| Message ID | 20201117010944.28457-2-rentao.bupt@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | hwmon: (max127) Add Maxim MAX127 hardware monitoring | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
On Mon, Nov 16, 2020 at 05:09:43PM -0800, rentao.bupt@gmail.com wrote: > From: Tao Ren <rentao.bupt@gmail.com> > > Add hardware monitoring driver for the Maxim MAX127 chip. > > MAX127 min/max range handling code is inspired by the max197 driver. > > Signed-off-by: Tao Ren <rentao.bupt@gmail.com> > --- > drivers/hwmon/Kconfig | 9 ++ > drivers/hwmon/Makefile | 1 + > drivers/hwmon/max127.c | 286 +++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 296 insertions(+) > create mode 100644 drivers/hwmon/max127.c > > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > index 9d600e0c5584..716df51edc87 100644 > --- a/drivers/hwmon/Kconfig > +++ b/drivers/hwmon/Kconfig > @@ -950,6 +950,15 @@ config SENSORS_MAX1111 > This driver can also be built as a module. If so, the module > will be called max1111. > > +config SENSORS_MAX127 > + tristate "Maxim MAX127 12-bit 8-channel Data Acquisition System" > + depends on I2C > + help > + Say y here to support Maxim's MAX127 DAS chips. > + > + This driver can also be built as a module. If so, the module > + will be called max127. > + > config SENSORS_MAX16065 > tristate "Maxim MAX16065 System Manager and compatibles" > depends on I2C > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile > index 1083bbfac779..01ca5d3fbad4 100644 > --- a/drivers/hwmon/Makefile > +++ b/drivers/hwmon/Makefile > @@ -127,6 +127,7 @@ obj-$(CONFIG_SENSORS_LTC4260) += ltc4260.o > obj-$(CONFIG_SENSORS_LTC4261) += ltc4261.o > obj-$(CONFIG_SENSORS_LTQ_CPUTEMP) += ltq-cputemp.o > obj-$(CONFIG_SENSORS_MAX1111) += max1111.o > +obj-$(CONFIG_SENSORS_MAX127) += max127.o > obj-$(CONFIG_SENSORS_MAX16065) += max16065.o > obj-$(CONFIG_SENSORS_MAX1619) += max1619.o > obj-$(CONFIG_SENSORS_MAX1668) += max1668.o > diff --git a/drivers/hwmon/max127.c b/drivers/hwmon/max127.c > new file mode 100644 > index 000000000000..df74a95bcf28 > --- /dev/null > +++ b/drivers/hwmon/max127.c > @@ -0,0 +1,286 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * Hardware monitoring driver for MAX127. > + * > + * Copyright (c) 2020 Facebook Inc. > + */ > + > +#include <linux/err.h> > +#include <linux/hwmon.h> > +#include <linux/hwmon-sysfs.h> > +#include <linux/i2c.h> > +#include <linux/init.h> > +#include <linux/module.h> > +#include <linux/sysfs.h> > + > +/* MAX127 Control Byte. */ > +#define MAX127_CTRL_START BIT(7) > +#define MAX127_CTRL_SEL_OFFSET 4 That would better be named _SHIFT. > +#define MAX127_CTRL_RNG BIT(3) > +#define MAX127_CTRL_BIP BIT(2) > +#define MAX127_CTRL_PD1 BIT(1) > +#define MAX127_CTRL_PD0 BIT(0) > + > +#define MAX127_NUM_CHANNELS 8 > +#define MAX127_SET_CHANNEL(ch) (((ch) & 7) << (MAX127_CTRL_SEL_OFFSET)) () around MAX127_CTRL_SEL_OFFSET is unnecessary. > + > +#define MAX127_INPUT_LIMIT 10 /* 10V */ > + > +/* > + * MAX127 returns 2 bytes at read: > + * - the first byte contains data[11:4]. > + * - the second byte contains data[3:0] (MSB) and 4 dummy 0s (LSB). > + */ > +#define MAX127_DATA1_SHIFT 4 > + > +struct max127_data { > + struct mutex lock; > + struct i2c_client *client; > + int input_limit; > + u8 ctrl_byte[MAX127_NUM_CHANNELS]; > +}; > + > +static int max127_select_channel(struct max127_data *data, int channel) > +{ > + int