[PATCH 1/6] drivers: bus: add a new driver for WEIM

[PATCH 1/6] drivers: bus: add a new driver for WEIM

[Huang Shijie]

The WEIM(Wireless External Interface Module) works like a bus.
You can attach many different devices on it, such as NOR, onenand.

In the case of i.MX6q-sabreauto, the NOR is connected to WEIM.

This patch also adds the devicetree binding document.
The driver only works when the devicetree is enabled.

Signed-off-by: Huang Shijie <b32955@freescale.com>
---
 Documentation/devicetree/bindings/bus/imx-weim.txt |   69 +++++++++
 drivers/bus/Kconfig                                |    9 ++
 drivers/bus/Makefile                               |    1 +
 drivers/bus/imx-weim.c                             |  145 ++++++++++++++++++++
 4 files changed, 224 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/bus/imx-weim.txt
 create mode 100644 drivers/bus/imx-weim.c

diff --git a/Documentation/devicetree/bindings/bus/imx-weim.txt b/Documentation/devicetree/bindings/bus/imx-weim.txt
new file mode 100644
index 0000000..9913454
--- /dev/null
+++ b/Documentation/devicetree/bindings/bus/imx-weim.txt
@@ -0,0 +1,69 @@
+Device tree bindings for i.MX Wireless External Interface Module (WEIM)
+
+The term “wireless” does not imply that the WEIM is literally an interface
+without wires. It simply means that this module was originally designed for
+wireless and mobile applications that use low-power technology.
+
+The actual devices are instantiated from the child nodes of a WEIM node.
+But now we only have the NOR device.
+
+NOR flash connected to the WEIM (found on i.MX boards) are represented as
+child nodes with a name of "nor".
+
+Required properties:
+
+ - compatible:		Should be set to "fsl, imx6q-weim"
+ - reg:			A resource specifier for the register space
+			(see the example below)
+ - interrupts:		the interrupt number, see the example below.
+ - clocks:		the clock, see the example below.
+ - #address-cells:	Must be set to 2 to allow memory address translation
+ - #size-cells:		Must be set to 1 to allow CS address passing
+ - ranges:		Must be set up to reflect the memory layout with four
+			integer values for each chip-select line in use:
+
+			   <cs-number> 0 <physical address of mapping> <size>
+
+Timing properties for child nodes. All are mandatory, not optional.
+
+ -weim-cs-index:	The CS index which the device is attaching on.
+ -weim-cs-timing:	The timing array, contains 6 timing values for the
+			weim-cs-index.
+
+Example for an i.MX6q-sabreauto board:
+	weim: weim@021b8000 {
+		compatible = "fsl,imx6q-weim";
+		reg = <0x021b8000 0x4000>;
+		interrupts = <0 14 0x04>;
+		clocks = <&clks 196>;
+		#address-cells = <2>;
+		#size-cells = <1>;
+		ranges = <0 0 0x08000000 0x08000000>;
+
+		nor@0,0 {
+			compatible = "cfi-flash";
+			reg = <0 0 0x02000000>;
+			#address-cells = <1>;
+			#size-cells = <1>;
+			bank-width = <2>;
+
+			weim-cs-index = <0>;
+			weim-cs-timing = <0x00620081 0x00000001 0x1C022000
+					0x0000C000 0x1404a38e 0x00000000>;
+			partition@0 {
+				label = "U-Boot";
+				reg = <0x0 0x40000>;
+			};
+
+			partition@40000 {
+				label = "U-Boot-ENV";
+				reg = <0x40000 0x10000>;
+				read-only;
+			};
+
+			partition@50000 {
+				label = "Kernel";
+				reg = <0x50000 0x3b0000>;
+			};
+		};
+	};
diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
index b05ecab..0f997af 100644
--- a/drivers/bus/Kconfig
+++ b/drivers/bus/Kconfig
@@ -4,6 +4,15 @@
 
 menu "Bus devices"
 
+config IMX_WEIM
+	tristate "Freescale EIM DRIVER"
+	depends on ARCH_MXC && MTD_PHYSMAP_OF
+	help
+	  Driver for i.MX6 WEIM controller.
+	  The WEIM(Wireless External Interface Module) works like a bus.
+	  You can attach many different devices on it, such as NOR, onenand.
+	  But now, we only support the Parallel NOR.
+
 config MVEBU_MBUS
 	bool
 	depends on PLAT_ORION
diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile
index 3c7b53c..436bbcc 100644
--- a/drivers/bus/Makefile
+++ b/drivers/bus/Makefile
@@ -2,6 +2,7 @@
 # Makefile for the bus drivers.
 #
 
