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linux/drivers/misc/ics932s401.c
Darrick J. Wong a73b6a3b41 ics932s401: fix broken handling of errors when word reading fails 
In commit b05ae01fdb, someone tried to make the driver handle i2c read
errors by simply zeroing out the register contents, but for some reason
left unaltered the code that sets the cached register value the function
call return value.

The original patch was authored by a member of the Underhanded
Mangle-happy Nerds, I'm not terribly surprised.  I don't have the
hardware anymore so I can't test this, but it seems like a pretty
obvious API usage fix to me...

Fixes: b05ae01fdb ("misc/ics932s401: Add a missing check to i2c_smbus_read_word_data")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20210428222534.GJ3122264@magnolia
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13 17:21:54 +02:00

485 lines
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* A driver for the Integrated Circuits ICS932S401
* Copyright (C) 2008 IBM
*
* Author: Darrick J. Wong <darrick.wong@oracle.com>
*/
#include <linux/module.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/delay.h>
#include <linux/log2.h>
#include <linux/slab.h>
/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x69, I2C_CLIENT_END };
/* ICS932S401 registers */
#define ICS932S401_REG_CFG2 0x01
#define ICS932S401_CFG1_SPREAD 0x01
#define ICS932S401_REG_CFG7 0x06
#define ICS932S401_FS_MASK 0x07
#define ICS932S401_REG_VENDOR_REV 0x07
#define ICS932S401_VENDOR 1
#define ICS932S401_VENDOR_MASK 0x0F
#define ICS932S401_REV 4
#define ICS932S401_REV_SHIFT 4
#define ICS932S401_REG_DEVICE 0x09
#define ICS932S401_DEVICE 11
#define ICS932S401_REG_CTRL 0x0A
#define ICS932S401_MN_ENABLED 0x80
#define ICS932S401_CPU_ALT 0x04
#define ICS932S401_SRC_ALT 0x08
#define ICS932S401_REG_CPU_M_CTRL 0x0B
#define ICS932S401_M_MASK 0x3F
#define ICS932S401_REG_CPU_N_CTRL 0x0C
#define ICS932S401_REG_CPU_SPREAD1 0x0D
#define ICS932S401_REG_CPU_SPREAD2 0x0E
#define ICS932S401_SPREAD_MASK 0x7FFF
#define ICS932S401_REG_SRC_M_CTRL 0x0F
#define ICS932S401_REG_SRC_N_CTRL 0x10
#define ICS932S401_REG_SRC_SPREAD1 0x11
#define ICS932S401_REG_SRC_SPREAD2 0x12
#define ICS932S401_REG_CPU_DIVISOR 0x13
#define ICS932S401_CPU_DIVISOR_SHIFT 4
#define ICS932S401_REG_PCISRC_DIVISOR 0x14
#define ICS932S401_SRC_DIVISOR_MASK 0x0F
#define ICS932S401_PCI_DIVISOR_SHIFT 4
/* Base clock is 14.318MHz */
#define BASE_CLOCK 14318
#define NUM_REGS 21
#define NUM_MIRRORED_REGS 15
static int regs_to_copy[NUM_MIRRORED_REGS] = {
ICS932S401_REG_CFG2,
ICS932S401_REG_CFG7,
ICS932S401_REG_VENDOR_REV,
ICS932S401_REG_DEVICE,
ICS932S401_REG_CTRL,
ICS932S401_REG_CPU_M_CTRL,
ICS932S401_REG_CPU_N_CTRL,
ICS932S401_REG_CPU_SPREAD1,
ICS932S401_REG_CPU_SPREAD2,
ICS932S401_REG_SRC_M_CTRL,
ICS932S401_REG_SRC_N_CTRL,
ICS932S401_REG_SRC_SPREAD1,
ICS932S401_REG_SRC_SPREAD2,
ICS932S401_REG_CPU_DIVISOR,
ICS932S401_REG_PCISRC_DIVISOR,
};
/* How often do we reread sensors values? (In jiffies) */
#define SENSOR_REFRESH_INTERVAL (2 * HZ)
/* How often do we reread sensor limit values? (In jiffies) */
#define LIMIT_REFRESH_INTERVAL (60 * HZ)
struct ics932s401_data {
struct attribute_group attrs;
struct mutex lock;
char sensors_valid;
