[PATCH] bus: imx-weim: support weim-cs-gpr for imx6q-weim

[Shawn Guo]

For imx6q-weim type of device, there might a WEIM CS space configuration
register in General Purpose Register controller, e.g. IOMUXC_GPR1 on
i.MX6Q.

Depending on which configuration of the following 4 is chosen for given
system, IOMUXC_GPR1[11:0] should be set up as 0x5, 0x1b, 0x4b or 0x249
correspondingly.

	CS0(128M) CS1(0M)  CS2(0M)  CS3(0M)
	CS0(64M)  CS1(64M) CS2(0M)  CS3(0M)
	CS0(64M)  CS1(32M) CS2(32M) CS3(0M)
	CS0(32M)  CS1(32M) CS2(32M) CS3(32M)

The patch creates a table in the driver for above configurations, and
detects which one is being used for the booting system by looking at
'ranges' property of WEIM node.  Thus the WEIM CS GPR can be set up
automatically at boot time.

Signed-off-by: Shawn Guo <shawn.guo at linaro.org>
---
 Documentation/devicetree/bindings/bus/imx-weim.txt |    6 ++
 drivers/bus/imx-weim.c                             |   83 ++++++++++++++++++++
 2 files changed, 89 insertions(+)

diff --git a/Documentation/devicetree/bindings/bus/imx-weim.txt b/Documentation/devicetree/bindings/bus/imx-weim.txt
index 0fd76c4..d114460f 100644
--- a/Documentation/devicetree/bindings/bus/imx-weim.txt
+++ b/Documentation/devicetree/bindings/bus/imx-weim.txt
@@ -19,6 +19,12 @@ Required properties:
 
 			   <cs-number> 0 <physical address of mapping> <size>
 
+Optional properties:
+
+ - fsl,weim-cs-gpr:	Should be the phandle to the General Purpose Register
+			controller that contains WEIM CS GPR register, e.g.
+			IOMUXC_GPR1 on i.MX6Q.
+
 Timing property for child nodes. It is mandatory, not optional.
 
  - fsl,weim-cs-timing:	The timing array, contains timing values for the
diff --git a/drivers/bus/imx-weim.c b/drivers/bus/imx-weim.c
index 3ef58c8..9c8a522 100644
--- a/drivers/bus/imx-weim.c
+++ b/drivers/bus/imx-weim.c
@@ -11,6 +11,9 @@
 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/of_device.h>
+#include <linux/mfd/syscon.h>
+#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
+#include <linux/regmap.h>
 
 struct imx_weim_devtype {
 	unsigned int	cs_count;
@@ -56,6 +59,83 @@ static const struct of_device_id weim_id_table[] = {
 };
 MODULE_DEVICE_TABLE(of, weim_id_table);
 
+struct imx6q_weim_gpr {
+	u32 cssize[4];
+	u32 gprval;
+};
+
+static const struct imx6q_weim_gpr imx6q_weim_gpr_data[] __initconst = {
+	{
+		/* CS0(128M) CS1(0M) CS2(0M) CS3(0M) */
+		.cssize = { 128, 0, 0, 0 },
+		.gprval = 0x5,
+	}, {
+		/* CS0(64M) CS1(64M) CS2(0M) CS3(0M) */
+		.cssize = { 64, 64, 0, 0 },
+		.gprval = 0x1b,
+	}, {
+		/* CS0(64M) CS1(32M) CS2(32M) CS3(0M) */
+		.cssize = { 64, 32, 32, 0 },
+		.gprval = 0x4b,
+	}, {
+		/* CS0(64M) CS1(32M) CS2(32M) CS3(0M) */
+		.cssize = { 32, 32, 32, 32 },
+		.gprval = 0x249,
+	},
+};
+
+static int __init imx6q_weim_gpr_setup(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	const struct property *prop;
+	struct regmap *gpr;
+	u32 cssize[4] = { 0, 0, 0, 0 };
+	int len;
+	int ret;
+	int i;
+
+	gpr = syscon_regmap_lookup_by_phandle(np, "fsl,weim-cs-gpr");
+	if (IS_ERR(gpr)) {
+		dev_dbg(&pdev->dev, "No weim-cs-gpr to set up\n");
+		return 0;
+	}
+
+	prop = of_find_property(np, "ranges", &len);
+	if (prop == NULL)
+		return -ENOENT;
+	if (len % (sizeof(u32) * 4))
+		return -EINVAL;
+
+	for (i = 0; i < len / (sizeof(u32) * 4); i++) {
+		int cs;
+		/* read cs index */
+		ret = of_property_read_u32_index(np, "ranges", i * 4, &cs);
+		if (ret)
+			return ret;
+		/* read cs size */
+		ret = of_property_read_u32_index(np, "ranges", i * 4 + 3,
+						 &cssize[cs]);
+		if (ret)
+			return ret;
+		/* turn to MB */
+		cssize[cs] >>= 20;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(imx6q_weim_gpr_data); i++) {
+		ret = memcmp(cssize, imx6q_weim_gpr_data[i].cssize,
+			     sizeof(cssize));
+		if (ret == 0) {
+			/* Find it. Set up IOMUXC_GPR1[11:0] with the gprval. */
+			regmap_update_bits(gpr, IOMUXC_GPR1, 0xfff,
+					   imx6q_weim_gpr_data[i].gprval);
+			return 0;
+		}
+	}
+
+	dev_err(&pdev->dev, "Invalid 'ranges' configuration\n");
+	return -EINVAL;
+}
+
 /* Parse and set the timing for this device. */
 static int __init weim_timing_setup(struct device_node *np, void __iomem *base,
 				    const struct imx_weim_devtype *devtype)
@@ -92,6 +172,9 @@ static int __init weim_parse_dt(struct platform_device *pdev,
 	struct device_node *child;
 	int ret;
 
+	if (of_device_is_compatible(pdev->dev.of_node, "fsl,imx6q-weim"))
+		imx6q_weim_gpr_setup(pdev);
+
 	for_each_child_of_node(pdev->dev.of_node, child) {
 		if (!child->name)
 			continue;
-- 
1.7.9.5