[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@xxxxxxxxxxxxx>
---
 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 â??wirelessâ?? 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


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