Ira Snyder wrote: > Add Linux support for the Linear Technology LTC4245 Multiple Supply Hot > Swap controller I2C monitoring interface. > > Signed-off-by: Ira W. Snyder <iws at ovro.caltech.edu> > --- > > I'm pretty sure this should be the final revision of the driver. Please > go ahead and forward it upstream. :) > Looks good now :) Jean, can you put this patch in your for Linus for 2.6.28 queue please? This is: Reviewed-by: Hans de Goede <hdegoede at redhat.com> or Signed-off-by: Hans de Goede <hdegoede at redhat.com> Whatever you deem more appropriate. Thanks & Regards, Hans > Changes v3 -> v4: > * simplify ltc4245_get_voltage(), removing special casing for -12v > * power should always be a positive value > > Changes v2 -> v3: > * fix units (power?_input in uW, curr?_input in mA) > * combine all alarm functions > * rename power[1-4]_alarm to in[5-8]_min_alarm, per suggestions > > Changes v1 -> v2: > * fixed checkpatch warnings > * removed raw register access, per suggestions > * changed sysfs interface, per suggestions (current, power, alarms) > > > Documentation/hwmon/ltc4245 | 69 +++++ > drivers/hwmon/Kconfig | 11 + > drivers/hwmon/Makefile | 1 + > drivers/hwmon/ltc4245.c | 574 +++++++++++++++++++++++++++++++++++++++++++ > 4 files changed, 655 insertions(+), 0 deletions(-) > create mode 100644 Documentation/hwmon/ltc4245 > create mode 100644 drivers/hwmon/ltc4245.c > > diff --git a/Documentation/hwmon/ltc4245 b/Documentation/hwmon/ltc4245 > new file mode 100644 > index 0000000..d2f411a > --- /dev/null > +++ b/Documentation/hwmon/ltc4245 > @@ -0,0 +1,69 @@ > +Kernel driver ltc4245 > +===================== > + > +Supported chips: > + * Linear Technology LTC4245 > + Prefix: 'ltc4245' > + Addresses scanned: 0x20-0x3f > + Datasheet: > + http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517 > + > +Author: Ira W. Snyder <iws at ovro.caltech.edu> > + > + > +Description > +----------- > + > +The LTC4245 controller allows a board to be safely inserted and removed > +from a live backplane in multiple supply systems such as CompactPCI and > +PCI Express. > + > + > +Sysfs entries > +------------- > + > +The LTC4245 has built-in limits for over and under current warnings. This > +makes it very likely that the reference circuit will be used. > + > +This driver uses the values in the datasheet to change the register values > +into the values specified in the sysfs-interface document. The current readings > +rely on the sense resistors listed in Table 2: "Sense Resistor Values". > + > +in1_input 12v input voltage (mV) > +in2_input 5v input voltage (mV) > +in3_input 3v input voltage (mV) > +in4_input Vee (-12v) input voltage (mV) > + > +in1_min_alarm 12v input undervoltage alarm > +in2_min_alarm 5v input undervoltage alarm > +in3_min_alarm 3v input undervoltage alarm > +in4_min_alarm Vee (-12v) input undervoltage alarm > + > +curr1_input 12v current (mA) > +curr2_input 5v current (mA) > +curr3_input 3v current (mA) > +curr4_input Vee (-12v) current (mA) > + > +curr1_max_alarm 12v overcurrent alarm > +curr2_max_alarm 5v overcurrent alarm > +curr3_max_alarm 3v overcurrent alarm > +curr4_max_alarm Vee (-12v) overcurrent