linux-kernel - [RFC PATCH 2/2] HISI LPC: Add PNP device support

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Message-ID: <1524218846-169934-3-git-send-email-john.garry@huawei.com>
Date:   Fri, 20 Apr 2018 18:07:26 +0800
From:   John Garry <john.garry@...wei.com>
To:     <rjw@...ysocki.net>, <andriy.shevchenko@...ux.intel.com>,
        <linux-acpi@...r.kernel.org>, <lenb@...nel.org>,
        <mika.westerberg@...ux.intel.com>, <lorenzo.pieralisi@....com>
CC:     <linux-kernel@...r.kernel.org>, <arnd@...db.de>,
        <graeme.gregory@...aro.org>, <helgaas@...nel.org>,
        <linuxarm@...wei.com>, <z.liuxinliang@...ilicon.com>,
        John Garry <john.garry@...wei.com>
Subject: [RFC PATCH 2/2] HISI LPC: Add PNP device support

Currently the driver creates an per-ACPI device mfd_cell
for child devices. This does not suit devices which are
PNP-compatible, as we expect PNP-compatible devices to
derive PNP devices.

To add PNP device support, we continue to allow the PNP
scan code to create the PNP device (which have the
enumeration_by_parent flag set), but expect the PNP
scan to defer adding the device to allow the host probe
code to do this. In addition, no longer do we create an
mfd_cell (platform_device) for PNP-compatible devices.

We take this approach so that host probe code can
translate the IO resources of the PNP device prior
to adding the device.

Signed-off-by: John Garry <john.garry@...wei.com>
---
 drivers/bus/hisi_lpc.c | 38 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/drivers/bus/hisi_lpc.c b/drivers/bus/hisi_lpc.c
index 2d4611e..d228bc5 100644
--- a/drivers/bus/hisi_lpc.c
+++ b/drivers/bus/hisi_lpc.c
@@ -17,8 +17,11 @@
 #include <linux/of_address.h>
 #include <linux/of_platform.h>
 #include <linux/pci.h>
+#include <linux/pnp.h>
 #include <linux/slab.h>
 
+#include "../pnp/base.h"
+
 #define DRV_NAME "hisi-lpc"
 
 /*
@@ -469,8 +472,11 @@ static int hisi_lpc_acpi_probe(struct device *hostdev)
 	struct acpi_device *child;
 	int size, ret, count = 0, cell_num = 0;
 
-	list_for_each_entry(child, &adev->children, node)
+	list_for_each_entry(child, &adev->children, node) {
+		if (acpi_is_pnp_device(child))
+			continue;
 		cell_num++;
+	}
 
 	/* allocate the mfd cell and companion ACPI info, one per child */
 	size = sizeof(*mfd_cells) + sizeof(*hisi_lpc_mfd_cells);
@@ -492,6 +498,9 @@ static int hisi_lpc_acpi_probe(struct device *hostdev)
 			.pnpid = pnpid,
 		};
 
+		if (acpi_is_pnp_device(child))
+			continue;
+
 		/*
 		 * For any instances of this host controller (Hip06 and Hip07
 		 * are the only chipsets), we would not have multiple slaves
@@ -523,6 +532,33 @@ static int hisi_lpc_acpi_probe(struct device *hostdev)
 		return ret;
 	}
 
+	list_for_each_entry(child, &adev->children, node) {
+		struct pnp_resource *pnp_res;
+		struct pnp_dev *pnp_dev;
+		int rc;
+
+		if (!acpi_is_pnp_device(child))
+			continue;
+
+		pnp_dev = child->driver_data;
+
+		/*
+		 * Prior to adding the device, we need to translate the
+		 * resources to logical PIO addresses.
+		 */
+		list_for_each_entry(pnp_res, &pnp_dev->resources, list) {
+			struct resource *res = &pnp_res->res;
+
+			if (res->flags | IORESOURCE_IO)
+				hisi_lpc_acpi_xlat_io_res(child, adev, res);
+		}
+		rc = pnp_add_device(pnp_dev);
+		if (rc) {
+			put_device(&pnp_dev->dev);
+			return rc;
+		}
+	}
+
 	return 0;
 }
 
-- 
1.9.1