ics932s401: new clock generator chip driver

The ics932s401 is a clock generator chip.  This driver allows users to
read the current clock outputs.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 557 insertions, 0 deletions

diff --git a/Documentation/ics932s401 b/Documentation/ics932s401
new file mode 100644
index 00000000000..07a739f406d
--- /dev/null
+++ b/Documentation/ics932s401
@@ -0,0 +1,31 @@
+Kernel driver ics932s401
+======================
+
+Supported chips:
+  * IDT ICS932S401
+    Prefix: 'ics932s401'
+    Addresses scanned: I2C 0x69
+    Datasheet: Publically available at the IDT website
+
+Author: Darrick J. Wong
+
+Description
+-----------
+
+This driver implements support for the IDT ICS932S401 chip family.
+
+This chip has 4 clock outputs--a base clock for the CPU (which is likely
+multiplied to get the real CPU clock), a system clock, a PCI clock, a USB
+clock, and a reference clock.  The driver reports selected and actual
+frequency.  If spread spectrum mode is enabled, the driver also reports by what
+percent the clock signal is being spread, which should be between 0 and -0.5%.
+All frequencies are reported in KHz.
+
+The ICS932S401 monitors all inputs continuously. The driver will not read
+the registers more often than once every other second.
+
+Special Features
+----------------
+
+The clocks could be reprogrammed to increase system speed.  I will not help you
+do this, as you risk damaging your system!
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 4494ad27cbf..dcac7ca7693 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -227,6 +227,16 @@ config HP_WMI
          To compile this driver as a module, choose M here: the module will
          be called hp-wmi.
 
+config ICS932S401
+        tristate "Integrated Circuits ICS932S401"
+        depends on I2C && EXPERIMENTAL
+        help
+          If you say yes here you get support for the Integrated Circuits
+          ICS932S401 clock control chips.
+
+          This driver can also be built as a module. If so, the module
+          will be called ics932s401.
+
 config MSI_LAPTOP
         tristate "MSI Laptop Extras"
         depends on X86
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 909e2468cdc..bb14633d136 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_ATMEL_PWM)		+= atmel_pwm.o
 obj-$(CONFIG_ATMEL_SSC)         += atmel-ssc.o
 obj-$(CONFIG_ATMEL_TCLIB)       += atmel_tclib.o
 obj-$(CONFIG_HP_WMI)            += hp-wmi.o
+obj-$(CONFIG_ICS932S401)        += ics932s401.o
 obj-$(CONFIG_TC1100_WMI)        += tc1100-wmi.o
 obj-$(CONFIG_LKDTM)             += lkdtm.o
 obj-$(CONFIG_TIFM_CORE)         += tifm_core.o
diff --git a/drivers/misc/ics932s401.c b/drivers/misc/ics932s401.c
new file mode 100644
index 00000000000..6e43ab4231a
--- /dev/null
+++ b/drivers/misc/ics932s401.c
@@ -0,0 +1,515 @@
+/*
+ * A driver for the Integrated Circuits ICS932S401
+ * Copyright (C) 2008 IBM
+ *
+ * Author: Darrick J. Wong <djwong@us.ibm.com>
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/module.h>
+#include <linux/jiffies.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/log2.h>
+
+/* Addresses to scan */
+static const unsigned short normal_i2c[] = { 0x69, I2C_CLIENT_END };
+
+/* Insmod parameters */
+I2C_CLIENT_INSMOD_1(ics932s401);
+
+/* ICS932S401 registers */
+#define ICS932S401_REG_CFG2                     0x01
+#define         ICS932S401_CFG1_SPREAD          0x01
+#define ICS932S401_REG_CFG7                     0x06
+#define         ICS932S401_FS_MASK              0x07
+#define ICS932S401_REG_VENDOR_REV               0x07
+#define         ICS932S401_VENDOR               1
+#define         ICS932S401_VENDOR_MASK          0x0F
+#define         ICS932S401_REV                  4
+#define         ICS932S401_REV_SHIFT            4
+#define ICS932S401_REG_DEVICE                   0x09
+#define         ICS932S401_DEVICE               11
+#define ICS932S401_REG_CTRL                     0x0A
+#define         ICS932S401_MN_ENABLED           0x80
+#define         ICS932S401_CPU_ALT              0x04
+#define         ICS932S401_SRC_ALT              0x08
+#define ICS932S401_REG_CPU_M_CTRL               0x0B
+#define         ICS932S401_M_MASK               0x3F
+#define ICS932S401_REG_CPU_N_CTRL               0x0C
+#define ICS932S401_REG_CPU_SPREAD1              0x0D
+#define ICS932S401_REG_CPU_SPREAD2              0x0E
+#define         ICS932S401_SPREAD_MASK          0x7FFF
+#define ICS932S401_REG_SRC_M_CTRL               0x0F
+#define ICS932S401_REG_SRC_N_CTRL               0x10
+#define ICS932S401_REG_SRC_SPREAD1              0x11
+#define ICS932S401_REG_SRC_SPREAD2              0x12
+#define ICS932S401_REG_CPU_DIVISOR              0x13
+#define         ICS932S401_CPU_DIVISOR_SHIFT    4
+#define ICS932S401_REG_PCISRC_DIVISOR           0x14
+#define         ICS932S401_SRC_DIVISOR_MASK     0x0F
+#define         ICS932S401_PCI_DIVISOR_SHIFT    4
+
+/* Base clock is 14.318MHz */
+#define BASE_CLOCK                              14318
+
+#define NUM_REGS                                21
+#define NUM_MIRRORED_REGS                       15
+
+static int regs_to_copy[NUM_MIRRORED_REGS] = {
+        ICS932S401_REG_CFG2,
+        ICS932S401_REG_CFG7,
+        ICS932S401_REG_VENDOR_REV,
+        ICS932S401_REG_DEVICE,
+        ICS932S401_REG_CTRL,
+        ICS932S401_REG_CPU_M_CTRL,
+        ICS932S401_REG_CPU_N_CTRL,
+        ICS932S401_REG_CPU_SPREAD1,
+        ICS932S401_REG_CPU_SPREAD2,
+        ICS932S401_REG_SRC_M_CTRL,
+        ICS932S401_REG_SRC_N_CTRL,
+        ICS932S401_REG_SRC_SPREAD1,
+        ICS932S401_REG_SRC_SPREAD2,
+        ICS932S401_REG_CPU_DIVISOR,
+        ICS932S401_REG_PCISRC_DIVISOR,
+};
+
+/* How often do we reread sensors values? (In jiffies) */
+#define SENSOR_REFRESH_INTERVAL (2 * HZ)
+
+/* How often do we reread sensor limit values? (In jiffies) */
+#define LIMIT_REFRESH_INTERVAL  (60 * HZ)
+
+struct ics932s401_data {
+        struct attribute_group  attrs;
+        struct mutex            lock;
+        char                    sensors_valid;
+        unsigned long           sensors_last_updated;   /* In jiffies */
+
+        u8                      regs[NUM_REGS];
+};
+
+static int ics932s401_probe(struct i2c_client *client,
+                         const struct i2c_device_id *id);
+static int ics932s401_detect(struct i2c_client *client, int kind,
+                          struct i2c_board_info *info);
+static int ics932s401_remove(struct i2c_client *client);
+
+static const struct i2c_device_id ics932s401_id[] = {
+        { "ics932s401", ics932s401 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, ics932s401_id);
+
+static struct i2c_driver ics932s401_driver = {
+        .class          = I2C_CLASS_HWMON,
+        .driver = {
+                .name   = "ics932s401",
+        },
+        .probe          = ics932s401_probe,
+        .remove         = ics932s401_remove,
+        .id_table       = ics932s401_id,
+        .detect         = ics932s401_detect,
+        .address_data   = &addr_data,
+};
+
+static struct ics932s401_data *ics932s401_update_device(struct device *dev)
+{
+        struct i2c_client *client = to_i2c_client(dev);
+        struct ics932s401_data *data = i2c_get_clientdata(client);
+        unsigned long local_jiffies = jiffies;
+        int i, temp;
+
+        mutex_lock(&data->lock);
+        if (time_before(local_jiffies, data->sensors_last_updated +
+                SENSOR_REFRESH_INTERVAL)
+                && data->sensors_valid)
+                goto out;
+
+        /*
+         * Each register must be read as a word and then right shifted 8 bits.
+         * Not really sure why this is; setting the "byte count programming"
+         * register to 1 does not fix this problem.
+         */
+        for (i = 0; i < NUM_MIRRORED_REGS; i++) {
+                temp = i2c_smbus_read_word_data(client, regs_to_copy[i]);
+                data->regs[regs_to_copy[i]] = temp >> 8;
+        }
+
+        data->sensors_last_updated = local_jiffies;
+        data->sensors_valid = 1;
+
+out:
+        mutex_unlock(&data->lock);
+        return data;
+}
+
+static ssize_t show_spread_enabled(struct device *dev,
+                                   struct device_attribute *devattr,
+                                   char *buf)
+{
+        struct ics932s401_data *data = ics932s401_update_device(dev);
+
+        if (data->regs[ICS932S401_REG_CFG2] & ICS932S401_CFG1_SPREAD)
+                return sprintf(buf, "1\n");
+
+        return sprintf(buf, "0\n");
+}
+
+/* bit to cpu khz map */
+static const int fs_speeds[] = {
+        266666,
+        133333,
+        200000,
+        166666,
+        333333,
+        100000,
+        400000,
+        0,
+};
+
+/* clock divisor map */
+static const int divisors[] = {2, 3, 5, 15, 4, 6, 10, 30, 8, 12, 20, 60, 16,
+                               24, 40, 120};
+
+/* Calculate CPU frequency from the M/N registers. */
+static int calculate_cpu_freq(struct ics932s401_data *data)
+{
+        int m, n, freq;
+
+        m = data->regs[ICS932S401_REG_CPU_M_CTRL] & ICS932S401_M_MASK;
+        n = data->regs[ICS932S401_REG_CPU_N_CTRL];
+
+        /* Pull in bits 8 & 9 from the M register */
+        n |= ((int)data->regs[ICS932S401_REG_CPU_M_CTRL] & 0x80) << 1;
+        n |= ((int)data->regs[ICS932S401_REG_CPU_M_CTRL] & 0x40) << 3;
+
+        freq = BASE_CLOCK * (n + 8) / (m + 2);
+        freq /= divisors[data->regs[ICS932S401_REG_CPU_DIVISOR] >>
+                         ICS932S401_CPU_DIVISOR_SHIFT];
+
+        return freq;
+}
+
+static ssize_t show_cpu_clock(struct device *dev,
+                              struct device_attribute *devattr,
+                              char *buf)
+{
+        struct ics932s401_data *data = ics932s401_update_device(dev);
+
+        return sprintf(buf, "%d\n", calculate_cpu_freq(data));
+}
+
+static ssize_t show_cpu_clock_sel(struct device *dev,
+                                  struct device_attribute *devattr,
+                                  char *buf)
+{
+        struct ics932s401_data *data = ics932s401_update_device(dev);
+        int freq;
+
+        if (data->regs[ICS932S401_REG_CTRL] & ICS932S401_MN_ENABLED)
+                freq = calculate_cpu_freq(data);
+        else {
+                /* Freq is neatly wrapped up for us */
+                int fid = data->regs[ICS932S401_REG_CFG7] & ICS932S401_FS_MASK;
+                freq = fs_speeds[fid];
+                if (data->regs[ICS932S401_REG_CTRL] & ICS932S401_CPU_ALT) {
+                        switch (freq) {
+                        case 166666:
+                                freq = 160000;
+                                break;
+                        case 333333:
+                                freq = 320000;
+                                break;
+                        }
+                }
+        }
+
+        return sprintf(buf, "%d\n", freq);
+}
+
+/* Calculate SRC frequency from the M/N registers. */
+static int calculate_src_freq(struct ics932s401_data *data)
+{
+        int m, n, freq;
+
+        m = data->regs[ICS932S401_REG_SRC_M_CTRL] & ICS932S401_M_MASK;
+        n = data->regs[ICS932S401_REG_SRC_N_CTRL];
+
+        /* Pull in bits 8 & 9 from the M register */
+        n |= ((int)data->regs[ICS932S401_REG_SRC_M_CTRL] & 0x80) << 1;
+        n |= ((int)data->regs[ICS932S401_REG_SRC_M_CTRL] & 0x40) << 3;
+
+        freq = BASE_CLOCK * (n + 8) / (m + 2);
+        freq /= divisors[data->regs[ICS932S401_REG_PCISRC_DIVISOR] &
+                         ICS932S401_SRC_DIVISOR_MASK];
+
+        return freq;
+}
+
+static ssize_t show_src_clock(struct device *dev,
+                              struct device_attribute *devattr,
+                              char *buf)
+{
+        struct ics932s401_data *data = ics932s401_update_device(dev);
+
+        return sprintf(buf, "%d\n", calculate_src_freq(data));
+}
+
+static ssize_t show_src_clock_sel(struct device *dev,
+                                  struct device_attribute *devattr,
+                                  char *buf)
+{
+        struct ics932s401_data *data = ics932s401_update_device(dev);
+        int freq;
+
+        if (data->regs[ICS932S401_REG_CTRL] & ICS932S401_MN_ENABLED)
+                freq = calculate_src_freq(data);
+        else
+                /* Freq is neatly wrapped up for us */
+                if (data->regs[ICS932S401_REG_CTRL] & ICS932S401_CPU_ALT &&
+                    data->regs[ICS932S401_REG_CTRL] & ICS932S401_SRC_ALT)
+                        freq = 96000;
+                else
+                        freq = 100000;
+
+        return sprintf(buf, "%d\n", freq);
+}
+
+/* Calculate PCI frequency from the SRC M/N registers. */
+static int calculate_pci_freq(struct ics932s401_data *data)
+{
+        int m, n, freq;
+
+        m = data->regs[ICS932S401_REG_SRC_M_CTRL] & ICS932S401_M_MASK;
+        n = data->regs[ICS932S401_REG_SRC_N_CTRL];
+
+        /* Pull in bits 8 & 9 from the M register */
+        n |= ((int)data->regs[ICS932S401_REG_SRC_M_CTRL] & 0x80) << 1;
+        n |= ((int)data->regs[ICS932S401_REG_SRC_M_CTRL] & 0x40) << 3;
+
+        freq = BASE_CLOCK * (n + 8) / (m + 2);
+        freq /= divisors[data->regs[ICS932S401_REG_PCISRC_DIVISOR] >>
+                         ICS932S401_PCI_DIVISOR_SHIFT];
+
+        return freq;
+}
+
+static ssize_t show_pci_clock(struct device *dev,
+                              struct device_attribute *devattr,
+                              char *buf)
+{
+        struct ics932s401_data *data = ics932s401_update_device(dev);
+
+        return sprintf(buf, "%d\n", calculate_pci_freq(data));
+}
+
+static ssize_t show_pci_clock_sel(struct device *dev,
+                                  struct device_attribute *devattr,
+                                  char *buf)
+{
+        struct ics932s401_data *data = ics932s401_update_device(dev);
+        int freq;
+
+        if (data->regs[ICS932S401_REG_CTRL] & ICS932S401_MN_ENABLED)
+                freq = calculate_pci_freq(data);
+        else
+                freq = 33333;
+
+        return sprintf(buf, "%d\n", freq);
+}
+
+static ssize_t show_value(struct device *dev,
+                          struct device_attribute *devattr,
+                          char *buf);
+
+static ssize_t show_spread(struct device *dev,
+                           struct device_attribute *devattr,
+                           char *buf);
+
+static DEVICE_ATTR(spread_enabled, S_IRUGO, show_spread_enabled, NULL);
+static DEVICE_ATTR(cpu_clock_selection, S_IRUGO, show_cpu_clock_sel, NULL);
+static DEVICE_ATTR(cpu_clock, S_IRUGO, show_cpu_clock, NULL);
+static DEVICE_ATTR(src_clock_selection, S_IRUGO, show_src_clock_sel, NULL);
+static DEVICE_ATTR(src_clock, S_IRUGO, show_src_clock, NULL);
+static DEVICE_ATTR(pci_clock_selection, S_IRUGO, show_pci_clock_sel, NULL);
+static DEVICE_ATTR(pci_clock, S_IRUGO, show_pci_clock, NULL);
+static DEVICE_ATTR(usb_clock, S_IRUGO, show_value, NULL);
+static DEVICE_ATTR(ref_clock, S_IRUGO, show_value, NULL);
+static DEVICE_ATTR(cpu_spread, S_IRUGO, show_spread, NULL);
+static DEVICE_ATTR(src_spread, S_IRUGO, show_spread, NULL);
+
+static struct attribute *ics932s401_attr[] =
+{
+        &dev_attr_spread_enabled.attr,
+        &dev_attr_cpu_clock_selection.attr,
+        &dev_attr_cpu_clock.attr,
+        &dev_attr_src_clock_selection.attr,
+        &dev_attr_src_clock.attr,
+        &dev_attr_pci_clock_selection.attr,
+        &dev_attr_pci_clock.attr,
+        &dev_attr_usb_clock.attr,
+        &dev_attr_ref_clock.attr,
+        &dev_attr_cpu_spread.attr,
+        &dev_attr_src_spread.attr,
+        NULL
+};
+
+static ssize_t show_value(struct device *dev,
+                          struct device_attribute *devattr,
+                          char *buf)
+{
+        int x;
+
+        if (devattr == &dev_attr_usb_clock)
+                x = 48000;
