Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1135 insertions, 0 deletions

diff --git a/drivers/sbus/char/envctrl.c b/drivers/sbus/char/envctrl.c
new file mode 100644
index 000000000..843e830b5
--- /dev/null
+++ b/drivers/sbus/char/envctrl.c
@@ -0,0 +1,1135 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* envctrl.c: Temperature and Fan monitoring on Machines providing it.
+ *
+ * Copyright (C) 1998  Eddie C. Dost  (ecd@skynet.be)
+ * Copyright (C) 2000  Vinh Truong    (vinh.truong@eng.sun.com)
+ * VT - The implementation is to support Sun Microelectronics (SME) platform
+ *      environment monitoring.  SME platforms use pcf8584 as the i2c bus 
+ *      controller to access pcf8591 (8-bit A/D and D/A converter) and 
+ *      pcf8571 (256 x 8-bit static low-voltage RAM with I2C-bus interface).
+ *      At board level, it follows SME Firmware I2C Specification. Reference:
+ * 	http://www-eu2.semiconductors.com/pip/PCF8584P
+ * 	http://www-eu2.semiconductors.com/pip/PCF8574AP
+ * 	http://www-eu2.semiconductors.com/pip/PCF8591P
+ *
+ * EB - Added support for CP1500 Global Address and PS/Voltage monitoring.
+ * 		Eric Brower <ebrower@usa.net>
+ *
+ * DB - Audit every copy_to_user in envctrl_read.
+ *              Daniele Bellucci <bellucda@tiscali.it>
+ */
+
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/delay.h>
+#include <linux/ioport.h>
+#include <linux/miscdevice.h>
+#include <linux/kmod.h>
+#include <linux/reboot.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+
+#include <linux/uaccess.h>
+#include <asm/envctrl.h>
+#include <asm/io.h>
+
+#define DRIVER_NAME	"envctrl"
+#define PFX		DRIVER_NAME ": "
+
+#define PCF8584_ADDRESS	0x55
+
+#define CONTROL_PIN	0x80
+#define CONTROL_ES0	0x40
+#define CONTROL_ES1	0x20
+#define CONTROL_ES2	0x10
+#define CONTROL_ENI	0x08
+#define CONTROL_STA	0x04
+#define CONTROL_STO	0x02
+#define CONTROL_ACK	0x01
+
+#define STATUS_PIN	0x80
+#define STATUS_STS	0x20
+#define STATUS_BER	0x10
+#define STATUS_LRB	0x08
+#define STATUS_AD0	0x08
+#define STATUS_AAB	0x04
+#define STATUS_LAB	0x02
+#define STATUS_BB	0x01
+
+/*
+ * CLK Mode Register.
+ */
+#define BUS_CLK_90	0x00
+#define BUS_CLK_45	0x01
+#define BUS_CLK_11	0x02
+#define BUS_CLK_1_5	0x03
+
+#define CLK_3		0x00
+#define CLK_4_43	0x10
+#define CLK_6		0x14
+#define CLK_8		0x18
+#define CLK_12		0x1c
+
+#define OBD_SEND_START	0xc5    /* value to generate I2c_bus START condition */
+#define OBD_SEND_STOP 	0xc3    /* value to generate I2c_bus STOP condition */
+
+/* Monitor type of i2c child device.
+ * Firmware definitions.
+ */
+#define PCF8584_MAX_CHANNELS            8
+#define PCF8584_GLOBALADDR_TYPE			6  /* global address monitor */
+#define PCF8584_FANSTAT_TYPE            3  /* fan status monitor */
+#define PCF8584_VOLTAGE_TYPE            2  /* voltage monitor    */
+#define PCF8584_TEMP_TYPE	        	1  /* temperature monitor*/
+
+/* Monitor type of i2c child device.
+ * Driver definitions.
+ */
+#define ENVCTRL_NOMON				0
+#define ENVCTRL_CPUTEMP_MON			1    /* cpu temperature monitor */
+#define ENVCTRL_CPUVOLTAGE_MON	  	2    /* voltage monitor         */
+#define ENVCTRL_FANSTAT_MON  		3    /* fan status monitor      */
+#define ENVCTRL_ETHERTEMP_MON		4    /* ethernet temperature */
+					     /* monitor                     */
+#define ENVCTRL_VOLTAGESTAT_MON	  	5    /* voltage status monitor  */
+#define ENVCTRL_MTHRBDTEMP_MON		6    /* motherboard temperature */
+#define ENVCTRL_SCSITEMP_MON		7    /* scsi temperature */
+#define ENVCTRL_GLOBALADDR_MON		8    /* global address */
+
+/* Child device type.
+ * Driver definitions.
+ */
+#define I2C_ADC				0    /* pcf8591 */
+#define I2C_GPIO			1    /* pcf8571 */
+
+/* Data read from child device may need to decode
+ * through a data table and a scale.
+ * Translation type as defined by firmware.
