mfd: watchdog: iTCO_wdt: Expose watchdog properties using platform data

Intel Sunrisepoint (Skylake PCH) has the iTCO watchdog accessible across
the SMBus, unlike previous generations of PCH/ICH where it was on the
LPC bus. Because it's on the SMBus, it doesn't make sense to pass around
a 'struct lpc_ich_info', and leaking the type of bus into the iTCO
watchdog driver is kind of backwards anyway.

This change introduces a new 'struct itco_wdt_platform_data' for use
inside the iTCO watchdog driver and by the upcoming Intel Sunrisepoint
code, which neatly avoids having to include lpc_ich headers in the i801
i2c driver.

This change is overdue because lpc_ich_info has already found its way
into other TCO watchdog users, notably the intel_pmc_ipc driver where
the watchdog actually isn't on the LPC bus as far as I can see.

A simple translation layer is provided for converting from the existing
'struct lpc_ich_info' inside the lpc_ich mfd driver.

Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Acked-by: Darren Hart <dvhart@linux.intel.com> [drivers/x86 refactoring]
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/lpc_ich.c

@@ -66,6 +66,7 @@
 #include <linux/pci.h>
 #include <linux/mfd/core.h>
 #include <linux/mfd/lpc_ich.h>
+#include <linux/platform_data/itco_wdt.h>
 
 #define ACPIBASE		0x40
 #define ACPIBASE_GPE_OFF	0x28
@@ -835,9 +836,31 @@ static void lpc_ich_enable_pmc_space(struct pci_dev *dev)
 	priv->actrl_pbase_save = reg_save;
 }
 
-static void lpc_ich_finalize_cell(struct pci_dev *dev, struct mfd_cell *cell)
+static int lpc_ich_finalize_wdt_cell(struct pci_dev *dev)
 {
+	struct itco_wdt_platform_data *pdata;
 	struct lpc_ich_priv *priv = pci_get_drvdata(dev);
+	struct lpc_ich_info *info;
+	struct mfd_cell *cell = &lpc_ich_cells[LPC_WDT];
+
+	pdata = devm_kzalloc(&dev->dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return -ENOMEM;
+
+	info = &lpc_chipset_info[priv->chipset];
+
+	pdata->version = info->iTCO_version;
+	strlcpy(pdata->name, info->name, sizeof(pdata->name));
+
+	cell->platform_data = pdata;
+	cell->pdata_size = sizeof(*pdata);
+	return 0;
+}
+
+static void lpc_ich_finalize_gpio_cell(struct pci_dev *dev)
+{
+	struct lpc_ich_priv *priv = pci_get_drvdata(dev);
+	struct mfd_cell *cell = &lpc_ich_cells[LPC_GPIO];
 
 	cell->platform_data = &lpc_chipset_info[priv->chipset];
 	cell->pdata_size = sizeof(struct lpc_ich_info);
@@ -933,7 +956,7 @@ static int lpc_ich_init_gpio(struct pci_dev *dev)
 	lpc_chipset_info[priv->chipset].use_gpio = ret;
 	lpc_ich_enable_gpio_space(dev);
 
-	lpc_ich_finalize_cell(dev, &lpc_ich_cells[LPC_GPIO]);
+	lpc_ich_finalize_gpio_cell(dev);
 	ret = mfd_add_devices(&dev->dev, PLATFORM_DEVID_AUTO,
 			      &lpc_ich_cells[LPC_GPIO], 1, NULL, 0, NULL);
 
@@ -1007,7 +1030,10 @@ static int lpc_ich_init_wdt(struct pci_dev *dev)
 		res->end = base_addr + ACPIBASE_PMC_END;
 	}
 
-	lpc_ich_finalize_cell(dev, &lpc_ich_cells[LPC_WDT]);
+	ret = lpc_ich_finalize_wdt_cell(dev);
+	if (ret)
+		goto wdt_done;
+
 	ret = mfd_add_devices(&dev->dev, PLATFORM_DEVID_AUTO,
 			      &lpc_ich_cells[LPC_WDT], 1, NULL, 0, NULL);
 

drivers/platform/x86/intel_pmc_ipc.c

@@ -33,7 +33,7 @@
 #include <linux/suspend.h>
 #include <linux/acpi.h>
 #include <asm/intel_pmc_ipc.h>
-#include <linux/mfd/lpc_ich.h>
+#include <linux/platform_data/itco_wdt.h>
 
