[PATCH] I2C: add new atxp1 driver

Adds support for the Attansic ATXP1 I2C device, found on some x86
plattforms to change CPU and other voltages.  Depends on the previous
i2c-vid.h patch.

Signed-off-by: Sebastian Witt <se.witt@gmx.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 361 insertions, 0 deletions

diff --git a/drivers/i2c/chips/atxp1.c b/drivers/i2c/chips/atxp1.c
new file mode 100644
index 000000000000..570b36c6c2ac
--- /dev/null
+++ b/drivers/i2c/chips/atxp1.c
@@ -0,0 +1,361 @@
+/*
+    atxp1.c - kernel module for setting CPU VID and general purpose
+                     I/Os using the Attansic ATXP1 chip.
+
+    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/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/i2c-sensor.h>
+#include <linux/i2c-vid.h>
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("System voltages control via Attansic ATXP1");
+MODULE_VERSION("0.6.2");
+MODULE_AUTHOR("Sebastian Witt <se.witt@gmx.net>");
+
+#define ATXP1_VID       0x00
+#define ATXP1_CVID      0x01
+#define ATXP1_GPIO1     0x06
+#define ATXP1_GPIO2     0x0a
+#define ATXP1_VIDENA    0x20
+#define ATXP1_VIDMASK   0x1f
+#define ATXP1_GPIO1MASK 0x0f
+
+static unsigned short normal_i2c[] = { 0x37, 0x4e, I2C_CLIENT_END };
+static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };
+
+SENSORS_INSMOD_1(atxp1);
+
+static int atxp1_attach_adapter(struct i2c_adapter * adapter);
+static int atxp1_detach_client(struct i2c_client * client);
+static struct atxp1_data * atxp1_update_device(struct device *dev);
+static int atxp1_detect(struct i2c_adapter *adapter, int address, int kind);
+
+static struct i2c_driver atxp1_driver = {
+        .owner          = THIS_MODULE,
+        .name           = "atxp1",
+        .flags          = I2C_DF_NOTIFY,
+        .attach_adapter = atxp1_attach_adapter,
+        .detach_client  = atxp1_detach_client,
+};
+
+struct atxp1_data {
+        struct i2c_client client;
+        struct semaphore update_lock;
+        unsigned long last_updated;
+        u8 valid;
+        struct {
+                u8 vid;         /* VID output register */
+                u8 cpu_vid; /* VID input from CPU */
+                u8 gpio1;   /* General purpose I/O register 1 */
+                u8 gpio2;   /* General purpose I/O register 2 */
+        } reg;
+        u8 vrm;                 /* Detected CPU VRM */
+};
+
+static struct atxp1_data * atxp1_update_device(struct device *dev)
+{
+        struct i2c_client *client;
+        struct atxp1_data *data;
+
+        client = to_i2c_client(dev);
+        data = i2c_get_clientdata(client);
+
+        down(&data->update_lock);
+
+        if ((jiffies - data->last_updated > HZ) ||
+            (jiffies < data->last_updated) ||
+            !data->valid) {
+
+                /* Update local register data */
+                data->reg.vid = i2c_smbus_read_byte_data(client, ATXP1_VID);
+                data->reg.cpu_vid = i2c_smbus_read_byte_data(client, ATXP1_CVID);
+                data->reg.gpio1 = i2c_smbus_read_byte_data(client, ATXP1_GPIO1);
+                data->reg.gpio2 = i2c_smbus_read_byte_data(client, ATXP1_GPIO2);
+
+                data->valid = 1;
+        }
+
+        up(&data->update_lock);
+
+        return(data);
+}
+
+/* sys file functions for cpu0_vid */
+ssize_t atxp1_showvcore(struct device *dev, char *buf)
+{
+        int size;
+        struct atxp1_data *data;
+
+        data = atxp1_update_device(dev);
+
+        size = sprintf(buf, "%d\n", vid_from_reg(data->reg.vid & ATXP1_VIDMASK, data->vrm));
