/*
* Windfarm PowerMac thermal control. AD7417 sensors
*
* Copyright 2012 Benjamin Herrenschmidt, IBM Corp.
*
* Released under the term of the GNU GPL v2.
*/
#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"
struct wf_ad7417_priv {
struct kref ref;
struct i2c_client *i2c;
u8 config;
u8 cpu;
const struct mpu_data *mpu;
struct wf_sensor sensors[5];
struct mutex lock;
};
static int wf_ad7417_temp_get(struct wf_sensor *sr, s32 *value)
{
struct wf_ad7417_priv *pv = sr->priv;
u8 buf[2];
s16 raw;
int rc;
*value = 0;
mutex_lock(&pv->lock);
/* Read temp register */
buf[0] = 0;
rc = i2c_master_send(pv->i2c, buf, 1);
if (rc < 0)
goto error;
rc = i2c_master_recv(pv->i2c, buf, 2);
if (rc < 0)
goto error;
/* Read a a 16-bit signed value */
raw = be16_to_cpup((__le16 *)buf);
/* Convert 8.8-bit to 16.16 fixed point */
*value = ((s32)raw) << 8;
mutex_unlock(&pv->lock);
return 0;
error:
mutex_unlock(&pv->lock);
return -1;
}
/*
* Scaling factors for the AD7417 ADC converters (except
* for the CPU diode which is obtained from the EEPROM).
* Those values are obtained from the property list of
* the darwin driver
*/
#define ADC_12V_CURRENT_SCALE 0x0320 /* _AD2 */
#define ADC_CPU_VOLTAGE_SCALE 0x00a0 /* _AD3 */
#define ADC_CPU_CURRENT_SCALE 0x1f40 /* _AD4 */
static void wf_ad7417_adc_convert(struct wf_ad7417_priv *pv,
int chan, s32 raw, s32 *value)
{
switch(chan) {
case 1: /* Diode */
*value = (raw * (s32)pv->mpu->mdiode +
((s32)pv->mpu->bdiode << 12)) >> 2;
break;
case 2: /* 12v current */
*value = raw * ADC_12V_CURRENT_SCALE;
break;
case 3: /* core voltage */
*value = raw * ADC_CPU_VOLTAGE_SCALE;
break;
case 4: /* core current */
*value = raw * ADC_CPU_CURRENT_SCALE;
break;
}
}
static int wf_ad7417_adc_get(struct wf_sensor *sr, s32 *value)
{
struct wf_ad7417_priv *pv = sr->priv;
int chan = sr - pv->sensors;
int i, rc;
u8 buf[2];
u16 raw;
*value = 0;
mutex_lock(&pv->lock);
for (i = 0; i < 10; i++) {
/* Set channel */
buf[0] = 1;
buf[1] = (pv->config & 0x1f) | (chan << 5);
rc = i2c_master_send(pv->i2c, buf, 2);
if (rc < 0)
goto error;
/* Wait for conversion */
msleep(1);
/* Switch to data register */
buf[0] = 4;
rc = i2c_master_send(pv->i2c, buf, 1);
if (rc < 0)
goto error;
/* Read result */
rc = i2c_master_recv(pv->i2c, buf, 2);
if (rc < 0)
goto error;
/* Read a a 16-bit signed value */
raw = be16_to_cpup((__le16 *)buf) >> 6;
wf_ad7417_adc_convert(pv, chan, raw, value);
dev_vdbg(&pv->i2c->dev, "ADC chan %d [%s]"
" raw value: 0x%x, conv to: 0x%08x\n",
chan, sr->name, raw, *value);
mutex_unlock(&pv->lock);
return 0;
error:
dev_dbg(&pv->i2c->dev,
"Error reading ADC, try %d...\n", i);
if (i < 9)
msleep(10);
}
mutex_unlock(&pv->lock);
return -1;
}
static void wf_ad7417_release(struct kref *ref)
{
struct wf_ad7417_priv *pv = container_of(ref,
struct wf_ad7417_priv, ref);
kfree(pv);
}
static void wf_ad7417_sensor_release(struct wf_sensor *sr)
{
struct wf_ad7417_priv *pv = sr->priv;
kfree(sr->name);
kref_put(&pv->ref, wf_ad7417_release);
}
static const struct wf_sensor_ops wf_ad7417_temp_ops = {
.get_value = wf_ad7417_temp_get,
.release = wf_ad7417_sensor_release,
.owner = THIS_MODULE,
};
static const struct wf_sensor_ops wf_ad7417_adc_ops = {
.get_value = wf_ad7417_adc_get,
.release = wf_ad7417_sensor_release,
.owner = THIS_MODULE,
};
static void wf_ad7417_add_sensor(struct wf_ad7417_priv *pv,
int index, const char *name,
const struct wf_sensor_ops *ops)
{
pv->sensors[index].name = kasprintf(GFP_KERNEL, "%s-%d", name, pv->cpu);
pv->sensors[index].priv = pv;