+ */
+#define ENVCTRL_TRANSLATE_NO		0
+#define ENVCTRL_TRANSLATE_PARTIAL	1
+#define ENVCTRL_TRANSLATE_COMBINED	2
+#define ENVCTRL_TRANSLATE_FULL		3     /* table[data] */
+#define ENVCTRL_TRANSLATE_SCALE		4     /* table[data]/scale */
+
+/* Driver miscellaneous definitions. */
+#define ENVCTRL_MAX_CPU			4
+#define CHANNEL_DESC_SZ			256
+
+/* Mask values for combined GlobalAddress/PowerStatus node */
+#define ENVCTRL_GLOBALADDR_ADDR_MASK 	0x1F
+#define ENVCTRL_GLOBALADDR_PSTAT_MASK	0x60
+
+/* Node 0x70 ignored on CompactPCI CP1400/1500 platforms 
+ * (see envctrl_init_i2c_child)
+ */
+#define ENVCTRL_CPCI_IGNORED_NODE		0x70
+
+#define PCF8584_DATA	0x00
+#define PCF8584_CSR	0x01
+
+/* Each child device can be monitored by up to PCF8584_MAX_CHANNELS.
+ * Property of a port or channel as defined by the firmware.
+ */
+struct pcf8584_channel {
+        unsigned char chnl_no;
+        unsigned char io_direction;
+        unsigned char type;
+        unsigned char last;
+};
+
+/* Each child device may have one or more tables of bytes to help decode
+ * data. Table property as defined by the firmware.
+ */ 
+struct pcf8584_tblprop {
+        unsigned int type;
+        unsigned int scale;  
+        unsigned int offset; /* offset from the beginning of the table */
+        unsigned int size;
+};
+
+/* i2c child */
+struct i2c_child_t {
+	/* Either ADC or GPIO. */
+	unsigned char i2ctype;
+        unsigned long addr;    
+        struct pcf8584_channel chnl_array[PCF8584_MAX_CHANNELS];
+
+	/* Channel info. */ 
+	unsigned int total_chnls;	/* Number of monitor channels. */
+	unsigned char fan_mask;		/* Byte mask for fan status channels. */
+	unsigned char voltage_mask;	/* Byte mask for voltage status channels. */
+        struct pcf8584_tblprop tblprop_array[PCF8584_MAX_CHANNELS];
+
+	/* Properties of all monitor channels. */
+	unsigned int total_tbls;	/* Number of monitor tables. */
+        char *tables;			/* Pointer to table(s). */
+	char chnls_desc[CHANNEL_DESC_SZ]; /* Channel description. */
+	char mon_type[PCF8584_MAX_CHANNELS];
+};
+
+static void __iomem *i2c;
+static struct i2c_child_t i2c_childlist[ENVCTRL_MAX_CPU*2];
+static unsigned char chnls_mask[] = { 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80 };
+static unsigned int warning_temperature = 0;
+static unsigned int shutdown_temperature = 0;
+static char read_cpu;
+
+/* Forward declarations. */
+static struct i2c_child_t *envctrl_get_i2c_child(unsigned char);
+
+/* Function Description: Test the PIN bit (Pending Interrupt Not) 
+ * 			 to test when serial transmission is completed .
+ * Return : None.
+ */
+static void envtrl_i2c_test_pin(void)
+{
+	int limit = 1000000;
+
+	while (--limit > 0) {
+		if (!(readb(i2c + PCF8584_CSR) & STATUS_PIN)) 
+			break;
+		udelay(1);
+	} 
+
+	if (limit <= 0)
+		printk(KERN_INFO PFX "Pin status will not clear.\n");
+}
+
+/* Function Description: Test busy bit.
+ * Return : None.
+ */
+static void envctrl_i2c_test_bb(void)
+{
+	int limit = 1000000;
+
+	while (--limit > 0) {
+		/* Busy bit 0 means busy. */
+		if (readb(i2c + PCF8584_CSR) & STATUS_BB)
+			break;
+		udelay(1);
+	} 
+
+	if (limit <= 0)
+		printk(KERN_INFO PFX "Busy bit will not clear.\n");
+}
+
+/* Function Description: Send the address for a read access.
+ * Return : 0 if not acknowledged, otherwise acknowledged.
+ */
+static int envctrl_i2c_read_addr(unsigned char addr)
+{
+	envctrl_i2c_test_bb();
+
+	/* Load address. */
+	writeb(addr + 1, i2c + PCF8584_DATA);
+
+	envctrl_i2c_test_bb();
+
+	writeb(OBD_SEND_START, i2c + PCF8584_CSR);
+
+	/* Wait for PIN. */
+	envtrl_i2c_test_pin();
+
+	/* CSR 0 means acknowledged. */
+	if (!(readb(i2c + PCF8584_CSR) & STATUS_LRB)) {
+		return readb(i2c + PCF8584_DATA);
+	} else {
+		writeb(OBD_SEND_STOP, i2c + PCF8584_CSR);
+		return 0;
+	}
+}
+
+/* Function Description: Send the address for write mode.  
+ * Return : None.
+ */
+static void envctrl_i2c_write_addr(unsigned char addr)
+{
+	envctrl_i2c_test_bb();
+	writeb(addr, i2c + PCF8584_DATA);
+
+	/* Generate Start condition. */
+	writeb(OBD_SEND_START, i2c + PCF8584_CSR);
+}
+
+/* Function Description: Read 1 byte of data from addr 
+ *			 set by envctrl_i2c_read_addr() 
+ * Return : Data from address set by envctrl_i2c_read_addr().
+ */
+static unsigned char envctrl_i2c_read_data(void)
+{
+	envtrl_i2c_test_pin();
+	writeb(CONTROL_ES0, i2c + PCF8584_CSR);  /* Send neg ack. */
+	return readb(i2c + PCF8584_DATA);
+}
+
+/* Function Description: Instruct the device which port to read data from.  
