drivers: bus: add a new driver for WEIM

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.

Required properties:

 - compatible:		Should be set to "fsl,imx6q-weim"

 - reg:			A resource specifier for the register space

			(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 property for child nodes. It is mandatory, not optional.

 - fsl,weim-cs-timing:	The timing array, contains 6 timing values for the

			child node. We can get the CS index from the child

			node's "reg" property. This property contains the values

			for the registers EIM_CSnGCR1, EIM_CSnGCR2, EIM_CSnRCR1,

			EIM_CSnRCR2, EIM_CSnWCR1, EIM_CSnWCR2 in this order.

Example for an imx6q-sabreauto board, the NOR flash connected to the WEIM:

	weim: weim@021b8000 {

		compatible = "fsl,imx6q-weim";

		reg = <0x021b8000 0x4000>;

		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>;

			fsl,weim-cs-timing = <0x00620081 0x00000001 0x1c022000

					0x0000c000 0x1404a38e 0x00000000>;

		};

	};

menu "Bus devices"

config IMX_WEIM

	bool "Freescale EIM DRIVER"

	depends on ARCH_MXC

	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

# 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

/*

 * 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_setup(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;

	/* get the CS index from this child node's "reg" property. */

	ret = of_property_read_u32(np, "reg", &cs_idx);

	if (ret)

		return ret;

	/* The weim has four chip selects. */

	if (cs_idx > 3)

		return -EINVAL;

	ret = of_property_read_u32_array(np, "fsl,weim-cs-timing",

					value, CS_TIMING_LEN);

	if (ret)

		return ret;

	/* 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;

}

static int weim_parse_dt(struct platform_device *pdev)

{

	struct device_node *child;

	int ret;

	for_each_child_of_node(pdev->dev.of_node, child) {

		if (!child->name)

			continue;

		ret = weim_timing_setup(pdev, child);

		if (ret) {

			dev_err(&pdev->dev, "%s set timing failed.\n",

				child->full_name);

			return ret;

		}

	}

	ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);

	if (ret)

		dev_err(&pdev->dev, "%s fail to create devices.\n",

			pdev->dev.of_node->full_name);

	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);

	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;

	ret = clk_prepare_enable(weim->clk);

	if (ret)

		goto weim_err;

	/* 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 struct platform_driver weim_driver = {

	.driver = {

		.name = "imx-weim",

		.of_match_table = weim_id_table,

	},

	.probe   = weim_probe,

};

module_platform_driver(weim_driver);

MODULE_AUTHOR("Freescale Semiconductor Inc.");

MODULE_DESCRIPTION("i.MX EIM Controller Driver");

MODULE_LICENSE("GPL");