From patchwork Wed Feb 24 04:15:55 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 8399341 Return-Path: X-Original-To: patchwork-linux-spi@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 18F15C0553 for ; Wed, 24 Feb 2016 04:16:53 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id CAFC72034C for ; Wed, 24 Feb 2016 04:16:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 64BE02012E for ; Wed, 24 Feb 2016 04:16:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932428AbcBXEQe (ORCPT ); Tue, 23 Feb 2016 23:16:34 -0500 Received: from mezzanine.sirena.org.uk ([106.187.55.193]:59972 "EHLO mezzanine.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932299AbcBXEQP (ORCPT ); Tue, 23 Feb 2016 23:16:15 -0500 Received: from [175.126.181.164] (helo=finisterre) by mezzanine.sirena.org.uk with esmtpsa (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.80) (envelope-from ) id 1aYQrk-0002hj-Vn; Wed, 24 Feb 2016 04:15:57 +0000 Received: from broonie by finisterre with local (Exim 4.86) (envelope-from ) id 1aYQrj-000110-6S; Wed, 24 Feb 2016 13:15:55 +0900 From: Mark Brown To: Sergei Ianovich , Rob Herring , Mark Brown Cc: linux-spi@vger.kernel.org In-Reply-To: <1456224272-4391-1-git-send-email-ynvich@gmail.com> Message-Id: Date: Wed, 24 Feb 2016 13:15:55 +0900 X-SA-Exim-Connect-IP: 175.126.181.164 X-SA-Exim-Mail-From: broonie@sirena.org.uk 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, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Subject: Applied "spi: master driver to enable RTC on ICPDAS LP-8841" to the spi tree X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on mezzanine.sirena.org.uk) 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 The patch spi: master driver to enable RTC on ICPDAS LP-8841 has been applied to the spi tree at git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted. You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed. If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced. Please add any relevant lists and maintainers to the CCs when replying to this mail. Thanks, Mark From 7ecbfff6711fb331591003ac32c002ce55a0758f Mon Sep 17 00:00:00 2001 From: Sergei Ianovich Date: Tue, 23 Feb 2016 13:44:28 +0300 Subject: [PATCH] spi: master driver to enable RTC on ICPDAS LP-8841 ICP DAS LP-8841 contains a DS-1302 RTC. This driver provides an SPI master which makes the RTC usable. The driver is not supposed to work with anything else. The driver uses the standard MicroWire half-duplex transfer timing. Master output is set on low clock and sensed by the RTC on the rising edge. Master input is set by the RTC on the trailing edge and is sensed by the master on low clock. Signed-off-by: Sergei Ianovich Acked-by: Rob Herring Signed-off-by: Mark Brown --- .../bindings/spi/icpdas-lp8841-spi-rtc.txt | 54 +++++ drivers/spi/Kconfig | 10 + drivers/spi/Makefile | 1 + drivers/spi/spi-lp8841-rtc.c | 255 +++++++++++++++++++++ 4 files changed, 320 insertions(+) create mode 100644 Documentation/devicetree/bindings/spi/icpdas-lp8841-spi-rtc.txt create mode 100644 drivers/spi/spi-lp8841-rtc.c diff --git a/Documentation/devicetree/bindings/spi/icpdas-lp8841-spi-rtc.txt b/Documentation/devicetree/bindings/spi/icpdas-lp8841-spi-rtc.txt new file mode 100644 index 000000000000..852b651f3bc5 --- /dev/null +++ b/Documentation/devicetree/bindings/spi/icpdas-lp8841-spi-rtc.txt @@ -0,0 +1,54 @@ +* ICP DAS LP-8841 SPI Controller for RTC + +ICP DAS LP-8841 contains a DS-1302 RTC. RTC is connected to an IO +memory register, which acts as an SPI master device. + +The device uses the standard MicroWire half-duplex transfer timing. +Master output is set on low clock and sensed by the RTC on the rising +edge. Master input is set by the RTC on the trailing edge and is sensed +by the master on low clock. + +Required properties: + +- #address-cells: should be 1 + +- #size-cells: should be 0 + +- compatible: should