alarm > + > +in5_input 12v output voltage (mV) > +in6_input 5v output voltage (mV) > +in7_input 3v output voltage (mV) > +in8_input Vee (-12v) output voltage (mV) > + > +in5_min_alarm 12v output undervoltage alarm > +in6_min_alarm 5v output undervoltage alarm > +in7_min_alarm 3v output undervoltage alarm > +in8_min_alarm Vee (-12v) output undervoltage alarm > + > +in9_input GPIO #1 voltage data > +in10_input GPIO #2 voltage data > +in11_input GPIO #3 voltage data > + > +power1_input 12v power usage (mW) > +power2_input 5v power usage (mW) > +power3_input 3v power usage (mW) > +power4_input Vee (-12v) power usage (mW) > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > index d402e8d..91bec8a 100644 > --- a/drivers/hwmon/Kconfig > +++ b/drivers/hwmon/Kconfig > @@ -836,6 +836,17 @@ config SENSORS_APPLESMC > Say Y here if you have an applicable laptop and want to experience > the awesome power of applesmc. > > +config SENSORS_LTC4245 > + tristate "Linear Technology LTC4245" > + depends on I2C && EXPERIMENTAL > + default n > + help > + If you say yes here you get support for Linear Technology LTC4245 > + Multiple Supply Hot Swap Controller I2C interface. > + > + This driver can also be built as a module. If so, the module will > + be called ltc4245. > + > config HWMON_DEBUG_CHIP > bool "Hardware Monitoring Chip debugging messages" > default n > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile > index 950134a..0ed56ac 100644 > --- a/drivers/hwmon/Makefile > +++ b/drivers/hwmon/Makefile > @@ -59,6 +59,7 @@ obj-$(CONFIG_SENSORS_LM87) += lm87.o > obj-$(CONFIG_SENSORS_LM90) += lm90.o > obj-$(CONFIG_SENSORS_LM92) += lm92.o > obj-$(CONFIG_SENSORS_LM93) += lm93.o > +obj-$(CONFIG_SENSORS_LTC4245) += ltc4245.o > obj-$(CONFIG_SENSORS_MAX1619) += max1619.o > obj-$(CONFIG_SENSORS_MAX6650) += max6650.o > obj-$(CONFIG_SENSORS_PC87360) += pc87360.o > diff --git a/drivers/hwmon/ltc4245.c b/drivers/hwmon/ltc4245.c > new file mode 100644 > index 0000000..5d0528b > --- /dev/null > +++ b/drivers/hwmon/ltc4245.c > @@ -0,0 +1,574 @@ > +/* > + * Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller > + * > + * Copyright (C) 2008 Ira W. Snyder <iws at ovro.caltech.edu> > + * > + * 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. > + * > + * This driver is based on the ds1621 and ina209 drivers. > + * > + * Datasheet: > + * http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517 > + */ > + > +#include <linux/module.h> > +#include <linux/init.h> > +#include <linux/err.h> > +#include <linux/slab.h> > +#include <linux/i2c.h> > +#include <linux/hwmon.h> > +#include <linux/hwmon-sysfs.h> > + > +/* Addresses to probe */ > +static unsigned short normal_i2c[] = { > + 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, > + 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, > + 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, > + 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, > + I2C_CLIENT_END}; > + > +/* Insmod parameters */ > +I2C_CLIENT_INSMOD_1(ltc4245); > + > +/* Here are names of the chip's registers (a.k.a. commands) */ > +enum ltc4245_cmd { > + LTC4245_STATUS = 0x00, /* readonly */ > + LTC4245_ALERT = 