+obj-$(CONFIG_IMX_WEIM)	+= imx-weim.o
 obj-$(CONFIG_MVEBU_MBUS) += mvebu-mbus.o
 obj-$(CONFIG_OMAP_OCP2SCP)	+= omap-ocp2scp.o
 
diff --git a/drivers/bus/imx-weim.c b/drivers/bus/imx-weim.c
new file mode 100644
index 0000000..8bd9362
--- /dev/null
+++ b/drivers/bus/imx-weim.c
@@ -0,0 +1,145 @@
+/*
+ * EIM driver for Freescale's i.MX chips
+ *
+ * Copyright (C) 2013 Freescale Semiconductor, Inc.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+#include <linux/module.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/of_device.h>
+
+struct imx_weim {
+	void __iomem *base;
+	struct clk *clk;
+};
+
+static const struct of_device_id weim_id_table[] = {
+	{ .compatible = "fsl,imx6q-weim", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, weim_id_table);
+
+#define CS_TIMING_LEN 6
+#define CS_REG_RANGE  0x18
+/* Parse and set the timing for this device. */
+static int weim_timing(struct platform_device *pdev, struct device_node *np)
+{
+	struct imx_weim *weim = platform_get_drvdata(pdev);
+	u32 value[CS_TIMING_LEN];
+	u32 cs_idx;
+	int ret;
+	int i;
+
+	ret = of_property_read_u32(np, "weim-cs-index", &cs_idx);
+	if (ret)
+		goto weim_parse_err;
+
+	ret = of_property_read_u32_array(np, "weim-cs-timing",
+					value, CS_TIMING_LEN);
+	if (ret)
+		goto weim_parse_err;
+
+	/* set the timing for WEIM */
+	for (i = 0; i < CS_TIMING_LEN; i++)
+		writel(value[i], weim->base + cs_idx * CS_REG_RANGE + i * 4);
+	return 0;
+
+weim_parse_err:
+	return ret;
+}
+
+static int weim_parse_dt(struct platform_device *pdev)
+{
+	struct device_node *child;
+	int ret;
+
+	/* We only support the Parallel NOR now. We may add more in future. */
+	child = of_find_node_by_name(NULL, "nor");
+	if (child) {
+		ret = weim_timing(pdev, child);
+		if (ret)
+			goto parse_fail;
+
+		if (!of_platform_device_create(child, NULL, &pdev->dev)) {
+			ret = -EINVAL;
+			goto parse_fail;
+		}
+	}
+	return 0;
+
+parse_fail:
+	return ret;
+}
+
+static int weim_probe(struct platform_device *pdev)
+{
+	struct imx_weim *weim;
+	struct resource *res;
+	int ret = -EINVAL;
+
+	weim = devm_kzalloc(&pdev->dev, sizeof(*weim), GFP_KERNEL);
+	if (!weim) {
+		ret = -ENOMEM;
+		goto weim_err;
+	}
+	platform_set_drvdata(pdev, weim);
+
+	/* get the resource */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		ret = -ENOENT;
+		goto weim_err;
+	}
+
+	weim->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(weim->base)) {
+		ret = PTR_ERR(weim->base);
+		goto weim_err;
+	}
+
+	/* get the clock */
+	weim->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(weim->clk))
+		goto weim_err;
+
+	clk_prepare_enable(weim->clk);
+
+	/* parse the device node */
+	ret = weim_parse_dt(pdev);
+	if (ret) {
+		clk_disable_unprepare(weim->clk);
+		goto weim_err;
+	}
+
+	dev_info(&pdev->dev, "WEIM driver registered.\n");
+	return 0;
+
+weim_err:
+	return ret;
+}
+
+static int weim_remove(struct platform_device *pdev)
+{
+	struct imx_weim *weim = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(weim->clk);
+	return 0;
+}
+
+static struct platform_driver weim_driver = {
+	.driver = {
+		.name = "imx-weim",
+		.of_match_table = weim_id_table,
+	},
+	.probe   = weim_probe,
+	.remove  = weim_remove,
+};
+
+module_platform_driver(weim_driver);
+MODULE_AUTHOR("Freescale Inc.");
+MODULE_DESCRIPTION("i.MX EIM Controller Driver");
+MODULE_LICENSE("GPL");
-- 
1.7.1

Re: [PATCH 1/6] drivers: bus: add a new driver for WEIM

[Sascha Hauer]