+ * Return : None.
+ */
+static void envctrl_i2c_write_data(unsigned char port)
+{
+	envtrl_i2c_test_pin();
+	writeb(port, i2c + PCF8584_DATA);
+}
+
+/* Function Description: Generate Stop condition after last byte is sent.
+ * Return : None.
+ */
+static void envctrl_i2c_stop(void)
+{
+	envtrl_i2c_test_pin();
+	writeb(OBD_SEND_STOP, i2c + PCF8584_CSR);
+}
+
+/* Function Description: Read adc device.
+ * Return : Data at address and port.
+ */
+static unsigned char envctrl_i2c_read_8591(unsigned char addr, unsigned char port)
+{
+	/* Send address. */
+	envctrl_i2c_write_addr(addr);
+
+	/* Setup port to read. */
+	envctrl_i2c_write_data(port);
+	envctrl_i2c_stop();
+
+	/* Read port. */
+	envctrl_i2c_read_addr(addr);
+
+	/* Do a single byte read and send stop. */
+	envctrl_i2c_read_data();
+	envctrl_i2c_stop();
+
+	return readb(i2c + PCF8584_DATA);
+}
+
+/* Function Description: Read gpio device.
+ * Return : Data at address.
+ */
+static unsigned char envctrl_i2c_read_8574(unsigned char addr)
+{
+	unsigned char rd;
+
+	envctrl_i2c_read_addr(addr);
+
+	/* Do a single byte read and send stop. */
+	rd = envctrl_i2c_read_data();
+	envctrl_i2c_stop();
+	return rd;
+}
+
+/* Function Description: Decode data read from an adc device using firmware
+ *                       table.
+ * Return: Number of read bytes. Data is stored in bufdata in ascii format.
+ */
+static int envctrl_i2c_data_translate(unsigned char data, int translate_type,
+				      int scale, char *tbl, char *bufdata)
+{
+	int len = 0;
+
+	switch (translate_type) {
+	case ENVCTRL_TRANSLATE_NO:
+		/* No decode necessary. */
+		len = 1;
+		bufdata[0] = data;
+		break;
+
+	case ENVCTRL_TRANSLATE_FULL:
+		/* Decode this way: data = table[data]. */
+		len = 1;
+		bufdata[0] = tbl[data];
+		break;
+
+	case ENVCTRL_TRANSLATE_SCALE:
+		/* Decode this way: data = table[data]/scale */
+		sprintf(bufdata,"%d ", (tbl[data] * 10) / (scale));
+		len = strlen(bufdata);
+		bufdata[len - 1] = bufdata[len - 2];
+		bufdata[len - 2] = '.';
+		break;
+
+	default:
+		break;
+	}
+
+	return len;
+}
+
+/* Function Description: Read cpu-related data such as cpu temperature, voltage.
+ * Return: Number of read bytes. Data is stored in bufdata in ascii format.
+ */
+static int envctrl_read_cpu_info(int cpu, struct i2c_child_t *pchild,
+				 char mon_type, unsigned char *bufdata)
+{
+	unsigned char data;
+	int i;
+	char *tbl, j = -1;
+
+	/* Find the right monitor type and channel. */
+	for (i = 0; i < PCF8584_MAX_CHANNELS; i++) {
+		if (pchild->mon_type[i] == mon_type) {
+			if (++j == cpu) {
+				break;
+			}
+		}
+	}
+
+	if (j != cpu)
+		return 0;
+
+        /* Read data from address and port. */
+	data = envctrl_i2c_read_8591((unsigned char)pchild->addr,
+				     (unsigned char)pchild->chnl_array[i].chnl_no);
+
+	/* Find decoding table. */
+	tbl = pchild->tables + pchild->tblprop_array[i].offset;
+
+	return envctrl_i2c_data_translate(data, pchild->tblprop_array[i].type,
+					  pchild->tblprop_array[i].scale,
+					  tbl, bufdata);
+}
+
+/* Function Description: Read noncpu-related data such as motherboard 
+ *                       temperature.
+ * Return: Number of read bytes. Data is stored in bufdata in ascii format.
+ */
+static int envctrl_read_noncpu_info(struct i2c_child_t *pchild,
+				    char mon_type, unsigned char *bufdata)
+{
+	unsigned char data;
+	int i;
+	char *tbl = NULL;
+
+	for (i = 0; i < PCF8584_MAX_CHANNELS; i++) {
+		if (pchild->mon_type[i] == mon_type)
+			break;
+	}
+
+	if (i >= PCF8584_MAX_CHANNELS)
+		return 0;
+
+        /* Read data from address and port. */
+	data = envctrl_i2c_read_8591((unsigned char)pchild->addr,
+				     (unsigned char)pchild->chnl_array[i].chnl_no);
+
+	/* Find decoding table. */
+	tbl = pchild->tables + pchild->tblprop_array[i].offset;
+
+	return envctrl_i2c_data_translate(data, pchild->tblprop_array[i].type,
+					  pchild->tblprop_array[i].scale,
+					  tbl, bufdata);
+}
+
+/* Function Description: Read fan status.
+ * Return : Always 1 byte. Status stored in bufdata.