0x01, > + LTC4245_CONTROL = 0x02, > + LTC4245_ON = 0x03, > + LTC4245_FAULT1 = 0x04, > + LTC4245_FAULT2 = 0x05, > + LTC4245_GPIO = 0x06, > + LTC4245_ADCADR = 0x07, > + > + LTC4245_12VIN = 0x10, > + LTC4245_12VSENSE = 0x11, > + LTC4245_12VOUT = 0x12, > + LTC4245_5VIN = 0x13, > + LTC4245_5VSENSE = 0x14, > + LTC4245_5VOUT = 0x15, > + LTC4245_3VIN = 0x16, > + LTC4245_3VSENSE = 0x17, > + LTC4245_3VOUT = 0x18, > + LTC4245_VEEIN = 0x19, > + LTC4245_VEESENSE = 0x1a, > + LTC4245_VEEOUT = 0x1b, > + LTC4245_GPIOADC1 = 0x1c, > + LTC4245_GPIOADC2 = 0x1d, > + LTC4245_GPIOADC3 = 0x1e, > +}; > + > +struct ltc4245_data { > + struct device *hwmon_dev; > + > + struct mutex update_lock; > + bool valid; > + unsigned long last_updated; /* in jiffies */ > + > + /* Control registers */ > + u8 cregs[0x08]; > + > + /* Voltage registers */ > + u8 vregs[0x0f]; > +}; > + > +/* All registers are byte-sized (8 bit) */ > +static s32 ltc4245_read_reg(struct i2c_client *client, u8 reg) > +{ > + return i2c_smbus_read_byte_data(client, reg); > +} > + > +#if 0 > +static s32 ltc4245_write_reg(struct i2c_client *client, u8 reg, u8 val) > +{ > + return i2c_smbus_write_byte_data(client, reg, val); > +} > +#endif > + > +static struct ltc4245_data *ltc4245_update_device(struct device *dev) > +{ > + struct i2c_client *client = to_i2c_client(dev); > + struct ltc4245_data *data = i2c_get_clientdata(client); > + int i; > + > + mutex_lock(&data->update_lock); > + > + if (time_after(jiffies, data->last_updated + HZ) || !data->valid) { > + > + dev_dbg(&client->dev, "Starting ltc4245 update\n"); > + > + /* Read control registers -- 0x00 to 0x07 */ > + for (i = 0; i < ARRAY_SIZE(data->cregs); i++) > + data->cregs[i] = ltc4245_read_reg(client, i); > + > + /* Read voltage registers -- 0x10 to 0x1f */ > + for (i = 0; i < ARRAY_SIZE(data->vregs); i++) > + data->vregs[i] = ltc4245_read_reg(client, i+0x10); > + > + data->last_updated = jiffies; > + data->valid = 1; > + } > + > + mutex_unlock(&data->update_lock); > + > + return data; > +} > + > +/* Return the voltage from the given register in millivolts */ > +static int ltc4245_get_voltage(struct device *dev, u8 reg) > +{ > + struct ltc4245_data *data = ltc4245_update_device(dev); > + const s32 val = data->vregs[reg - 0x10]; > + const u8 regval = val; > + u32 voltage = 0; > + > + if (unlikely(val < 0)) > + return 0; > + > + switch (reg) { > + case LTC4245_12VIN: > + case LTC4245_12VOUT: > + voltage = regval * 55; > + break; > + case LTC4245_5VIN: > + case LTC4245_5VOUT: > + voltage = regval * 22; > + break; > + case LTC4245_3VIN: > + case LTC4245_3VOUT: > + voltage = regval * 15; > + break; > + case LTC4245_VEEIN: > + case LTC4245_VEEOUT: > + voltage = regval * -55; > + break; > + case LTC4245_GPIOADC1: > + case LTC4245_GPIOADC2: > + case LTC4245_GPIOADC3: > + voltage = regval * 10; > + break; > + default: > + /* If we get here, the developer messed up */ > + WARN_ON_ONCE(1); > + break; > + } > + > + return voltage; > +} > + > +/* Return the current in the given sense register in milliAmperes */ > +static u32 ltc4245_get_current(struct device *dev, u8 reg) > +{ > + struct ltc4245_data *data = ltc4245_update_device(dev); > + const