 /*
  * IPC registers
@@ -460,9 +460,9 @@ static struct resource tco_res[] = {
 	},
 };
 
-static struct lpc_ich_info tco_info = {
+static struct itco_wdt_platform_data tco_info = {
 	.name = "Apollo Lake SoC",
-	.iTCO_version = 3,
+	.version = 3,
 };
 
 static int ipc_create_punit_device(void)
@@ -539,8 +539,7 @@ static int ipc_create_tco_device(void)
 		goto err;
 	}
 
-	ret = platform_device_add_data(pdev, &tco_info,
-				       sizeof(struct lpc_ich_info));
+	ret = platform_device_add_data(pdev, &tco_info, sizeof(tco_info));
 	if (ret) {
 		dev_err(ipcdev.dev, "Failed to add tco platform data\n");
 		goto err;

drivers/watchdog/iTCO_wdt.c

@@ -66,8 +66,7 @@
 #include <linux/spinlock.h>		/* For spin_lock/spin_unlock/... */
 #include <linux/uaccess.h>		/* For copy_to_user/put_user/... */
 #include <linux/io.h>			/* For inb/outb/... */
-#include <linux/mfd/core.h>
-#include <linux/mfd/lpc_ich.h>
+#include <linux/platform_data/itco_wdt.h>
 
 #include "iTCO_vendor.h"
 
@@ -418,9 +417,9 @@ static int iTCO_wdt_probe(struct platform_device *dev)
 {
 	int ret = -ENODEV;
 	unsigned long val32;
-	struct lpc_ich_info *ich_info = dev_get_platdata(&dev->dev);
+	struct itco_wdt_platform_data *pdata = dev_get_platdata(&dev->dev);
 
-	if (!ich_info)
+	if (!pdata)
 		goto out;
 
 	spin_lock_init(&iTCO_wdt_private.io_lock);
@@ -435,7 +434,7 @@ static int iTCO_wdt_probe(struct platform_device *dev)
 	if (!iTCO_wdt_private.smi_res)
 		goto out;
 
-	iTCO_wdt_private.iTCO_version = ich_info->iTCO_version;
+	iTCO_wdt_private.iTCO_version = pdata->version;
 	iTCO_wdt_private.dev = dev;
 	iTCO_wdt_private.pdev = to_pci_dev(dev->dev.parent);
 
@@ -501,7 +500,7 @@ static int iTCO_wdt_probe(struct platform_device *dev)
 	}
 
 	pr_info("Found a %s TCO device (Version=%d, TCOBASE=0x%04llx)\n",
-		ich_info->name, ich_info->iTCO_version, (u64)TCOBASE);
+		pdata->name, pdata->version, (u64)TCOBASE);
 
 	/* Clear out the (probably old) status */
 	if (iTCO_wdt_private.iTCO_version == 3) {

include/linux/mfd/lpc_ich.h

@@ -20,12 +20,6 @@
 #ifndef LPC_ICH_H
 #define LPC_ICH_H
 
-/* Watchdog resources */
-#define ICH_RES_IO_TCO		0
-#define ICH_RES_IO_SMI		1
-#define ICH_RES_MEM_OFF		2
-#define ICH_RES_MEM_GCS_PMC	0
-
 /* GPIO resources */
 #define ICH_RES_GPIO	0
 #define ICH_RES_GPE0	1

include/linux/platform_data/itco_wdt.h

@@ -0,0 +1,19 @@
+/*
+ * Platform data for the Intel TCO Watchdog
+ */
+
+#ifndef _ITCO_WDT_H_
+#define _ITCO_WDT_H_
+
+/* Watchdog resources */
+#define ICH_RES_IO_TCO		0
+#define ICH_RES_IO_SMI		1
+#define ICH_RES_MEM_OFF		2
+#define ICH_RES_MEM_GCS_PMC	0
+
+struct itco_wdt_platform_data {
+	char name[32];
+	unsigned int version;
+};
+
+#endif /* _ITCO_WDT_H_ */