unsigned long sensors_last_updated; /* In jiffies */
u8 regs[NUM_REGS];
};
static int ics932s401_probe(struct i2c_client *client,
const struct i2c_device_id *id);
static int ics932s401_detect(struct i2c_client *client,
struct i2c_board_info *info);
static int ics932s401_remove(struct i2c_client *client);
static const struct i2c_device_id ics932s401_id[] = {
{ "ics932s401", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ics932s401_id);
static struct i2c_driver ics932s401_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = "ics932s401",
},
.probe = ics932s401_probe,
.remove = ics932s401_remove,
.id_table = ics932s401_id,
.detect = ics932s401_detect,
.address_list = normal_i2c,
};
static struct ics932s401_data *ics932s401_update_device(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct ics932s401_data *data = i2c_get_clientdata(client);
unsigned long local_jiffies = jiffies;
int i, temp;
mutex_lock(&data->lock);
if (time_before(local_jiffies, data->sensors_last_updated +
SENSOR_REFRESH_INTERVAL)
&& data->sensors_valid)
goto out;
/*
* Each register must be read as a word and then right shifted 8 bits.
* Not really sure why this is; setting the "byte count programming"
* register to 1 does not fix this problem.
*/
for (i = 0; i < NUM_MIRRORED_REGS; i++) {
temp = i2c_smbus_read_word_data(client, regs_to_copy[i]);
if (temp < 0)
temp = 0;
data->regs[regs_to_copy[i]] = temp >> 8;
}
data->sensors_last_updated = local_jiffies;
data->sensors_valid = 1;
out:
mutex_unlock(&data->lock);
return data;
}
static ssize_t show_spread_enabled(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct ics932s401_data *data = ics932s401_update_device(dev);
if (data->regs[ICS932S401_REG_CFG2] & ICS932S401_CFG1_SPREAD)
return sprintf(buf, "1\n");
return sprintf(buf, "0\n");
}
/* bit to cpu khz map */
static const int fs_speeds[] = {
266666,
133333,
200000,
166666,
333333,
100000,
400000,
0,
};
/* clock divisor map */
static const int divisors[] = {2, 3, 5, 15, 4, 6, 10, 30, 8, 12, 20, 60, 16,
24, 40, 120};
/* Calculate CPU frequency from the M/N registers. */
static int calculate_cpu_freq(struct ics932s401_data *data)
{
int m, n, freq;
m = data->regs[ICS932S401_REG_CPU_M_CTRL] & ICS932S401_M_MASK;
n = data->regs[ICS932S401_REG_CPU_N_CTRL];
/* Pull in bits 8 & 9 from the M register */
n |= ((int)data->regs[ICS932S401_REG_CPU_M_CTRL] & 0x80) << 1;
n |= ((int)data->regs[ICS932S401_REG_CPU_M_CTRL] & 0x40) << 3;
freq = BASE_CLOCK * (n + 8) / (m + 2);
freq /= divisors[data->regs[ICS932S401_REG_CPU_DIVISOR] >>
ICS932S401_CPU_DIVISOR_SHIFT];
return freq;
}
static ssize_t show_cpu_clock(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct ics932s401_data *data = ics932s401_update_device(dev);
return sprintf(buf, "%d\n", calculate_cpu_freq(data));
}
static ssize_t show_cpu_clock_sel(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct ics932s401_data *data = ics932s401_update_device(dev);
int freq;
if (data->regs[ICS932S401_REG_CTRL] & ICS932S401_MN_ENABLED)
freq = calculate_cpu_freq(data);
else {
/* Freq is neatly wrapped up for us */
int fid = data->regs[ICS932S401_REG_CFG7] & ICS932S401_FS_MASK;
freq = fs_speeds[fid];
if (data->regs[ICS932S401_REG_CTRL] & ICS932S401_CPU_ALT) {
switch (freq) {
case 166666:
