bus: imx-weim

Ensure that timing values for the child node are applied to all chip selects in the child's address ranges.

Note that this does not support multiple timing settings per child; this can be added in the future if required.

Example:

&weim {
	acme@0 {
		compatible = "acme,whatever";
		reg = <0 0 0x100>, <0 0x400000 0x800>,
				<1 0x400000 0x800>;
		fsl,weim-cs-timing = <0x024400b1 0x00001010 0x20081100
				0x00000000 0xa0000240 0x00000000>;
	};
};

Signed-off-by Sven Van Asbroeck <[email protected]>

---
 drivers/bus/imx-weim.c | 36 +++++++++++++++++++++++++-----------
 1 file changed, 25 insertions(+), 11 deletions(-)

drivers/bus/imx-weim.c +1 -0

index d84996a4528e..5452d22d1bd8 100644
@@ -46,6 +46,7 @@ static const struct imx_weim_devtype imx51_weim_devtype = {
 };
 
 #define MAX_CS_REGS_COUNT	6
+#define OF_REG_SIZE		3
 
 static const struct of_device_id weim_id_table[] = {
 	/* i.MX1/21 */

drivers/bus/imx-weim.c +5 -3

 	if (WARN_ON(devtype->cs_regs_count > MAX_CS_REGS_COUNT))
 		return -EINVAL;
 
-	/* get the CS index from this child node's "reg" property. */
-	ret = of_property_read_u32(np, "reg", &cs_idx);
+	ret = of_property_read_u32_array(np, "fsl,weim-cs-timing",
+					 value, devtype->cs_regs_count);
 	if (ret)
 		return ret;
 
-	if (cs_idx >= devtype->cs_count)
+	/*
+	 * the child node's "reg" property may contain multiple address ranges,
+	 * extract the chip select for each.

drivers/bus/imx-weim.c +9 -7

+		if (ret)
+			break;
 
-	ret = of_property_read_u32_array(np, "fsl,weim-cs-timing",
-					 value, devtype->cs_regs_count);
-	if (ret)
-		return ret;
+		if (cs_idx >= devtype->cs_count)
+			return -EINVAL;
 
-	/* set the timing for WEIM */
-	for (i = 0; i < devtype->cs_regs_count; i++)
-		writel(value[i], base + cs_idx * devtype->cs_stride + i * 4);
+		/* set the timing for WEIM */
+		for (i = 0; i < devtype->cs_regs_count; i++)
+			writel(value[i],
+				base + cs_idx * devtype->cs_stride + i * 4);
+	}
 
 	return 0;
 }

Signature · 1 line

2.17.1

The imx-weim driver was patched to allow correct WEIM configuration when multiple address ranges are used in a child node. Update the dt-bindings to reflect this.

Signed-off-by Sven Van Asbroeck <[email protected]>

---
 .../devicetree/bindings/bus/imx-weim.txt      | 32 +++++++++++++++++--
 1 file changed, 29 insertions(+), 3 deletions(-)

The imx-weim driver was patched to allow correct WEIM configuration when multiple address ranges are used in a child node. Update the dt-bindings to reflect this.

Signed-off-by Sven Van Asbroeck <[email protected]>

When specifying weim child devices, there is a risk that more than one timing setting is specified for the same chip select.

The driver cannot support such a configuration.

In case of conflict, this patch will print a warning to the log, and will ignore the child node in question.

In this example, node acme@1 will be ignored, as it tries to modify timing settings for CS0:

&weim {
	acme@0 {
		compatible = "acme,whatever";
		reg = <0 0 0x100>;
		fsl,weim-cs-timing = <something>;
	};
	acme@1 {
		compatible = "acme,whatnot";
		reg = <0 0x500 0x100>;
		fsl,weim-cs-timing = <something else>;
	};
};

However in this example, the driver will be happy:

&weim {
        acme@0 {
                compatible = "acme,whatever";
                reg = <0 0 0x100>;
                fsl,weim-cs-timing = <something>;
        };
        acme@1 {
                compatible = "acme,whatnot";
                reg = <0 0x500 0x100>;
                fsl,weim-cs-timing = <something>;
        };
};

Signed-off-by Sven Van Asbroeck <[email protected]>

---
 drivers/bus/imx-weim.c | 33 ++++++++++++++++++++++++++++++---
 1 file changed, 30 insertions(+), 3 deletions(-)

drivers/bus/imx-weim.c +0 -0

index 5452d22d1bd8..dfe74b8c512a 100644

drivers/bus/imx-weim.c +14 -2

 #define OF_REG_SIZE		3
 
+struct cs_timing {
+	bool is_applied;
+	u32 regs[MAX_CS_REGS_COUNT];
+};
+
+struct cs_timing_state {
+	struct cs_timing cs[MAX_CS_REGS];
+};
+
 static const struct of_device_id weim_id_table[] = {
 	/* i.MX1/21 */
 	{ .compatible = "fsl,imx1-weim", .data = &imx1_weim_devtype, },

@@ -112,11 +122,14 @@ static int __init imx_weim_gpr_setup(struct platform_device *pdev)
 }
 
 /* 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)
+static int __init weim_timing_setup(struct device *dev,
+				    struct device_node *np, void __iomem *base,
+				    const struct imx_weim_devtype *devtype,
+				    struct cs_timing_state *ts)
 {
 	u32 cs_idx, value[MAX_CS_REGS_COUNT];
 	int i, ret, reg_idx, num_regs;
+	struct cs_timing *cst;
 
 	if (WARN_ON(devtype->cs_regs_count > MAX_CS_REGS_COUNT))
 		return -EINVAL;

drivers/bus/imx-weim.c +3 -1

+		}
 	}
 
 	return 0;

@@ -162,6 +188,7 @@ static int __init weim_parse_dt(struct platform_device *pdev,
 	const struct imx_weim_devtype *devtype = of_id->data;
 	struct device_node *child;
 	int ret, have_child = 0;
+	struct cs_timing_state ts = {};
 
 	if (devtype == &imx50_weim_devtype) {
 		ret = imx_weim_gpr_setup(pdev);

@@ -170,7 +197,7 @@ static int __init weim_parse_dt(struct platform_device *pdev,
 	}
 
 	for_each_available_child_of_node(pdev->dev.of_node, child) {
-		ret = weim_timing_setup(child, base, devtype);
+		ret = weim_timing_setup(&pdev->dev, child, base, devtype, &ts);
 		if (ret)
 			dev_warn(&pdev->dev, "%pOF set timing failed.\n",
 				child);

Signature · 1 line

2.17.1