+ */
+static int envctrl_i2c_fan_status(struct i2c_child_t *pchild,
+				  unsigned char data,
+				  char *bufdata)
+{
+	unsigned char tmp, ret = 0;
+	int i, j = 0;
+
+	tmp = data & pchild->fan_mask;
+
+	if (tmp == pchild->fan_mask) {
+		/* All bits are on. All fans are functioning. */
+		ret = ENVCTRL_ALL_FANS_GOOD;
+	} else if (tmp == 0) {
+		/* No bits are on. No fans are functioning. */
+		ret = ENVCTRL_ALL_FANS_BAD;
+	} else {
+		/* Go through all channels, mark 'on' the matched bits.
+		 * Notice that fan_mask may have discontiguous bits but
+		 * return mask are always contiguous. For example if we
+		 * monitor 4 fans at channels 0,1,2,4, the return mask
+		 * should be 00010000 if only fan at channel 4 is working.
+		 */
+		for (i = 0; i < PCF8584_MAX_CHANNELS;i++) {
+			if (pchild->fan_mask & chnls_mask[i]) {
+				if (!(chnls_mask[i] & tmp))
+					ret |= chnls_mask[j];
+
+				j++;
+			}
+		}
+	}
+
+	bufdata[0] = ret;
+	return 1;
+}
+
+/* Function Description: Read global addressing line.
+ * Return : Always 1 byte. Status stored in bufdata.
+ */
+static int envctrl_i2c_globaladdr(struct i2c_child_t *pchild,
+				  unsigned char data,
+				  char *bufdata)
+{
+	/* Translatation table is not necessary, as global
+	 * addr is the integer value of the GA# bits.
+	 *
+	 * NOTE: MSB is documented as zero, but I see it as '1' always....
+	 *
+	 * -----------------------------------------------
+	 * | 0 | FAL | DEG | GA4 | GA3 | GA2 | GA1 | GA0 |
+	 * -----------------------------------------------
+	 * GA0 - GA4	integer value of Global Address (backplane slot#)
+	 * DEG			0 = cPCI Power supply output is starting to degrade
+	 * 				1 = cPCI Power supply output is OK
+	 * FAL			0 = cPCI Power supply has failed
+	 * 				1 = cPCI Power supply output is OK
+	 */
+	bufdata[0] = (data & ENVCTRL_GLOBALADDR_ADDR_MASK);
+	return 1;
+}
+
+/* Function Description: Read standard voltage and power supply status.
+ * Return : Always 1 byte. Status stored in bufdata.
+ */
+static unsigned char envctrl_i2c_voltage_status(struct i2c_child_t *pchild,
+						unsigned char data,
+						char *bufdata)
+{
+	unsigned char tmp, ret = 0;
+	int i, j = 0;
+
+	tmp = data & pchild->voltage_mask;
+
+	/* Two channels are used to monitor voltage and power supply. */
+	if (tmp == pchild->voltage_mask) {
+		/* All bits are on. Voltage and power supply are okay. */
+		ret = ENVCTRL_VOLTAGE_POWERSUPPLY_GOOD;
+	} else if (tmp == 0) {
+		/* All bits are off. Voltage and power supply are bad */
+		ret = ENVCTRL_VOLTAGE_POWERSUPPLY_BAD;
+	} else {
+		/* Either voltage or power supply has problem. */
+		for (i = 0; i < PCF8584_MAX_CHANNELS; i++) {
+			if (pchild->voltage_mask & chnls_mask[i]) {
+				j++;
+
+				/* Break out when there is a mismatch. */
+				if (!(chnls_mask[i] & tmp))
+					break; 
+			}
+		}
+
+		/* Make a wish that hardware will always use the
+		 * first channel for voltage and the second for
+		 * power supply.
+		 */
+		if (j == 1)
+			ret = ENVCTRL_VOLTAGE_BAD;
+		else
+			ret = ENVCTRL_POWERSUPPLY_BAD;
+	}
+
+	bufdata[0] = ret;
+	return 1;
+}
+
+/* Function Description: Read a byte from /dev/envctrl. Mapped to user read().
+ * Return: Number of read bytes. 0 for error.
+ */
+static ssize_t
+envctrl_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+	struct i2c_child_t *pchild;
+	unsigned char data[10];
+	int ret = 0;
+
+	/* Get the type of read as decided in ioctl() call.
+	 * Find the appropriate i2c child.
+	 * Get the data and put back to the user buffer.
