ChangeLog
v1:
This series of patches a support to the Atmel Flexcom, a wrapper which
integrates an USART, a SPI controller and a TWI controller. Only one
peripheral can be used at a time. The active function is selected though
the Flexcom Mode Register.
Cyrille Pitchen (2):
mfd: devicetree: add bindings for Atmel Flexcom
mfd: flexcom: add a driver for Atmel Flexible Serial Communication
Unit
.../devicetree/bindings/mfd/atmel-flexcom.txt | 28 +++++++
drivers/mfd/Kconfig | 11 +++
drivers/mfd/Makefile | 1 +
drivers/mfd/atmel-flexcom.c | 97 ++++++++++++++++++++++
4 files changed, 137 insertions(+)
create mode 100644 Documentation/devicetree/bindings/mfd/atmel-flexcom.txt
create mode 100644 drivers/mfd/atmel-flexcom.c
--
1.8.2.2
Signed-off-by: Cyrille Pitchen <[email protected]>
---
.../devicetree/bindings/mfd/atmel-flexcom.txt | 28 ++++++++++++++++++++++
1 file changed, 28 insertions(+)
create mode 100644 Documentation/devicetree/bindings/mfd/atmel-flexcom.txt
diff --git a/Documentation/devicetree/bindings/mfd/atmel-flexcom.txt b/Documentation/devicetree/bindings/mfd/atmel-flexcom.txt
new file mode 100644
index 0000000..6b1a32e
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/atmel-flexcom.txt
@@ -0,0 +1,28 @@
+* Device tree bindings for Atmel Flexcom (Flexible Serial Communication Unit)
+
+The Atmel Flexcom is just a wrapper which embeds a SPI controller, an I2C
+controller and an USART. Only one function can be used at a time and is chosen
+at boot time according to the device tree.
+
+Required properties:
+- compatible: "atmel,sama5d2-flexcom"
+- reg: shall be the offset/length value for Flexcom dedicated I/O registers
+ (without USART, TWI or SPI registers).
+- clocks: shall be the Flexcom peripheral clock from PMC.
+- #address-cells: should be <1>
+- #size-cells: should be <1>
+- ranges: must be present
+- atmel,flexcom-mode: shall be a string among { "spi", "usart", "i2c", "twi" }.
+ "i2c" and "twi" are synonymous.
+
+Example:
+
+flx0: flexcom@f8034000 {
+ compatible = "atmel,sama5d2-flexcom";
+ reg = <0xf8034000 0x200>;
+ clocks = <&flx0_clk>;
+ #address-cells = <1>;
+ #size-cells = <1>;
+ ranges;
+ atmel,flexcom-mode = "spi";
+};
--
1.8.2.2
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 <[email protected]>
---
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 <[email protected]>
+ *
+ * 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 <[email protected]>");
+MODULE_DESCRIPTION("Atmel Flexcom MFD driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:atmel_flexcom");
--
1.8.2.2
Hi Cyrille,
On Mon, 15 Jun 2015 18:38:04 +0200
Cyrille Pitchen <[email protected]> wrote:
> Signed-off-by: Cyrille Pitchen <[email protected]>
> ---
> .../devicetree/bindings/mfd/atmel-flexcom.txt | 28 ++++++++++++++++++++++
> 1 file changed, 28 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/mfd/atmel-flexcom.txt
>
> diff --git a/Documentation/devicetree/bindings/mfd/atmel-flexcom.txt b/Documentation/devicetree/bindings/mfd/atmel-flexcom.txt
> new file mode 100644
> index 0000000..6b1a32e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mfd/atmel-flexcom.txt
> @@ -0,0 +1,28 @@
> +* Device tree bindings for Atmel Flexcom (Flexible Serial Communication Unit)
> +
> +The Atmel Flexcom is just a wrapper which embeds a SPI controller, an I2C
> +controller and an USART. Only one function can be used at a time and is chosen
> +at boot time according to the device tree.
> +
> +Required properties:
> +- compatible: "atmel,sama5d2-flexcom"
> +- reg: shall be the offset/length value for Flexcom dedicated I/O registers
> + (without USART, TWI or SPI registers).
> +- clocks: shall be the Flexcom peripheral clock from PMC.
> +- #address-cells: should be <1>
> +- #size-cells: should be <1>
> +- ranges: must be present
> +- atmel,flexcom-mode: shall be a string among { "spi", "usart", "i2c", "twi" }.
> + "i2c" and "twi" are synonymous.
> +
> +Example:
> +
> +flx0: flexcom@f8034000 {
> + compatible = "atmel,sama5d2-flexcom";
> + reg = <0xf8034000 0x200>;
> + clocks = <&flx0_clk>;
> + #address-cells = <1>;
> + #size-cells = <1>;
> + ranges;
> + atmel,flexcom-mode = "spi";
> +};
Since the subdevices are using a set of registers contained by the
flexcom device I would define it like this:
flx0: flexcom@f8034000 {
compatible = "atmel,sama5d2-flexcom";
reg = <0xf8034000 0x800>;
clocks = <&flx0_clk>;
#address-cells = <1>;
#size-cells = <1>;
ranges = <0x0 0xf8034000 0x800>;
atmel,flexcom-mode = "spi";
usart@200 {
reg = <0x200 0x100>;
/* ... */
};
spi@400 {
reg = <0x400 0x100>;
/* ... */
};
i2c@600 {
reg = <0x600 0x100>;
/* ... */
};
};
Best Regards,
Boris
--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
On Mon, 15 Jun 2015 18:38:05 +0200
Cyrille Pitchen <[email protected]> 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 <[email protected]>
> ---
> 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 <[email protected]>
> + *
> + * 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 ?
--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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.
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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