From patchwork Wed Jun 12 15:48:31 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Conor Dooley X-Patchwork-Id: 13695245 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E685C180A9B; Wed, 12 Jun 2024 15:48:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718207335; cv=none; b=ev7aZmG3LT0oCk7y8Yhye6hDs25MwYjPcVmv8kd0CqO56iibb1RpMmuDyuclyUILegxE5zgIWhu9oGfq/aXMJUEuxoDT8SdZI7UtmOBmoTJtrb1g24g26glqnrA7w/m4ox+V1THwQtzGT7HVCFJd4QoQI7vs7bcH8icMeZcqXI0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718207335; c=relaxed/simple; bh=P1vOj2Rn7zuoaBh6AcqrcUTEi1rovxUtpHsy8CmdHr0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GKH/xprh0/s3EeBnlaCjPCXZIZF9ZKCgbEgrtxNGXnoinssUsFhAfprjTDRXs5x6oWKJ2Rd/cFPfKMZieOyhkprvAg/CpLwU97jGCyo1pTYsKQeUOBYuOIpN/7KXw4a44U48MnJZkspVtF0g1TXE6w5HHqS0/p0HbbICcEP4Lp0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RM5rd5EJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RM5rd5EJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9393DC4AF1A; Wed, 12 Jun 2024 15:48:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1718207334; bh=P1vOj2Rn7zuoaBh6AcqrcUTEi1rovxUtpHsy8CmdHr0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RM5rd5EJCfJaPHSF6RHPKysoR8lv3CkSLd4g2Berb4nT2sHLtIYnFt6NS60oRpl9g oELj9VAHV47yQv/PW5bqKN4G8Pzc0J1OY+DCv21YxQEmcmfzvEUyCFc6XGpr3gaL8v m42aKyyJ1o1WH/8kPZXWMVyo3tMASfqukyObPz/hrVo29vqFl0+HXgLAaFlXJvcA2h 5/zX4wXMTZOpYBUz+HtYelymZidotMFyoqz6B3QVwizDw5s+ubMk2Io9m2dkQ83SVE Jpi6Eyt0tUJpbyJ0XNr/yRaFoytL9m/duTvKpg9sooyAurw9t6/PBbTepntmShB9Rn 7x12qvQbD/Rxw== 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 1/3] mmc: mmc_spi: allow for spi controllers incapable of getting as low as 400k Date: Wed, 12 Jun 2024 16:48:31 +0100 Message-ID: <20240612-dense-resample-563f07c30185@spud> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240612-brigade-shell-1f626e7e592f@spud> References: <20240612-brigade-shell-1f626e7e592f@spud> Precedence: bulk X-Mailing-List: linux-spi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1284; i=conor.dooley@microchip.com; h=from:subject:message-id; bh=tXCkjnYnQevs4Hom30XLCG5d2XL7igKpnQRl5B2TRkw=; b=owGbwMvMwCFWscWwfUFT0iXG02pJDGmZh32YQ6LF1YxuVN44oVfcacC3NEQq8fP2UjmeHOsvU xz69Sd3lLIwiHEwyIopsiTe7muRWv/HZYdzz1uYOaxMIEMYuDgFYCIsPIwMn456V+r3ir64lrdo KmPhpIDV4u8mNB94t0Rwf1q/maEiD8NfmZ3axzc5JC2xrbjnZyYflvhFedPN8EPp4tfsC9ds3DW BGQA= X-Developer-Key: i=conor.dooley@microchip.com; a=openpgp; fpr=F9ECA03CF54F12CD01F1655722E2C55B37CF380C From: Conor Dooley Some controllers may not be able to reach a bus clock as low as 400 KHz due to a lack of sufficient divisors. In these cases, the SD card slot becomes non-functional as Linux continuously attempts to set the bus clock to 400 KHz. If the controller is incapable of getting that low, set its minimum frequency instead. While this may eliminate some SD cards, it allows those capable of operating at the controller's minimum frequency to be used. Signed-off-by: Conor Dooley --- drivers/mmc/host/mmc_spi.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c index 09d7a6a0dc1a..c9caa1ece7ef 100644 --- a/drivers/mmc/host/mmc_spi.c +++ b/drivers/mmc/host/mmc_spi.c @@ -1208,7 +1208,10 @@ static int mmc_spi_probe(struct spi_device *spi) * that's the only reason not to use a few MHz for f_min (until * the upper layer reads the target frequency from the CSD). */ - mmc->f_min = 400000; + if (spi->controller->min_speed_hz > 400000) + dev_warn(&spi->dev,"Controller unable to reduce bus clock to 400 KHz\n"); + + mmc->f_min = max(spi->controller->min_speed_hz, 400000); mmc->f_max = spi->max_speed_hz; host = mmc_priv(mmc);