freq = 160000;
break;
case 333333:
freq = 320000;
break;
}
}
}
return sprintf(buf, "%d\n", freq);
}
/* Calculate SRC frequency from the M/N registers. */
static int calculate_src_freq(struct ics932s401_data *data)
{
int m, n, freq;
m = data->regs[ICS932S401_REG_SRC_M_CTRL] & ICS932S401_M_MASK;
n = data->regs[ICS932S401_REG_SRC_N_CTRL];
/* Pull in bits 8 & 9 from the M register */
n |= ((int)data->regs[ICS932S401_REG_SRC_M_CTRL] & 0x80) << 1;
n |= ((int)data->regs[ICS932S401_REG_SRC_M_CTRL] & 0x40) << 3;
freq = BASE_CLOCK * (n + 8) / (m + 2);
freq /= divisors[data->regs[ICS932S401_REG_PCISRC_DIVISOR] &
ICS932S401_SRC_DIVISOR_MASK];
return freq;
}
static ssize_t show_src_clock(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct ics932s401_data *data = ics932s401_update_device(dev);
return sprintf(buf, "%d\n", calculate_src_freq(data));
}
static ssize_t show_src_clock_sel(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct ics932s401_data *data = ics932s401_update_device(dev);
int freq;
if (data->regs[ICS932S401_REG_CTRL] & ICS932S401_MN_ENABLED)
freq = calculate_src_freq(data);
else
/* Freq is neatly wrapped up for us */
if (data->regs[ICS932S401_REG_CTRL] & ICS932S401_CPU_ALT &&
data->regs[ICS932S401_REG_CTRL] & ICS932S401_SRC_ALT)
freq = 96000;
else
freq = 100000;
return sprintf(buf, "%d\n", freq);
}
/* Calculate PCI frequency from the SRC M/N registers. */
static int calculate_pci_freq(struct ics932s401_data *data)
{
int m, n, freq;
m = data->regs[ICS932S401_REG_SRC_M_CTRL] & ICS932S401_M_MASK;
n = data->regs[ICS932S401_REG_SRC_N_CTRL];
/* Pull in bits 8 & 9 from the M register */
n |= ((int)data->regs[ICS932S401_REG_SRC_M_CTRL] & 0x80) << 1;
n |= ((int)data->regs[ICS932S401_REG_SRC_M_CTRL] & 0x40) << 3;
freq = BASE_CLOCK * (n + 8) / (m + 2);
freq /= divisors[data->regs[ICS932S401_REG_PCISRC_DIVISOR] >>
ICS932S401_PCI_DIVISOR_SHIFT];
return freq;
}
static ssize_t show_pci_clock(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct ics932s401_data *data = ics932s401_update_device(dev);
return sprintf(buf, "%d\n", calculate_pci_freq(data));
}
static ssize_t show_pci_clock_sel(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct ics932s401_data *data = ics932s401_update_device(dev);
int freq;
if (data->regs[ICS932S401_REG_CTRL] & ICS932S401_MN_ENABLED)
freq = calculate_pci_freq(data);
else
freq = 33333;
return sprintf(buf, "%d\n", freq);
}
static ssize_t show_value(struct device *dev,
struct device_attribute *devattr,
char *buf);
static ssize_t show_spread(struct device *dev,
struct device_attribute *devattr,
char *buf);
static DEVICE_ATTR(spread_enabled, S_IRUGO, show_spread_enabled, NULL);
static DEVICE_ATTR(cpu_clock_selection, S_IRUGO, show_cpu_clock_sel, NULL);
static DEVICE_ATTR(cpu_clock, S_IRUGO, show_cpu_clock, NULL);
static DEVICE_ATTR(src_clock_selection, S_IRUGO, show_src_clock_sel, NULL);
static DEVICE_ATTR(src_clock, S_IRUGO, show_src_clock, NULL);
static DEVICE_ATTR(pci_clock_selection, S_IRUGO, show_pci_clock_sel, NULL);
static DEVICE_ATTR(pci_clock, S_IRUGO, show_pci_clock, NULL);
static DEVICE_ATTR(usb_clock, S_IRUGO, show_value, NULL);
static DEVICE_ATTR(ref_clock, S_IRUGO, show_value, NULL);
static DEVICE_ATTR(cpu_spread, S_IRUGO, show_spread, NULL);