+	 */
+
+	switch ((int)(long)file->private_data) {
+	case ENVCTRL_RD_WARNING_TEMPERATURE:
+		if (warning_temperature == 0)
+			return 0;
+
+		data[0] = (unsigned char)(warning_temperature);
+		ret = 1;
+		if (copy_to_user(buf, data, ret))
+			ret = -EFAULT;
+		break;
+
+	case ENVCTRL_RD_SHUTDOWN_TEMPERATURE:
+		if (shutdown_temperature == 0)
+			return 0;
+
+		data[0] = (unsigned char)(shutdown_temperature);
+		ret = 1;
+		if (copy_to_user(buf, data, ret))
+			ret = -EFAULT;
+		break;
+
+	case ENVCTRL_RD_MTHRBD_TEMPERATURE:
+		if (!(pchild = envctrl_get_i2c_child(ENVCTRL_MTHRBDTEMP_MON)))
+			return 0;
+		ret = envctrl_read_noncpu_info(pchild, ENVCTRL_MTHRBDTEMP_MON, data);
+		if (copy_to_user(buf, data, ret))
+			ret = -EFAULT;
+		break;
+
+	case ENVCTRL_RD_CPU_TEMPERATURE:
+		if (!(pchild = envctrl_get_i2c_child(ENVCTRL_CPUTEMP_MON)))
+			return 0;
+		ret = envctrl_read_cpu_info(read_cpu, pchild, ENVCTRL_CPUTEMP_MON, data);
+
+		/* Reset cpu to the default cpu0. */
+		if (copy_to_user(buf, data, ret))
+			ret = -EFAULT;
+		break;
+
+	case ENVCTRL_RD_CPU_VOLTAGE:
+		if (!(pchild = envctrl_get_i2c_child(ENVCTRL_CPUVOLTAGE_MON)))
+			return 0;
+		ret = envctrl_read_cpu_info(read_cpu, pchild, ENVCTRL_CPUVOLTAGE_MON, data);
+
+		/* Reset cpu to the default cpu0. */
+		if (copy_to_user(buf, data, ret))
+			ret = -EFAULT;
+		break;
+
+	case ENVCTRL_RD_SCSI_TEMPERATURE:
+		if (!(pchild = envctrl_get_i2c_child(ENVCTRL_SCSITEMP_MON)))
+			return 0;
+		ret = envctrl_read_noncpu_info(pchild, ENVCTRL_SCSITEMP_MON, data);
+		if (copy_to_user(buf, data, ret))
+			ret = -EFAULT;
+		break;
+
+	case ENVCTRL_RD_ETHERNET_TEMPERATURE:
+		if (!(pchild = envctrl_get_i2c_child(ENVCTRL_ETHERTEMP_MON)))
+			return 0;
+		ret = envctrl_read_noncpu_info(pchild, ENVCTRL_ETHERTEMP_MON, data);
+		if (copy_to_user(buf, data, ret))
+			ret = -EFAULT;
+		break;
+
+	case ENVCTRL_RD_FAN_STATUS:
+		if (!(pchild = envctrl_get_i2c_child(ENVCTRL_FANSTAT_MON)))
+			return 0;
+		data[0] = envctrl_i2c_read_8574(pchild->addr);
+		ret = envctrl_i2c_fan_status(pchild,data[0], data);
+		if (copy_to_user(buf, data, ret))
+			ret = -EFAULT;
+		break;
+	
+	case ENVCTRL_RD_GLOBALADDRESS:
+		if (!(pchild = envctrl_get_i2c_child(ENVCTRL_GLOBALADDR_MON)))
+			return 0;
+		data[0] = envctrl_i2c_read_8574(pchild->addr);
+		ret = envctrl_i2c_globaladdr(pchild, data[0], data);
+		if (copy_to_user(buf, data, ret))
+			ret = -EFAULT;
+		break;
+
+	case ENVCTRL_RD_VOLTAGE_STATUS:
+		if (!(pchild = envctrl_get_i2c_child(ENVCTRL_VOLTAGESTAT_MON)))
+			/* If voltage monitor not present, check for CPCI equivalent */
+			if (!(pchild = envctrl_get_i2c_child(ENVCTRL_GLOBALADDR_MON)))
+				return 0;
+		data[0] = envctrl_i2c_read_8574(pchild->addr);
+		ret = envctrl_i2c_voltage_status(pchild, data[0], data);
+		if (copy_to_user(buf, data, ret))
+			ret = -EFAULT;
+		break;
+
+	default:
+		break;
+
+	}
+
+	return ret;
+}
+
+/* Function Description: Command what to read.  Mapped to user ioctl().
+ * Return: Gives 0 for implemented commands, -EINVAL otherwise.
+ */
+static long
+envctrl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	char __user *infobuf;
+
+	switch (cmd) {
+	case ENVCTRL_RD_WARNING_TEMPERATURE:
+	case ENVCTRL_RD_SHUTDOWN_TEMPERATURE:
+	case ENVCTRL_RD_MTHRBD_TEMPERATURE:
+	case ENVCTRL_RD_FAN_STATUS:
+	case ENVCTRL_RD_VOLTAGE_STATUS:
+	case ENVCTRL_RD_ETHERNET_TEMPERATURE:
+	case ENVCTRL_RD_SCSI_TEMPERATURE:
+	case ENVCTRL_RD_GLOBALADDRESS:
+		file->private_data = (void *)(long)cmd;
+		break;
+
+	case ENVCTRL_RD_CPU_TEMPERATURE:
+	case ENVCTRL_RD_CPU_VOLTAGE:
+		/* Check to see if application passes in any cpu number,
+		 * the default is cpu0.
+		 */
+		infobuf = (char __user *) arg;
+		if (infobuf == NULL) {
+			read_cpu = 0;
+		}else {
+			get_user(read_cpu, infobuf);
+		}
+
+		/* Save the command for use when reading. */
+		file->private_data = (void *)(long)cmd;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/* Function Description: open device. Mapped to user open().
+ * Return: Always 0.
+ */
+static int
+envctrl_open(struct inode *inode, struct file *file)
+{
+	file->private_data = NULL;
+	return 0;
+}
+
+/* Function Description: Open device. Mapped to user close().
+ * Return: Always 0.
+ */
+static int
+envctrl_release(struct inode *inode, struct file *file)
+{
+	return 0;
+}
+
+static const struct file_operations envctrl_fops = {
+	.owner =		THIS_MODULE,
+	.read =			envctrl_read,
+	.unlocked_ioctl =	envctrl_ioctl,
+	.compat_ioctl =		compat_ptr_ioctl,
+	.open =			envctrl_open,
+	.release =		envctrl_release,
+	.llseek =		noop_llseek,
+};	
+
+static struct miscdevice envctrl_dev = {
+	ENVCTRL_MINOR,
+	"envctrl",
+	&envctrl_fops
+};
+
+/* Function Description: Set monitor type based on firmware description.
+ * Return: None.
+ */
+static void envctrl_set_mon(struct i2c_child_t *pchild,
+			    const char *chnl_desc,
+			    int chnl_no)
+{
+	/* Firmware only has temperature type.  It does not distinguish
+	 * different kinds of temperatures.  We use channel description
+	 * to disinguish them.
+	 */
+	if (!(strcmp(chnl_desc,"temp,cpu")) ||
+	    !(strcmp(chnl_desc,"temp,cpu0")) ||
+	    !(strcmp(chnl_desc,"temp,cpu1")) ||
+	    !(strcmp(chnl_desc,"temp,cpu2")) ||
+	    !(strcmp(chnl_desc,"temp,cpu3")))
+		pchild->mon_type[chnl_no] = ENVCTRL_CPUTEMP_MON;
+
+	if (!(strcmp(chnl_desc,"vddcore,cpu0")) ||
+	    !(strcmp(chnl_desc,"vddcore,cpu1")) ||
+	    !(strcmp(chnl_desc,"vddcore,cpu2")) ||
+	    !(strcmp(chnl_desc,"vddcore,cpu3")))
+		pchild->mon_type[chnl_no] = ENVCTRL_CPUVOLTAGE_MON;
+
+	if (!(strcmp(chnl_desc,"temp,motherboard")))
+		pchild->mon_type[chnl_no] = ENVCTRL_MTHRBDTEMP_MON;
+
+	if (!(strcmp(chnl_desc,"temp,scsi")))
+		pchild->mon_type[chnl_no] = ENVCTRL_SCSITEMP_MON;
+
+	if (!(strcmp(chnl_desc,"temp,ethernet")))
+		pchild->mon_type[chnl_no] = ENVCTRL_ETHERTEMP_MON;
+}
+
+/* Function Description: Initialize monitor channel with channel desc,
+ *                       decoding tables, monitor type, optional properties.
+ * Return: None.
+ */
+static void envctrl_init_adc(struct i2c_child_t *pchild, struct device_node *dp)
+{
+	int i = 0, len;
+	const char *pos;
+	const unsigned int *pval;
+
+	/* Firmware describe channels into a stream separated by a '\0'. */
+	pos = of_get_property(dp, "channels-description", &len);
+
+	while (len > 0) {
+		int l = strlen(pos) + 1;
+		envctrl_set_mon(pchild, pos, i++);
+		len -= l;
+		pos += l;
+	}
+
+	/* Get optional properties. */
+	pval = of_get_property(dp, "warning-temp", NULL);
+	if (pval)
+		warning_temperature = *pval;
+
+	pval = of_get_property(dp, "shutdown-temp", NULL);
+	if (pval)
+		shutdown_temperature = *pval;
+}
+
+/* Function Description: Initialize child device monitoring fan status.
+ * Return: None.
+ */
+static void envctrl_init_fanstat(struct i2c_child_t *pchild)
+{
+	int i;
+
+	/* Go through all channels and set up the mask. */
+	for (i = 0; i < pchild->total_chnls; i++)
+		pchild->fan_mask |= chnls_mask[(pchild->chnl_array[i]).chnl_no];
+
+	/* We only need to know if this child has fan status monitored.
+	 * We don't care which channels since we have the mask already.
+	 */
+	pchild->mon_type[0] = ENVCTRL_FANSTAT_MON;
+}
+
+/* Function Description: Initialize child device for global addressing line.
+ * Return: None.
+ */
+static void envctrl_init_globaladdr(struct i2c_child_t *pchild)
+{
+	int i;
+
+	/* Voltage/PowerSupply monitoring is piggybacked 
+	 * with Global Address on CompactPCI.  See comments
+	 * within envctrl_i2c_globaladdr for bit assignments.
+	 *
+	 * The mask is created here by assigning mask bits to each
+	 * bit position that represents PCF8584_VOLTAGE_TYPE data.
+	 * Channel numbers are not consecutive within the globaladdr
+	 * node (why?), so we use the actual counter value as chnls_mask
+	 * index instead of the chnl_array[x].chnl_no value.
+	 *
+	 * NOTE: This loop could be replaced with a constant representing
+	 * a mask of bits 5&6 (ENVCTRL_GLOBALADDR_PSTAT_MASK).
+	 */
+	for (i = 0; i < pchild->total_chnls; i++) {
+		if (PCF8584_VOLTAGE_TYPE == pchild->chnl_array[i].type) {
+			pchild->voltage_mask |= chnls_mask[i];
+		}
+	}
+
+	/* We only need to know if this child has global addressing 
+	 * line monitored.  We don't care which channels since we know 
+	 * the mask already (ENVCTRL_GLOBALADDR_ADDR_MASK).
+	 */
+	pchild->mon_type[0] = ENVCTRL_GLOBALADDR_MON;
+}
+
+/* Initialize child device monitoring voltage status. */
+static void envctrl_init_voltage_status(struct i2c_child_t *pchild)
+{
+	int i;
+
+	/* Go through all channels and set up the mask. */
+	for (i = 0; i < pchild->total_chnls; i++)
+		pchild->voltage_mask |= chnls_mask[(pchild->chnl_array[i]).chnl_no];
+
+	/* We only need to know if this child has voltage status monitored.
+	 * We don't care which channels since we have the mask already.
+	 */
+	pchild->mon_type[0] = ENVCTRL_VOLTAGESTAT_MON;
+}
+
+/* Function Description: Initialize i2c child device.
+ * Return: None.
+ */
+static void envctrl_init_i2c_child(struct device_node *dp,
+				   struct i2c_child_t *pchild)
+{
+	int len, i, tbls_size = 0;
+	const void *pval;
+
+	/* Get device address. */
+	pval = of_get_property(dp, "reg", &len);
+	memcpy(&pchild->addr, pval, len);
+
+	/* Get tables property.  Read firmware temperature tables. */
+	pval = of_get_property(dp, "translation", &len);
+	if (pval && len > 0) {
+		memcpy(pchild->tblprop_array, pval, len);
+                pchild->total_tbls = len / sizeof(struct pcf8584_tblprop);
+		for (i = 0; i < pchild->total_tbls; i++) {
+			if ((pchild->tblprop_array[i].size + pchild->tblprop_array[i].offset) > tbls_size) {
+				tbls_size = pchild->tblprop_array[i].size + pchild->tblprop_array[i].offset;
+			}
+		}
+
+                pchild->tables = kmalloc(tbls_size, GFP_KERNEL);
+		if (pchild->tables == NULL){
+			printk(KERN_ERR PFX "Failed to allocate table.\n");
+			return;
+		}
+		pval = of_get_property(dp, "tables", &len);
+                if (!pval || len <= 0) {
+			printk(KERN_ERR PFX "Failed to get table.\n");
+			return;
+		}
+		memcpy(pchild->tables, pval, len);
+	}
+
+	/* SPARCengine ASM Reference Manual (ref. SMI doc 805-7581-04)
+	 * sections 2.5, 3.5, 4.5 state node 0x70 for CP1400/1500 is
+	 * "For Factory Use Only."
+	 *
+	 * We ignore the node on these platforms by assigning the
+	 * 'NULL' monitor type.
+	 */
+	if (ENVCTRL_CPCI_IGNORED_NODE == pchild->addr) {
+		struct device_node *root_node;
+		int len;
+
+		root_node = of_find_node_by_path("/");
+		if (of_node_name_eq(root_node, "SUNW,UltraSPARC-IIi-cEngine")) {
+			for (len = 0; len < PCF8584_MAX_CHANNELS; ++len) {
+				pchild->mon_type[len] = ENVCTRL_NOMON;
+			}
+			of_node_put(root_node);
+			return;
+		}
+		of_node_put(root_node);
+	}
+
+	/* Get the monitor channels. */
+	pval = of_get_property(dp, "channels-in-use", &len);
+	memcpy(pchild->chnl_array, pval, len);
+	pchild->total_chnls = len / sizeof(struct pcf8584_channel);
+
+	for (i = 0; i < pchild->total_chnls; i++) {
+		switch (pchild->chnl_array[i].type) {
+		case PCF8584_TEMP_TYPE:
+			envctrl_init_adc(pchild, dp);
+			break;
+
+		case PCF8584_GLOBALADDR_TYPE:
+			envctrl_init_globaladdr(pchild);
+			i = pchild->total_chnls;
+			break;
+
+		case PCF8584_FANSTAT_TYPE:
+			envctrl_init_fanstat(pchild);
+			i = pchild->total_chnls;
+			break;
+
+		case PCF8584_VOLTAGE_TYPE:
+			if (pchild->i2ctype == I2C_ADC) {
+				envctrl_init_adc(pchild,dp);
+			} else {
+				envctrl_init_voltage_status(pchild);
+			}
+			i = pchild->total_chnls;
+			break;
+
+		default:
+			break;
+		}
+	}
+}
+
+/* Function Description: Search the child device list for a device.
+ * Return : The i2c child if found. NULL otherwise.
+ */
+static struct i2c_child_t *envctrl_get_i2c_child(unsigned char mon_type)
+{
+	int i, j;
+
+	for (i = 0; i < ENVCTRL_MAX_CPU*2; i++) {
+		for (j = 0; j < PCF8584_MAX_CHANNELS; j++) {
+			if (i2c_childlist[i].mon_type[j] == mon_type) {
+				return (struct i2c_child_t *)(&(i2c_childlist[i]));
+			}
+		}
+	}
+	return NULL;
+}
+
+static void envctrl_do_shutdown(void)
+{
+	static int inprog = 0;
+
+	if (inprog != 0)
+		return;
+
+	inprog = 1;
+	printk(KERN_CRIT "kenvctrld: WARNING: Shutting down the system now.\n");
+	orderly_poweroff(true);
+}
+
+static struct task_struct *kenvctrld_task;
+
+static int kenvctrld(void *__unused)
+{
+	int poll_interval;
+	int whichcpu;
+	char tempbuf[10];
+	struct i2c_child_t *cputemp;
+
+	if (NULL == (cputemp = envctrl_get_i2c_child(ENVCTRL_CPUTEMP_MON))) {
+		printk(KERN_ERR  PFX
+		       "kenvctrld unable to monitor CPU temp-- exiting\n");
+		return -ENODEV;
+	}
+
+	poll_interval = 5000; /* TODO env_mon_interval */
+
+	printk(KERN_INFO PFX "%s starting...\n", current->comm);
+	for (;;) {
+		msleep_interruptible(poll_interval);
+
+		if (kthread_should_stop())
+			break;
+		
+		for (whichcpu = 0; whichcpu < ENVCTRL_MAX_CPU; ++whichcpu) {
+			if (0 < envctrl_read_cpu_info(whichcpu, cputemp,
+						      ENVCTRL_CPUTEMP_MON,
+						      tempbuf)) {
+				if (tempbuf[0] >= shutdown_temperature) {
+					printk(KERN_CRIT 
+						"%s: WARNING: CPU%i temperature %i C meets or exceeds "\
+						"shutdown threshold %i C\n", 
+						current->comm, whichcpu, 
+						tempbuf[0], shutdown_temperature);
+					envctrl_do_shutdown();
+				}
+			}
+		}
+	}
+	printk(KERN_INFO PFX "%s exiting...\n", current->comm);
+	return 0;
+}
+
+static int envctrl_probe(struct platform_device *op)
+{
+	struct device_node *dp;
+	int index, err;
+
+	if (i2c)
+		return -EINVAL;
+
+	i2c = of_ioremap(&op->resource[0], 0, 0x2, DRIVER_NAME);
+	if (!i2c)
+		return -ENOMEM;
+
+	index = 0;
+	dp = op->dev.of_node->child;
+	while (dp) {
+		if (of_node_name_eq(dp, "gpio")) {
+			i2c_childlist[index].i2ctype = I2C_GPIO;
+			envctrl_init_i2c_child(dp, &(i2c_childlist[index++]));
+		} else if (of_node_name_eq(dp, "adc")) {
+			i2c_childlist[index].i2ctype = I2C_ADC;
+			envctrl_init_i2c_child(dp, &(i2c_childlist[index++]));
+		}
+
+		dp = dp->sibling;
+	}
+
+	/* Set device address. */
+	writeb(CONTROL_PIN, i2c + PCF8584_CSR);
+	writeb(PCF8584_ADDRESS, i2c + PCF8584_DATA);
+
+	/* Set system clock and SCL frequencies. */ 
+	writeb(CONTROL_PIN | CONTROL_ES1, i2c + PCF8584_CSR);
+	writeb(CLK_4_43 | BUS_CLK_90, i2c + PCF8584_DATA);
+
+	/* Enable serial interface. */
+	writeb(CONTROL_PIN | CONTROL_ES0 | CONTROL_ACK, i2c + PCF8584_CSR);
+	udelay(200);
+
+	/* Register the device as a minor miscellaneous device. */
+	err = misc_register(&envctrl_dev);
+	if (err) {
+		printk(KERN_ERR PFX "Unable to get misc minor %d\n",
+		       envctrl_dev.minor);
+		goto out_iounmap;
+	}
+
+	/* Note above traversal routine post-incremented 'i' to accommodate 
+	 * a next child device, so we decrement before reverse-traversal of
+	 * child devices.
+	 */
+	printk(KERN_INFO PFX "Initialized ");
+	for (--index; index >= 0; --index) {
+		printk("[%s 0x%lx]%s", 
+			(I2C_ADC == i2c_childlist[index].i2ctype) ? "adc" : 
+			((I2C_GPIO == i2c_childlist[index].i2ctype) ? "gpio" : "unknown"), 
+			i2c_childlist[index].addr, (0 == index) ? "\n" : " ");
+	}
+
+	kenvctrld_task = kthread_run(kenvctrld, NULL, "kenvctrld");
+	if (IS_ERR(kenvctrld_task)) {
+		err = PTR_ERR(kenvctrld_task);
+		goto out_deregister;
+	}
+
+	return 0;
+
+out_deregister:
+	misc_deregister(&envctrl_dev);
+out_iounmap:
+	of_iounmap(&op->resource[0], i2c, 0x2);
+	for (index = 0; index < ENVCTRL_MAX_CPU * 2; index++)
+		kfree(i2c_childlist[index].tables);
+
+	return err;
+}
+
+static int envctrl_remove(struct platform_device *op)
+{
+	int index;
+
+	kthread_stop(kenvctrld_task);
+
+	of_iounmap(&op->resource[0], i2c, 0x2);
+	misc_deregister(&envctrl_dev);
+
+	for (index = 0; index < ENVCTRL_MAX_CPU * 2; index++)
+		kfree(i2c_childlist[index].tables);
+
+	return 0;
+}
+
+static const struct of_device_id envctrl_match[] = {
+	{
+		.name = "i2c",
+		.compatible = "i2cpcf,8584",
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, envctrl_match);
+
+static struct platform_driver envctrl_driver = {
+	.driver = {
+		.name = DRIVER_NAME,
+		.of_match_table = envctrl_match,
+	},
+	.probe		= envctrl_probe,
+	.remove		= envctrl_remove,
+};
+
+module_platform_driver(envctrl_driver);
+
+MODULE_LICENSE("GPL");