--- /dev/null
+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>;
+ };
+ };
--- /dev/null
+/*
+ * 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");
OSDN Git Service