On Mon, May 20, 2013 at 04:48:57PM +0800, Huang Shijie wrote:
> The WEIM(Wireless External Interface Module) works like a bus.
> You can attach many different devices on it, such as NOR, onenand.
> 
> In the case of i.MX6q-sabreauto, the NOR is connected to WEIM.
> 
> This patch also adds the devicetree binding document.
> The driver only works when the devicetree is enabled.
> 
> Signed-off-by: Huang Shijie <b32955-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
> ---
>  Documentation/devicetree/bindings/bus/imx-weim.txt |   69 +++++++++
>  drivers/bus/Kconfig                                |    9 ++
>  drivers/bus/Makefile                               |    1 +
>  drivers/bus/imx-weim.c                             |  145 ++++++++++++++++++++
>  4 files changed, 224 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/bus/imx-weim.txt
>  create mode 100644 drivers/bus/imx-weim.c
> 
> diff --git a/Documentation/devicetree/bindings/bus/imx-weim.txt b/Documentation/devicetree/bindings/bus/imx-weim.txt
> new file mode 100644
> index 0000000..9913454
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/bus/imx-weim.txt
> @@ -0,0 +1,69 @@
> +Device tree bindings for i.MX Wireless External Interface Module (WEIM)
> +
> +The term ???wireless??? does not imply that the WEIM is literally an interface
> +without wires. It simply means that this module was originally designed for
> +wireless and mobile applications that use low-power technology.
> +
> +The actual devices are instantiated from the child nodes of a WEIM node.
> +But now we only have the NOR device.
> +
> +NOR flash connected to the WEIM (found on i.MX boards) are represented as
> +child nodes with a name of "nor".
> +
> +Required properties:
> +
> + - compatible:		Should be set to "fsl, imx6q-weim"
> + - reg:			A resource specifier for the register space
> +			(see the example below)
> + - interrupts:		the interrupt number, see the example below.
> + - clocks:		the clock, see the example below.
> + - #address-cells:	Must be set to 2 to allow memory address translation
> + - #size-cells:		Must be set to 1 to allow CS address passing
> + - ranges:		Must be set up to reflect the memory layout with four
> +			integer values for each chip-select line in use:
> +
> +			   <cs-number> 0 <physical address of mapping> <size>
> +
> +Timing properties for child nodes. All are mandatory, not optional.
> +
> + -weim-cs-index:	The CS index which the device is attaching on.
> + -weim-cs-timing:	The timing array, contains 6 timing values for the
> +			weim-cs-index.
> +
> +Example for an i.MX6q-sabreauto board:
> +	weim: weim@021b8000 {
> +		compatible = "fsl,imx6q-weim";
> +		reg = <0x021b8000 0x4000>;
> +		interrupts = <0 14 0x04>;
> +		clocks = <&clks 196>;
> +		#address-cells = <2>;

Why is address cells 2 in this example?

> +		#size-cells = <1>;
> +		ranges = <0 0 0x08000000 0x08000000>;
> +
> +		nor@0,0 {
> +			compatible = "cfi-flash";
> +			reg = <0 0 0x02000000>;
> +			#address-cells = <1>;
> +			#size-cells = <1>;
> +			bank-width = <2>;
> +
> +			weim-cs-index = <0>;
> +			weim-cs-timing = <0x00620081 0x00000001 0x1C022000
> +					0x0000C000 0x1404a38e 0x00000000>;
> +			partition@0 {
> +				label = "U-Boot";
> +				reg = <0x0 0x40000>;
> +			};
> +
> +			partition@40000 {
> +				label = "U-Boot-ENV";
> +				reg = <0x40000 0x10000>;
> +				read-only;
> +			};
> +
> +			partition@50000 {
> +				label = "Kernel";
> +				reg = <0x50000 0x3b0000>;
> +			};

The partitions are unnecessary to understand the example. Please drop them.

> +#define CS_TIMING_LEN 6
> +#define CS_REG_RANGE  0x18
> +/* Parse and set the timing for this device. */
> +static int weim_timing(struct platform_device *pdev, struct device_node *np)
> +{
> +	struct imx_weim *weim = platform_get_drvdata(pdev);
> +	u32 value[CS_TIMING_LEN];
> +	u32 cs_idx;
> +	int ret;
> +	int i;
> +
> +	ret = of_property_read_u32(np, "weim-cs-index", &cs_idx);
> +	if (ret)
> +		goto weim_parse_err;

It would be nice to check for cs_idx being valid.

