Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753546AbbFXOZG (ORCPT ); Wed, 24 Jun 2015 10:25:06 -0400 Received: from mail-wi0-f181.google.com ([209.85.212.181]:36890 "EHLO mail-wi0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752877AbbFXOZB (ORCPT ); Wed, 24 Jun 2015 10:25:01 -0400 Date: Wed, 24 Jun 2015 15:24:56 +0100 From: Lee Jones To: Cyrille Pitchen Cc: nicolas.ferre@atmel.com, boris.brezillon@free-electrons.com, alexandre.belloni@free-electrons.com, sameo@linux.intel.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, devicetree@vger.kernel.org Subject: Re: [PATCH v4 2/2] mfd: flexcom: add a driver for Atmel Flexible Serial Communication Unit Message-ID: <20150624142456.GS15013@x1> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6109 Lines: 182 On Mon, 22 Jun 2015, Cyrille Pitchen wrote: > This driver supports the new Atmel Flexcom. The Flexcom is a wrapper which > integrates one SPI controller, one I2C controller and one USART. Only one > function can be enabled at a time. This driver selects the function once > for all, when the Flexcom is probed, according to the value of the new > "atmel,flexcom-mode" device tree property. > > This driver has chosen to present the Flexcom to the system as a MFD so > the implementation is seamless for the existing Atmel SPI, I2C and USART > drivers. No need for this driver. Just create your 3 platform drivers and get them to read the mode at probe time. If the mode isn't the one pertaining to itself return -ENODEV and the Device Driver API will attempt the probe the next device. Ensure all of the devices have the same compatible string i.e. atmel,sama5d2-flexcom. > Also the Flexcom embeds FIFOs: the latest patches of the SPI, I2C and > USART drivers take advantage of this new feature. > > Signed-off-by: Cyrille Pitchen > Acked-by: Boris Brezillon > Acked-by: Alexandre Belloni > --- > drivers/mfd/Kconfig | 11 +++++ > drivers/mfd/Makefile | 1 + > drivers/mfd/atmel-flexcom.c | 98 +++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 110 insertions(+) > create mode 100644 drivers/mfd/atmel-flexcom.c > > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig > index d5ad04d..9b33ad0 100644 > --- a/drivers/mfd/Kconfig > +++ b/drivers/mfd/Kconfig > @@ -59,6 +59,17 @@ config MFD_AAT2870_CORE > additional drivers must be enabled in order to use the > functionality of the device. > > +config MFD_ATMEL_FLEXCOM > + tristate "Atmel Flexcom (Flexible Serial Communication Unit)" > + select MFD_CORE > + depends on OF > + help > + Select this to get support for Atmel Flexcom. This is a wrapper > + which embeds a SPI controller, a I2C controller and a USART. Only > + one function can be used at a time. The choice is done at boot time > + by the probe function of this MFD driver according to a device tree > + property. > + > config MFD_ATMEL_HLCDC > tristate "Atmel HLCDC (High-end LCD Controller)" > select MFD_CORE > diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile > index 0e5cfeb..c666bf5 100644 > --- a/drivers/mfd/Makefile > +++ b/drivers/mfd/Makefile > @@ -160,6 +160,7 @@ obj-$(CONFIG_MFD_SPMI_PMIC) += qcom-spmi-pmic.o > obj-$(CONFIG_TPS65911_COMPARATOR) += tps65911-comparator.o > obj-$(CONFIG_MFD_TPS65090) += tps65090.o > obj-$(CONFIG_MFD_AAT2870_CORE) += aat2870-core.o > +obj-$(CONFIG_MFD_ATMEL_FLEXCOM) += atmel-flexcom.o > obj-$(CONFIG_MFD_ATMEL_HLCDC) += atmel-hlcdc.o > obj-$(CONFIG_MFD_INTEL_MSIC) += intel_msic.o > obj-$(CONFIG_MFD_PALMAS) += palmas.o > diff --git a/drivers/mfd/atmel-flexcom.c b/drivers/mfd/atmel-flexcom.c > new file mode 100644 > index 0000000..7e7d4b8 > --- /dev/null > +++ b/drivers/mfd/atmel-flexcom.c > @@ -0,0 +1,98 @@ > +/* > + * Driver for Atmel Flexcom > + * > + * Copyright (C) 2015 Atmel Corporation > + * > + * Author: Cyrille Pitchen > + * > + * 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. > + * > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define FX_MR 0x0 > +#define FX_RHR 0x10 > +#define FX_THR 0x20 > +#define FX_VERSION 0xfc > + > +#define FX_MR_NO_COM 0 > +#define FX_MR_USART 1 > +#define FX_MR_SPI 2 > +#define FX_MR_TWI 3 > + > + > +static int atmel_flexcom_probe(struct platform_device *pdev) > +{ > + struct clk *clk; > + struct resource *res; > + unsigned char __iomem *map; > + unsigned int version, mr; > + const char *mode; > + int err; > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + map = devm_ioremap_resource(&pdev->dev, res); > + if (IS_ERR(map)) > + return PTR_ERR(map); > + > + clk = devm_clk_get(&pdev->dev, NULL); > + if (IS_ERR(clk)) > + return PTR_ERR(clk); > + > + err = of_property_read_string(pdev->dev.of_node, > + "atmel,flexcom-mode", &mode); > + if (err) > + return err; > + > + if (!strcmp(mode, "usart")) > + mr = FX_MR_USART; > + else if (!strcmp(mode, "spi")) > + mr = FX_MR_SPI; > + else if (!strcmp(mode, "twi") || !strcmp(mode, "i2c")) > + mr = FX_MR_TWI; > + else > + return -EINVAL; > + > + err = clk_prepare_enable(clk); > + if (err) > + return err; > + version = readl(map + FX_VERSION); > + writel(mr, map + FX_MR); > + clk_disable_unprepare(clk); > + > + dev_info(&pdev->dev, "version: %#x, mode: %s\n", version, mode); > + > + return of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev); > +} > + > +static const struct of_device_id atmel_flexcom_of_match[] = { > + { .compatible = "atmel,sama5d2-flexcom" }, > + { /* sentinel */ } > +}; > +MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match); > + > +static struct platform_driver atmel_flexcom_driver = { > + .driver = { > + .name = "atmel_flexcom", > + .of_match_table = atmel_flexcom_of_match, > + }, > + .probe = atmel_flexcom_probe, > +}; > + > +module_platform_driver(atmel_flexcom_driver); > + > +MODULE_AUTHOR("Cyrille Pitchen "); > +MODULE_DESCRIPTION("Atmel Flexcom MFD driver"); > +MODULE_LICENSE("GPL"); -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/