powerpc/windfarm: Add ad7417 sensor

For user by the upcoming windfarm_pm72 and windfarm_rm31

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 347 insertions, 0 deletions

diff --git a/drivers/macintosh/windfarm_ad7417_sensor.c b/drivers/macintosh/windfarm_ad7417_sensor.c
new file mode 100644
index 000000000000..ac3f243b9c5a
--- /dev/null
+++ b/drivers/macintosh/windfarm_ad7417_sensor.c
@@ -0,0 +1,347 @@
+/*
+ * 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 __devinit 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 __devinit 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 __devinit 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 __devexit 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 __devinit 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 __devexit 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");
+