linux-kernel - [PATCH v2 1/2] bus: imx-weim: support multiple address ranges per child node

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Date:   Fri, 30 Nov 2018 15:56:23 -0500
From:   thesven73@...il.com
To:     TheSven73@...glemail.com, Shawn Guo <shawnguo@...nel.org>,
        Kees Cook <keescook@...omium.org>,
        Rob Herring <robh@...nel.org>, Arnd Bergmann <arnd@...db.de>
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH v2 1/2] bus: imx-weim: support multiple address ranges per child node

From: Sven Van Asbroeck <TheSven73@...glemail.com>

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@0,0 {
		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 <TheSven73@...glemail.com>
---
 drivers/bus/imx-weim.c | 36 +++++++++++++++++++++++++-----------
 1 file changed, 25 insertions(+), 11 deletions(-)

diff --git a/drivers/bus/imx-weim.c b/drivers/bus/imx-weim.c
index f01308172de9..24f22285395d 100644
--- a/drivers/bus/imx-weim.c
+++ b/drivers/bus/imx-weim.c
@@ -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 */
@@ -115,27 +116,40 @@ static int __init weim_timing_setup(struct device_node *np, void __iomem *base,
 				    const struct imx_weim_devtype *devtype)
 {
 	u32 cs_idx, value[MAX_CS_REGS_COUNT];
-	int i, ret;
+	int i, ret, reg_idx, num_regs;
 
 	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.
+	 */
+	num_regs = of_property_count_elems_of_size(np, "reg", OF_REG_SIZE);
+	if (num_regs < 0)
+		return num_regs;
+	if (!num_regs)
 		return -EINVAL;
+	for (reg_idx = 0; reg_idx < num_regs; reg_idx++) {
+		/* get the CS index from this child node's "reg" property. */
+		ret = of_property_read_u32_index(np, "reg",
+					reg_idx*OF_REG_SIZE, &cs_idx);
+		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;
 }
-- 
2.17.1