> +
> +	ret = of_property_read_u32_array(np, "weim-cs-timing",
> +					value, CS_TIMING_LEN);
> +	if (ret)
> +		goto weim_parse_err;
> +
> +	/* set the timing for WEIM */
> +	for (i = 0; i < CS_TIMING_LEN; i++)
> +		writel(value[i], weim->base + cs_idx * CS_REG_RANGE + i * 4);
> +	return 0;
> +
> +weim_parse_err:
> +	return ret;
> +}
> +
> +static int weim_parse_dt(struct platform_device *pdev)
> +{
> +	struct device_node *child;
> +	int ret;
> +
> +	/* We only support the Parallel NOR now. We may add more in future. */
> +	child = of_find_node_by_name(NULL, "nor");
> +	if (child) {
> +		ret = weim_timing(pdev, child);
> +		if (ret)
> +			goto parse_fail;
> +
> +		if (!of_platform_device_create(child, NULL, &pdev->dev)) {
> +			ret = -EINVAL;
> +			goto parse_fail;
> +		}
> +	}

What you want to do here is:

- iterate over your child nodes
- call weim_timing() for each of them
- call of_platform_device_create for each child (or even
  of_platform_populate() with the parent node)


> +	return 0;
> +
> +parse_fail:
> +	return ret;
> +}
> +
> +static int weim_probe(struct platform_device *pdev)
> +{
> +	struct imx_weim *weim;
> +	struct resource *res;
> +	int ret = -EINVAL;
> +
> +	weim = devm_kzalloc(&pdev->dev, sizeof(*weim), GFP_KERNEL);
> +	if (!weim) {
> +		ret = -ENOMEM;
> +		goto weim_err;
> +	}
> +	platform_set_drvdata(pdev, weim);
> +
> +	/* get the resource */
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!res) {
> +		ret = -ENOENT;
> +		goto weim_err;
> +	}

No need to do error checking here. devm_ioremap_resource() will do this
for you and also print an error message.

> +
> +	weim->base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(weim->base)) {
> +		ret = PTR_ERR(weim->base);
> +		goto weim_err;
> +	}
> +
> +	/* get the clock */
> +	weim->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(weim->clk))
> +		goto weim_err;
> +
> +	clk_prepare_enable(weim->clk);

what is this clock used for? Is it necessary for the register access or
is it necessary for the chipselects on the WEIM to work?

Sascha


-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

Re: [PATCH 1/6] drivers: bus: add a new driver for WEIM

[Shawn Guo]

On Mon, May 20, 2013 at 04:48:57PM +0800, Huang Shijie wrote:
> The WEIM(Wireless External Interface Module) works like a bus.
> You can attach many different devices on it, such as NOR, onenand.
> 
> In the case of i.MX6q-sabreauto, the NOR is connected to WEIM.
> 
> This patch also adds the devicetree binding document.
> The driver only works when the devicetree is enabled.
> 
> Signed-off-by: Huang Shijie <b32955-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
> ---
>  Documentation/devicetree/bindings/bus/imx-weim.txt |   69 +++++++++
>  drivers/bus/Kconfig                                |    9 ++
>  drivers/bus/Makefile                               |    1 +
>  drivers/bus/imx-weim.c                             |  145 ++++++++++++++++++++
>  4 files changed, 224 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/bus/imx-weim.txt
>  create mode 100644 drivers/bus/imx-weim.c
> 
> diff --git a/Documentation/devicetree/bindings/bus/imx-weim.txt b/Documentation/devicetree/bindings/bus/imx-weim.txt
> new file mode 100644
> index 0000000..9913454
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/bus/imx-weim.txt
> @@ -0,0 +1,69 @@
> +Device tree bindings for i.MX Wireless External Interface Module (WEIM)
> +
> +The term ???wireless??? does not imply that the WEIM is literally an interface

"wireless"

> +without wires. It simply means that this module was originally designed for
> +wireless and mobile applications that use low-power technology.
> +
> +The actual devices are instantiated from the child nodes of a WEIM node.
> +But now we only have the NOR device.
> +
> +NOR flash connected to the WEIM (found on i.MX boards) are represented as
> +child nodes with a name of "nor".

I doubt that WEIM should care the particular device type connected on
it.

> +
> +Required properties:
> +
> + - compatible:		Should be set to "fsl, imx6q-weim"

Drop the space in middle of compatible string.

> + - reg:			A resource specifier for the register space
> +			(see the example below)
> + - interrupts:		the interrupt number, see the example below.
> + - clocks:		the clock, see the example below.
> + - #address-cells:	Must be set to 2 to allow memory address translation
> + - #size-cells:		Must be set to 1 to allow CS address passing
> + - ranges:		Must be set up to reflect the memory layout with four
> +			integer values for each chip-select line in use:
> +
> +			   <cs-number> 0 <physical address of mapping> <size>
> +
> +Timing properties for child nodes. All are mandatory, not optional.
> +
> + -weim-cs-index:	The CS index which the device is attaching on.