pv->sensors[index].ops = ops;
if (!wf_register_sensor(&pv->sensors[index]))
kref_get(&pv->ref);
}
static void wf_ad7417_init_chip(struct wf_ad7417_priv *pv)
{
int rc;
u8 buf[2];
u8 config = 0;
/*
* Read ADC the configuration register and cache it. We
* also make sure Config2 contains proper values, I've seen
* cases where we got stale grabage in there, thus preventing
* proper reading of conv. values
*/
/* Clear Config2 */
buf[0] = 5;
buf[1] = 0;
i2c_master_send(pv->i2c, buf, 2);
/* Read & cache Config1 */
buf[0] = 1;
rc = i2c_master_send(pv->i2c, buf, 1);
if (rc > 0) {
rc = i2c_master_recv(pv->i2c, buf, 1);
if (rc > 0) {
config = buf[0];
dev_dbg(&pv->i2c->dev, "ADC config reg: %02x\n",
config);
/* Disable shutdown mode */
config &= 0xfe;
buf[0] = 1;
buf[1] = config;
rc = i2c_master_send(pv->i2c, buf, 2);
}
}
if (rc <= 0)
dev_err(&pv->i2c->dev, "Error reading ADC config\n");
pv->config = config;
}
static int wf_ad7417_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct wf_ad7417_priv *pv;
const struct mpu_data *mpu;
const char *loc;
int cpu_nr;
loc = of_get_property(client->dev.of_node, "hwsensor-location", NULL);
if (!loc) {
dev_warn(&client->dev, "Missing hwsensor-location property!\n");
return -ENXIO;
}
/*
* Identify which CPU we belong to by looking at the first entry
* in the hwsensor-location list
*/
if (!strncmp(loc, "CPU A", 5))
cpu_nr = 0;
else if (!strncmp(loc, "CPU B", 5))
cpu_nr = 1;
else {
pr_err("wf_ad7417: Can't identify location %s\n", loc);
return -ENXIO;
}
mpu = wf_get_mpu(cpu_nr);
if (!mpu) {
dev_err(&client->dev, "Failed to retrieve MPU data\n");
return -ENXIO;
}
pv = kzalloc(sizeof(struct wf_ad7417_priv), GFP_KERNEL);
if (pv == NULL)
return -ENODEV;
kref_init(&pv->ref);
mutex_init(&pv->lock);
pv->i2c = client;
pv->cpu = cpu_nr;
pv->mpu = mpu;
dev_set_drvdata(&client->dev, pv);
/* Initialize the chip */
wf_ad7417_init_chip(pv);
/*
* We cannot rely on Apple device-tree giving us child
* node with the names of the individual sensors so we
* just hard code what we know about them
*/
wf_ad7417_add_sensor(pv, 0, "cpu-amb-temp", &wf_ad7417_temp_ops);
wf_ad7417_add_sensor(pv, 1, "cpu-diode-temp", &wf_ad7417_adc_ops);
wf_ad7417_add_sensor(pv, 2, "cpu-12v-current", &wf_ad7417_adc_ops);
wf_ad7417_add_sensor(pv, 3, "cpu-voltage", &wf_ad7417_adc_ops);
wf_ad7417_add_sensor(pv, 4, "cpu-current", &wf_ad7417_adc_ops);
return 0;
}
static int wf_ad7417_remove(struct i2c_client *client)
{
struct wf_ad7417_priv *pv = dev_get_drvdata(&client->dev);
int i;
/* Mark client detached */
pv->i2c = NULL;
/* Release sensor */
for (i = 0; i < 5; i++)
wf_unregister_sensor(&pv->sensors[i]);
kref_put(&pv->ref, wf_ad7417_release);
return 0;
}
static const struct i2c_device_id wf_ad7417_id[] = {
{ "MAC,ad7417", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, wf_ad7417_id);
static struct i2c_driver wf_ad7417_driver = {
.driver = {
.name = "wf_ad7417",
},
.probe = wf_ad7417_probe,
.remove = wf_ad7417_remove,
.id_table = wf_ad7417_id,
};
static int wf_ad7417_init(void)
{
/* This is only supported on these machines */
if (!of_machine_is_compatible("PowerMac7,2") &&
!of_machine_is_compatible("PowerMac7,3") &&
!of_machine_is_compatible("RackMac3,1"))
return -ENODEV;
return i2c_add_driver(&wf_ad7417_driver);
}
static void wf_ad7417_exit(void)
{
i2c_del_driver(&wf_ad7417_driver);
}
module_init(wf_ad7417_init);
module_exit(wf_ad7417_exit);
MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
MODULE_DESCRIPTION("ad7417 sensor driver for PowerMacs");
MODULE_LICENSE("GPL");