status; > + struct i2c_client *client = data->client; > + struct i2c_msg msg = { > + .addr = client->addr, > + .flags = 0, > + .len = 1, > + .buf = &data->ctrl_byte[channel], > + }; > + > + status = i2c_transfer(client->adapter, &msg, 1); > + if (status != 1) > + return status; > + Other drivers assume that this function can return 0. Please take that into account as well. > + return 0; > +} > + > +static int max127_read_channel(struct max127_data *data, int channel, u16 *vin) > +{ > + int status; > + u8 i2c_data[2]; > + struct i2c_client *client = data->client; > + struct i2c_msg msg = { > + .addr = client->addr, > + .flags = I2C_M_RD, > + .len = 2, > + .buf = i2c_data, > + }; > + > + status = i2c_transfer(client->adapter, &msg, 1); > + if (status != 1) > + return status; Same as above. > + > + *vin = ((i2c_data[0] << 8) | i2c_data[1]) >> MAX127_DATA1_SHIFT; THis seems wrong. D4..D11 end up in but 8..15, and D0..D3 end up in bit 0..3. Seems to me the upper byte should be left shifted 4 bit. The result then needs to be scaled to mV (see below). Also, for consistency I would suggest to either use () for both parts of the logical or operation or for none. > + return 0; > +} > + > +static ssize_t max127_input_show(struct device *dev, > + struct device_attribute *dev_attr, > + char *buf) > +{ > + u16 vin; > + int status; > + struct max127_data *data = dev_get_drvdata(dev); > + struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr); > + > + if (mutex_lock_interruptible(&data->lock)) > + return -ERESTARTSYS; I don't think the _interruptible is warranted in this driver. > + > + status = max127_select_channel(data, attr->index); > + if (status) > + goto exit; > + > + status = max127_read_channel(data, attr->index, &vin); > + if (status) > + goto exit; > + > + status = sprintf(buf, "%u", vin); This is not correct. The ABI expects values in milli-Volt, and per datasheet the values need to be scaled depending on polarity and range settings (see table 3 in datasheet). Also, if the range includes negative numbers, the reported voltage can obviously be negative. That means %u (and u16) can not be correct. "Transfer Function" in the datasheet describes how to convert/scale the received data. > + > +exit: > + mutex_unlock(&data->lock); > + return status; > +} > + > +static ssize_t max127_range_show(struct device *dev, > + struct device_attribute *dev_attr, > + char *buf) > +{ > + u8 ctrl, rng_bip; > + struct max127_data *data = dev_get_drvdata(dev); > + struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(dev_attr); > + int rng_type = attr->nr; /* 0 for min, 1 for max */ > + int channel = attr->index; > + int full = data->input_limit; > + int half = full / 2; > + int range_table[4][2] = { > + [0] = {0, half}, /* RNG=0, BIP=0 */ > + [1] = {-half, half}, /* RNG=0, BIP=1 */ > + [2] = {0, full}, /* RNG=1, BIP=0 */ > + [3] = {-full, full}, /* RNG=1, BIP=1 */ > + }; This can be a static const table. The variables 'full' and 'half' are effectively constants and not really needed. > + > + if (mutex_lock_interruptible(&data->lock)) > + return -ERESTARTSYS; > + ctrl = data->ctrl_byte[channel]; > + mutex_unlock(&data->lock); This lock is only needed because "ctrl" is written piece by piece. I would suggest to rewrite the store function to write ctrl atomically. Then the lock here is no longer needed. > + > + rng_bip = (ctrl >> 2) & 3; > + return