static DEVICE_ATTR(src_spread, S_IRUGO, show_spread, NULL);
static struct attribute *ics932s401_attr[] = {
&dev_attr_spread_enabled.attr,
&dev_attr_cpu_clock_selection.attr,
&dev_attr_cpu_clock.attr,
&dev_attr_src_clock_selection.attr,
&dev_attr_src_clock.attr,
&dev_attr_pci_clock_selection.attr,
&dev_attr_pci_clock.attr,
&dev_attr_usb_clock.attr,
&dev_attr_ref_clock.attr,
&dev_attr_cpu_spread.attr,
&dev_attr_src_spread.attr,
NULL
};
static ssize_t show_value(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
int x;
if (devattr == &dev_attr_usb_clock)
x = 48000;
else if (devattr == &dev_attr_ref_clock)
x = BASE_CLOCK;
else
BUG();
return sprintf(buf, "%d\n", x);
}
static ssize_t show_spread(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct ics932s401_data *data = ics932s401_update_device(dev);
int reg;
unsigned long val;
if (!(data->regs[ICS932S401_REG_CFG2] & ICS932S401_CFG1_SPREAD))
return sprintf(buf, "0%%\n");
if (devattr == &dev_attr_src_spread)
reg = ICS932S401_REG_SRC_SPREAD1;
else if (devattr == &dev_attr_cpu_spread)
reg = ICS932S401_REG_CPU_SPREAD1;
else
BUG();
val = data->regs[reg] | (data->regs[reg + 1] << 8);
val &= ICS932S401_SPREAD_MASK;
/* Scale 0..2^14 to -0.5. */
val = 500000 * val / 16384;
return sprintf(buf, "-0.%lu%%\n", val);
}
/* Return 0 if detection is successful, -ENODEV otherwise */
static int ics932s401_detect(struct i2c_client *client,
struct i2c_board_info *info)
{
struct i2c_adapter *adapter = client->adapter;
int vendor, device, revision;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
return -ENODEV;
vendor = i2c_smbus_read_word_data(client, ICS932S401_REG_VENDOR_REV);
vendor >>= 8;
revision = vendor >> ICS932S401_REV_SHIFT;
vendor &= ICS932S401_VENDOR_MASK;
if (vendor != ICS932S401_VENDOR)
return -ENODEV;
device = i2c_smbus_read_word_data(client, ICS932S401_REG_DEVICE);
device >>= 8;
if (device != ICS932S401_DEVICE)
return -ENODEV;
if (revision != ICS932S401_REV)
dev_info(&adapter->dev, "Unknown revision %d\n", revision);
strlcpy(info->type, "ics932s401", I2C_NAME_SIZE);
return 0;
}
static int ics932s401_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct ics932s401_data *data;
int err;
data = kzalloc(sizeof(struct ics932s401_data), GFP_KERNEL);
if (!data) {
err = -ENOMEM;
goto exit;
}
i2c_set_clientdata(client, data);
mutex_init(&data->lock);
dev_info(&client->dev, "%s chip found\n", client->name);
/* Register sysfs hooks */
data->attrs.attrs = ics932s401_attr;
err = sysfs_create_group(&client->dev.kobj, &data->attrs);
if (err)
goto exit_free;
return 0;
exit_free:
kfree(data);
exit:
return err;
}
static int ics932s401_remove(struct i2c_client *client)
{
struct ics932s401_data *data = i2c_get_clientdata(client);
sysfs_remove_group(&client->dev.kobj, &data->attrs);
kfree(data);
return 0;
}
module_i2c_driver(ics932s401_driver);
MODULE_AUTHOR("Darrick J. Wong <darrick.wong@oracle.com>");
MODULE_DESCRIPTION("ICS932S401 driver");
MODULE_LICENSE("GPL");
/* IBM IntelliStation Z30 */
MODULE_ALIAS("dmi:bvnIBM:*:rn9228:*");
MODULE_ALIAS("dmi:bvnIBM:*:rn9232:*");
/* IBM x3650/x3550 */
MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3650*");
MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3550*");
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