max6875: new driver

drivers/i2c/chips/Kconfig +12 -0

@@ -388,6 +388,18 @@
 	  This driver can also be built as a module.  If so, the module
 	  will be called eeprom.
 
+config SENSORS_MAX6875
+	tristate "MAXIM MAX6875 Power supply supervisor"
+	depends on I2C && EXPERIMENTAL
+	help
+	  If you say yes here you get support for the MAX6875
+	  EEPROM-Programmable, Hex/Quad, Power-Suppy Sequencers/Supervisors.
+	  
+          This provides a interface to program the user and config EEPROMs.
+	  
+	  This driver can also be built as a module.  If so, the module
+	  will be called max6875.
+
 config SENSORS_PCF8574
 	tristate "Philips PCF8574 and PCF8574A"
 	depends on I2C && EXPERIMENTAL

diff -urEbBN linux-2.6.12-rc4-clean/drivers/i2c/chips/Makefile linux-2.6.12-rc4-max6875/drivers/i2c/chips/Makefile

drivers/i2c/chips/Makefile +1 -0

@@ -30,6 +30,7 @@
 obj-$(CONFIG_SENSORS_LM90)	+= lm90.o
 obj-$(CONFIG_SENSORS_LM92)	+= lm92.o
 obj-$(CONFIG_SENSORS_MAX1619)	+= max1619.o
+obj-$(CONFIG_SENSORS_MAX6875)	+= max6875.o
 obj-$(CONFIG_SENSORS_M41T00)	+= m41t00.o
 obj-$(CONFIG_SENSORS_PC87360)	+= pc87360.o
 obj-$(CONFIG_SENSORS_PCF8574)	+= pcf8574.o

diff -urEbBN linux-2.6.12-rc4-clean/drivers/i2c/chips/max6875.c linux-2.6.12-rc4-max6875/drivers/i2c/chips/max6875.c

drivers/i2c/chips/max6875.c +26 -0

+    
+    Based on i2c/chips/eeprom.c
+    
+    The MAX6875 has two EEPROM sections: config and user.
+    At reset, the config EEPROM is read into the registers.
+    
+    This driver make 3 binary files available in sysfs: 
+      reg_config    - direct access to the registers
+      eeprom_config - acesses configuration eeprom space
+      eeprom_user   - free for application use
+      
+    In our application, we put device serial & model numbers in user eeprom.
+    
+    Notes:
+      1) The datasheet says that register 0x44 / EEPROM 0x8044 should NOT
+         be overwritten, so the driver explicitly prevents that.
+      2) It's a good idea to keep the config (0x45) locked in config EEPROM.
+         You can temporarily enable config writes by changing register 0x45.
+
+    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; version 2 of the License.
+*/
+
+#include <linux/config.h>
+#include <linux/kernel.h>

drivers/i2c/chips/max6875.c +26 -0

+
+/* Insmod parameters */
+SENSORS_INSMOD_1(max6875);
+
+/* this param will prevent 'accidental' writes to the eeprom */
+static int allow_write = 0;
+module_param(allow_write, int, 0);
+MODULE_PARM_DESC(allow_write,
+		 "Enable write access:\n"
+		 "*0: Read only\n"
+		 " 1: Read/Write access");
+
+/* The MAX6875 can only read/write 16 bytes at a time */
+#define SLICE_SIZE			16
+#define SLICE_BITS			4
+
+/* CONFIG EEPROM is at addresses 0x8000 - 0x8045, registers are at 0 - 0x45 */
+#define CONFIG_EEPROM_BASE		0x8000
+#define CONFIG_EEPROM_SIZE		0x0046
+#define CONFIG_EEPROM_SLICES		5
+
+/* USER EEPROM is at addresses 0x8100 - 0x82FF */
+#define USER_EEPROM_BASE		0x8100
+#define USER_EEPROM_SIZE		0x0200
+#define USER_EEPROM_SLICES		32
+