It seems we can find it out from "reg" property, so that we can save
this property?

> + -weim-cs-timing:	The timing array, contains 6 timing values for the
> +			weim-cs-index.

This is a vendor specific property, and should have a vendor (fsl)
perfix.  Also please put a space after the first "-" which acts as
a bullet symbol here.

> +
> +Example for an i.MX6q-sabreauto board:

You can write it as i.MX6Q SABRE Auto or imx6q-sabreauto.

> +	weim: weim@021b8000 {
> +		compatible = "fsl,imx6q-weim";
> +		reg = <0x021b8000 0x4000>;
> +		interrupts = <0 14 0x04>;
> +		clocks = <&clks 196>;
> +		#address-cells = <2>;
> +		#size-cells = <1>;
> +		ranges = <0 0 0x08000000 0x08000000>;
> +
> +		nor@0,0 {
> +			compatible = "cfi-flash";
> +			reg = <0 0 0x02000000>;
> +			#address-cells = <1>;
> +			#size-cells = <1>;
> +			bank-width = <2>;
> +
> +			weim-cs-index = <0>;
> +			weim-cs-timing = <0x00620081 0x00000001 0x1C022000
> +					0x0000C000 0x1404a38e 0x00000000>;
> +			partition@0 {
> +				label = "U-Boot";
> +				reg = <0x0 0x40000>;
> +			};
> +
> +			partition@40000 {
> +				label = "U-Boot-ENV";
> +				reg = <0x40000 0x10000>;
> +				read-only;
> +			};
> +
> +			partition@50000 {
> +				label = "Kernel";
> +				reg = <0x50000 0x3b0000>;
> +			};
> +		};
> +	};
> diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
> index b05ecab..0f997af 100644
> --- a/drivers/bus/Kconfig
> +++ b/drivers/bus/Kconfig
> @@ -4,6 +4,15 @@
>  
>  menu "Bus devices"
>  
> +config IMX_WEIM
> +	tristate "Freescale EIM DRIVER"
> +	depends on ARCH_MXC && MTD_PHYSMAP_OF

I do not see how this driver depends on MTD_PHYSMAP_OF.

> +	help
> +	  Driver for i.MX6 WEIM controller.
> +	  The WEIM(Wireless External Interface Module) works like a bus.
> +	  You can attach many different devices on it, such as NOR, onenand.
> +	  But now, we only support the Parallel NOR.
> +
>  config MVEBU_MBUS
>  	bool
>  	depends on PLAT_ORION
> diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile
> index 3c7b53c..436bbcc 100644
> --- a/drivers/bus/Makefile
> +++ b/drivers/bus/Makefile
> @@ -2,6 +2,7 @@
>  # Makefile for the bus drivers.
>  #
>  
> +obj-$(CONFIG_IMX_WEIM)	+= imx-weim.o
>  obj-$(CONFIG_MVEBU_MBUS) += mvebu-mbus.o
>  obj-$(CONFIG_OMAP_OCP2SCP)	+= omap-ocp2scp.o
>  
> diff --git a/drivers/bus/imx-weim.c b/drivers/bus/imx-weim.c
> new file mode 100644
> index 0000000..8bd9362
> --- /dev/null
> +++ b/drivers/bus/imx-weim.c
> @@ -0,0 +1,145 @@
> +/*
> + * EIM driver for Freescale's i.MX chips
> + *
> + * Copyright (C) 2013 Freescale Semiconductor, Inc.
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2. This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */
> +#include <linux/module.h>
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/of_device.h>
> +
> +struct imx_weim {
> +	void __iomem *base;
> +	struct clk *clk;
> +};
> +
> +static const struct of_device_id weim_id_table[] = {
> +	{ .compatible = "fsl,imx6q-weim", },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, weim_id_table);
> +
> +#define CS_TIMING_LEN 6
> +#define CS_REG_RANGE  0x18

Nit: put a blank line here.

> +/* Parse and set the timing for this device. */
> +static int weim_timing(struct platform_device *pdev, struct device_node *np)

Name the function weim_timing_setup for better?

> +{
> +	struct imx_weim *weim = platform_get_drvdata(pdev);
> +	u32 value[CS_TIMING_LEN];
> +	u32 cs_idx;
> +	int ret;
> +	int i;
> +
> +	ret = of_property_read_u32(np, "weim-cs-index", &cs_idx);
> +	if (ret)
> +		goto weim_parse_err;

Why not simply "return ret;"?