be "icpdas,lp8841-spi-rtc" + +- reg: should provide IO memory address + +Requirements to SPI slave nodes: + +- There can be only one slave device. + +- The spi slave node should claim the following flags which are + required by the spi controller. + + - spi-3wire: The master itself has only 3 wire. It cannor work in + full duplex mode. + + - spi-cs-high: DS-1302 has active high chip select line. The master + doesn't support active low. + + - spi-lsb-first: DS-1302 requires least significant bit first + transfers. The master only support this type of bit ordering. + + +Example: + +spi@901c { + #address-cells = <1>; + #size-cells = <0>; + compatible = "icpdas,lp8841-spi-rtc"; + reg = <0x901c 0x1>; + + rtc@0 { + compatible = "maxim,ds1302"; + reg = <0>; + spi-max-frequency = <500000>; + spi-3wire; + spi-lsb-first; + spi-cs-high; + }; +}; diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index 77064160dd76..1206a6651e70 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -271,6 +271,16 @@ config SPI_LM70_LLP which interfaces to an LM70 temperature sensor using a parallel port. +config SPI_LP8841_RTC + tristate "ICP DAS LP-8841 SPI Controller for RTC" + depends on MACH_PXA27X_DT || COMPILE_TEST + help + This driver provides an SPI master device to drive Maxim + DS-1302 real time clock. + + Say N here unless you plan to run the kernel on an ICP DAS + LP-8x4x industrial computer. + config SPI_MPC52xx tristate "Freescale MPC52xx SPI (non-PSC) controller support" depends on PPC_MPC52xx diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index 8991ffce6e12..9d10ddc1c51f 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -46,6 +46,7 @@ obj-$(CONFIG_SPI_GPIO) += spi-gpio.o obj-$(CONFIG_SPI_IMG_SPFI) += spi-img-spfi.o obj-$(CONFIG_SPI_IMX) += spi-imx.o obj-$(CONFIG_SPI_LM70_LLP) += spi-lm70llp.o +obj-$(CONFIG_SPI_LP8841_RTC) += spi-lp8841-rtc.o obj-$(CONFIG_SPI_MESON_SPIFC) += spi-meson-spifc.o obj-$(CONFIG_SPI_MPC512x_PSC) += spi-mpc512x-psc.o obj-$(CONFIG_SPI_MPC52xx_PSC) += spi-mpc52xx-psc.o diff --git a/drivers/spi/spi-lp8841-rtc.c b/drivers/spi/spi-lp8841-rtc.c new file mode 100644 index 000000000000..44bb69c3f1d6 --- /dev/null +++ b/drivers/spi/spi-lp8841-rtc.c @@ -0,0 +1,255 @@ +/* + * SPI master driver for ICP DAS LP-8841 RTC + * + * Copyright (C) 2016 Sergei Ianovich + * + * based on + * + * Dallas DS1302 RTC Support + * Copyright (C) 2002 David McCullough + * Copyright (C) 2003 - 2007 Paul Mundt + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ +#include +#include +#include +#include +#include +#include +#include + +#define DRIVER_NAME "spi_lp8841_rtc" + +#define SPI_LP8841_RTC_CE 0x01 +#define SPI_LP8841_RTC_CLK 0x02 +#define SPI_LP8841_RTC_nWE 0x04 +#define SPI_LP8841_RTC_MOSI 0x08 +#define SPI_LP8841_RTC_MISO 0x01 + +/* + * REVISIT If there is support for SPI_3WIRE and SPI_LSB_FIRST in SPI + * GPIO driver, this SPI driver can be replaced by a simple GPIO driver + * providing 3 GPIO pins. + */ + +struct spi_lp8841_rtc { + void *iomem; + unsigned long state; +}; + +static inline void +setsck(struct spi_lp8841_rtc *data, int is_on) +{ + if (is_on) + data->state |= SPI_LP8841_RTC_CLK; + else + data->state &= ~SPI_LP8841_RTC_CLK; + writeb(data->state, data->iomem); +} + +static inline void +setmosi(struct spi_lp8841_rtc *data, int is_on) +{ + if (is_on) + data->state |= SPI_LP8841_RTC_MOSI; + else + data->state &= ~SPI_LP8841_RTC_MOSI; + writeb(data->state, data->iomem); +} + +static inline int +getmiso(struct spi_lp8841_rtc *data) +{ + return ioread8(data->iomem) & SPI_LP8841_RTC_MISO; +} + +static inline u32 +bitbang_txrx_be_cpha0_lsb(struct spi_lp8841_rtc *data, + unsigned usecs, unsigned cpol, unsigned flags, + u32 word, u8 bits) +{ + /* if (cpol == 0) this is SPI_MODE_0; else this is SPI_MODE_2 */ + + u32 shift = 32 - bits; + /* clock starts at inactive polarity */ + for (; likely(bits); bits--) { + + /* setup LSB (to slave) on leading edge */ + if ((flags & SPI_MASTER_NO_TX) == 0) + setmosi(data, (word & 1)); + + usleep_range(usecs, usecs + 1); /* T(setup) */ + + /* sample LSB (from slave) on trailing edge */ + word >>= 1; + if ((flags & SPI_MASTER_NO_RX) == 0) + word |= (getmiso(data) << 31); + + setsck(data, !cpol); + usleep_range(usecs, usecs + 1); + + setsck(data, cpol); + } + + word >>= shift; + return word; +} + +static int +spi_lp8841_rtc_transfer_one(struct spi_master *master, + struct spi_device *spi, + struct spi_transfer *t) +{ + struct spi_lp8841_rtc *data = spi_master_get_devdata(master); + unsigned count = t->len; + const u8 *tx = t->tx_buf; + u8 *rx = t->rx_buf; + u8 word = 0; + int ret = 0; + + if (tx) { + data->state &= ~SPI_LP8841_RTC_nWE; + writeb(data->state, data->iomem); + while (likely(count > 0)) { + word = *tx++; + bitbang_txrx_be_cpha0_lsb(data, 1, 0, + SPI_MASTER_NO_RX, word, 8); + count--; + } + } else if (rx) { + data->state |= SPI_LP8841_RTC_nWE; + writeb(data->state, data->iomem); + while (likely(count > 0)) { + word = bitbang_txrx_be_cpha0_lsb(data, 1, 0, + SPI_MASTER_NO_TX, word, 8); + *rx++ = word; + count--; + } + } else { + ret = -EINVAL; + } + + spi_finalize_current_transfer(master); + + return ret; +} + +static void +spi_lp8841_rtc_set_cs(struct spi_device *spi, bool enable) +{ + struct spi_lp8841_rtc *data = spi_master_get_devdata(spi->master); + + data->state = 0; + writeb(data->state, data->iomem); + if (enable) { + usleep_range(4, 5); + data->state |= SPI_LP8841_RTC_CE; + writeb(data->state, data->iomem); + usleep_range(4, 5); + } +} + +static int +spi_lp8841_rtc_setup(struct spi_device *spi) +{ + if ((spi->mode & SPI_CS_HIGH) == 0) { + dev_err(&spi->dev, "unsupported active low chip select\n"); + return -EINVAL; + } + + if ((spi->mode & SPI_LSB_FIRST) == 0) { + dev_err(&spi->dev, "unsupported MSB first mode\n"); + return -EINVAL; + } + + if ((spi->mode & SPI_3WIRE) == 0) { + dev_err(&spi->dev, "unsupported wiring. 3 wires required\n"); + return -EINVAL; + } + + return 0; +} + +#ifdef CONFIG_OF +static const struct of_device_id spi_lp8841_rtc_dt_ids[] = { + { .compatible = "icpdas,lp8841-spi-rtc" }, + { } +}; + +MODULE_DEVICE_TABLE(of, spi_lp8841_rtc_dt_ids); +#endif + +static int +spi_lp8841_rtc_probe(struct platform_device *pdev) +{ + int ret; + struct spi_master *master; + struct spi_lp8841_rtc *data; + void *iomem; + + master = spi_alloc_master(&pdev->dev, sizeof(*data)); + if (!master) + return -ENOMEM; + platform_set_drvdata(pdev, master); + + master->flags = SPI_MASTER_HALF_DUPLEX; + master->mode_bits = SPI_CS_HIGH | SPI_3WIRE | SPI_LSB_FIRST; + + master->bus_num = pdev->id; + master->num_chipselect = 1; + master->setup = spi_lp8841_rtc_setup; + master->set_cs = spi_lp8841_rtc_set_cs; + master->transfer_one = spi_lp8841_rtc_transfer_one; + master->bits_per_word_mask = SPI_BPW_MASK(8); +#ifdef CONFIG_OF + master->dev.of_node = pdev->dev.of_node; +#endif + + data = spi_master_get_devdata(master); + + iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0); + data->iomem = devm_ioremap_resource(&pdev->dev, iomem); + if (IS_ERR(data->iomem)) { + dev_err(&pdev->dev, "failed to get IO address\n"); + goto err_put_master; + } + + /* register with the SPI framework */ + ret = devm_spi_register_master(&pdev->dev, master); + if (ret) { + dev_err(&pdev->dev, "cannot register spi master\n"); + goto err_put_master; + } + + return ret; + + +err_put_master: + spi_master_put(master); + + return ret; +} + +MODULE_ALIAS("platform:" DRIVER_NAME); + +static struct platform_driver spi_lp8841_rtc_driver = { + .driver = { + .name = DRIVER_NAME, + .of_match_table = of_match_ptr(spi_lp8841_rtc_dt_ids), + }, + .probe = spi_lp8841_rtc_probe, +}; +module_platform_driver(spi_lp8841_rtc_driver); + +MODULE_DESCRIPTION("SPI master driver for ICP DAS LP-8841 RTC"); +MODULE_AUTHOR("Sergei Ianovich"); +MODULE_LICENSE("GPL");