drivers: bus: add a new driver for WEIM

[karo-tx-linux.git] / drivers / bus / imx-weim.c

diff --git a/drivers/bus/imx-weim.c b/drivers/bus/imx-weim.c
new file mode 100644 (file)
index 0000000..349f14e
--- /dev/null
+++ b/drivers/bus/imx-weim.c
@@ -0,0 +1,138 @@
+/*
+ * 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");