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);