+        else if (devattr == &dev_attr_ref_clock)
+                x = BASE_CLOCK;
+        else
+                BUG();
+
+        return sprintf(buf, "%d\n", x);
+}
+
+static ssize_t show_spread(struct device *dev,
+                           struct device_attribute *devattr,
+                           char *buf)
+{
+        struct ics932s401_data *data = ics932s401_update_device(dev);
+        int reg;
+        unsigned long val;
+
+        if (!(data->regs[ICS932S401_REG_CFG2] & ICS932S401_CFG1_SPREAD))
+                return sprintf(buf, "0%%\n");
+
+        if (devattr == &dev_attr_src_spread)
+                reg = ICS932S401_REG_SRC_SPREAD1;
+        else if (devattr == &dev_attr_cpu_spread)
+                reg = ICS932S401_REG_CPU_SPREAD1;
+        else
+                BUG();
+
+        val = data->regs[reg] | (data->regs[reg + 1] << 8);
+        val &= ICS932S401_SPREAD_MASK;
+
+        /* Scale 0..2^14 to -0.5. */
+        val = 500000 * val / 16384;
+        return sprintf(buf, "-0.%lu%%\n", val);
+}
+
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static int ics932s401_detect(struct i2c_client *client, int kind,
+                          struct i2c_board_info *info)
+{
+        struct i2c_adapter *adapter = client->adapter;
+
+        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+                return -ENODEV;
+
+        if (kind <= 0) {
+                int vendor, device, revision;
+
+                vendor = i2c_smbus_read_word_data(client,
+                                                  ICS932S401_REG_VENDOR_REV);
+                vendor >>= 8;
+                revision = vendor >> ICS932S401_REV_SHIFT;
+                vendor &= ICS932S401_VENDOR_MASK;
+                if (vendor != ICS932S401_VENDOR)
+                        return -ENODEV;
+
+                device = i2c_smbus_read_word_data(client,
+                                                  ICS932S401_REG_DEVICE);
+                device >>= 8;
+                if (device != ICS932S401_DEVICE)
+                        return -ENODEV;
+
+                if (revision != ICS932S401_REV)
+                        dev_info(&adapter->dev, "Unknown revision %d\n",
+                                 revision);
+        } else
+                dev_dbg(&adapter->dev, "detection forced\n");
+
+        strlcpy(info->type, "ics932s401", I2C_NAME_SIZE);
+
+        return 0;
+}
+
+static int ics932s401_probe(struct i2c_client *client,
+                         const struct i2c_device_id *id)
+{
+        struct ics932s401_data *data;
+        int err;
+
+        data = kzalloc(sizeof(struct ics932s401_data), GFP_KERNEL);
+        if (!data) {
+                err = -ENOMEM;
+                goto exit;
+        }
+
+        i2c_set_clientdata(client, data);
+        mutex_init(&data->lock);
+
+        dev_info(&client->dev, "%s chip found\n", client->name);
+
+        /* Register sysfs hooks */
+        data->attrs.attrs = ics932s401_attr;
+        err = sysfs_create_group(&client->dev.kobj, &data->attrs);
+        if (err)
+                goto exit_free;
+
+        return 0;
+
+exit_free:
+        kfree(data);
+exit:
+        return err;
+}
+
+static int ics932s401_remove(struct i2c_client *client)
+{
+        struct ics932s401_data *data = i2c_get_clientdata(client);
+
+        sysfs_remove_group(&client->dev.kobj, &data->attrs);
+        kfree(data);
+        return 0;
+}
+
+static int __init ics932s401_init(void)
+{
+        return i2c_add_driver(&ics932s401_driver);
+}
+
+static void __exit ics932s401_exit(void)
+{
+        i2c_del_driver(&ics932s401_driver);
+}
+
+MODULE_AUTHOR("Darrick J. Wong <djwong@us.ibm.com>");
+MODULE_DESCRIPTION("ICS932S401 driver");
+MODULE_LICENSE("GPL");
+
+module_init(ics932s401_init);
+module_exit(ics932s401_exit);
+
+/* IBM IntelliStation Z30 */
+MODULE_ALIAS("dmi:bvnIBM:*:rn9228:*");
+MODULE_ALIAS("dmi:bvnIBM:*:rn9232:*");
+
+/* IBM x3650/x3550 */
+MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3650*");
+MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3550*");