| Message ID | e85ceae28a0b382b12b809ac7cca891fcb7ac846.1434386119.git.cyrille.pitchen@atmel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, 15 Jun 2015 18:38:05 +0200 Cyrille Pitchen <cyrille.pitchen@atmel.com> 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. > > 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 <cyrille.pitchen@atmel.com> > --- > drivers/mfd/Kconfig | 11 +++++ > drivers/mfd/Makefile | 1 + > drivers/mfd/atmel-flexcom.c | 97 +++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 109 insertions(+) > create mode 100644 drivers/mfd/atmel-flexcom.c > > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig > index aefbbbf..4aebf08 100644 > --- a/drivers/mfd/Kconfig > +++ b/drivers/mfd/Kconfig > @@ -60,6 +60,17 @@ 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 ea40e07..0705eb2 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..14c35e6 > --- /dev/null > +++ b/drivers/mfd/atmel-flexcom.c > @@ -0,0 +1,97 @@ > +/* > + * Driver for Atmel Flexcom > + * > + * Copyright (C) 2015 Atmel Corporation > + * > + * Author: Cyrille Pitchen <cyrille.pitchen@atmel.com> > + * > + * 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 <linux/module.h> > +#include <linux/types.h> > +#include <linux/kernel.h> > +#include <linux/platform_device.h> > +#include <linux/of.h> > +#include <linux/of_platform.h> > +#include <linux/err.h> > +#include <linux/io.h> > +#include <linux/clk.h> > + > +#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 you take the approach I suggested in the DT binding review, you shouldn't reserve the whole memory region, just the flexcom part(0x0 to 0x200). > + 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; > + > + clk_prepare_enable(clk); > + version = __raw_readl(map + FX_VERSION); > + __raw_writel(mr, map + FX_MR); > + clk_disable_unprepare(clk); Is there a good reason to use the __raw versions of the writel/readl functions ?
Hi, On 15/06/2015 at 18:38:05 +0200, Cyrille Pitchen wrote : > + 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; > + > + clk_prepare_enable(clk); > + version = __raw_readl(map + FX_VERSION); > + __raw_writel(mr, map + FX_MR); > + clk_disable_unprepare(clk); > + > + dev_info(&pdev->dev, "version: %#x\n", version); > + I would also print the selected mode for debugging convenience, especially if this is used with device tree overlays.
Just a nit: a license mismatch. On Mon, 2015-06-15 at 18:38 +0200, Cyrille Pitchen wrote: > --- /dev/null > +++ b/drivers/mfd/atmel-flexcom.c > + * 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 states the license is GPL v2 (or later) > +MODULE_LICENSE("GPL v2"); According to include/linux/module.h this states the license is (just) GPL v2. So I think that either the comment at the top of this file or the ident used in the MODULE_LICENSE() macro needs to change. Thanks, Paul Bolle
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig index aefbbbf..4aebf08 100644 --- a/drivers/mfd/Kconfig +++ b/drivers/mfd/Kconfig @@ -60,6 +60,17 @@ 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 ea40e07..0705eb2 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..14c35e6 --- /dev/null +++ b/drivers/mfd/atmel-flexcom.c @@ -0,0 +1,97 @@ +/* + * Driver for Atmel Flexcom + * + * Copyright (C) 2015 Atmel Corporation + * + * Author: Cyrille Pitchen <cyrille.pitchen@atmel.com> + * + * 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 <linux/module.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/platform_device.h> +#include <linux/of.h> +#include <linux/of_platform.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/clk.h> + +#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; + + clk_prepare_enable(clk); + version = __raw_readl(map + FX_VERSION); + __raw_writel(mr, map + FX_MR); + clk_disable_unprepare(clk); + + dev_info(&pdev->dev, "version: %#x\n", version); + + 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 <cyrille.pitchen@atmel.com>"); +MODULE_DESCRIPTION("Atmel Flexcom MFD driver"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:atmel_flexcom");
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. 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 <cyrille.pitchen@atmel.com> --- drivers/mfd/Kconfig | 11 +++++ drivers/mfd/Makefile | 1 + drivers/mfd/atmel-flexcom.c | 97 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 109 insertions(+) create mode 100644 drivers/mfd/atmel-flexcom.c