+
+        return size;
+}
+
+ssize_t atxp1_storevcore(struct device *dev, const char* buf, size_t count)
+{
+        struct atxp1_data *data;
+        struct i2c_client *client;
+        char vid;
+        char cvid;
+        unsigned int vcore;
+
+        client = to_i2c_client(dev);
+        data = atxp1_update_device(dev);
+
+        vcore = simple_strtoul(buf, NULL, 10);
+        vcore /= 25;
+        vcore *= 25;
+
+        /* Calculate VID */
+        vid = vid_to_reg(vcore, data->vrm);
+
+        if (vid < 0) {
+                dev_err(dev, "VID calculation failed.\n");
+                return -1;
+        }
+
+        /* If output enabled, use control register value. Otherwise original CPU VID */
+        if (data->reg.vid & ATXP1_VIDENA)
+                cvid = data->reg.vid & ATXP1_VIDMASK;
+        else
+                cvid = data->reg.cpu_vid;
+
+        /* Nothing changed, aborting */
+        if (vid == cvid)
+                return count;
+
+        dev_info(dev, "Setting VCore to %d mV (0x%02x)\n", vcore, vid);
+
+        /* Write every 25 mV step to increase stability */
+        if (cvid > vid) {
+                for (; cvid >= vid; cvid--) {
+                        i2c_smbus_write_byte_data(client, ATXP1_VID, cvid | ATXP1_VIDENA);
+                }
+        }
+        else {
+                for (; cvid <= vid; cvid++) {
+                        i2c_smbus_write_byte_data(client, ATXP1_VID, cvid | ATXP1_VIDENA);
+                }
+        }
+
+        data->valid = 0;
+
+        return count;
+}
+
+/* CPU core reference voltage
+    unit: millivolt
+*/
+static DEVICE_ATTR(cpu0_vid, S_IRUGO | S_IWUSR, atxp1_showvcore, atxp1_storevcore);
+
+/* sys file functions for GPIO1 */
+ssize_t atxp1_showgpio1(struct device *dev, char *buf)
+{
+        int size;
+        struct atxp1_data *data;
+
+        data = atxp1_update_device(dev);
+
+        size = sprintf(buf, "0x%02x\n", data->reg.gpio1 & ATXP1_GPIO1MASK);
+
+        return size;
+}
+
+ssize_t atxp1_storegpio1(struct device *dev, const char* buf, size_t count)
+{
+        struct atxp1_data *data;
+        struct i2c_client *client;
+        unsigned int value;
+
+        client = to_i2c_client(dev);
+        data = atxp1_update_device(dev);
+
+        value = simple_strtoul(buf, NULL, 16);
+
+        value &= ATXP1_GPIO1MASK;
+
+        if (value != (data->reg.gpio1 & ATXP1_GPIO1MASK)) {
+                dev_info(dev, "Writing 0x%x to GPIO1.\n", value);
+
+                i2c_smbus_write_byte_data(client, ATXP1_GPIO1, value);
+
+                data->valid = 0;
+        }
+
+        return count;
+}
+
+/* GPIO1 data register
+    unit: Four bit as hex (e.g. 0x0f)
+*/
+static DEVICE_ATTR(gpio1, S_IRUGO | S_IWUSR, atxp1_showgpio1, atxp1_storegpio1);
+
+/* sys file functions for GPIO2 */
+ssize_t atxp1_showgpio2(struct device *dev, char *buf)
+{
+        int size;
+        struct atxp1_data *data;
+
+        data = atxp1_update_device(dev);
+
+        size = sprintf(buf, "0x%02x\n", data->reg.gpio2);
+
+        return size;
+}
+
+ssize_t atxp1_storegpio2(struct device *dev, const char* buf, size_t count)
+{
+        struct atxp1_data *data;
+        struct i2c_client *client;
+        unsigned int value;
+
+        client = to_i2c_client(dev);
+        data = atxp1_update_device(dev);
+
+        value = simple_strtoul(buf, NULL, 16) & 0xff;
+
+        if (value != data->reg.gpio2) {
+                dev_info(dev, "Writing 0x%x to GPIO1.\n", value);
+