drivers/i2c/chips/max6875.c +104 -0

+static void max6875_update_slice(struct i2c_client *client, 
+				 struct eeprom_block *blk,
+				 int slice)
+{
+	struct max6875_data *data = i2c_get_clientdata(client);
+	int i, j, addr, count;
+	u8 rdbuf[SLICE_SIZE];
+
+	if (slice >= blk->slices)
+		return;
+
+	down(&data->update_lock);
+
+	if (!(blk->valid & (1 << slice)) ||
+	    (jiffies - blk->updated[slice] > 300 * HZ) ||
+	    (jiffies < blk->updated[slice])) {
+		dev_dbg(&client->dev, "Starting eeprom update, slice %u, base %u\n", 
+			slice, blk->base);
+
+		addr = blk->base + (slice << SLICE_BITS);
+		count = blk->size - (slice << SLICE_BITS);
+		if (count > SLICE_SIZE) {
+			count = SLICE_SIZE;
+		}
+
+		/* Preset the read address */
+		if (addr < 0x100) {
+			/* select the register */
+			if (i2c_smbus_write_byte(client, addr & 0xFF)) {
+				dev_dbg(&client->dev, "max6875 register select has failed!\n");
+				goto exit;
+			}
+		} else {
+			/* select the eeprom */
+			if (i2c_smbus_write_byte_data(client, addr >> 8, addr & 0xFF)) {
+				dev_dbg(&client->dev, "max6875 address set has failed!\n");
+				goto exit;
+			}
+		}
+
+		if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
+			if (i2c_smbus_read_i2c_block_data(client, MAX6875_CMD_BLOCK_READ, 
+							  rdbuf) != SLICE_SIZE)
+				goto exit;
+
+			memcpy(&blk->data[slice << SLICE_BITS], rdbuf, count);
+		} else {
+			for (i = 0; i < count; i++) {
+				j = i2c_smbus_read_byte(client);
+				if (j < 0)
+					goto exit;
+				blk->data[(slice << SLICE_BITS) + i] = (u8) j;
+			}
+		}
+		blk->updated[slice] = jiffies;
+		blk->valid |= (1 << slice);
+	}
+	exit:
+	up(&data->update_lock);
+}
+
+static ssize_t max6875_read(struct kobject *kobj, char *buf, loff_t off, size_t count, 
+			    enum max6875_area_type area_type)
+{
+	struct i2c_client *client = to_i2c_client(container_of(kobj, struct device, kobj));
+	struct max6875_data *data = i2c_get_clientdata(client);
+	struct eeprom_block *blk;
+	int slice;
+
+	blk = &data->blocks[area_type];
+
+	if (off > blk->size)
+		return 0;
+	if (off + count > blk->size)
+		count = blk->size - off;
+
+	/* Only refresh slices which contain requested bytes */
+	for (slice = (off >> SLICE_BITS); slice <= ((off + count - 1) >> SLICE_BITS); slice++)
+		max6875_update_slice(client, blk, slice);
+
+	memcpy(buf, &blk->data[off], count);
+
+	return count;
+}
+
+static ssize_t max6875_user_read(struct kobject *kobj, char *buf, loff_t off, size_t count)
+{
+	return max6875_read(kobj, buf, off, count, max6875_eeprom_user);
+}
+
+static ssize_t max6875_config_read(struct kobject *kobj, char *buf, loff_t off, size_t count)
+{
+	return max6875_read(kobj, buf, off, count, max6875_eeprom_config);
+}
+
+static ssize_t max6875_cfgreg_read(struct kobject *kobj, char *buf, loff_t off, size_t count)
+{
+	return max6875_read(kobj, buf, off, count, max6875_register_config);
+}
+
+
+static ssize_t max6875_write(struct kobject *kobj, char *buf, loff_t off, size_t count, 
+			     enum max6875_area_type area_type)
+{

