hwmon: (pmbus) Add support for Intersil power management chips

Add support for Intersil / Zilker Labs ZL2004, ZL2006, ZL2008, ZL2105, ZL2106,
ZL6100, and ZL6105.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Robert Coulson <robert.coulson@ericsson.com>

3 files changed, 268 insertions, 0 deletions

diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index 37575582e51a..efaf340651a0 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -98,4 +98,15 @@ config SENSORS_UCD9200
           This driver can also be built as a module. If so, the module will
           be called ucd9200.
 
+config SENSORS_ZL6100
+        tristate "Intersil ZL6100 and compatibles"
+        default n
+        help
+          If you say yes here you get hardware monitoring support for Intersil
+          ZL2004, ZL2006, ZL2008, ZL2105, ZL2106, ZL6100, and ZL6105 Digital
+          DC/DC Controllers.
+
+          This driver can also be built as a module. If so, the module will
+          be called zl6100.
+
 endif # PMBUS
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 623eedb1ed9a..b9e4fb421f6c 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -11,3 +11,4 @@ obj-$(CONFIG_SENSORS_MAX34440)	+= max34440.o
 obj-$(CONFIG_SENSORS_MAX8688)   += max8688.o
 obj-$(CONFIG_SENSORS_UCD9000)   += ucd9000.o
 obj-$(CONFIG_SENSORS_UCD9200)   += ucd9200.o
+obj-$(CONFIG_SENSORS_ZL6100)    += zl6100.o
diff --git a/drivers/hwmon/pmbus/zl6100.c b/drivers/hwmon/pmbus/zl6100.c
new file mode 100644
index 000000000000..2bc980006f83
--- /dev/null
+++ b/drivers/hwmon/pmbus/zl6100.c
@@ -0,0 +1,256 @@
+/*
+ * Hardware monitoring driver for ZL6100 and compatibles
+ *
+ * Copyright (c) 2011 Ericsson AB.
+ *
+ * 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/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/ktime.h>
+#include <linux/delay.h>
+#include "pmbus.h"
+
+enum chips { zl2004, zl2006, zl2008, zl2105, zl2106, zl6100, zl6105 };
+
+struct zl6100_data {
+        int id;
+        ktime_t access;         /* chip access time */
+        struct pmbus_driver_info info;
+};
+
+#define to_zl6100_data(x)  container_of(x, struct zl6100_data, info)
+
+#define ZL6100_DEVICE_ID                0xe4
+
+#define ZL6100_WAIT_TIME                1000    /* uS   */
+
+static ushort delay = ZL6100_WAIT_TIME;
+module_param(delay, ushort, 0644);
+MODULE_PARM_DESC(delay, "Delay between chip accesses in uS");
+
+/* Some chips need a delay between accesses */
+static inline void zl6100_wait(const struct zl6100_data *data)
+{
+        if (delay) {
+                s64 delta = ktime_us_delta(ktime_get(), data->access);
+                if (delta < delay)
+                        udelay(delay - delta);
+        }
+}
+
+static int zl6100_read_word_data(struct i2c_client *client, int page, int reg)
+{
+        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+        struct zl6100_data *data = to_zl6100_data(info);
+        int ret;
+
+        if (page || reg >= PMBUS_VIRT_BASE)
+                return -ENXIO;
+
+        zl6100_wait(data);
+        ret = pmbus_read_word_data(client, page, reg);
+        data->access = ktime_get();
+
+        return ret;
+}
+
+static int zl6100_read_byte_data(struct i2c_client *client, int page, int reg)
+{
+        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+        struct zl6100_data *data = to_zl6100_data(info);
+        int ret;
+
+        if (page > 0)
+                return -ENXIO;
+
+        zl6100_wait(data);
+        ret = pmbus_read_byte_data(client, page, reg);
+        data->access = ktime_get();
+
+        return ret;
+}
+
+static int zl6100_write_word_data(struct i2c_client *client, int page, int reg,
+                                  u16 word)
+{
+        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+        struct zl6100_data *data = to_zl6100_data(info);
+        int ret;
+
+        if (page || reg >= PMBUS_VIRT_BASE)
+                return -ENXIO;
+
+        zl6100_wait(data);
+        ret = pmbus_write_word_data(client, page, reg, word);
+        data->access = ktime_get();
+
+        return ret;
+}
+
+static int zl6100_write_byte(struct i2c_client *client, int page, u8 value)
+{
+        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+        struct zl6100_data *data = to_zl6100_data(info);
+        int ret;
+
+        if (page > 0)
+                return -ENXIO;
+
+        zl6100_wait(data);
+        ret = pmbus_write_byte(client, page, value);