> +
> +	ret = of_property_read_u32_array(np, "weim-cs-timing",
> +					value, CS_TIMING_LEN);
> +	if (ret)
> +		goto weim_parse_err;

Ditto

> +
> +	/* set the timing for WEIM */
> +	for (i = 0; i < CS_TIMING_LEN; i++)
> +		writel(value[i], weim->base + cs_idx * CS_REG_RANGE + i * 4);
> +	return 0;
> +
> +weim_parse_err:
> +	return ret;
> +}
> +
> +static int weim_parse_dt(struct platform_device *pdev)
> +{
> +	struct device_node *child;
> +	int ret;
> +
> +	/* We only support the Parallel NOR now. We may add more in future. */
> +	child = of_find_node_by_name(NULL, "nor");
> +	if (child) {
> +		ret = weim_timing(pdev, child);
> +		if (ret)
> +			goto parse_fail;
> +
> +		if (!of_platform_device_create(child, NULL, &pdev->dev)) {
> +			ret = -EINVAL;
> +			goto parse_fail;
> +		}
> +	}
> +	return 0;
> +
> +parse_fail:
> +	return ret;
> +}

I second Sascha's comments on this function.

> +
> +static int weim_probe(struct platform_device *pdev)
> +{
> +	struct imx_weim *weim;
> +	struct resource *res;
> +	int ret = -EINVAL;
> +
> +	weim = devm_kzalloc(&pdev->dev, sizeof(*weim), GFP_KERNEL);
> +	if (!weim) {
> +		ret = -ENOMEM;
> +		goto weim_err;
> +	}
> +	platform_set_drvdata(pdev, weim);
> +
> +	/* get the resource */
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!res) {
> +		ret = -ENOENT;
> +		goto weim_err;
> +	}
> +
> +	weim->base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(weim->base)) {
> +		ret = PTR_ERR(weim->base);
> +		goto weim_err;
> +	}
> +
> +	/* get the clock */
> +	weim->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(weim->clk))
> +		goto weim_err;
> +
> +	clk_prepare_enable(weim->clk);
> +
> +	/* parse the device node */
> +	ret = weim_parse_dt(pdev);
> +	if (ret) {
> +		clk_disable_unprepare(weim->clk);
> +		goto weim_err;
> +	}
> +
> +	dev_info(&pdev->dev, "WEIM driver registered.\n");
> +	return 0;
> +
> +weim_err:
> +	return ret;
> +}
> +
> +static int weim_remove(struct platform_device *pdev)
> +{
> +	struct imx_weim *weim = platform_get_drvdata(pdev);
> +
> +	clk_disable_unprepare(weim->clk);
> +	return 0;
> +}
> +
> +static struct platform_driver weim_driver = {
> +	.driver = {
> +		.name = "imx-weim",
> +		.of_match_table = weim_id_table,
> +	},
> +	.probe   = weim_probe,
> +	.remove  = weim_remove,
> +};
> +
> +module_platform_driver(weim_driver);
> +MODULE_AUTHOR("Freescale Inc.");

"Freescale Semiconductor, Inc."

Shawn

> +MODULE_DESCRIPTION("i.MX EIM Controller Driver");
> +MODULE_LICENSE("GPL");
> -- 
> 1.7.1
> 
> 

Re: [PATCH 1/6] drivers: bus: add a new driver for WEIM

[Chaiken, Alison]

> +	weim: weim at 021b8000 {
> +		compatible = "fsl,imx6q-weim";
> +		reg = <0x021b8000 0x4000>;
> +		interrupts = <0 14 0x04>;
> +		clocks = <&clks 196>;
> +		#address-cells = <2>;
> +		#size-cells = <1>;
> +		ranges = <0 0 0x08000000 0x08000000>;
> +
> +		nor at 0,0 {
> +			compatible = "cfi-flash";

Why not use 

compatible = "micron,M29W256G", "cfi-flash";

since that's what's on the SABRE-AI board?

> diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
> index b05ecab..0f997af 100644
> --- a/drivers/bus/Kconfig
> +++ b/drivers/bus/Kconfig
> @@ -4,6 +4,15 @@
>  
>  menu "Bus devices"
>  
> +config IMX_WEIM
> +	tristate "Freescale EIM DRIVER"
> +	depends on ARCH_MXC && MTD_PHYSMAP_OF

Shawn Guo:
I do not see how this driver depends on MTD_PHYSMAP_OF.

physmap_of is the module that provides the mapping driver for the cfi-flash that associates memory with the "reg" properties of the nor node.   However, since EIM can also attach Bluetooth module or GPS, the EIM driver itself certainly does not depend on the map module.

