From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Subject: Re: [PATCH v4 2/2] mfd: flexcom: add a driver for Atmel Flexible Serial Communication Unit Date: Tue, 21 Jul 2015 10:18:45 +0100 Message-ID: <20150721091845.GH3061@x1> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: devicetree@vger.kernel.org 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 o= nce > for all, when the Flexcom is probed, according to the value of the ne= w > "atmel,flexcom-mode" device tree property. >=20 > 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 US= ART > drivers. >=20 > Also the Flexcom embeds FIFOs: the latest patches of the SPI, I2C and > USART drivers take advantage of this new feature. >=20 > 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 >=20 > 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. > =20 > +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 ti= me > + by the probe function of this MFD driver according to a device tr= ee > + 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-$(CONFIG_MFD_SPMI_PMIC) +=3D qcom-spmi-pmic.o > obj-$(CONFIG_TPS65911_COMPARATOR) +=3D tps65911-comparator.o > obj-$(CONFIG_MFD_TPS65090) +=3D tps65090.o > obj-$(CONFIG_MFD_AAT2870_CORE) +=3D aat2870-core.o > +obj-$(CONFIG_MFD_ATMEL_FLEXCOM) +=3D atmel-flexcom.o > obj-$(CONFIG_MFD_ATMEL_HLCDC) +=3D atmel-hlcdc.o > obj-$(CONFIG_MFD_INTEL_MSIC) +=3D intel_msic.o > obj-$(CONFIG_MFD_PALMAS) +=3D 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 mod= ify > + * 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; Would prefer: void __iomem *base; > + unsigned int version, mr; 'mr' is not a good variable name. > + const char *mode; > + int err; > + > + res =3D platform_get_resource(pdev, IORESOURCE_MEM, 0); > + map =3D devm_ioremap_resource(&pdev->dev, res); > + if (IS_ERR(map)) > + return PTR_ERR(map); > + > + clk =3D devm_clk_get(&pdev->dev, NULL); > + if (IS_ERR(clk)) > + return PTR_ERR(clk); > + > + err =3D of_property_read_string(pdev->dev.of_node, > + "atmel,flexcom-mode", &mode); > + if (err) > + return err; > + > + if (!strcmp(mode, "usart")) > + mr =3D FX_MR_USART; > + else if (!strcmp(mode, "spi")) > + mr =3D FX_MR_SPI; > + else if (!strcmp(mode, "twi") || !strcmp(mode, "i2c")) > + mr =3D FX_MR_TWI; > + else > + return -EINVAL; Just use a numerical constant in the DT, then you can of_property_read_u32(np, "atmel,flexcom-mode", &mr); Although, hopefully you'll rename 'mr' to be something more forthcoming. > + err =3D clk_prepare_enable(clk); > + if (err) > + return err; '\n' here. > + version =3D readl(map + FX_VERSION); > + writel(mr, map + FX_MR); '\n' here. > + clk_disable_unprepare(clk); > + > + dev_info(&pdev->dev, "version: %#x, mode: %s\n", version, mode); How important is it to clog up the bootlog and slow down boot with this stuff? > + return of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->d= ev); > +} > + > +static const struct of_device_id atmel_flexcom_of_match[] =3D { > + { .compatible =3D "atmel,sama5d2-flexcom" }, > + { /* sentinel */ } > +}; > +MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match); > + > +static struct platform_driver atmel_flexcom_driver =3D { > + .driver =3D { > + .name =3D "atmel_flexcom", > + .of_match_table =3D atmel_flexcom_of_match, > + }, > + .probe =3D atmel_flexcom_probe, > +}; > + > +module_platform_driver(atmel_flexcom_driver); > + > +MODULE_AUTHOR("Cyrille Pitchen "); > +MODULE_DESCRIPTION("Atmel Flexcom MFD driver"); > +MODULE_LICENSE("GPL"); --=20 Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org =E2=94=82 Open source software for ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog