powerpc/windfarm: Add Fan Control Unit controls for G5s

The FCU operates the fans on the earlier generation G5 machines,
this module will be used by upcoming windfarm drivers.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

drivers/macintosh/windfarm_fcu_controls.c

+/*
+ * Windfarm PowerMac thermal control. FCU fan control
+ *
+ * Copyright 2012 Benjamin Herrenschmidt, IBM Corp.
+ *
+ * Released under the term of the GNU GPL v2.
+ */
+#undef DEBUG
+
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/wait.h>
+#include <linux/i2c.h>
+#include <asm/prom.h>
+#include <asm/machdep.h>
+#include <asm/io.h>
+#include <asm/sections.h>
+
+#include "windfarm.h"
+#include "windfarm_mpu.h"
+
+#define VERSION "1.0"
+
+#ifdef DEBUG
+#define DBG(args...)	printk(args)
+#else
+#define DBG(args...)	do { } while(0)
+#endif
+
+/*
+ * This option is "weird" :) Basically, if you define this to 1
+ * the control loop for the RPMs fans (not PWMs) will apply the
+ * correction factor obtained from the PID to the actual RPM
+ * speed read from the FCU.
+ *
+ * If you define the below constant to 0, then it will be
+ * applied to the setpoint RPM speed, that is basically the
+ * speed we proviously "asked" for.
+ *
+ * I'm not sure which of these Apple's algorithm is supposed
+ * to use
+ */
+#define RPM_PID_USE_ACTUAL_SPEED	1
+
+/* Default min/max for pumps */
+#define CPU_PUMP_OUTPUT_MAX		3200
+#define CPU_PUMP_OUTPUT_MIN		1250
+
+#define FCU_FAN_RPM		0
+#define FCU_FAN_PWM		1
+
+struct wf_fcu_priv {
+	struct kref		ref;
+	struct i2c_client	*i2c;
+	struct mutex		lock;
+	struct list_head	fan_list;
+	int			rpm_shift;
+};
+
+struct wf_fcu_fan {
+	struct list_head	link;
+	int			id;
+	s32			min, max, target;
+	struct wf_fcu_priv	*fcu_priv;
+	struct wf_control	ctrl;
+};
+
+static void wf_fcu_release(struct kref *ref)
+{
+	struct wf_fcu_priv *pv = container_of(ref, struct wf_fcu_priv, ref);
+
+	kfree(pv);
+}
+
+static void wf_fcu_fan_release(struct wf_control *ct)
+{
+	struct wf_fcu_fan *fan = ct->priv;
+
+	kref_put(&fan->fcu_priv->ref, wf_fcu_release);
+	kfree(fan);
+}
+
+static int wf_fcu_read_reg(struct wf_fcu_priv *pv, int reg,
+			   unsigned char *buf, int nb)
+{
+	int tries, nr, nw;
+
+	mutex_lock(&pv->lock);
+
+	buf[0] = reg;
+	tries = 0;
+	for (;;) {
+		nw = i2c_master_send(pv->i2c, buf, 1);
+		if (nw > 0 || (nw < 0 && nw != -EIO) || tries >= 100)
+			break;
+		msleep(10);
+		++tries;
+	}
+	if (nw <= 0) {
+		pr_err("Failure writing address to FCU: %d", nw);
+		nr = nw;
+		goto bail;
+	}
+	tries = 0;
+	for (;;) {
+		nr = i2c_master_recv(pv->i2c, buf, nb);
+		if (nr > 0 || (nr < 0 && nr != -ENODEV) || tries >= 100)
+			break;
+		msleep(10);
+		++tries;
+	}
+	if (nr <= 0)
+		pr_err("wf_fcu: Failure reading data from FCU: %d", nw);
+ bail:
+	mutex_unlock(&pv->lock);
+	return nr;
+}
+
+static int wf_fcu_write_reg(struct wf_fcu_priv *pv, int reg,
+			    const unsigned char *ptr, int nb)
+{
+	int tries, nw;
+	unsigned char buf[16];
+
+	buf[0] = reg;
+	memcpy(buf+1, ptr, nb);
+	++nb;
+	tries = 0;
+	for (;;) {
+		nw = i2c_master_send(pv->i2c, buf, nb);
+		if (nw > 0 || (nw < 0 && nw != -EIO) || tries >= 100)
+			break;
+		msleep(10);
+		++tries;
+	}
+	if (nw < 0)
+		pr_err("wf_fcu: Failure writing to FCU: %d", nw);
+	return nw;
+}
+
+static int wf_fcu_fan_set_rpm(struct wf_control *ct, s32 value)
+{
+	struct wf_fcu_fan *fan = ct->priv;
+	struct wf_fcu_priv *pv = fan->fcu_priv;
+	int rc, shift = pv->rpm_shift;
+	unsigned char buf[2];
+
+	if (value < fan->min)
+		value = fan->min;
+	if (value > fan->max)
+		value = fan->max;
+
+	if (fan->target && fan->target == value)
+		return 0;
+	fan->target = value;
+
+	buf[0] = value >> (8 - shift);
+	buf[1] = value << shift;
+	rc = wf_fcu_write_reg(pv, 0x10 + (fan->id * 2), buf, 2);
+	if (rc < 0)
+		return -EIO;
+	return 0;
+}
+
+static int wf_fcu_fan_get_rpm(struct wf_control *ct, s32 *value)
+{
+	struct wf_fcu_fan *fan = ct->priv;
+	struct wf_fcu_priv *pv = fan->fcu_priv;
+	int rc, reg_base, shift = pv->rpm_shift;
+	unsigned char failure;
+	unsigned char active;
+	unsigned char buf[2];
+
+	rc = wf_fcu_read_reg(pv, 0xb, &failure, 1);
+	if (rc != 1)
+		return -EIO;
+	if ((failure & (1 << fan->id)) != 0)
+		return -EFAULT;
+	rc = wf_fcu_read_reg(pv, 0xd, &active, 1);
+	if (rc != 1)
+		return -EIO;
+	if ((active & (1 << fan->id)) == 0)
+		return -ENXIO;
+
+	/* Programmed value or real current speed */
+#if RPM_PID_USE_ACTUAL_SPEED
+	reg_base = 0x11;
+#else
+	reg_base = 0x10;
+#endif
+	rc = wf_fcu_read_reg(pv, reg_base + (fan->id * 2), buf, 2);
+	if (rc != 2)
+		return -EIO;
+
+	*value = (buf[0] << (8 - shift)) | buf[1] >> shift;
+
+	return 0;
+}
+
+static int wf_fcu_fan_set_pwm(struct wf_control *ct, s32 value)
+{
+	struct wf_fcu_fan *fan = ct->priv;
+	struct wf_fcu_priv *pv = fan->fcu_priv;
+	unsigned char buf[2];
+	int rc;
+
+	if (value < fan->min)
+		value = fan->min;
+	if (value > fan->max)
+		value = fan->max;
+
+	if (fan->target && fan->target == value)
+		return 0;
+	fan->target = value;
+
+	value = (value * 2559) / 1000;
+	buf[0] = value;
+	rc = wf_fcu_write_reg(pv, 0x30 + (fan->id * 2), buf, 1);
+	if (rc < 0)
+		return -EIO;
+	return 0;
+}
+
+static int wf_fcu_fan_get_pwm(struct wf_control *ct, s32 *value)
+{
+	struct wf_fcu_fan *fan = ct->priv;
+	struct wf_fcu_priv *pv = fan->fcu_priv;
+	unsigned char failure;
+	unsigned char active;
+	unsigned char buf[2];
+	int rc;
+
+	rc = wf_fcu_read_reg(pv, 0x2b, &failure, 1);
+	if (rc != 1)
+		return -EIO;
+	if ((failure & (1 << fan->id)) != 0)
+		return -EFAULT;
+	rc = wf_fcu_read_reg(pv, 0x2d, &active, 1);
+	if (rc != 1)
+		return -EIO;
+	if ((active & (1 << fan->id)) == 0)
+		return -ENXIO;
+
+	rc = wf_fcu_read_reg(pv, 0x30 + (fan->id * 2), buf, 1);
+	if (rc != 1)
+		return -EIO;
+
+	*value = (((s32)buf[0]) * 1000) / 2559;
+
+	return 0;
+}
+
+static s32 wf_fcu_fan_min(struct wf_control *ct)
+{
+	struct wf_fcu_fan *fan = ct->priv;
+
+	return fan->min;
+}
+
+static s32 wf_fcu_fan_max(struct wf_control *ct)
+{
+	struct wf_fcu_fan *fan = ct->priv;
+
+	return fan->max;
+}
+
+static const struct wf_control_ops wf_fcu_fan_rpm_ops = {
+	.set_value	= wf_fcu_fan_set_rpm,
+	.get_value	= wf_fcu_fan_get_rpm,
+	.get_min	= wf_fcu_fan_min,
+	.get_max	= wf_fcu_fan_max,
+	.release	= wf_fcu_fan_release,
+	.owner		= THIS_MODULE,
+};
+
+static const struct wf_control_ops wf_fcu_fan_pwm_ops = {
+	.set_value	= wf_fcu_fan_set_pwm,
+	.get_value	= wf_fcu_fan_get_pwm,
+	.get_min	= wf_fcu_fan_min,
+	.get_max	= wf_fcu_fan_max,
+	.release	= wf_fcu_fan_release,
+	.owner		= THIS_MODULE,
+};
+
+static void __devinit wf_fcu_get_pump_minmax(struct wf_fcu_fan *fan)
+{
+	const struct mpu_data *mpu = wf_get_mpu(0);
+	u16 pump_min = 0, pump_max = 0xffff;
+	u16 tmp[4];
+
+	/* Try to fetch pumps min/max infos from eeprom */
+	if (mpu) {
+		memcpy(&tmp, mpu->processor_part_num, 8);
+		if (tmp[0] != 0xffff && tmp[1] != 0xffff) {
+			pump_min = max(pump_min, tmp[0]);
+			pump_max = min(pump_max, tmp[1]);
+		}
+		if (tmp[2] != 0xffff && tmp[3] != 0xffff) {
+			pump_min = max(pump_min, tmp[2]);
+			pump_max = min(pump_max, tmp[3]);
+		}
+	}
+
+	/* Double check the values, this _IS_ needed as the EEPROM on
+	 * some dual 2.5Ghz G5s seem, at least, to have both min & max
+	 * same to the same value ... (grrrr)
+	 */
+	if (pump_min == pump_max || pump_min == 0 || pump_max == 0xffff) {
+		pump_min = CPU_PUMP_OUTPUT_MIN;
+		pump_max = CPU_PUMP_OUTPUT_MAX;
+	}
+
+	fan->min = pump_min;
+	fan->max = pump_max;
+
+	DBG("wf_fcu: pump min/max for %s set to: [%d..%d] RPM\n",
+	    fan->ctrl.name, pump_min, pump_max);
+}
+
+static void __devinit wf_fcu_get_rpmfan_minmax(struct wf_fcu_fan *fan)
+{
+	struct wf_fcu_priv *pv = fan->fcu_priv;
+	const struct mpu_data *mpu0 = wf_get_mpu(0);
+	const struct mpu_data *mpu1 = wf_get_mpu(1);
+
+	/* Default */
+	fan->min = 2400 >> pv->rpm_shift;
+	fan->max = 56000 >> pv->rpm_shift;
+
+	/* CPU fans have min/max in MPU */
+	if (mpu0 && !strcmp(fan->ctrl.name, "cpu-front-fan-0")) {
+		fan->min = max(fan->min, (s32)mpu0->rminn_intake_fan);
+		fan->max = min(fan->max, (s32)mpu0->rmaxn_intake_fan);
+		goto bail;
+	}
+	if (mpu1 && !strcmp(fan->ctrl.name, "cpu-front-fan-1")) {
+		fan->min = max(fan->min, (s32)mpu1->rminn_intake_fan);
+		fan->max = min(fan->max, (s32)mpu1->rmaxn_intake_fan);
+		goto bail;
+	}
+	if (mpu0 && !strcmp(fan->ctrl.name, "cpu-rear-fan-0")) {
+		fan->min = max(fan->min, (s32)mpu0->rminn_exhaust_fan);
+		fan->max = min(fan->max, (s32)mpu0->rmaxn_exhaust_fan);
+		goto bail;
+	}
+	if (mpu1 && !strcmp(fan->ctrl.name, "cpu-rear-fan-1")) {
+		fan->min = max(fan->min, (s32)mpu1->rminn_exhaust_fan);
+		fan->max = min(fan->max, (s32)mpu1->rmaxn_exhaust_fan);
+		goto bail;
+	}
+	/* Rackmac variants, we just use mpu0 intake */
+	if (!strncmp(fan->ctrl.name, "cpu-fan", 7)) {
+		fan->min = max(fan->min, (s32)mpu0->rminn_intake_fan);
+		fan->max = min(fan->max, (s32)mpu0->rmaxn_intake_fan);
+		goto bail;
+	}
+ bail:
+	DBG("wf_fcu: fan min/max for %s set to: [%d..%d] RPM\n",
+	    fan->ctrl.name, fan->min, fan->max);
+}
+
+static void __devinit wf_fcu_add_fan(struct wf_fcu_priv *pv,
+				     const char *name,
+				     int type, int id)
+{
+	struct wf_fcu_fan *fan;
+
+	fan = kzalloc(sizeof(*fan), GFP_KERNEL);
+	if (!fan)
+		return;
+	fan->fcu_priv = pv;
+	fan->id = id;
+	fan->ctrl.name = name;
+	fan->ctrl.priv = fan;
+
+	/* min/max is oddball but the code comes from
+	 * therm_pm72 which seems to work so ...
+	 */
+	if (type == FCU_FAN_RPM) {
+		if (!strncmp(name, "cpu-pump", strlen("cpu-pump")))
+			wf_fcu_get_pump_minmax(fan);
+		else
+			wf_fcu_get_rpmfan_minmax(fan);
+		fan->ctrl.type = WF_CONTROL_RPM_FAN;
+		fan->ctrl.ops = &wf_fcu_fan_rpm_ops;
+	} else {
+		fan->min = 10;
+		fan->max = 100;
+		fan->ctrl.type = WF_CONTROL_PWM_FAN;
+		fan->ctrl.ops = &wf_fcu_fan_pwm_ops;
+	}
+
+	if (wf_register_control(&fan->ctrl)) {
+		pr_err("wf_fcu: Failed to register fan %s\n", name);
+		kfree(fan);
+		return;
+	}
+	list_add(&fan->link, &pv->fan_list);
+	kref_get(&pv->ref);
+}
+
+static void __devinit wf_fcu_lookup_fans(struct wf_fcu_priv *pv)
+{
+	/* Translation of device-tree location properties to
+	 * windfarm fan names
+	 */
+	static const struct {
+		const char *dt_name;	/* Device-tree name */
+		const char *ct_name;	/* Control name */
+	} loc_trans[] = {
+		{ "BACKSIDE",		"backside-fan",		},
+		{ "SYS CTRLR FAN",	"backside-fan",		},
+		{ "DRIVE BAY",		"drive-bay-fan",	},
+		{ "SLOT",		"slots-fan",		},
+		{ "PCI FAN",		"slots-fan",		},
+		{ "CPU A INTAKE",	"cpu-front-fan-0",	},
+		{ "CPU A EXHAUST",	"cpu-rear-fan-0",	},
+		{ "CPU B INTAKE",	"cpu-front-fan-1",	},
+		{ "CPU B EXHAUST",	"cpu-rear-fan-1",	},
+		{ "CPU A PUMP",		"cpu-pump-0",		},
+		{ "CPU B PUMP",		"cpu-pump-1",		},
+		{ "CPU A 1",		"cpu-fan-a-0",		},
+		{ "CPU A 2",		"cpu-fan-b-0",		},
+		{ "CPU A 3",		"cpu-fan-c-0",		},
+		{ "CPU B 1",		"cpu-fan-a-1",		},
+		{ "CPU B 2",		"cpu-fan-b-1",		},
+		{ "CPU B 3",		"cpu-fan-c-1",		},
+	};
+	struct device_node *np = NULL, *fcu = pv->i2c->dev.of_node;
+	int i;
+
+	DBG("Looking up FCU controls in device-tree...\n");
+
+	while ((np = of_get_next_child(fcu, np)) != NULL) {
+		int id, type = -1;
+		const char *loc;
+		const char *name;
+		const u32 *reg;
+
+		DBG(" control: %s, type: %s\n", np->name, np->type);
+
+		/* Detect control type */
+		if (!strcmp(np->type, "fan-rpm-control") ||
+		    !strcmp(np->type, "fan-rpm"))
+			type = FCU_FAN_RPM;
+		if (!strcmp(np->type, "fan-pwm-control") ||
+		    !strcmp(np->type, "fan-pwm"))
+			type = FCU_FAN_PWM;
+		/* Only care about fans for now */
+		if (type == -1)
+			continue;
+
+		/* Lookup for a matching location */
+		loc = of_get_property(np, "location", NULL);
+		reg = of_get_property(np, "reg", NULL);
+		if (loc == NULL || reg == NULL)
+			continue;
+		DBG(" matching location: %s, reg: 0x%08x\n", loc, *reg);
+
+		for (i = 0; i < ARRAY_SIZE(loc_trans); i++) {
+			if (strncmp(loc, loc_trans[i].dt_name,
+				    strlen(loc_trans[i].dt_name)))
+				continue;
+			name = loc_trans[i].ct_name;
+
+			DBG(" location match, name: %s\n", name);
+
+			if (type == FCU_FAN_RPM)
+				id = ((*reg) - 0x10) / 2;
+			else
+				id = ((*reg) - 0x30) / 2;
+			if (id > 7) {
+				pr_warning("wf_fcu: Can't parse "
+				       "fan ID in device-tree for %s\n",
+					   np->full_name);
+				break;
+			}
+			wf_fcu_add_fan(pv, name, type, id);
+			break;
+		}
+	}
+}
+
+static void __devinit wf_fcu_default_fans(struct wf_fcu_priv *pv)
+{
+	/* We only support the default fans for PowerMac7,2 */
+	if (!of_machine_is_compatible("PowerMac7,2"))
+		return;
+
+	wf_fcu_add_fan(pv, "backside-fan",	FCU_FAN_PWM, 1);
+	wf_fcu_add_fan(pv, "drive-bay-fan",	FCU_FAN_RPM, 2);
+	wf_fcu_add_fan(pv, "slots-fan",		FCU_FAN_PWM, 2);
+	wf_fcu_add_fan(pv, "cpu-front-fan-0",	FCU_FAN_RPM, 3);
+	wf_fcu_add_fan(pv, "cpu-rear-fan-0",	FCU_FAN_RPM, 4);
+	wf_fcu_add_fan(pv, "cpu-front-fan-1",	FCU_FAN_RPM, 5);
+	wf_fcu_add_fan(pv, "cpu-rear-fan-1",	FCU_FAN_RPM, 6);
+}
+
+static int __devinit wf_fcu_init_chip(struct wf_fcu_priv *pv)
+{
+	unsigned char buf = 0xff;
+	int rc;
+
+	rc = wf_fcu_write_reg(pv, 0xe, &buf, 1);
+	if (rc < 0)
+		return -EIO;
+	rc = wf_fcu_write_reg(pv, 0x2e, &buf, 1);
+	if (rc < 0)
+		return -EIO;
+	rc = wf_fcu_read_reg(pv, 0, &buf, 1);
+	if (rc < 0)
+		return -EIO;
+	pv->rpm_shift = (buf == 1) ? 2 : 3;
+
+	pr_debug("wf_fcu: FCU Initialized, RPM fan shift is %d\n",
+		 pv->rpm_shift);
+
+	return 0;
+}
+
+static int __devinit wf_fcu_probe(struct i2c_client *client,
+				  const struct i2c_device_id *id)
+{
+	struct wf_fcu_priv *pv;
+
+	pv = kzalloc(sizeof(*pv), GFP_KERNEL);
+	if (!pv)
+		return -ENOMEM;
+
+	kref_init(&pv->ref);
+	mutex_init(&pv->lock);
+	INIT_LIST_HEAD(&pv->fan_list);
+	pv->i2c = client;
+
+	/*
+	 * First we must start the FCU which will query the
+	 * shift value to apply to RPMs
+	 */
+	if (wf_fcu_init_chip(pv)) {
+		pr_err("wf_fcu: Initialization failed !\n");
+		kfree(pv);
+		return -ENXIO;
+	}
+
+	/* First lookup fans in the device-tree */
+	wf_fcu_lookup_fans(pv);
+
+	/*
+	 * Older machines don't have the device-tree entries
+	 * we are looking for, just hard code the list
+	 */
+	if (list_empty(&pv->fan_list))
+		wf_fcu_default_fans(pv);
+
+	/* Still no fans ? FAIL */
+	if (list_empty(&pv->fan_list)) {
+		pr_err("wf_fcu: Failed to find fans for your machine\n");
+		kfree(pv);
+		return -ENODEV;
+	}
+
+	dev_set_drvdata(&client->dev, pv);
+
+	return 0;
+}
+
+static int __devexit wf_fcu_remove(struct i2c_client *client)
+{
+	struct wf_fcu_priv *pv = dev_get_drvdata(&client->dev);
+	struct wf_fcu_fan *fan;
+
+	while (!list_empty(&pv->fan_list)) {
+		fan = list_first_entry(&pv->fan_list, struct wf_fcu_fan, link);
+		list_del(&fan->link);
+		wf_unregister_control(&fan->ctrl);
+	}
+	kref_put(&pv->ref, wf_fcu_release);
+	return 0;
+}
+
+static const struct i2c_device_id wf_fcu_id[] = {
+	{ "MAC,fcu", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, wf_fcu_id);
+
+static struct i2c_driver wf_fcu_driver = {
+	.driver = {
+		.name	= "wf_fcu",
+	},
+	.probe		= wf_fcu_probe,
+	.remove		= wf_fcu_remove,
+	.id_table	= wf_fcu_id,
+};
+
+static int __init wf_fcu_init(void)
+{
+	return i2c_add_driver(&wf_fcu_driver);
+}
+
+static void __exit wf_fcu_exit(void)
+{
+	i2c_del_driver(&wf_fcu_driver);
+}
+
+
+module_init(wf_fcu_init);
+module_exit(wf_fcu_exit);
+
+MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
+MODULE_DESCRIPTION("FCU control objects for PowerMacs thermal control");
+MODULE_LICENSE("GPL");
+