi.c | 224 +++++++++++++++++++++++++- 2 files changed, 226 insertions(+), 3 deletions(-)