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linux/drivers/hwmon/ltc4245.c
Stephen Kitt 6748703856 hwmon: use simple i2c probe function 
Many hwmon drivers don't use the id information provided by the old
i2c probe function, and the remainder can easily be adapted to the new
form ("probe_new") by calling i2c_match_id explicitly.

This avoids scanning the identifier tables during probes.

Drivers which didn't use the id are converted as-is; drivers which did
are modified as follows:

* if the information in i2c_client is sufficient, that's used instead
  (client->name);
* anything else is handled by calling i2c_match_id() with the same
  level of error-handling (if any) as before.

A few drivers aren't included in this patch because they have a
different set of maintainers. They will be covered by other patches.

Signed-off-by: Stephen Kitt <steve@sk2.org>
Link: https://lore.kernel.org/r/20200813160222.1503401-1-steve@sk2.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2020-09-23 09:42:39 -07:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
*
* Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu>
*
* 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/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/jiffies.h>
#include <linux/platform_data/ltc4245.h>
/* 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_GPIOADC = 0x1c,
};
struct ltc4245_data {
struct i2c_client *client;
struct mutex update_lock;
bool valid;
unsigned long last_updated; /* in jiffies */
/* Control registers */
u8 cregs[0x08];
/* Voltage registers */
u8 vregs[0x0d];
/* GPIO ADC registers */
bool use_extra_gpios;
int gpios[3];
};
/*
* Update the readings from the GPIO pins. If the driver has been configured to
* sample all GPIO's as analog voltages, a round-robin sampling method is used.
* Otherwise, only the configured GPIO pin is sampled.
*
* LOCKING: must hold data->update_lock
*/
static void ltc4245_update_gpios(struct device *dev)
{
struct ltc4245_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
u8 gpio_curr, gpio_next, gpio_reg;
int i;
/* no extra gpio support, we're basically done */
if (!data->use_extra_gpios) {
data->gpios[0] = data->vregs[LTC4245_GPIOADC - 0x10];
return;
}
/*
* If the last reading was too long ago, then we mark all old GPIO
* readings as stale by setting them to -EAGAIN
*/
if (time_after(jiffies, data->last_updated + 5 * HZ)) {
for (i = 0; i < ARRAY_SIZE(data->gpios); i++)
data->gpios[i] = -EAGAIN;
}
/*
* Get the current GPIO pin
*
* The datasheet calls these GPIO[1-3], but we'll calculate the zero
* based array index instead, and call them GPIO[0-2]. This is much
* easier to think about.
*/
gpio_curr = (data->cregs[LTC4245_GPIO] & 0xc0) >> 6;
if (gpio_curr > 0)
gpio_curr -= 1;
/* Read the GPIO voltage from the GPIOADC register */
data->gpios[gpio_curr] = data->vregs[LTC4245_GPIOADC - 0x10];
/* Find the next GPIO pin to read */
gpio_next = (gpio_curr + 1) % ARRAY_SIZE(data->gpios);
/*
* Calculate the correct setting for the GPIO register so it will
* sample the next GPIO pin
*/
gpio_reg = (data->cregs[LTC4245_GPIO] & 0x3f) | ((gpio_next + 1) << 6);
/* Update the GPIO register */
i2c_smbus_write_byte_data(client, LTC4245_GPIO, gpio_reg);
/* Update saved data */
data->cregs[LTC4245_GPIO] = gpio_reg;
}
static struct ltc4245_data *ltc4245_update_device(struct device *dev)
{
struct ltc4245_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