-- 
Alison Chaiken
alison_chaiken-nmGgyN9QBj3QT0dZR+AlfA@public.gmane.org

Re: [PATCH 1/6] drivers: bus: add a new driver for WEIM

[Huang Shijie]

于 2013年05月22日 00:29, Chaiken, Alison 写道:
>> +	weim: weim at 021b8000 {
>> +		compatible = "fsl,imx6q-weim";
>> +		reg =<0x021b8000 0x4000>;
>> +		interrupts =<0 14 0x04>;
>> +		clocks =<&clks 196>;
>> +		#address-cells =<2>;
>> +		#size-cells =<1>;
>> +		ranges =<0 0 0x08000000 0x08000000>;
>> +
>> +		nor at 0,0 {
>> +			compatible = "cfi-flash";
> Why not use
>
> compatible = "micron,M29W256G", "cfi-flash";
>
> since that's what's on the SABRE-AI board?
>
we may use other NOR. :)
so it's better do not bind the specific NOR, even for SABRE-AI.
I even tested Spanion NOR in the SABRE-AI boards.
>> diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
>> index b05ecab..0f997af 100644
>> --- a/drivers/bus/Kconfig
>> +++ b/drivers/bus/Kconfig
>> @@ -4,6 +4,15 @@
>>
>>   menu "Bus devices"
>>
>> +config IMX_WEIM
>> +	tristate "Freescale EIM DRIVER"
>> +	depends on ARCH_MXC&&  MTD_PHYSMAP_OF
> Shawn Guo:
> I do not see how this driver depends on MTD_PHYSMAP_OF.
>
> physmap_of is the module that provides the mapping driver for the cfi-flash that associates memory with the "reg" properties of the nor node.   However, since EIM can also attach Bluetooth module or GPS, the EIM driver itself certainly does not depend on the map module.
>
ok.

i will remove it in next version.

thanks for the comment and review.


Huang Shijie


_______________________________________________
devicetree-discuss mailing list
devicetree-discuss@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/devicetree-discuss

Re: [PATCH 1/6] drivers: bus: add a new driver for WEIM

[Huang Shijie]

于 2013年05月21日 13:43, Shawn Guo 写道:
> It seems we can find it out from "reg" property, so that we can save
> this property?
>
we may have several devices attaching to the weim, each device has its 
own CS index.
it's better to keep this property, make it more clear.

thanks
Huang Shijie

Re: [PATCH 1/6] drivers: bus: add a new driver for WEIM

[Huang Shijie]

