[PATCH v2 0/2] mfd: flexcom: add a driver for Flexcom

[PATCH v2 0/2] mfd: flexcom: add a driver for Flexcom

[Cyrille Pitchen]

ChangeLog

v2:
- enhance the documentation of DT bindings and change the way the "ranges"
  property is used.
- replace __raw_readl() and __raw_writel() by readl() and writel().
- change the module license to "GPL" for v2 or later
- print the selected flexcom mode after the hardware version

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      | 58 +++++++++++++
 drivers/mfd/Kconfig                                | 11 +++
 drivers/mfd/Makefile                               |  1 +
 drivers/mfd/atmel-flexcom.c                        | 97 ++++++++++++++++++++++
 4 files changed, 167 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mfd/atmel-flexcom.txt
 create mode 100644 drivers/mfd/atmel-flexcom.c

-- 
1.8.2.2

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[PATCH v2 1/2] mfd: devicetree: add bindings for Atmel Flexcom

[Cyrille Pitchen]

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
---
 .../devicetree/bindings/mfd/atmel-flexcom.txt      | 58 ++++++++++++++++++++++
 1 file changed, 58 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..38f0e43
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/atmel-flexcom.txt
@@ -0,0 +1,58 @@
+* 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: one range for the full I/O register region (including USART, TWI and
+  SPI registers)
+- atmel,flexcom-mode: shall be a string among { "spi", "usart", "i2c", "twi" }.
+  "i2c" and "twi" are synonymous.
+
+Required child:
+a child device of type matching the "atmel,flexcom-mode" property.
+The reg property of this child should be:
+- <0x200 0x200> for USART
+- <0x400 0x200> for SPI
+- <0x600 0x200> for I2C
+The phandle provided by the clocks property of the child is the same as one for
+the Flexcom parent.
+Other properties remain unchanged. See documentation of the respective device.
+
+Example:
+
+flx0: flexcom@f8034000 {
+	compatible = "atmel,sama5d2-flexcom";
+	reg = <0xf8034000 0x200>;
+	clocks = <&flx0_clk>;
+	#address-cells = <1>;
+	#size-cells = <1>;
+	ranges = <0x0 0xf8034000 0x800>;
+	atmel,flexcom-mode = "spi";
+
+	spi@f8034400 {
+		compatible = "atmel,at91rm9200-spi";
+		reg = <0x400 0x200>;
+		interrupts = <19 IRQ_TYPE_LEVEL_HIGH 7>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&pinctrl_flx0_ioset1>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		clocks = <&flx0_clk>;
+		clock-names = "spi_clk";
+		atmel,fifo-size = <32>;
+
+		mtd_dataflash@0 {
+			compatible = "atmel,at25f512b";
+			reg = <0>;
+			spi-max-frequency = <20000000>;
+		};
+	};
+};
-- 
1.8.2.2

[PATCH v2 2/2] mfd: flexcom: add a driver for Atmel Flexible Serial Communication Unit

[Cyrille Pitchen]

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 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..fb348d9
--- /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 = readl(map + FX_VERSION);
+	writel(mr, map + FX_MR);
+	clk_disable_unprepare(clk);
+
+	dev_info(&pdev->dev, "hw 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");
+MODULE_ALIAS("platform:atmel_flexcom");
-- 
1.8.2.2

Re: [PATCH v2 2/2] mfd: flexcom: add a driver for Atmel Flexible Serial Communication Unit

[Paul Bolle]

On Thu, 2015-06-18 at 15:05 +0200, Cyrille Pitchen wrote:
> --- /dev/null
> +++ b/drivers/mfd/atmel-flexcom.c

> +MODULE_ALIAS("platform:atmel_flexcom");

(The day before yesterday and yesterday I had a, well, lively
conversation regarding this macro. The interesting bits start at
https://lkml.org/lkml/2015/6/17/383 . Let's see how things go here.)

As I understand it, this alias is only useful if there's a corresponding
struct platform_device, somewhere. Ie, this alias implies a
platform_device that will fire of a "MODALIAS=platform:atmel_flexcom"
uevent when it's created. That would be a platform_device using a
"atmel_flexcom" name.

If that's correct, then I think this MODULE_ALIAS macro isn't needed
here, as I couldn't find a platform_device using that name. (But perhaps
a patch that adds it is pending, somewhere.)

Thanks,


Paul Bolle

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Re: [PATCH v2 0/2] mfd: flexcom: add a driver for Flexcom

[Boris Brezillon]

On Thu, 18 Jun 2015 15:05:08 +0200
Cyrille Pitchen <cyrille.pitchen@atmel.com> wrote:

> ChangeLog
> 
> v2:
> - enhance the documentation of DT bindings and change the way the "ranges"
>   property is used.
> - replace __raw_readl() and __raw_writel() by readl() and writel().
> - change the module license to "GPL" for v2 or later
> - print the selected flexcom mode after the hardware version
> 
> 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.

For the whole series,

Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>

> 
> 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      | 58 +++++++++++++
>  drivers/mfd/Kconfig                                | 11 +++
>  drivers/mfd/Makefile                               |  1 +
>  drivers/mfd/atmel-flexcom.c                        | 97 ++++++++++++++++++++++
>  4 files changed, 167 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mfd/atmel-flexcom.txt
>  create mode 100644 drivers/mfd/atmel-flexcom.c
> 



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Embedded Linux and Kernel engineering
http://free-electrons.com

Re: [PATCH v2 0/2] mfd: flexcom: add a driver for Flexcom

[Alexandre Belloni]

On 18/06/2015 at 15:05:08 +0200, Cyrille Pitchen wrote :
> ChangeLog
> 
> v2:
> - enhance the documentation of DT bindings and change the way the "ranges"
>   property is used.
> - replace __raw_readl() and __raw_writel() by readl() and writel().
> - change the module license to "GPL" for v2 or later
> - print the selected flexcom mode after the hardware version
> 
> 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.
> 

For the whole set:
Acked-by: Alexandre Belloni <alexandre.belloni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>


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