+        data->access = ktime_get();
+
+        return ret;
+}
+
+static const struct i2c_device_id zl6100_id[] = {
+        {"zl2004", zl2004},
+        {"zl2006", zl2006},
+        {"zl2008", zl2008},
+        {"zl2105", zl2105},
+        {"zl2106", zl2106},
+        {"zl6100", zl6100},
+        {"zl6105", zl6105},
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, zl6100_id);
+
+static int zl6100_probe(struct i2c_client *client,
+                        const struct i2c_device_id *id)
+{
+        int ret;
+        struct zl6100_data *data;
+        struct pmbus_driver_info *info;
+        u8 device_id[I2C_SMBUS_BLOCK_MAX + 1];
+        const struct i2c_device_id *mid;
+
+        if (!i2c_check_functionality(client->adapter,
+                                     I2C_FUNC_SMBUS_READ_BYTE_DATA
+                                     | I2C_FUNC_SMBUS_READ_BLOCK_DATA))
+                return -ENODEV;
+
+        ret = i2c_smbus_read_block_data(client, ZL6100_DEVICE_ID,
+                                        device_id);
+        if (ret < 0) {
+                dev_err(&client->dev, "Failed to read device ID\n");
+                return ret;
+        }
+        device_id[ret] = '\0';
+        dev_info(&client->dev, "Device ID %s\n", device_id);
+
+        mid = NULL;
+        for (mid = zl6100_id; mid->name[0]; mid++) {
+                if (!strncasecmp(mid->name, device_id, strlen(mid->name)))
+                        break;
+        }
+        if (!mid->name[0]) {
+                dev_err(&client->dev, "Unsupported device\n");
+                return -ENODEV;
+        }
+        if (id->driver_data != mid->driver_data)
+                dev_notice(&client->dev,
+                           "Device mismatch: Configured %s, detected %s\n",
+                           id->name, mid->name);
+
+        data = kzalloc(sizeof(struct zl6100_data), GFP_KERNEL);
+        if (!data)
+                return -ENOMEM;
+
+        data->id = mid->driver_data;
+
+        /*
+         * ZL2008, ZL2105, and ZL6100 are known to require a wait time
+         * between I2C accesses. ZL2004 and ZL6105 are known to be safe.
+         *
+         * Only clear the wait time for chips known to be safe. The wait time
+         * can be cleared later for additional chips if tests show that it
+         * is not needed (in other words, better be safe than sorry).
+         */
+        if (data->id == zl2004 || data->id == zl6105)
+                delay = 0;
+
+        /*
+         * Since there was a direct I2C device access above, wait before
+         * accessing the chip again.
+         * Set the timestamp, wait, then set it again. This should provide
+         * enough buffer time to be safe.
+         */
+        data->access = ktime_get();
+        zl6100_wait(data);
+        data->access = ktime_get();
+
+        info = &data->info;
+
+        info->pages = 1;
+        info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
+          | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
+          | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
+          | PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP;
+
+        info->read_word_data = zl6100_read_word_data;
+        info->read_byte_data = zl6100_read_byte_data;
+        info->write_word_data = zl6100_write_word_data;
+        info->write_byte = zl6100_write_byte;
+
+        ret = pmbus_do_probe(client, mid, info);
+        if (ret)
+                goto err_mem;
+        return 0;
+
+err_mem:
+        kfree(data);
+        return ret;
+}
+
+static int zl6100_remove(struct i2c_client *client)
+{
+        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+        const struct zl6100_data *data = to_zl6100_data(info);
+
+        pmbus_do_remove(client);
+        kfree(data);
+        return 0;
+}
+
+static struct i2c_driver zl6100_driver = {
+        .driver = {
+                   .name = "zl6100",
+                   },
+        .probe = zl6100_probe,
+        .remove = zl6100_remove,
+        .id_table = zl6100_id,
+};
+
+static int __init zl6100_init(void)
+{
+        return i2c_add_driver(&zl6100_driver);
+}
+
+static void __exit zl6100_exit(void)
+{
+        i2c_del_driver(&zl6100_driver);
+}
+
+MODULE_AUTHOR("Guenter Roeck");
+MODULE_DESCRIPTION("PMBus driver for ZL6100 and compatibles");
+MODULE_LICENSE("GPL");
+module_init(zl6100_init);
+module_exit(zl6100_exit);