From patchwork Wed Apr 15 15:43:52 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bert Vermeulen X-Patchwork-Id: 6221701 Return-Path: X-Original-To: patchwork-linux-spi@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id EB3029F313 for ; Wed, 15 Apr 2015 15:44:22 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id C41B3202A1 for ; Wed, 15 Apr 2015 15:44:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8F62420274 for ; Wed, 15 Apr 2015 15:44:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756175AbbDOPoT (ORCPT ); Wed, 15 Apr 2015 11:44:19 -0400 Received: from kiutl.biot.com ([31.172.244.210]:57432 "EHLO kiutl.biot.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755704AbbDOPoQ (ORCPT ); Wed, 15 Apr 2015 11:44:16 -0400 Received: from spamd by kiutl.biot.com with sa-checked (Exim 4.83) (envelope-from ) id 1YiPU6-0000W9-Bk for linux-spi@vger.kernel.org; Wed, 15 Apr 2015 17:44:14 +0200 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from [2a02:578:4a04:2a00::5] (helo=sumner.biot.com) by kiutl.biot.com with esmtps (TLSv1.2:DHE-RSA-AES128-SHA:128) (Exim 4.83) (envelope-from ) id 1YiPTv-0000S5-VA; Wed, 15 Apr 2015 17:44:04 +0200 Received: from bert by sumner.biot.com with local (Exim 4.82) (envelope-from ) id 1YiPTu-0008NK-OM; Wed, 15 Apr 2015 17:44:02 +0200 From: Bert Vermeulen To: ralf@linux-mips.org, broonie@kernel.org, linux-mips@linux-mips.org, linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, andy.shevchenko@gmail.com, jogo@openwrt.org Cc: Bert Vermeulen Subject: [PATCH v7] spi: Add SPI driver for Mikrotik RB4xx series boards Date: Wed, 15 Apr 2015 17:43:52 +0200 Message-Id: <1429112632-32153-1-git-send-email-bert@biot.com> X-Mailer: git-send-email 1.9.1 Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This driver mediates access between the connected CPLD and other devices on the bus. The m25p80-compatible boot flash and (some models) MMC use regular SPI, bitbanged as required by the SoC. However the SPI-connected CPLD has a two-wire mode, in which two bits are transferred per SPI clock cycle. The second bit is transmitted with the SoC's CS2 pin. Signed-off-by: Bert Vermeulen --- Changes in v7: - use SPI_TX_DUAL/tx_nbits to signal two-wire mode - use SPI_MASTER_MUST_TX for dummy writes - use bits_per_word_mask to restrict word size - properly disable/unprepare clock on module removal - code cleanup Changes in v6: - removed unnecessary SPI mode check - whitespace fixes drivers/spi/Kconfig | 6 ++ drivers/spi/Makefile | 1 + drivers/spi/spi-rb4xx.c | 210 ++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 217 insertions(+) create mode 100644 drivers/spi/spi-rb4xx.c diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index ab8dfbe..8b1beaf6 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -429,6 +429,12 @@ config SPI_ROCKCHIP The main usecase of this controller is to use spi flash as boot device. +config SPI_RB4XX + tristate "Mikrotik RB4XX SPI master" + depends on SPI_MASTER && ATH79 + help + SPI controller driver for the Mikrotik RB4xx series boards. + config SPI_RSPI tristate "Renesas RSPI/QSPI controller" depends on SUPERH || ARCH_SHMOBILE || COMPILE_TEST diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index d8cbf65..0218f39 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -66,6 +66,7 @@ obj-$(CONFIG_SPI_PXA2XX) += spi-pxa2xx-platform.o obj-$(CONFIG_SPI_PXA2XX_PCI) += spi-pxa2xx-pci.o obj-$(CONFIG_SPI_QUP) += spi-qup.o obj-$(CONFIG_SPI_ROCKCHIP) += spi-rockchip.o +obj-$(CONFIG_SPI_RB4XX) += spi-rb4xx.o obj-$(CONFIG_SPI_RSPI) += spi-rspi.o obj-$(CONFIG_SPI_S3C24XX) += spi-s3c24xx-hw.o spi-s3c24xx-hw-y := spi-s3c24xx.o diff --git a/drivers/spi/spi-rb4xx.c b/drivers/spi/spi-rb4xx.c new file mode 100644 index 0000000..9b449d4 --- /dev/null +++ b/drivers/spi/spi-rb4xx.c @@ -0,0 +1,210 @@ +/* + * SPI controller driver for the Mikrotik RB4xx boards + * + * Copyright (C) 2010 Gabor Juhos + * Copyright (C) 2015 Bert Vermeulen + * + * This file was based on the patches for Linux 2.6.27.39 published by + * MikroTik for their RouterBoard 4xx series devices. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +#include +#include +#include +#include +#include + +#include + +struct rb4xx_spi { + void __iomem *base; + struct clk *clk; +}; + +static inline u32 rb4xx_read(struct rb4xx_spi *rbspi, u32 reg) +{ + return __raw_readl(rbspi->base + reg); +} + +static inline void rb4xx_write(struct rb4xx_spi *rbspi, u32 reg, u32 value) +{ + __raw_writel(value, rbspi->base + reg); +} + +static inline void do_spi_clk(struct rb4xx_spi *rbspi, u32 spi_ioc, int value) +{ + u32 regval; + + regval = spi_ioc; + if (value & BIT(0)) + regval |= AR71XX_SPI_IOC_DO; + + rb4xx_write(rbspi, AR71XX_SPI_REG_IOC, regval); + rb4xx_write(rbspi, AR71XX_SPI_REG_IOC, regval | AR71XX_SPI_IOC_CLK); +} + +static void do_spi_byte(struct rb4xx_spi *rbspi, u32 spi_ioc, u8 byte) +{ + int i; + + for (i = 7; i >= 0; i--) + do_spi_clk(rbspi, spi_ioc, byte >> i); +} + +/* The CS2 pin is used to clock in a second bit per clock cycle. */ +static inline void do_spi_clk_two(struct rb4xx_spi *rbspi, u32 spi_ioc, + u8 value) +{ + u32 regval; + + regval = spi_ioc; + if (value & BIT(1)) + regval |= AR71XX_SPI_IOC_DO; + if (value & BIT(0)) + regval |= AR71XX_SPI_IOC_CS2; + + rb4xx_write(rbspi, AR71XX_SPI_REG_IOC, regval); + rb4xx_write(rbspi, AR71XX_SPI_REG_IOC, regval | AR71XX_SPI_IOC_CLK); +} + +/* Two bits at a time, msb first */ +static void do_spi_byte_two(struct rb4xx_spi *rbspi, u32 spi_ioc, u8 byte) +{ + do_spi_clk_two(rbspi, spi_ioc, byte >> 6); + do_spi_clk_two(rbspi, spi_ioc, byte >> 4); + do_spi_clk_two(rbspi, spi_ioc, byte >> 2); + do_spi_clk_two(rbspi, spi_ioc, byte >> 0); +} + +static void rb4xx_set_cs(struct spi_device *spi, bool enable) +{ + struct rb4xx_spi *rbspi = spi_master_get_devdata(spi->master); + + /* + * Setting CS is done along with bitbanging the actual values, + * since it's all on the same hardware register. However the + * CPLD needs CS deselected after every command. + */ + if (!enable) + rb4xx_write(rbspi, AR71XX_SPI_REG_IOC, + AR71XX_SPI_IOC_CS0 | AR71XX_SPI_IOC_CS1); +} + +static int rb4xx_transfer_one(struct spi_master *master, + struct spi_device *spi, struct spi_transfer *t) +{ + struct rb4xx_spi *rbspi = spi_master_get_devdata(master); + int i; + u32 spi_ioc; + u8 *rx_buf; + const u8 *tx_buf; + + /* + * Prime the SPI register with the SPI device selected. The m25p80 boot + * flash and CPLD share the CS0 pin. This works because the CPLD's + * command set was designed to almost not clash with that of the + * boot flash. + */ + if (spi->chip_select == 2) + /* MMC */ + spi_ioc = AR71XX_SPI_IOC_CS0; + else + /* Boot flash and CPLD */ + spi_ioc = AR71XX_SPI_IOC_CS1; + + tx_buf = t->tx_buf; + rx_buf = t->rx_buf; + for (i = 0; i < t->len; ++i) { + if (t->tx_nbits == SPI_NBITS_DUAL) + /* CPLD can use two-wire transfers */ + do_spi_byte_two(rbspi, spi_ioc, tx_buf[i]); + else + do_spi_byte(rbspi, spi_ioc, tx_buf[i]); + if (!rx_buf) + continue; + rx_buf[i] = rb4xx_read(rbspi, AR71XX_SPI_REG_RDS); + } + spi_finalize_current_transfer(master); + + return 0; +} + +static int rb4xx_spi_probe(struct platform_device *pdev) +{ + struct spi_master *master; + struct clk *ahb_clk; + struct rb4xx_spi *rbspi; + struct resource *r; + int err; + void __iomem *spi_base; + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + spi_base = devm_ioremap_resource(&pdev->dev, r); + if (!spi_base) + return PTR_ERR(spi_base); + + master = spi_alloc_master(&pdev->dev, sizeof(*rbspi)); + if (!master) + return -ENOMEM; + + ahb_clk = devm_clk_get(&pdev->dev, "ahb"); + if (IS_ERR(ahb_clk)) + return PTR_ERR(ahb_clk); + + master->bus_num = 0; + master->num_chipselect = 3; + master->mode_bits = SPI_TX_DUAL; + master->bits_per_word_mask = BIT(7); + master->flags = SPI_MASTER_MUST_TX; + master->transfer_one = rb4xx_transfer_one; + master->set_cs = rb4xx_set_cs; + + err = devm_spi_register_master(&pdev->dev, master); + if (err) { + dev_err(&pdev->dev, "failed to register SPI master\n"); + return err; + } + + err = clk_prepare_enable(ahb_clk); + if (err) + return err; + + rbspi = spi_master_get_devdata(master); + rbspi->base = spi_base; + rbspi->clk = ahb_clk; + platform_set_drvdata(pdev, rbspi); + + /* Enable SPI */ + rb4xx_write(rbspi, AR71XX_SPI_REG_FS, AR71XX_SPI_FS_GPIO); + + return 0; +} + +static int rb4xx_spi_remove(struct platform_device *pdev) +{ + struct rb4xx_spi *rbspi = platform_get_drvdata(pdev); + + clk_disable_unprepare(rbspi->clk); + + return 0; +} + +static struct platform_driver rb4xx_spi_drv = { + .probe = rb4xx_spi_probe, + .remove = rb4xx_spi_remove, + .driver = { + .name = "rb4xx-spi", + }, +}; + +module_platform_driver(rb4xx_spi_drv); + +MODULE_DESCRIPTION("Mikrotik RB4xx SPI controller driver"); +MODULE_AUTHOR("Gabor Juhos "); +MODULE_AUTHOR("Bert Vermeulen "); +MODULE_LICENSE("GPL v2");