drivers/i2c/chips/max6875.c +9 -0

+
+	if (off > blk->size)
+		return 0;
+	if ((off + count) > blk->size)
+		count = blk->size - off;
+
+	if (down_interruptible(&data->update_lock))
+		return -EAGAIN;
+

drivers/i2c/chips/max6875.c +73 -0

+
+			retval = i2c_smbus_write_word_data(client, cmd, val);
+
+			if (retval) {
+				goto error_exit;
+			}
+
+			/* A write takes up to 11 ms */
+			msleep(11);
+		}
+	}
+
+	/* Invalidate the scratch buffer */
+	for (slice = (off >> SLICE_BITS); slice <= ((off + count - 1) >> SLICE_BITS); slice++)
+		blk->valid &= ~(1 << slice);
+
+	error_exit:
+	up(&data->update_lock);
+
+	return sent;
+}
+
+static ssize_t max6875_user_write(struct kobject *kobj, char *buf, loff_t off, size_t count)
+{
+	return max6875_write(kobj, buf, off, count, max6875_eeprom_user);
+}
+
+static ssize_t max6875_config_write(struct kobject *kobj, char *buf, loff_t off, size_t count)
+{
+	return max6875_write(kobj, buf, off, count, max6875_eeprom_config);
+}
+
+static ssize_t max6875_cfgreg_write(struct kobject *kobj, char *buf, loff_t off, size_t count)
+{
+	return max6875_write(kobj, buf, off, count, max6875_register_config);
+}
+
+static struct bin_attribute user_eeprom_attr = {
+	.attr = {
+		.name = "eeprom_user",
+		.mode = S_IRUGO | S_IWUSR | S_IWGRP,
+		.owner = THIS_MODULE,
+	},
+	.size  = USER_EEPROM_SIZE,
+	.read  = max6875_user_read,
+	.write = max6875_user_write,
+};
+
+static struct bin_attribute config_eeprom_attr = {
+	.attr = {
+		.name = "eeprom_config",
+		.mode = S_IRUGO | S_IWUSR,
+		.owner = THIS_MODULE,
+	},
+	.size  = CONFIG_EEPROM_SIZE,
+	.read  = max6875_config_read,
+	.write = max6875_config_write,
+};
+
+static struct bin_attribute config_register_attr = {
+	.attr = {
+		.name = "reg_config",
+		.mode = S_IRUGO | S_IWUSR,
+		.owner = THIS_MODULE,
+	},
+	.size  = CONFIG_EEPROM_SIZE,
+	.read  = max6875_cfgreg_read,
+	.write = max6875_cfgreg_write,
+};
+
+static int max6875_attach_adapter(struct i2c_adapter *adapter)
+{
+	return i2c_detect(adapter, &addr_data, max6875_detect);

