From patchwork Thu Nov 17 10:52:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tudor Ambarus X-Patchwork-Id: 13046575 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87AF5C433FE for ; Thu, 17 Nov 2022 10:54:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239657AbiKQKyB (ORCPT ); Thu, 17 Nov 2022 05:54:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41782 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239518AbiKQKxO (ORCPT ); Thu, 17 Nov 2022 05:53:14 -0500 Received: from esa.microchip.iphmx.com (esa.microchip.iphmx.com [68.232.154.123]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D942E5ADE2; Thu, 17 Nov 2022 02:53:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1668682390; x=1700218390; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=IV3iY/5nH2v6r5LMDzPfNG3LT1Nn/MAxR36s7csPy5k=; b=U9kX07y6nRcNudQwmHcO4ZBs1IB8awZk2TdS44EIWq32WbLdjGt0we0/ 0UMb/QjkbrCkk7T4ByizojGgYFdEGl+DygYDHu8RsChRhXIvkiaz5SZGc RZ1IMN9o+xfXORuhUNgmA8wjuOZ4RIc1mzrN/jslijHdcTVX+2Y2hsQy5 +zceDMnnPqWE2HXZOcZW2ASBAnKepI/BPB8kNqk6zUzQJ+7ksY6KQfebq q7Q6Nr3luWoo3MSJ7iNWcnM9D2SQ4PqnqBMR6ITKU6ss304cy+D6UeA+1 TllPLZ1t8M2fKG6NWHnZq16qLm10nqaMUaed6nQuWhNi9NP97nEXoPVjF A==; X-IronPort-AV: E=Sophos;i="5.96,171,1665471600"; d="scan'208";a="183965627" Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa4.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 17 Nov 2022 03:53:09 -0700 Received: from chn-vm-ex02.mchp-main.com (10.10.87.72) by chn-vm-ex02.mchp-main.com (10.10.87.72) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.12; Thu, 17 Nov 2022 03:53:05 -0700 Received: from ROB-ULT-M18064N.mchp-main.com (10.10.115.15) by chn-vm-ex02.mchp-main.com (10.10.85.144) with Microsoft SMTP Server id 15.1.2507.12 via Frontend Transport; Thu, 17 Nov 2022 03:53:02 -0700 From: Tudor Ambarus To: , , , , , CC: , , , , , Tudor Ambarus Subject: [PATCH 4/8] spi: atmel-quadspi: Add support for configuring CS timing Date: Thu, 17 Nov 2022 12:52:45 +0200 Message-ID: <20221117105249.115649-5-tudor.ambarus@microchip.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221117105249.115649-1-tudor.ambarus@microchip.com> References: <20221117105249.115649-1-tudor.ambarus@microchip.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org The at91 QSPI IP uses a default value of half of the period of the QSPI clock period for the cs-setup time, which is not always enough, an example being the sst26vf064b SPI NOR flash which requires a minimum cs-setup time of 5 ns. It was observed that none of the at91 SoCs can fulfill the minimum CS setup time for the aforementioned flash, as they operate at high frequencies and half a period does not suffice for the required CS setup time. Add support for configuring the CS timing in the controller. Signed-off-by: Tudor Ambarus --- drivers/spi/atmel-quadspi.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/drivers/spi/atmel-quadspi.c b/drivers/spi/atmel-quadspi.c index 976a217e356d..70637e46290a 100644 --- a/drivers/spi/atmel-quadspi.c +++ b/drivers/spi/atmel-quadspi.c @@ -510,6 +510,39 @@ static int atmel_qspi_setup(struct spi_device *spi) return 0; } +static int atmel_qspi_set_cs_timing(struct spi_device *spi) +{ + struct spi_controller *ctrl = spi->master; + struct atmel_qspi *aq = spi_controller_get_devdata(ctrl); + unsigned long clk_rate; + u32 cs_setup; + int delay; + int ret; + + delay = spi_delay_to_ns(&spi->cs_setup, NULL); + if (delay <= 0) + return delay; + + clk_rate = clk_get_rate(aq->pclk); + if (!clk_rate) + return -EINVAL; + + cs_setup = DIV_ROUND_UP((delay * DIV_ROUND_UP(clk_rate, 1000000)), + 1000); + + ret = pm_runtime_resume_and_get(ctrl->dev.parent); + if (ret < 0) + return ret; + + aq->scr |= QSPI_SCR_DLYBS(cs_setup); + atmel_qspi_write(aq->scr, aq, QSPI_SCR); + + pm_runtime_mark_last_busy(ctrl->dev.parent); + pm_runtime_put_autosuspend(ctrl->dev.parent); + + return 0; +} + static void atmel_qspi_init(struct atmel_qspi *aq) { /* Reset the QSPI controller */ @@ -555,6 +588,7 @@ static int atmel_qspi_probe(struct platform_device *pdev) ctrl->mode_bits = SPI_RX_DUAL | SPI_RX_QUAD | SPI_TX_DUAL | SPI_TX_QUAD; ctrl->setup = atmel_qspi_setup; + ctrl->set_cs_timing = atmel_qspi_set_cs_timing; ctrl->bus_num = -1; ctrl->mem_ops = &atmel_qspi_mem_ops; ctrl->num_chipselect = 1;