s32 val = data->vregs[reg - 0x10]; > + const u8 regval = val; > + u32 voltage; > + u32 current; > + > + if (unlikely(val) < 0) > + return 0; > + > + /* The strange looking conversions that follow are fixed-point > + * math, since we cannot do floating point in the kernel. > + * > + * Step 1: convert sense register to microVolts > + * Step 2: convert voltage to milliAmperes > + * > + * If you play around with the V=IR equation, you come up with > + * the following: X uV / Y mOhm == Z mA > + * > + * With the resistors that are fractions of a milliOhm, we multiply > + * the voltage and resistance by 10, to shift the decimal point. > + * Now we can use the normal division operator again. > + */ > + > + switch (reg) { > + case LTC4245_12VSENSE: > + voltage = regval * 250; /* voltage in uV */ > + current = voltage / 50; /* sense resistor 50 mOhm */ > + break; > + case LTC4245_5VSENSE: > + voltage = regval * 125; /* voltage in uV */ > + current = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */ > + break; > + case LTC4245_3VSENSE: > + voltage = regval * 125; /* voltage in uV */ > + current = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */ > + break; > + case LTC4245_VEESENSE: > + voltage = regval * 250; /* voltage in uV */ > + current = voltage / 100; /* sense resistor 100 mOhm */ > + break; > + default: > + /* If we get here, the developer messed up */ > + WARN_ON_ONCE(1); > + current = 0; > + break; > + } > + > + return current; > +} > + > +static ssize_t ltc4245_show_voltage(struct device *dev, > + struct device_attribute *da, > + char *buf) > +{ > + struct sensor_device_attribute *attr = to_sensor_dev_attr(da); > + const u32 voltage = ltc4245_get_voltage(dev, attr->index); > + > + return snprintf(buf, PAGE_SIZE, "%d\n", voltage); > +} > + > +static ssize_t ltc4245_show_current(struct device *dev, > + struct device_attribute *da, > + char *buf) > +{ > + struct sensor_device_attribute *attr = to_sensor_dev_attr(da); > + const u32 current = ltc4245_get_current(dev, attr->index); > + > + return snprintf(buf, PAGE_SIZE, "%u\n", current); > +} > + > +static ssize_t ltc4245_show_power(struct device *dev, > + struct device_attribute *da, > + char *buf) > +{ > + struct sensor_device_attribute *attr = to_sensor_dev_attr(da); > + const u32 current = ltc4245_get_current(dev, attr->index); > + const u32 output_voltage = ltc4245_get_voltage(dev, attr->index+1); > + > + /* current in mA * voltage in mV == power in uW */ > + const unsigned int power = abs(output_voltage * current); > + > + return snprintf(buf, PAGE_SIZE, "%u\n", power); > +} > + > +static ssize_t ltc4245_show_alarm(struct device *dev, > + struct device_attribute *da, > + char *buf) > +{ > + struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da); > + struct ltc4245_data *data = ltc4245_update_device(dev); > + const s32 reg = data->cregs[attr->index]; > + const u32 mask = attr->nr; > + > + if (unlikely(reg < 0)) { > + memset(buf, 0, PAGE_SIZE); /* user should not see old data */ > + return 0; > + } > + > + return snprintf(buf, PAGE_SIZE, "%u\n", (reg & mask) ? 