drivers/i2c/chips/max6875.c +116 -0

+
+	/* There are three ways we can read the EEPROM data:
+	   (1) I2C block reads (faster, but unsupported by most adapters)
+	   (2) Consecutive byte reads (100% overhead)
+	   (3) Regular byte data reads (200% overhead)
+	   The third method is not implemented by this driver because all
+	   known adapters support at least the second. */
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA | 
+				     I2C_FUNC_SMBUS_BYTE |
+				     I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
+		goto exit;
+
+	/* OK. For now, we presume we have a valid client. We now create the
+	   client structure, even though we cannot fill it completely yet.
+	   But it allows us to access eeprom_{read,write}_value. */
+	if (!(data = kmalloc(sizeof(struct max6875_data), GFP_KERNEL))) {
+		err = -ENOMEM;
+		goto exit;
+	}
+	memset(data, 0, sizeof(struct max6875_data));
+
+	new_client = &data->client;
+	i2c_set_clientdata(new_client, data);
+	new_client->addr = address;
+	new_client->adapter = adapter;
+	new_client->driver = &max6875_driver;
+	new_client->flags = 0;
+
+	/* Setup the user section */
+	data->blocks[max6875_eeprom_user].type    = max6875_eeprom_user;
+	data->blocks[max6875_eeprom_user].slices  = USER_EEPROM_SLICES;
+	data->blocks[max6875_eeprom_user].size    = USER_EEPROM_SIZE;
+	data->blocks[max6875_eeprom_user].base    = USER_EEPROM_BASE;
+	data->blocks[max6875_eeprom_user].data    = data->data;
+	data->blocks[max6875_eeprom_user].updated = data->last_updated;
+
+	/* Setup the config section */
+	data->blocks[max6875_eeprom_config].type    = max6875_eeprom_config;
+	data->blocks[max6875_eeprom_config].slices  = CONFIG_EEPROM_SLICES;
+	data->blocks[max6875_eeprom_config].size    = CONFIG_EEPROM_SIZE;
+	data->blocks[max6875_eeprom_config].base    = CONFIG_EEPROM_BASE;
+	data->blocks[max6875_eeprom_config].data    = &data->data[USER_EEPROM_SIZE];
+	data->blocks[max6875_eeprom_config].updated = &data->last_updated[USER_EEPROM_SLICES];
+
+	/* Setup the register section */
+	data->blocks[max6875_register_config].type    = max6875_register_config;
+	data->blocks[max6875_register_config].slices  = CONFIG_EEPROM_SLICES;
+	data->blocks[max6875_register_config].size    = CONFIG_EEPROM_SIZE;
+	data->blocks[max6875_register_config].base    = 0;
+	data->blocks[max6875_register_config].data    = &data->data[USER_EEPROM_SIZE+CONFIG_EEPROM_SIZE];
+	data->blocks[max6875_register_config].updated = &data->last_updated[USER_EEPROM_SLICES+CONFIG_EEPROM_SLICES];
+
+	/* Init the data */
+	memset(data->data, 0xff, sizeof(data->data));
+
+	/* Fill in the remaining client fields */
+	strlcpy(new_client->name, "max6875", I2C_NAME_SIZE);
+	init_MUTEX(&data->update_lock);
+
+	/* Tell the I2C layer a new client has arrived */
+	if ((err = i2c_attach_client(new_client)))
+		goto exit_kfree;
+
+	/* create the sysfs eeprom files with the correct permissions */
+	if (allow_write = 0) {
+		user_eeprom_attr.attr.mode &= ~S_IWUGO;
+		user_eeprom_attr.write = NULL;
+		config_eeprom_attr.attr.mode &= ~S_IWUGO;
+		config_eeprom_attr.write = NULL;
+		config_register_attr.attr.mode &= ~S_IWUGO;
+		config_register_attr.write = NULL;
+	}
+	sysfs_create_bin_file(&new_client->dev.kobj, &user_eeprom_attr);
+	sysfs_create_bin_file(&new_client->dev.kobj, &config_eeprom_attr);
+	sysfs_create_bin_file(&new_client->dev.kobj, &config_register_attr);
+
+	return 0;
+
+	exit_kfree:
+	kfree(data);
+	exit:
+	return err;
+}
+
+static int max6875_detach_client(struct i2c_client *client)
+{
+	int err;
+
+	err = i2c_detach_client(client);
+	if (err) {
+		dev_err(&client->dev, "Client deregistration failed, client not detached.\n");
+		return err;
+	}
+
+	kfree(i2c_get_clientdata(client));
+
+	return 0;
+}
+
+static int __init max6875_init(void)
+{
+	return i2c_add_driver(&max6875_driver);
+}
+
+static void __exit max6875_exit(void)
+{
+	i2c_del_driver(&max6875_driver);
+}
+
+
+MODULE_AUTHOR("Ben Gardner <[email protected]>");
+MODULE_DESCRIPTION("MAX6875 driver");
+MODULE_LICENSE("GPL");
+
+module_init(max6875_init);
+module_exit(max6875_exit);