+                i2c_smbus_write_byte_data(client, ATXP1_GPIO2, value);
+
+                data->valid = 0;
+        }
+
+        return count;
+}
+
+/* GPIO2 data register
+    unit: Eight bit as hex (e.g. 0xff)
+*/
+static DEVICE_ATTR(gpio2, S_IRUGO | S_IWUSR, atxp1_showgpio2, atxp1_storegpio2);
+
+
+static int atxp1_attach_adapter(struct i2c_adapter *adapter)
+{
+        return i2c_detect(adapter, &addr_data, &atxp1_detect);
+};
+
+static int atxp1_detect(struct i2c_adapter *adapter, int address, int kind)
+{
+        struct i2c_client * new_client;
+        struct atxp1_data * data;
+        int err = 0;
+        u8 temp;
+
+        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+                goto exit;
+
+        if (!(data = kmalloc(sizeof(struct atxp1_data), GFP_KERNEL))) {
+                err = -ENOMEM;
+                goto exit;
+        }
+
+        memset(data, 0, sizeof(struct atxp1_data));
+        new_client = &data->client;
+        i2c_set_clientdata(new_client, data);
+
+        new_client->addr = address;
+        new_client->adapter = adapter;
+        new_client->driver = &atxp1_driver;
+        new_client->flags = 0;
+
+        /* Detect ATXP1, checking if vendor ID registers are all zero */
+        if (!((i2c_smbus_read_byte_data(new_client, 0x3e) == 0) &&
+             (i2c_smbus_read_byte_data(new_client, 0x3f) == 0) &&
+             (i2c_smbus_read_byte_data(new_client, 0xfe) == 0) &&
+             (i2c_smbus_read_byte_data(new_client, 0xff) == 0) )) {
+
+                /* No vendor ID, now checking if registers 0x10,0x11 (non-existent)
+                 * showing the same as register 0x00 */
+                temp = i2c_smbus_read_byte_data(new_client, 0x00);
+
+                if (!((i2c_smbus_read_byte_data(new_client, 0x10) == temp) &&
+                         (i2c_smbus_read_byte_data(new_client, 0x11) == temp) ))
+                        goto exit_free;
+        }
+
+        /* Get VRM */
+        data->vrm = i2c_which_vrm();
+
+        if ((data->vrm != 90) && (data->vrm != 91)) {
+                dev_err(&new_client->dev, "Not supporting VRM %d.%d\n",
+                                data->vrm / 10, data->vrm % 10);
+                goto exit_free;
+        }
+
+        strncpy(new_client->name, "atxp1", I2C_NAME_SIZE);
+
+        data->valid = 0;
+
+        init_MUTEX(&data->update_lock);
+
+        err = i2c_attach_client(new_client);
+
+        if (err)
+        {
+                dev_err(&new_client->dev, "Attach client error.\n");
+                goto exit_free;
+        }
+
+        device_create_file(&new_client->dev, &dev_attr_gpio1);
+        device_create_file(&new_client->dev, &dev_attr_gpio2);
+        device_create_file(&new_client->dev, &dev_attr_cpu0_vid);
+
+        dev_info(&new_client->dev, "Using VRM: %d.%d\n",
+                         data->vrm / 10, data->vrm % 10);
+
+        return 0;
+
+exit_free:
+        kfree(data);
+exit:
+        return err;
+};
+
+static int atxp1_detach_client(struct i2c_client * client)
+{
+        int err;
+
+        err = i2c_detach_client(client);
+
+        if (err)
+                dev_err(&client->dev, "Failed to detach client.\n");
+        else
+                kfree(i2c_get_clientdata(client));
+
+        return err;
+};
+
+static int __init atxp1_init(void)
+{
+        return i2c_add_driver(&atxp1_driver);
+};
+
+static void __exit atxp1_exit(void)
+{
+        i2c_del_driver(&atxp1_driver);
+};
+
+module_init(atxp1_init);
+module_exit(atxp1_exit);