1 : 0); > +} > + > +/* These macros are used below in constructing device attribute objects > + * for use with sysfs_create_group() to make a sysfs device file > + * for each register. > + */ > + > +#define LTC4245_VOLTAGE(name, ltc4245_cmd_idx) \ > + static SENSOR_DEVICE_ATTR(name, S_IRUGO, \ > + ltc4245_show_voltage, NULL, ltc4245_cmd_idx) > + > +#define LTC4245_CURRENT(name, ltc4245_cmd_idx) \ > + static SENSOR_DEVICE_ATTR(name, S_IRUGO, \ > + ltc4245_show_current, NULL, ltc4245_cmd_idx) > + > +#define LTC4245_POWER(name, ltc4245_cmd_idx) \ > + static SENSOR_DEVICE_ATTR(name, S_IRUGO, \ > + ltc4245_show_power, NULL, ltc4245_cmd_idx) > + > +#define LTC4245_ALARM(name, mask, reg) \ > + static SENSOR_DEVICE_ATTR_2(name, S_IRUGO, \ > + ltc4245_show_alarm, NULL, (mask), reg) > + > +/* Construct a sensor_device_attribute structure for each register */ > + > +/* Input voltages */ > +LTC4245_VOLTAGE(in1_input, LTC4245_12VIN); > +LTC4245_VOLTAGE(in2_input, LTC4245_5VIN); > +LTC4245_VOLTAGE(in3_input, LTC4245_3VIN); > +LTC4245_VOLTAGE(in4_input, LTC4245_VEEIN); > + > +/* Input undervoltage alarms */ > +LTC4245_ALARM(in1_min_alarm, (1 << 0), LTC4245_FAULT1); > +LTC4245_ALARM(in2_min_alarm, (1 << 1), LTC4245_FAULT1); > +LTC4245_ALARM(in3_min_alarm, (1 << 2), LTC4245_FAULT1); > +LTC4245_ALARM(in4_min_alarm, (1 << 3), LTC4245_FAULT1); > + > +/* Currents (via sense resistor) */ > +LTC4245_CURRENT(curr1_input, LTC4245_12VSENSE); > +LTC4245_CURRENT(curr2_input, LTC4245_5VSENSE); > +LTC4245_CURRENT(curr3_input, LTC4245_3VSENSE); > +LTC4245_CURRENT(curr4_input, LTC4245_VEESENSE); > + > +/* Overcurrent alarms */ > +LTC4245_ALARM(curr1_max_alarm, (1 << 4), LTC4245_FAULT1); > +LTC4245_ALARM(curr2_max_alarm, (1 << 5), LTC4245_FAULT1); > +LTC4245_ALARM(curr3_max_alarm, (1 << 6), LTC4245_FAULT1); > +LTC4245_ALARM(curr4_max_alarm, (1 << 7), LTC4245_FAULT1); > + > +/* Output voltages */ > +LTC4245_VOLTAGE(in5_input, LTC4245_12VOUT); > +LTC4245_VOLTAGE(in6_input, LTC4245_5VOUT); > +LTC4245_VOLTAGE(in7_input, LTC4245_3VOUT); > +LTC4245_VOLTAGE(in8_input, LTC4245_VEEOUT); > + > +/* Power Bad alarms */ > +LTC4245_ALARM(in5_min_alarm, (1 << 0), LTC4245_FAULT2); > +LTC4245_ALARM(in6_min_alarm, (1 << 1), LTC4245_FAULT2); > +LTC4245_ALARM(in7_min_alarm, (1 << 2), LTC4245_FAULT2); > +LTC4245_ALARM(in8_min_alarm, (1 << 3), LTC4245_FAULT2); > + > +/* GPIO voltages */ > +LTC4245_VOLTAGE(in9_input, LTC4245_GPIOADC1); > +LTC4245_VOLTAGE(in10_input, LTC4245_GPIOADC2); > +LTC4245_VOLTAGE(in11_input, LTC4245_GPIOADC3); > + > +/* Power Consumption (virtual) */ > +LTC4245_POWER(power1_input, LTC4245_12VSENSE); > +LTC4245_POWER(power2_input, LTC4245_5VSENSE); > +LTC4245_POWER(power3_input, LTC4245_3VSENSE); > +LTC4245_POWER(power4_input, LTC4245_VEESENSE); > + > +/* Finally, construct an array of pointers to members of the above objects, > + * as required for sysfs_create_group() > + */ > +static struct attribute *ltc4245_attributes[] = { > + &sensor_dev_attr_in1_input.dev_attr.attr, > + &sensor_dev_attr_in2_input.dev_attr.attr, > + &sensor_dev_attr_in3_input.dev_attr.attr, > + &sensor_dev_attr_in4_input.dev_attr.attr, > + > + &sensor_dev_attr_in1_min_alarm.dev_attr.attr, > + &sensor_dev_attr_in2_min_alarm.dev_attr.attr, > + &sensor_dev_attr_in3_min_alarm.dev_attr.attr, > + &sensor_dev_attr_in4_min_alarm.dev_attr.attr, > + > + &sensor_dev_attr_curr1_input.dev_attr.attr, > + &sensor_dev_attr_curr2_input.dev_attr.attr, > + &sensor_dev_attr_curr3_input.dev_attr.attr, > + &sensor_dev_attr_curr4_input.dev_attr.attr, > + > + &sensor_dev_attr_curr1_max_alarm.dev_attr.attr, > + &sensor_dev_attr_curr2_max_alarm.dev_attr.attr, > + &sensor_dev_attr_curr3_max_alarm.dev_attr.attr, > + &sensor_dev_attr_curr4_max_alarm.dev_attr.attr, > + > + &sensor_dev_attr_in5_input.dev_attr.attr, > + &sensor_dev_attr_in6_input.dev_attr.attr, > + &sensor_dev_attr_in7_input.dev_attr.attr, > + &sensor_dev_attr_in8_input.dev_attr.attr, > + > + &sensor_dev_attr_in5_min_alarm.dev_attr.attr, > + &sensor_dev_attr_in6_min_alarm.dev_attr.attr, > + &sensor_dev_attr_in7_min_alarm.dev_attr.attr, > + &sensor_dev_attr_in8_min_alarm.dev_attr.attr, > + > + &sensor_dev_attr_in9_input.dev_attr.attr, > + &sensor_dev_attr_in10_input.dev_attr.attr, > + &sensor_dev_attr_in11_input.dev_attr.attr, > + > + &sensor_dev_attr_power1_input.dev_attr.attr, > + &sensor_dev_attr_power2_input.dev_attr.attr, > + &sensor_dev_attr_power3_input.dev_attr.attr, > + &sensor_dev_attr_power4_input.dev_attr.attr, > + > + NULL, > +}; > + > +static struct attribute_group ltc4245_group = { > + .attrs = ltc4245_attributes, > +}; > + > +static int ltc4245_probe(struct i2c_client *client, > + const struct i2c_device_id *id) > +{ > + struct ltc4245_data *data; > + int ret; > + > + data = kzalloc(sizeof(*data), GFP_KERNEL); > + > + if (!data) { > + ret = -ENOMEM; > + goto out_kzalloc; > + } > + > + i2c_set_clientdata(client, data); > + mutex_init(&data->update_lock); > + > + /* Initialize the LTC4245 chip */ > + /* TODO */ > + > + /* Register sysfs hooks */ > + ret = sysfs_create_group(&client->dev.kobj, <c4245_group); > + > + if (ret) > + goto out_sysfs_create_group; > + > + data->hwmon_dev = hwmon_device_register(&client->dev); > + > + if (IS_ERR(data->hwmon_dev)) { > + ret = PTR_ERR(data->hwmon_dev); > + goto out_hwmon_device_register; > + } > + > + return 0; > + > +out_hwmon_device_register: > + sysfs_remove_group(&client->dev.kobj, <c4245_group); > +out_sysfs_create_group: > + kfree(data); > +out_kzalloc: > + return ret; > +} > + > +static int ltc4245_remove(struct i2c_client *client) > +{ > + struct ltc4245_data *data = i2c_get_clientdata(client); > + > + hwmon_device_unregister(data->hwmon_dev); > + sysfs_remove_group(&client->dev.kobj, <c4245_group); > + > + kfree(data); > + > + return 0; > +} > + > +/* Check that some bits in a control register appear at all possible > + * locations without changing value > + * > + * @client: the i2c client to use > + * @reg: the register to read > + * @bits: the bits to check (0xff checks all bits, > + * 0x03 checks only the last two bits) > + * > + * return -ENODEV if the register value doesn't stay constant at all > + * possible addresses > + * > + * return 0 for success > + */ > +static int ltc4245_check_control_reg(struct i2c_client *client, u8 reg, u8 bits) > +{ > + int i; > + s32 v, voff1, voff2; > + > + v = ltc4245_read_reg(client, reg) & bits; > + > + if (v < 0) > + return -ENODEV; > + > + for (i = 0x00; i < 0xff; i += 0x20) { > + voff1 = ltc4245_read_reg(client, reg + i) & bits; > + voff2 = ltc4245_read_reg(client, reg + i + 0x08) & bits; > + > + if (voff1 < 0 || voff2 < 0 || v != voff1 || v != voff2) > + return -ENODEV; > + } > + > + return 0; > +} > + > +static int ltc4245_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) { /* probed detection - check the chip type */ > + s32 v; /* 8 bits from the chip, or -ERRNO */ > + > + /* Chip registers 0x00-0x07 are control registers > + * Chip registers 0x10-0x1f are data registers > + * > + * Address bits b7-b5 are ignored. This makes the chip "repeat" > + * in steps of 0x20. Any control registers should appear with > + * the same values across all duplicated addresses. > + * > + * Register 0x02 bit b2 is reserved, expect 0 > + * Register 0x07 bits b7 to b4 are reserved, expect 0 > + * > + * Registers 0x01, 0x02 are control registers and should not > + * change on their own. > + * > + * Register 0x06 bits b6 and b7 are control bits, and should > + * not change on their own. > + * > + * Register 0x07 bits b3 to b0 are control bits, and should > + * not change on their own. > + */ > + > + /* read register 0x02 reserved bit, expect 0 */ > + v = ltc4245_read_reg(client, LTC4245_CONTROL); > + if (v < 0 || (v & 0x04) != 0) > + return -ENODEV; > + > + /* read register 0x07 reserved bits, expect 0 */ > + v = ltc4245_read_reg(client, LTC4245_ADCADR); > + if (v < 0 || (v & 0xf0) != 0) > + return -ENODEV; > + > + /* check that the alert register appears at all locations */ > + if (ltc4245_check_control_reg(client, LTC4245_ALERT, 0xff)) > + return -ENODEV; > + > + /* check that the control register appears at all locations */ > + if (ltc4245_check_control_reg(client, LTC4245_CONTROL, 0xff)) > + return -ENODEV; > + > + /* check that register 0x06 bits b6 and b7 stay constant */ > + if (ltc4245_check_control_reg(client, LTC4245_GPIO, 0xc0)) > + return -ENODEV; > + > + /* check that register 0x07 bits b3-b0 stay constant */ > + if (ltc4245_check_control_reg(client, LTC4245_ADCADR, 0x0f)) > + return -ENODEV; > + } > + > + strlcpy(info->type, "ltc4245", I2C_NAME_SIZE); > + pr_info("ltc4245: %s on i2c-%u address 0x%02x\n", > + kind < 0 ? "probed" : "forced", > + adapter->nr, client->addr); > + > + return 0; > +} > + > +static const struct i2c_device_id ltc4245_id[] = { > + { "ltc4245", ltc4245 }, > + { } > +}; > +MODULE_DEVICE_TABLE(i2c, ltc4245_id); > + > +/* This is the driver that will be inserted */ > +static struct i2c_driver ltc4245_driver = { > + .class = I2C_CLASS_HWMON, > + .driver = { > + .name = "ltc4245", > + }, > + .probe = ltc4245_probe, > + .remove = ltc4245_remove, > + .id_table = ltc4245_id, > + .detect = ltc4245_detect, > + .address_data = &addr_data, > +}; > + > +static int __init ltc4245_init(void) > +{ > + return i2c_add_driver(<c4245_driver); > +} > + > +static void __exit ltc4245_exit(void) > +{ > + i2c_del_driver(<c4245_driver); > +} > + > +MODULE_AUTHOR("Ira W. Snyder <iws at ovro.caltech.edu>"); > +MODULE_DESCRIPTION("LTC4245 driver"); > +MODULE_LICENSE("GPL"); > + > +module_init(ltc4245_init); > +module_exit(ltc4245_exit);