s32 val;
int i;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
/* Read control registers -- 0x00 to 0x07 */
for (i = 0; i < ARRAY_SIZE(data->cregs); i++) {
val = i2c_smbus_read_byte_data(client, i);
if (unlikely(val < 0))
data->cregs[i] = 0;
else
data->cregs[i] = val;
}
/* Read voltage registers -- 0x10 to 0x1c */
for (i = 0; i < ARRAY_SIZE(data->vregs); i++) {
val = i2c_smbus_read_byte_data(client, i+0x10);
if (unlikely(val < 0))
data->vregs[i] = 0;
else
data->vregs[i] = val;
}
/* Update GPIO readings */
ltc4245_update_gpios(dev);
data->last_updated = jiffies;
data->valid = true;
}
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 u8 regval = data->vregs[reg - 0x10];
u32 voltage = 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_GPIOADC:
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 unsigned int ltc4245_get_current(struct device *dev, u8 reg)
{
struct ltc4245_data *data = ltc4245_update_device(dev);
const u8 regval = data->vregs[reg - 0x10];
unsigned int voltage;
unsigned int curr;
/*
* 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 */
curr = voltage / 50; /* sense resistor 50 mOhm */
break;
case LTC4245_5VSENSE:
voltage = regval * 125; /* voltage in uV */
curr = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */
break;
case LTC4245_3VSENSE:
voltage = regval * 125; /* voltage in uV */
curr = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */
break;
case LTC4245_VEESENSE:
voltage = regval * 250; /* voltage in uV */
curr = voltage / 100; /* sense resistor 100 mOhm */
break;
default:
/* If we get here, the developer messed up */
WARN_ON_ONCE(1);
curr = 0;
break;
}
return curr;
}
/* Map from voltage channel index to voltage register */
static const s8 ltc4245_in_regs[] = {
LTC4245_12VIN, LTC4245_5VIN, LTC4245_3VIN, LTC4245_VEEIN,
LTC4245_12VOUT, LTC4245_5VOUT, LTC4245_3VOUT, LTC4245_VEEOUT,
};
/* Map from current channel index to current register */
static const s8 ltc4245_curr_regs[] = {
LTC4245_12VSENSE, LTC4245_5VSENSE, LTC4245_3VSENSE, LTC4245_VEESENSE,
};
static int ltc4245_read_curr(struct device *dev, u32 attr, int channel,
long *val)
{
struct ltc4245_data *data = ltc4245_update_device(dev);
switch (attr) {
case hwmon_curr_input:
*val = ltc4245_get_current(dev, ltc4245_curr_regs[channel]);
return 0;
case hwmon_curr_max_alarm:
*val = !!(data->cregs[LTC4245_FAULT1] & BIT(channel + 4));
return 0;
default:
return -EOPNOTSUPP;
}
}
static int ltc4245_read_in(struct device *dev, u32 attr, int channel, long *val)
{
struct ltc4245_data *data = ltc4245_update_device(dev);
switch (attr) {
case hwmon_in_input:
if (channel < 8) {
*val = ltc4245_get_voltage(dev,
ltc4245_in_regs[channel]);
} else {
int regval = data->gpios[channel - 8];
if (regval < 0)
return regval;
*val = regval * 10;
}
return 0;
case hwmon_in_min_alarm:
if (channel < 4)
*val = !!(data->cregs[LTC4245_FAULT1] & BIT(channel));
else
*val = !!(data->cregs[LTC4245_FAULT2] &
BIT(channel - 4));
return 0;
default:
return -EOPNOTSUPP;
}
}
static int ltc4245_read_power(struct device *dev, u32 attr, int channel,
long *val)
{
unsigned long curr;
long voltage;
switch (attr) {
case hwmon_power_input:
(void)ltc4245_update_device(dev);
curr = ltc4245_get_current(dev, ltc4245_curr_regs[channel]);
voltage = ltc4245_get_voltage(dev, ltc4245_in_regs[channel]);
*val = abs(curr * voltage);
return 0;
default:
return -EOPNOTSUPP;
}
}
