[RFC PATCH 15/17] ipmi: kcs: aspeed: Implement v2 bindings

[Andrew Jeffery <andrew@aj.id.au>]

The v2 bindings allow us to extract the resources from the devicetree.
The table in the driver is retained to derive the channel index, which
removes the need for kcs_chan property from the v1 bindings. The v2
bindings allow us to reduce the number of warnings generated by the
existing devicetree nodes.

Cc: Haiyue Wang <haiyue.wang@linux.intel.com>
Cc: Corey Minyard <minyard@acm.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: openipmi-developer@lists.sourceforge.net
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
---
 drivers/char/ipmi/kcs_bmc_aspeed.c | 156 +++++++++++++++++++++++------
 1 file changed, 127 insertions(+), 29 deletions(-)

diff --git a/drivers/char/ipmi/kcs_bmc_aspeed.c b/drivers/char/ipmi/kcs_bmc_aspeed.c
index e3dd09022589..509e0d3c6eb1 100644
--- a/drivers/char/ipmi/kcs_bmc_aspeed.c
+++ b/drivers/char/ipmi/kcs_bmc_aspeed.c
@@ -12,6 +12,7 @@
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_address.h>
 #include <linux/platform_device.h>
 #include <linux/poll.h>
 #include <linux/regmap.h>
@@ -233,38 +234,133 @@ static const struct kcs_ioreg ast_kcs_bmc_ioregs[KCS_CHANNEL_MAX] = {
 	{ .idr = LPC_IDR4, .odr = LPC_ODR4, .str = LPC_STR4 },
 };
 
+static struct kcs_bmc *aspeed_kcs_probe_of_v1(struct platform_device *pdev)
+{
+	struct aspeed_kcs_bmc *priv;
+	struct device_node *np;
+	struct kcs_bmc *kcs;
+	u32 channel;
+	u32 slave;
+	int rc;
+
+	np = pdev->dev.of_node;
+
+	rc = of_property_read_u32(np, "kcs_chan", &channel);
+	if ((rc != 0) || (channel == 0 || channel > KCS_CHANNEL_MAX)) {
+		dev_err(&pdev->dev, "no valid 'kcs_chan' configured\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	kcs = kcs_bmc_alloc(&pdev->dev, sizeof(struct aspeed_kcs_bmc), channel);
+	if (!kcs)
+		return ERR_PTR(-ENOMEM);
+
+	priv = kcs_bmc_priv(kcs);
+	priv->map = syscon_node_to_regmap(pdev->dev.parent->of_node);
+	if (IS_ERR(priv->map)) {
+		dev_err(&pdev->dev, "Couldn't get regmap\n");
+		return ERR_PTR(-ENODEV);
+	}
+
+	rc = of_property_read_u32(np, "kcs_addr", &slave);
+	if (rc) {
+		dev_err(&pdev->dev, "no valid 'kcs_addr' configured\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	kcs->ioreg = ast_kcs_bmc_ioregs[channel - 1];
+	aspeed_kcs_set_address(kcs, slave);
+
+	return 0;
+}
+
+static int aspeed_kcs_calculate_channel(const struct kcs_ioreg *regs)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ast_kcs_bmc_ioregs); i++) {
+		if (!memcmp(&ast_kcs_bmc_ioregs[i], regs, sizeof(*regs)))
+			return i + 1;
+	}
+
+	return -EINVAL;
+}
+
+static struct kcs_bmc *aspeed_kcs_probe_of_v2(struct platform_device *pdev)
+{
+	struct aspeed_kcs_bmc *priv;
+	struct device_node *np;
+	struct kcs_ioreg ioreg;
+	struct kcs_bmc *kcs;
+	const __be32 *reg;
+	int channel;
+	u32 slave;
+	int rc;
+
+	np = pdev->dev.of_node;
+
+	/* Don't translate addresses, we want offsets for the regmaps */
+	reg = of_get_address(np, 0, NULL, NULL);
+	if (!reg)
+		return ERR_PTR(-EINVAL);
+	ioreg.idr = be32_to_cpup(reg);
+
+	reg = of_get_address(np, 1, NULL, NULL);
+	if (!reg)
+		return ERR_PTR(-EINVAL);
+	ioreg.odr = be32_to_cpup(reg);
+
+	reg = of_get_address(np, 2, NULL, NULL);
+	if (!reg)
+		return ERR_PTR(-EINVAL);
+	ioreg.str = be32_to_cpup(reg);
+
+	channel = aspeed_kcs_calculate_channel(&ioreg);
+	if (channel < 0)
+		return ERR_PTR(channel);
+
+	kcs = kcs_bmc_alloc(&pdev->dev, sizeof(struct aspeed_kcs_bmc), channel);
+	if (!kcs)
+		return ERR_PTR(-ENOMEM);
+
+	kcs->ioreg = ioreg;
+
+	priv = kcs_bmc_priv(kcs);
+	priv->map = syscon_node_to_regmap(pdev->dev.parent->of_node);
+	if (IS_ERR(priv->map)) {
+		dev_err(&pdev->dev, "Couldn't get regmap\n");
+		return ERR_PTR(-ENODEV);
+	}
+
+	rc = of_property_read_u32(np, "slave-reg", &slave);
+	if (rc)
+		return ERR_PTR(rc);
+
+	aspeed_kcs_set_address(kcs, slave);
+
+	return kcs;
+}
+
 static int aspeed_kcs_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
-	struct aspeed_kcs_bmc *priv;
 	struct kcs_bmc *kcs_bmc;
-	u32 chan, addr;
+	struct device_node *np;
 	int rc;
 
