[PATCH v3 1/6] drivers: bus: add a new driver for WEIM
Huang Shijie
b32955 at freescale.com
Fri May 24 19:59:19 EST 2013
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 at freescale.com>
---
Documentation/devicetree/bindings/bus/imx-weim.txt | 50 +++++++
drivers/bus/Kconfig | 9 ++
drivers/bus/Makefile | 1 +
drivers/bus/imx-weim.c | 139 ++++++++++++++++++++
4 files changed, 199 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..e7a2950
--- /dev/null
+++ b/Documentation/devicetree/bindings/bus/imx-weim.txt
@@ -0,0 +1,50 @@
+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 at 021b8000 {
+ compatible = "fsl,imx6q-weim";
+ reg = <0x021b8000 0x4000>;
+ clocks = <&clks 196>;
+ #address-cells = <2>;
+ #size-cells = <1>;
+ ranges = <0 0 0x08000000 0x08000000>;
+
+ nor at 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>;
+ };
+ };
diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
index b05ecab..46cd5bb 100644
--- a/drivers/bus/Kconfig
+++ b/drivers/bus/Kconfig
@@ -4,6 +4,15 @@
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
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..aef865d
--- /dev/null
+++ b/drivers/bus/imx-weim.c
@@ -0,0 +1,139 @@
+/*
+ * 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 void weim_parse_dt(struct platform_device *pdev)
+{
+ struct device_node *child;
+
+ for_each_child_of_node(pdev->dev.of_node, child) {
+ if (!child->name)
+ continue;
+
+ if (weim_timing_setup(pdev, child)) {
+ dev_err(&pdev->dev, "%s set timing failed.\n",
+ child->full_name);
+ continue;
+ }
+ }
+
+ if (of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev) < 0)
+ dev_err(&pdev->dev, "%s fail to create devices.\n",
+ pdev->dev.of_node->full_name);
+}
+
+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 */
+ weim_parse_dt(pdev);
+
+ 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 Semiconductor Inc.");
+MODULE_DESCRIPTION("i.MX EIM Controller Driver");
+MODULE_LICENSE("GPL");
--
1.7.1
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