static int ltc4245_read(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long *val)
{
switch (type) {
case hwmon_curr:
return ltc4245_read_curr(dev, attr, channel, val);
case hwmon_power:
return ltc4245_read_power(dev, attr, channel, val);
case hwmon_in:
return ltc4245_read_in(dev, attr, channel - 1, val);
default:
return -EOPNOTSUPP;
}
}
static umode_t ltc4245_is_visible(const void *_data,
enum hwmon_sensor_types type,
u32 attr, int channel)
{
const struct ltc4245_data *data = _data;
switch (type) {
case hwmon_in:
if (channel == 0)
return 0;
switch (attr) {
case hwmon_in_input:
if (channel > 9 && !data->use_extra_gpios)
return 0;
return 0444;
case hwmon_in_min_alarm:
if (channel > 8)
return 0;
return 0444;
default:
return 0;
}
case hwmon_curr:
switch (attr) {
case hwmon_curr_input:
case hwmon_curr_max_alarm:
return 0444;
default:
return 0;
}
case hwmon_power:
switch (attr) {
case hwmon_power_input:
return 0444;
default:
return 0;
}
default:
return 0;
}
}
static const struct hwmon_channel_info *ltc4245_info[] = {
HWMON_CHANNEL_INFO(in,
HWMON_I_INPUT,
HWMON_I_INPUT | HWMON_I_MIN_ALARM,
HWMON_I_INPUT | HWMON_I_MIN_ALARM,
HWMON_I_INPUT | HWMON_I_MIN_ALARM,
HWMON_I_INPUT | HWMON_I_MIN_ALARM,
HWMON_I_INPUT | HWMON_I_MIN_ALARM,
HWMON_I_INPUT | HWMON_I_MIN_ALARM,
HWMON_I_INPUT | HWMON_I_MIN_ALARM,
HWMON_I_INPUT | HWMON_I_MIN_ALARM,
HWMON_I_INPUT,
HWMON_I_INPUT,
HWMON_I_INPUT),
HWMON_CHANNEL_INFO(curr,
HWMON_C_INPUT | HWMON_C_MAX_ALARM,
HWMON_C_INPUT | HWMON_C_MAX_ALARM,
HWMON_C_INPUT | HWMON_C_MAX_ALARM,
HWMON_C_INPUT | HWMON_C_MAX_ALARM),
HWMON_CHANNEL_INFO(power,
HWMON_P_INPUT,
HWMON_P_INPUT,
HWMON_P_INPUT,
HWMON_P_INPUT),
NULL
};
static const struct hwmon_ops ltc4245_hwmon_ops = {
.is_visible = ltc4245_is_visible,
.read = ltc4245_read,
};
static const struct hwmon_chip_info ltc4245_chip_info = {
.ops = &ltc4245_hwmon_ops,
.info = ltc4245_info,
};
static bool ltc4245_use_extra_gpios(struct i2c_client *client)
{
struct ltc4245_platform_data *pdata = dev_get_platdata(&client->dev);
struct device_node *np = client->dev.of_node;
/* prefer platform data */
if (pdata)
return pdata->use_extra_gpios;
/* fallback on OF */
if (of_find_property(np, "ltc4245,use-extra-gpios", NULL))
return true;
return false;
}
static int ltc4245_probe(struct i2c_client *client)
{
struct i2c_adapter *adapter = client->adapter;
struct ltc4245_data *data;
struct device *hwmon_dev;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
return -ENODEV;
data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->client = client;
mutex_init(&data->update_lock);
data->use_extra_gpios = ltc4245_use_extra_gpios(client);
/* Initialize the LTC4245 chip */
i2c_smbus_write_byte_data(client, LTC4245_FAULT1, 0x00);
i2c_smbus_write_byte_data(client, LTC4245_FAULT2, 0x00);
hwmon_dev = devm_hwmon_device_register_with_info(&client->dev,
client->name, data,
&ltc4245_chip_info,
NULL);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct i2c_device_id ltc4245_id[] = {
{ "ltc4245", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ltc4245_id);
/* This is the driver that will be inserted */
static struct i2c_driver ltc4245_driver = {
.driver = {
.name = "ltc4245",
},
.probe_new = ltc4245_probe,
.id_table = ltc4245_id,
};
module_i2c_driver(ltc4245_driver);
MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
MODULE_DESCRIPTION("LTC4245 driver");
MODULE_LICENSE("GPL");
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