-	rc = of_property_read_u32(dev->of_node, "kcs_chan", &chan);
-	if ((rc != 0) || (chan == 0 || chan > KCS_CHANNEL_MAX)) {
-		dev_err(dev, "no valid 'kcs_chan' configured\n");
-		return -ENODEV;
-	}
+	np = pdev->dev.of_node;
+	if (of_device_is_compatible(np, "aspeed,ast2400-kcs-bmc") ||
+			of_device_is_compatible(np, "aspeed,ast2500-kcs-bmc"))
+		kcs_bmc = aspeed_kcs_probe_of_v1(pdev);
+	else if (of_device_is_compatible(np, "aspeed,ast2400-kcs-bmc-v2") ||
+			of_device_is_compatible(np, "aspeed,ast2500-kcs-bmc-v2"))
+		kcs_bmc = aspeed_kcs_probe_of_v2(pdev);
+	else
+		return -EINVAL;
+
+	if (IS_ERR(kcs_bmc))
+		return PTR_ERR(kcs_bmc);
 
-	rc = of_property_read_u32(dev->of_node, "kcs_addr", &addr);
-	if (rc) {
-		dev_err(dev, "no valid 'kcs_addr' configured\n");
-		return -ENODEV;
-	}
-
-	kcs_bmc = kcs_bmc_alloc(dev, sizeof(*priv), chan);
-	if (!kcs_bmc)
-		return -ENOMEM;
-
-	priv = kcs_bmc_priv(kcs_bmc);
-	priv->map = syscon_node_to_regmap(dev->parent->of_node);
-	if (IS_ERR(priv->map)) {
-		dev_err(dev, "Couldn't get regmap\n");
-		return -ENODEV;
-	}
-
-	kcs_bmc->ioreg = ast_kcs_bmc_ioregs[chan - 1];
 	kcs_bmc->io_inputb = aspeed_kcs_inb;
 	kcs_bmc->io_outputb = aspeed_kcs_outb;
 
@@ -274,7 +370,6 @@ static int aspeed_kcs_probe(struct platform_device *pdev)
 
 	dev_set_drvdata(dev, kcs_bmc);
 
-	aspeed_kcs_set_address(kcs_bmc, addr);
 	aspeed_kcs_enable_channel(kcs_bmc, true);
 
 	rc = misc_register(&kcs_bmc->miscdev);
@@ -283,9 +378,10 @@ static int aspeed_kcs_probe(struct platform_device *pdev)
 		return rc;
 	}
 
-	pr_info("channel=%u addr=0x%x idr=0x%x odr=0x%x str=0x%x\n",
-		chan, addr,
-		kcs_bmc->ioreg.idr, kcs_bmc->ioreg.odr, kcs_bmc->ioreg.str);
+	dev_dbg(&pdev->dev,
+		"Probed KCS device %d (IDR=0x%x, ODR=0x%x, STR=0x%x)\n",
+		kcs_bmc->channel, kcs_bmc->ioreg.idr, kcs_bmc->ioreg.odr,
+		kcs_bmc->ioreg.str);
 
 	return 0;
 }
@@ -302,6 +398,8 @@ static int aspeed_kcs_remove(struct platform_device *pdev)
 static const struct of_device_id ast_kcs_bmc_match[] = {
 	{ .compatible = "aspeed,ast2400-kcs-bmc" },
 	{ .compatible = "aspeed,ast2500-kcs-bmc" },
+	{ .compatible = "aspeed,ast2400-kcs-bmc-v2" },
+	{ .compatible = "aspeed,ast2500-kcs-bmc-v2" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, ast_kcs_bmc_match);
-- 
2.20.1