于 2013年05月20日 21:18, Sascha Hauer 写道:
> On Mon, May 20, 2013 at 04:48:57PM +0800, Huang Shijie wrote:
>> 			weim-cs-index.
>> +
>> +Example for an i.MX6q-sabreauto board:
>> +	weim: weim@021b8000 {
>> +		compatible = "fsl,imx6q-weim";
>> +		reg =<0x021b8000 0x4000>;
>> +		interrupts =<0 14 0x04>;
>> +		clocks =<&clks 196>;
>> +		#address-cells =<2>;
> Why is address cells 2 in this example?
Must be set to 2 to allow memory address translation.
>> +		#size-cells =<1>;
>> +		ranges =<0 0 0x08000000 0x08000000>;
>> +
>> +		nor@0,0 {
>> +			compatible = "cfi-flash";
>> +			reg =<0 0 0x02000000>;
>> +			#address-cells =<1>;
>> +			#size-cells =<1>;
>> +			bank-width =<2>;
>> +
>> +			weim-cs-index =<0>;
>> +			weim-cs-timing =<0x00620081 0x00000001 0x1C022000
>> +					0x0000C000 0x1404a38e 0x00000000>;
>> +			partition@0 {
>> +				label = "U-Boot";
>> +				reg =<0x0 0x40000>;
>> +			};
>> +
>> +			partition@40000 {
>> +				label = "U-Boot-ENV";
>> +				reg =<0x40000 0x10000>;
>> +				read-only;
>> +			};
>> +
>> +			partition@50000 {
>> +				label = "Kernel";
>> +				reg =<0x50000 0x3b0000>;
>> +			};
> The partitions are unnecessary to understand the example. Please drop them.
okay.
>> +#define CS_TIMING_LEN 6
>> +#define CS_REG_RANGE  0x18
>> +/* Parse and set the timing for this device. */
>> +static int weim_timing(struct platform_device *pdev, struct device_node *np)
>> +{
>> +	struct imx_weim *weim = platform_get_drvdata(pdev);
>> +	u32 value[CS_TIMING_LEN];
>> +	u32 cs_idx;
>> +	int ret;
>> +	int i;
>> +
>> +	ret = of_property_read_u32(np, "weim-cs-index",&cs_idx);
>> +	if (ret)
>> +		goto weim_parse_err;
> It would be nice to check for cs_idx being valid.
>
>> +
>> +	ret = of_property_read_u32_array(np, "weim-cs-timing",
>> +					value, CS_TIMING_LEN);
>> +	if (ret)
>> +		goto weim_parse_err;
>> +
>> +	/* set the timing for WEIM */
>> +	for (i = 0; i<  CS_TIMING_LEN; i++)
>> +		writel(value[i], weim->base + cs_idx * CS_REG_RANGE + i * 4);
>> +	return 0;
>> +
>> +weim_parse_err:
>> +	return ret;
>> +}
>> +
>> +static int weim_parse_dt(struct platform_device *pdev)
>> +{
>> +	struct device_node *child;
>> +	int ret;
>> +
>> +	/* We only support the Parallel NOR now. We may add more in future. */
>> +	child = of_find_node_by_name(NULL, "nor");
>> +	if (child) {
>> +		ret = weim_timing(pdev, child);
>> +		if (ret)
>> +			goto parse_fail;
>> +
>> +		if (!of_platform_device_create(child, NULL,&pdev->dev)) {
>> +			ret = -EINVAL;
>> +			goto parse_fail;
>> +		}
>> +	}
> What you want to do here is:
>
> - iterate over your child nodes
> - call weim_timing() for each of them
> - call of_platform_device_create for each child (or even
>    of_platform_populate() with the parent node)
>
yes.
>> +	return 0;
>> +
>> +parse_fail:
>> +	return ret;
>> +}
>> +
>> +static int weim_probe(struct platform_device *pdev)
>> +{
>> +	struct imx_weim *weim;
>> +	struct resource *res;
>> +	int ret = -EINVAL;
>> +
>> +	weim = devm_kzalloc(&pdev->dev, sizeof(*weim), GFP_KERNEL);
>> +	if (!weim) {
>> +		ret = -ENOMEM;
>> +		goto weim_err;
>> +	}
>> +	platform_set_drvdata(pdev, weim);
>> +
>> +	/* get the resource */
>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +	if (!res) {
>> +		ret = -ENOENT;
>> +		goto weim_err;
>> +	}
> No need to do error checking here. devm_ioremap_resource() will do this
> for you and also print an error message.
>
>> +
>> +	weim->base = devm_ioremap_resource(&pdev->dev, res);
>> +	if (IS_ERR(weim->base)) {
>> +		ret = PTR_ERR(weim->base);
>> +		goto weim_err;
>> +	}
>> +
>> +	/* get the clock */
>> +	weim->clk = devm_clk_get(&pdev->dev, NULL);
>> +	if (IS_ERR(weim->clk))
>> +		goto weim_err;
>> +
>> +	clk_prepare_enable(weim->clk);
> what is this clock used for? Is it necessary for the register access or
> is it necessary for the chipselects on the WEIM to work?
>
>
yes. We need this clock.

in actually, this clock is just a clock gate for several clocks, 
including clock for register access, and
other necessary clocks.

thanks
Huang Shijie
.






_______________________________________________
devicetree-discuss mailing list
devicetree-discuss@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/devicetree-discuss

Re: [PATCH 1/6] drivers: bus: add a new driver for WEIM

[Arnd Bergmann]

On Wednesday 22 May 2013, Huang Shijie wrote:
> 于 2013年05月21日 13:43, Shawn Guo 写道:
> > It seems we can find it out from "reg" property, so that we can save
> > this property?
> >
> we may have several devices attaching to the weim, each device has its 
> own CS index.
> it's better to keep this property, make it more clear.

I agree with Shawn, we should not have this property when it is the
same as the upper half of the "reg" property.

	Arnd
_______________________________________________
devicetree-discuss mailing list
devicetree-discuss@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/devicetree-discuss

Re: [PATCH 1/6] drivers: bus: add a new driver for WEIM

[Huang Shijie]

于 2013年05月22日 20:59, Arnd Bergmann 写道:
> On Wednesday 22 May 2013, Huang Shijie wrote:
>> 于 2013年05月21日 13:43, Shawn Guo 写道:
>>> It seems we can find it out from "reg" property, so that we can save
>>> this property?
>>>
>> we may have several devices attaching to the weim, each device has its 
>> own CS index.
>> it's better to keep this property, make it more clear.
> I agree with Shawn, we should not have this property when it is the
> same as the upper half of the "reg" property.
okay. I will remove this property.

thanks
Huang Shijie


_______________________________________________
devicetree-discuss mailing list
devicetree-discuss@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/devicetree-discuss