[AS9716-32D] Support i2c mux reset (#10492)

Why I did it
    Prevent from i2c bus to get locked.

How I did it
    Add sysfs driver to access ioport.
    Command to reset i2c mux:
    echo 1 > /sys/devices/platform/as9716_32d_ioport/i2c_mux_rst
    Command to bring i2c mux out of reset:
    echo 0 > /sys/devices/platform/as9716_32d_ioport/i2c_mux_rst

Signed-off-by: Brandon Chuang <brandon_chuang@edge-core.com>

device/accton/x86_64-accton_as9716_32d-r0/pddf/pddf-device.json

@@ -53,7 +53,8 @@
         ],
         "custom_kos":
         [
-            "pddf_custom_psu"
+            "pddf_custom_psu",
+            "accton_as9716_32d_ioport"
         ]
     },
 

platform/broadcom/sonic-platform-modules-accton/as9716-32d/modules/Makefile

@@ -1,7 +1,7 @@
 ifneq ($(KERNELRELEASE),)
 obj-m:= accton_as9716_32d_cpld.o accton_as9716_32d_fan.o  \
 	    accton_as9716_32d_leds.o accton_as9716_32d_psu.o accton_i2c_psu.o \
-            pddf_custom_psu.o 
+	    pddf_custom_psu.o accton_as9716_32d_ioport.o
 
 CFLAGS_pddf_custom_psu.o := -I$(M)/../../../../pddf/i2c/modules/include
 KBUILD_EXTRA_SYMBOLS := $(M)/../../../../pddf/i2c/Module.symvers.PDDF

platform/broadcom/sonic-platform-modules-accton/as9716-32d/modules/accton_as9716_32d_ioport.c

@@ -0,0 +1,180 @@
+/*
+ * A hwmon driver for the Accton as9926 24d fan
+ *
+ * Copyright (C) 2016 Accton Technology Corporation.
+ * Brandon Chuang <brandon_chuang@accton.com.tw>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/jiffies.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/sysfs.h>
+#include <linux/slab.h>
+#include <linux/dmi.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/ioport.h>
+#include <asm/io.h>
+
+#define DRVNAME "as9716_32d_ioport"
+#define IOPORT_I2C_MUX_RST 0x50D
+
+static ssize_t show_i2c_mux_rst(struct device *dev, struct device_attribute *da,
+		char *buf);
+static ssize_t set_i2c_mux_rst(struct device *dev, struct device_attribute *da,
+		const char *buf, size_t count);
+
+static struct as9716_ioport_data *data = NULL;
+
+/* ioport data */
+struct as9716_ioport_data {
+	struct platform_device *pdev;
+	struct device *hwmon_dev;
+	struct mutex update_lock;
+};
+
+/* sysfs attributes for hwmon
+ */
+static SENSOR_DEVICE_ATTR(i2c_mux_rst, S_IRUGO | S_IWUSR, show_i2c_mux_rst,
+			set_i2c_mux_rst, 0);
+
+static struct attribute *sys_attributes[] = {
+	&sensor_dev_attr_i2c_mux_rst.dev_attr.attr,
+	NULL
+};
+
+static struct attribute_group sys_group = {
+	.attrs = sys_attributes,
+};
+
+static ssize_t show_i2c_mux_rst(struct device *dev, struct device_attribute *da,
+			 char *buf)
+{
+	u8 val = 0;
+	mutex_lock(&data->update_lock);
+	val = inb(IOPORT_I2C_MUX_RST);
+	mutex_unlock(&data->update_lock);
+	return sprintf(buf, "%d\n", !(val & 0xEF));
+}
+
+static ssize_t set_i2c_mux_rst(struct device *dev, struct device_attribute *da,
+			const char *buf, size_t count)
+{
+	u8 val = 0;
+	long value = 0;
+	int status = 0;
+
+	status = kstrtol(buf, 10, &value);
+	if (status)
+		return status;
+
+	mutex_lock(&data->update_lock);
+
+	val = inb(IOPORT_I2C_MUX_RST);
+	if (value)
+		outb(val & 0xEF, IOPORT_I2C_MUX_RST);
+	else
+		outb(val | 0x10, IOPORT_I2C_MUX_RST);
+
+	mutex_unlock(&data->update_lock);
+	return count;
+}
+
+static int as9716_32d_ioport_probe(struct platform_device *pdev)
+{
+	int status = -1;
+
+	request_region(IOPORT_I2C_MUX_RST, 1, "mux_rst");
+
+	/* Register sysfs hooks */
+	status = sysfs_create_group(&pdev->dev.kobj, &sys_group);
+	if (status) {
+		goto exit;
+	}
+
+	dev_info(&pdev->dev, "device created\n");
+	return 0;
+
+exit:
+	sysfs_remove_group(&pdev->dev.kobj, &sys_group);
+	return status;
+}
+
+static int as9716_32d_ioport_remove(struct platform_device *pdev)
+{
+	sysfs_remove_group(&pdev->dev.kobj, &sys_group);
+	release_region(IOPORT_I2C_MUX_RST, 1);
+	return 0;
+}
+
+static struct platform_driver as9716_32d_ioport_driver = {
+	.probe	  = as9716_32d_ioport_probe,
+	.remove	 = as9716_32d_ioport_remove,
+	.driver	 = {
+		.name   = DRVNAME,
+		.owner  = THIS_MODULE,
+	},
+};
+
+static int __init as9716_32d_ioport_init(void)
+{
+	int ret;
+
+	data = kzalloc(sizeof(struct as9716_ioport_data), GFP_KERNEL);
+	if (!data) {
+		ret = -ENOMEM;
+		goto alloc_err;
+	}
+
+	mutex_init(&data->update_lock);
+
+	ret = platform_driver_register(&as9716_32d_ioport_driver);
+	if (ret < 0)
+		goto dri_reg_err;
+
+	data->pdev = platform_device_register_simple(DRVNAME, -1, NULL, 0);
+	if (IS_ERR(data->pdev)) {
+		ret = PTR_ERR(data->pdev);
+		goto dev_reg_err;
+	}
+
+	return 0;
+
+dev_reg_err:
+	platform_driver_unregister(&as9716_32d_ioport_driver);
+dri_reg_err:
+	kfree(data);
+alloc_err:
+	return ret;
+}
+
+static void __exit as9716_32d_ioport_exit(void)
+{
+	platform_device_unregister(data->pdev);
+	platform_driver_unregister(&as9716_32d_ioport_driver);
+	kfree(data);
+}
+
+module_init(as9716_32d_ioport_init);
+module_exit(as9716_32d_ioport_exit);
+
+MODULE_AUTHOR("Brandon Chuang <brandon_chuang@accton.com.tw>");
+MODULE_DESCRIPTION("as9716_32d_ioport driver");
+MODULE_LICENSE("GPL");