| Message ID | dddf7a6d750967785255733a7931780b3c465d5f.1434967670.git.cyrille.pitchen@atmel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 <cyrille.pitchen@atmel.com> > Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com> > Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> > --- > 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 <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; > + > + 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 <cyrille.pitchen@atmel.com>"); > +MODULE_DESCRIPTION("Atmel Flexcom MFD driver"); > +MODULE_LICENSE("GPL");
Hi lee, Le 24/06/2015 16:24, Lee Jones a écrit : > 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. > The main idea of this patch was to hide the Flexcom overlay from the 3 serial drivers. The Flexcom is a kind of muxer which selects one of the 3 IPs: it doesn't change the internal of the IPs. For instance, on sama5d2x SoCs, some SPI controlers are still standalone whereas others are wrapped by a Flexcom but all these SPI controllers share the same IP version. Also, the Flexcom has its own I/O range. Especially, the Flexcom Mode Register which selects the active peripheral is outside the I/O ranges of the SPI, I2C or USART IPs. The active peripheral must be selected first then its driver can access its I/O registers but registers of the other inactive peripherals are still unavailable and would be read as zero since their peripherals are still disabled. That's why the very first version of the driver presented the Flexcom as a clock because most peripherals can't be used before enabling their clock. However the Flexcom is not an actual clock so I was told that it would be better to introduce the Flexcom as an MFD. The idea is to separate the serial controller drivers and the Flexcom driver the same way as a clock driver and a pin controller driver are separated from the driver of a peripheral which uses them. Best Regards, Cyrille
Hi all, based on my previous mail, do someone have any idea on how to add support to the Flexcom in the kernel ? We would like to manage the Flexcom separately so we avoid patching 3 existing drivers. Indeed, their associated devices have no need to know whether they're wrapped or not by a Flexcom: the Flexcom itself has no functional impact on the serial controllers it contains. Also, hiding the additional layer of the Flexcom from the USART, SPI and I2C drivers would ease their maintenance: it keeps the design of each IP independent from the others so it would be more easy to add support to future features. Best Regards, Cyrille Le 25/06/2015 12:11, Cyrille Pitchen a écrit : > Hi lee, > > Le 24/06/2015 16:24, Lee Jones a écrit : >> 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. >> > > The main idea of this patch was to hide the Flexcom overlay from the 3 serial > drivers. The Flexcom is a kind of muxer which selects one of the 3 IPs: it > doesn't change the internal of the IPs. For instance, on sama5d2x SoCs, > some SPI controlers are still standalone whereas others are wrapped by a > Flexcom but all these SPI controllers share the same IP version. > > Also, the Flexcom has its own I/O range. Especially, the Flexcom Mode Register > which selects the active peripheral is outside the I/O ranges of the SPI, I2C > or USART IPs. > > The active peripheral must be selected first then its driver can access its I/O > registers but registers of the other inactive peripherals are still unavailable > and would be read as zero since their peripherals are still disabled. > That's why the very first version of the driver presented the Flexcom as a > clock because most peripherals can't be used before enabling their clock. > However the Flexcom is not an actual clock so I was told that it would be > better to introduce the Flexcom as an MFD. > > The idea is to separate the serial controller drivers and the Flexcom driver > the same way as a clock driver and a pin controller driver are separated from > the driver of a peripheral which uses them. > > > Best Regards, > > Cyrille > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
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. > > 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> > Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com> > Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> > --- > 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 <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; Would prefer: void __iomem *base; > + unsigned int version, mr; 'mr' is not a good variable name. > + 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; 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 = clk_prepare_enable(clk); > + if (err) > + return err; '\n' here. > + version = 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->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");
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 <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; + + 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 <cyrille.pitchen@atmel.com>"); +MODULE_DESCRIPTION("Atmel Flexcom MFD driver"); +MODULE_LICENSE("GPL");