sprintf(buf, "%d", range_table[rng_bip][rng_type]); > +} > + > +static void max127_set_range(struct max127_data *data, int channel) > +{ > + data->ctrl_byte[channel] |= MAX127_CTRL_RNG; > +} > + > +static void max127_clear_range(struct max127_data *data, int channel) > +{ > + data->ctrl_byte[channel] &= ~MAX127_CTRL_RNG; > +} > + > +static void max127_set_polarity(struct max127_data *data, int channel) > +{ > + data->ctrl_byte[channel] |= MAX127_CTRL_BIP; > +} > + > +static void max127_clear_polarity(struct max127_data *data, int channel) > +{ > + data->ctrl_byte[channel] &= ~MAX127_CTRL_BIP; > +} > + > +static ssize_t max127_range_store(struct device *dev, > + struct device_attribute *devattr, > + const char *buf, > + size_t count) > +{ > + struct max127_data *data = dev_get_drvdata(dev); > + struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr); > + int rng_type = attr->nr; /* 0 for min, 1 for max */ > + int channel = attr->index; > + int full = data->input_limit; > + int half = full / 2; > + long input, output; > + > + if (kstrtol(buf, 0, &input)) > + return -EINVAL; > + > + if (rng_type == 0) { /* min input */ > + if (input <= -full) > + output = -full; > + else if (input < 0) > + output = -half; > + else > + output = 0; > + } else { /* max input */ > + output = (input >= full) ? full : half; > + } > + With the _info API, I would suggest to separate min and max functions. This would both simplify the code and make it easier to read and review. > + if (mutex_lock_interruptible(&data->lock)) > + return -ERESTARTSYS; This should be rewritten to update "ctrl" in one step. Something like u8 ctrl; ... ctrl = data->ctrl_byte[channel]; if (output == -MAX127_INPUT_LIMIT) ctrl |= MAX127_CTRL_RNG | MAX127_CTRL_BIP; else if (output == -half) ctrl |= MAX127_CTRL_BIP; ctrl &= ~MAX127_CTRL_RNG; else if (output == 0) ctrl &= ~MAX127_CTRL_BIP; else lf (output == half) ctrl &= ~MAX127_CTRL_RNG; else ctrl |= MAX127_CTRL_RNG; data->ctrl_byte[channel] = ctrl; I would suggest to separate the min and max functions, though. > + > + if (output == -full) { > + max127_set_polarity(data, channel); > + max127_set_range(data, channel); > + } else if (output == -half) { > + max127_set_polarity(data, channel); > + max127_clear_range(data, channel); > + } else if (output == 0) { > + max127_clear_polarity(data, channel); > + } else if (output == half) { > + max127_clear_range(data, channel); > + } else { > + max127_set_range(data, channel); > + } > + > + mutex_unlock(&data->lock); > + > + return count; > +} > + > +#define MAX127_SENSOR_DEV_ATTR_DEF(ch) \ > + static SENSOR_DEVICE_ATTR_RO(in##ch##_input, max127_input, ch); \ > + static SENSOR_DEVICE_ATTR_2_RW(in##ch##_min, max127_range, 0, ch); \ > + static SENSOR_DEVICE_ATTR_2_RW(in##ch##_max, max127_range, 1, ch) > + > +MAX127_SENSOR_DEV_ATTR_DEF(0); > +MAX127_SENSOR_DEV_ATTR_DEF(1); > +MAX127_SENSOR_DEV_ATTR_DEF(2); > +MAX127_SENSOR_DEV_ATTR_DEF(3); > +MAX127_SENSOR_DEV_ATTR_DEF(4); > +MAX127_SENSOR_DEV_ATTR_DEF(5); > +MAX127_SENSOR_DEV_ATTR_DEF(6); > +MAX127_SENSOR_DEV_ATTR_DEF(7); > + > +#define MAX127_SENSOR_DEVICE_ATTR(ch) \ > + &sensor_dev_attr_in##ch##_input.dev_attr.attr, \ > + &sensor_dev_attr_in##ch##_min.dev_attr.attr, \ > + &sensor_dev_attr_in##ch##_max.dev_attr.attr > + > +static struct attribute *max127_attrs[] = { > + MAX127_SENSOR_DEVICE_ATTR(0), > + MAX127_SENSOR_DEVICE_ATTR(1), > + MAX127_SENSOR_DEVICE_ATTR(2), > + MAX127_SENSOR_DEVICE_ATTR(3), > + MAX127_SENSOR_DEVICE_ATTR(4), > + MAX127_SENSOR_DEVICE_ATTR(5), > + MAX127_SENSOR_DEVICE_ATTR(6), > + MAX127_SENSOR_DEVICE_ATTR(7), > + NULL, > +}; > + > +ATTRIBUTE_GROUPS(max127); > + > +static const struct attribute_group max127_attr_groups = { > + .attrs = max127_attrs, > +}; > + > +static int max127_probe(struct i2c_client *client, > + const struct i2c_device_id *id) > +{ > + int i; > + struct device *hwmon_dev; > + struct max127_data *data; > + struct device *dev = &client->dev; > + > + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); > + if (!data) > + return -ENOMEM; > + > + data->client = client; > + mutex_init(&data->lock); > + data->input_limit = MAX127_INPUT_LIMIT; What is the point of input_limit ? It is never modified. Why not use MAX127_INPUT_LIMIT directly where needed ? > + for (i = 0; i < ARRAY_SIZE(data->ctrl_byte); i++) > + data->ctrl_byte[i] = (MAX127_CTRL_START | > + MAX127_SET_CHANNEL(i)); > + > + hwmon_dev = devm_hwmon_device_register_with_groups(dev, > + client->name, data, max127_groups); Please use the devm_hwmon_device_register_with_info() API. Thanks, Guenter > + > + return PTR_ERR_OR_ZERO(hwmon_dev); > +} > + > +static const struct i2c_device_id max127_id[] = { > + { "max127", 0 }, > + { } > +}; > +MODULE_DEVICE_TABLE(i2c, max127_id); > + > +static struct i2c_driver max127_driver = { > + .class = I2C_CLASS_HWMON, > + .driver = { > + .name = "max127", > + }, > + .probe = max127_probe, > + .id_table = max127_id, > +}; > + > +module_i2c_driver(max127_driver); > + > +MODULE_LICENSE("GPL"); > +MODULE_AUTHOR("Mike Choi <mikechoi@fb.com>"); > +MODULE_AUTHOR("Tao Ren <rentao.bupt@gmail.com>"); > +MODULE_DESCRIPTION("MAX127 Hardware Monitoring driver"); > -- > 2.17.1 >
Hi Guenter, Thanks for pointing out these problems. I'm working on the comments and will send out v2 soon. Cheers, Tao On Mon, Nov 16, 2020 at 09:13:52PM -0800, Guenter Roeck wrote: > On Mon, Nov 16, 2020 at 05:09:43PM -0800, rentao.bupt@gmail.com wrote: > > From: Tao Ren <rentao.bupt@gmail.com> > > > > Add hardware monitoring driver for the Maxim MAX127 chip. > > > > MAX127 min/max range handling code is inspired by the max197 driver. > > > > Signed-off-by: Tao Ren <rentao.bupt@gmail.com> > > --- > > drivers/hwmon/Kconfig | 9 ++ > > drivers/hwmon/Makefile | 1 + > > drivers/hwmon/max127.c | 286 +++++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 296 insertions(+) > > create mode 100644 drivers/hwmon/max127.c > > > > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > > index 9d600e0c5584..716df51edc87 100644 > > --- a/drivers/hwmon/Kconfig > > +++ b/drivers/hwmon/Kconfig > > @@ -950,6 +950,15 @@ config SENSORS_MAX1111 > > This driver can also be built as a module. If so, the module > > will be called max1111. > > > > +config SENSORS_MAX127 > > + tristate "Maxim MAX127 12-bit 8-channel Data Acquisition System" > > + depends on I2C > > + help > > + Say y here to support Maxim's MAX127 DAS chips. > > + > > + This driver can also be built as a module. If so, the module > > + will be called max127. > > + > > config SENSORS_MAX16065 > > tristate "Maxim MAX16065 System Manager and compatibles" > > depends on I2C > > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile > > index 1083bbfac779..01ca5d3fbad4 100644 > > --- a/drivers/hwmon/Makefile > > +++ b/drivers/hwmon/Makefile > > @@ -127,6 +127,7 @@ obj-$(CONFIG_SENSORS_LTC4260) += ltc4260.o > > obj-$(CONFIG_SENSORS_LTC4261) += ltc4261.o > > obj-$(CONFIG_SENSORS_LTQ_CPUTEMP) += ltq-cputemp.o > > obj-$(CONFIG_SENSORS_MAX1111) += max1111.o > > +obj-$(CONFIG_SENSORS_MAX127) += max127.o > > obj-$(CONFIG_SENSORS_MAX16065) += max16065.o > > obj-$(CONFIG_SENSORS_MAX1619) += max1619.o > > obj-$(CONFIG_SENSORS_MAX1668) += max1668.o > > diff --git a/drivers/hwmon/max127.c b/drivers/hwmon/max127.c > > new file mode 100644 > > index 000000000000..df74a95bcf28 > > --- /dev/null > > +++ b/drivers/hwmon/max127.c > > @@ -0,0 +1,286 @@ > > +// SPDX-License-Identifier: GPL-2.0+ > > +/* > > + * Hardware monitoring driver for MAX127. > > + * > > + * Copyright (c) 2020 Facebook Inc. > > + */ > > + > > +#include <linux/err.h> > > +#include <linux/hwmon.h> > > +#include <linux/hwmon-sysfs.h> > > +#include <linux/i2c.h> > > +#include <linux/init.h> > > +#include <linux/module.h> > > +#include <linux/sysfs.h> > > + > > +/* MAX127 Control Byte. */ > > +#define MAX127_CTRL_START BIT(7) > > +#define MAX127_CTRL_SEL_OFFSET 4 > > That would better be named _SHIFT. > > > +#define MAX127_CTRL_RNG BIT(3) > > +#define MAX127_CTRL_BIP BIT(2) > > +#define MAX127_CTRL_PD1 BIT(1) > > +#define MAX127_CTRL_PD0 BIT(0) > > + > > +#define MAX127_NUM_CHANNELS 8 > > +#define MAX127_SET_CHANNEL(ch) (((ch) & 7) << (MAX127_CTRL_SEL_OFFSET)) > > () around MAX127_CTRL_SEL_OFFSET is unnecessary. > > > + > > +#define MAX127_INPUT_LIMIT 10 /* 10V */ > > + > > +/* > > + * MAX127 returns 2 bytes at read: > > + * - the first byte contains data[11:4]. > > + * - the second byte contains data[3:0] (MSB) and 4 dummy 0s (LSB). > > + */ > > +#define MAX127_DATA1_SHIFT 4 > > + > > +struct max127_data { > > + struct mutex lock; > > + struct i2c_client *client; > > + int input_limit; > > + u8 ctrl_byte[MAX127_NUM_CHANNELS]; > > +}; > > + > > +static int max127_select_channel(struct max127_data *data, int channel) > > +{ > > + int status; > > + struct i2c_client *client = data->client; > > + struct i2c_msg msg = { > > + .addr = client->addr, > > + .flags = 0, > > + .len = 1, > > + .buf = &data->ctrl_byte[channel], > > + }; > > + > > + status = i2c_transfer(client->adapter, &msg, 1); > > + if (status != 1) > > + return status; > > + > > Other drivers assume that this function can return 0. Please > take that into account as well. > > > + return 0; > > +} > > + > > +static int max127_read_channel(struct max127_data *data, int channel, u16 *vin) > > +{ > > + int status; > > + u8 i2c_data[2]; > > + struct i2c_client *client = data->client; > > + struct i2c_msg msg = { > > + .addr = client->addr, > > + .flags = I2C_M_RD, > > + .len = 2, > > + .buf = i2c_data, > > + }; > > + > > + status = i2c_transfer(client->adapter, &msg, 1); > > + if (status != 1) > > + return status; > > Same as above. > > > + > > + *vin = ((i2c_data[0] << 8) | i2c_data[1]) >> MAX127_DATA1_SHIFT; > > THis seems wrong. D4..D11 end up in but 8..15, and D0..D3 end up in bit > 0..3. Seems to me the upper byte should be left shifted 4 bit. > The result then needs to be scaled to mV (see below). > > Also, for consistency I would suggest to either use () for both > parts of the logical or operation or for none. > > > + return 0; > > +} > > + > > +static ssize_t max127_input_show(struct device *dev, > > + struct device_attribute *dev_attr, > > + char *buf) > > +{ > > + u16 vin; > > + int status; > > + struct max127_data *data = dev_get_drvdata(dev); > > + struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr); > > + > > + if (mutex_lock_interruptible(&data->lock)) > > + return -ERESTARTSYS; > > I don't think the _interruptible is warranted in this driver. > > > + > > + status = max127_select_channel(data, attr->index); > > + if (status) > > + goto exit; > > + > > + status = max127_read_channel(data, attr->index, &vin); > > + if (status) > > + goto exit; > > + > > + status = sprintf(buf, "%u", vin); > > This is not correct. The ABI expects values in milli-Volt, and per datasheet > the values need to be scaled depending on polarity and range settings (see > table 3 in datasheet). Also, if the range includes negative numbers, > the reported voltage can obviously be negative. That means %u (and u16) > can not be correct. "Transfer Function" in the datasheet describes how to > convert/scale the received data. > > > + > > +exit: > > + mutex_unlock(&data->lock); > > + return status; > > +} > > + > > +static ssize_t max127_range_show(struct device *dev, > > + struct device_attribute *dev_attr, > > + char *buf) > > +{ > > + u8 ctrl, rng_bip; > > + struct max127_data *data = dev_get_drvdata(dev); > > + struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(dev_attr); > > + int rng_type = attr->nr; /* 0 for min, 1 for max */ > > + int channel = attr->index; > > + int full = data->input_limit; > > + int half = full / 2; > > + int range_table[4][2] = { > > + [0] = {0, half}, /* RNG=0, BIP=0 */ > > + [1] = {-half, half}, /* RNG=0, BIP=1 */ > > + [2] = {0, full}, /* RNG=1, BIP=0 */ > > + [3] = {-full, full}, /* RNG=1, BIP=1 */ > > + }; > > This can be a static const table. The variables 'full' and 'half' > are effectively constants and not really needed. > > > + > > + if (mutex_lock_interruptible(&data->lock)) > > + return -ERESTARTSYS; > > + ctrl = data->ctrl_byte[channel]; > > + mutex_unlock(&data->lock); > > This lock is only needed because "ctrl" is written piece by piece. > I would suggest to rewrite the store function to write ctrl atomically. > Then the lock here is no longer needed. > > > + > > + rng_bip = (ctrl >> 2) & 3; > > + return sprintf(buf, "%d", range_table[rng_bip][rng_type]); > > +} > > + > > +static void max127_set_range(struct max127_data *data, int channel) > > +{ > > + data->ctrl_byte[channel] |= MAX127_CTRL_RNG; > > +} > > + > > +static void max127_clear_range(struct max127_data *data, int channel) > > +{ > > + data->ctrl_byte[channel] &= ~MAX127_CTRL_RNG; > > +} > > + > > +static void max127_set_polarity(struct max127_data *data, int channel) > > +{ > > + data->ctrl_byte[channel] |= MAX127_CTRL_BIP; > > +} > > + > > +static void max127_clear_polarity(struct max127_data *data, int channel) > > +{ > > + data->ctrl_byte[channel] &= ~MAX127_CTRL_BIP; > > +} > > + > > +static ssize_t max127_range_store(struct device *dev, > > + struct device_attribute *devattr, > > + const char *buf, > > + size_t count) > > +{ > > + struct max127_data *data = dev_get_drvdata(dev); > > + struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr); > > + int rng_type = attr->nr; /* 0 for min, 1 for max */ > > + int channel = attr->index; > > + int full = data->input_limit; > > + int half = full / 2; > > + long input, output; > > + > > + if (kstrtol(buf, 0, &input)) > > + return -EINVAL; > > + > > + if (rng_type == 0) { /* min input */ > > + if (input <= -full) > > + output = -full; > > + else if (input < 0) > > + output = -half; > > + else > > + output = 0; > > + } else { /* max input */ > > + output = (input >= full) ? full : half; > > + } > > + > > With the _info API, I would suggest to separate min and max functions. > This would both simplify the code and make it easier to read and > review. > > > + if (mutex_lock_interruptible(&data->lock)) > > + return -ERESTARTSYS; > > This should be rewritten to update "ctrl" in one step. > Something like > > u8 ctrl; > ... > ctrl = data->ctrl_byte[channel]; > if (output == -MAX127_INPUT_LIMIT) > ctrl |= MAX127_CTRL_RNG | MAX127_CTRL_BIP; > else if (output == -half) > ctrl |= MAX127_CTRL_BIP; > ctrl &= ~MAX127_CTRL_RNG; > else if (output == 0) > ctrl &= ~MAX127_CTRL_BIP; > else lf (output == half) > ctrl &= ~MAX127_CTRL_RNG; > else > ctrl |= MAX127_CTRL_RNG; > > data->ctrl_byte[channel] = ctrl; > > I would suggest to separate the min and max functions, though. > > > + > > + if (output == -full) { > > + max127_set_polarity(data, channel); > > + max127_set_range(data, channel); > > + } else if (output == -half) { > > + max127_set_polarity(data, channel); > > + max127_clear_range(data, channel); > > + } else if (output == 0) { > > + max127_clear_polarity(data, channel); > > + } else if (output == half) { > > + max127_clear_range(data, channel); > > + } else { > > + max127_set_range(data, channel); > > + } > > + > > + mutex_unlock(&data->lock); > > + > > + return count; > > +} > > + > > +#define MAX127_SENSOR_DEV_ATTR_DEF(ch) \ > > + static SENSOR_DEVICE_ATTR_RO(in##ch##_input, max127_input, ch); \ > > + static SENSOR_DEVICE_ATTR_2_RW(in##ch##_min, max127_range, 0, ch); \ > > + static SENSOR_DEVICE_ATTR_2_RW(in##ch##_max, max127_range, 1, ch) > > + > > +MAX127_SENSOR_DEV_ATTR_DEF(0); > > +MAX127_SENSOR_DEV_ATTR_DEF(1); > > +MAX127_SENSOR_DEV_ATTR_DEF(2); > > +MAX127_SENSOR_DEV_ATTR_DEF(3); > > +MAX127_SENSOR_DEV_ATTR_DEF(4); > > +MAX127_SENSOR_DEV_ATTR_DEF(5); > > +MAX127_SENSOR_DEV_ATTR_DEF(6); > > +MAX127_SENSOR_DEV_ATTR_DEF(7); > > + > > +#define MAX127_SENSOR_DEVICE_ATTR(ch) \ > > + &sensor_dev_attr_in##ch##_input.dev_attr.attr, \ > > + &sensor_dev_attr_in##ch##_min.dev_attr.attr, \ > > + &sensor_dev_attr_in##ch##_max.dev_attr.attr > > + > > +static struct attribute *max127_attrs[] = { > > + MAX127_SENSOR_DEVICE_ATTR(0), > > + MAX127_SENSOR_DEVICE_ATTR(1), > > + MAX127_SENSOR_DEVICE_ATTR(2), > > + MAX127_SENSOR_DEVICE_ATTR(3), > > + MAX127_SENSOR_DEVICE_ATTR(4), > > + MAX127_SENSOR_DEVICE_ATTR(5), > > + MAX127_SENSOR_DEVICE_ATTR(6), > > + MAX127_SENSOR_DEVICE_ATTR(7), > > + NULL, > > +}; > > + > > +ATTRIBUTE_GROUPS(max127); > > + > > +static const struct attribute_group max127_attr_groups = { > > + .attrs = max127_attrs, > > +}; > > + > > +static int max127_probe(struct i2c_client *client, > > + const struct i2c_device_id *id) > > +{ > > + int i; > > + struct device *hwmon_dev; > > + struct max127_data *data; > > + struct device *dev = &client->dev; > > + > > + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); > > + if (!data) > > + return -ENOMEM; > > + > > + data->client = client; > > + mutex_init(&data->lock); > > + data->input_limit = MAX127_INPUT_LIMIT; > > What is the point of input_limit ? It is never modified. > Why not use MAX127_INPUT_LIMIT directly where needed ? > > > + for (i = 0; i < ARRAY_SIZE(data->ctrl_byte); i++) > > + data->ctrl_byte[i] = (MAX127_CTRL_START | > > + MAX127_SET_CHANNEL(i)); > > + > > + hwmon_dev = devm_hwmon_device_register_with_groups(dev, > > + client->name, data, max127_groups); > > Please use the devm_hwmon_device_register_with_info() API. > > Thanks, > Guenter > > > + > > + return PTR_ERR_OR_ZERO(hwmon_dev); > > +} > > + > > +static const struct i2c_device_id max127_id[] = { > > + { "max127", 0 }, > > + { } > > +}; > > +MODULE_DEVICE_TABLE(i2c, max127_id); > > + > > +static struct i2c_driver max127_driver = { > > + .class = I2C_CLASS_HWMON, > > + .driver = { > > + .name = "max127", > > + }, > > + .probe = max127_probe, > > + .id_table = max127_id, > > +}; > > + > > +module_i2c_driver(max127_driver); > > + > > +MODULE_LICENSE("GPL"); > > +MODULE_AUTHOR("Mike Choi <mikechoi@fb.com>"); > > +MODULE_AUTHOR("Tao Ren <rentao.bupt@gmail.com>"); > > +MODULE_DESCRIPTION("MAX127 Hardware Monitoring driver"); > > -- > > 2.17.1 > >
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig index 9d600e0c5584..716df51edc87 100644 --- a/drivers/hwmon/Kconfig +++ b/drivers/hwmon/Kconfig @@ -950,6 +950,15 @@ config SENSORS_MAX1111 This driver can also be built as a module. If so, the module will be called max1111. +config SENSORS_MAX127 + tristate "Maxim MAX127 12-bit 8-channel Data Acquisition System" + depends on I2C + help + Say y here to support Maxim's MAX127 DAS chips. + + This driver can also be built as a module. If so, the module + will be called max127. + config SENSORS_MAX16065 tristate "Maxim MAX16065 System Manager and compatibles" depends on I2C diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile index 1083bbfac779..01ca5d3fbad4 100644 --- a/drivers/hwmon/Makefile +++ b/drivers/hwmon/Makefile @@ -127,6 +127,7 @@ obj-$(CONFIG_SENSORS_LTC4260) += ltc4260.o obj-$(CONFIG_SENSORS_LTC4261) += ltc4261.o obj-$(CONFIG_SENSORS_LTQ_CPUTEMP) += ltq-cputemp.o obj-$(CONFIG_SENSORS_MAX1111) += max1111.o +obj-$(CONFIG_SENSORS_MAX127) += max127.o obj-$(CONFIG_SENSORS_MAX16065) += max16065.o obj-$(CONFIG_SENSORS_MAX1619) += max1619.o obj-$(CONFIG_SENSORS_MAX1668) += max1668.o diff --git a/drivers/hwmon/max127.c b/drivers/hwmon/max127.c new file mode 100644 index 000000000000..df74a95bcf28 --- /dev/null +++ b/drivers/hwmon/max127.c @@ -0,0 +1,286 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Hardware monitoring driver for MAX127. + * + * Copyright (c) 2020 Facebook Inc. + */ + +#include <linux/err.h> +#include <linux/hwmon.h> +#include <linux/hwmon-sysfs.h> +#include <linux/i2c.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/sysfs.h> + +/* MAX127 Control Byte. */ +#define MAX127_CTRL_START BIT(7) +#define MAX127_CTRL_SEL_OFFSET 4 +#define MAX127_CTRL_RNG BIT(3) +#define MAX127_CTRL_BIP BIT(2) +#define MAX127_CTRL_PD1 BIT(1) +#define MAX127_CTRL_PD0 BIT(0) + +#define MAX127_NUM_CHANNELS 8 +#define MAX127_SET_CHANNEL(ch) (((ch) & 7) << (MAX127_CTRL_SEL_OFFSET)) + +#define MAX127_INPUT_LIMIT 10 /* 10V */ + +/* + * MAX127 returns 2 bytes at read: + * - the first byte contains data[11:4]. + * - the second byte contains data[3:0] (MSB) and 4 dummy 0s (LSB). + */ +#define MAX127_DATA1_SHIFT 4 + +struct max127_data { + struct mutex lock; + struct i2c_client *client; + int input_limit; + u8 ctrl_byte[MAX127_NUM_CHANNELS]; +}; + +static int max127_select_channel(struct max127_data *data, int channel) +{ + int status; + struct i2c_client *client = data->client; + struct i2c_msg msg = { + .addr = client->addr, + .flags = 0, + .len = 1, + .buf = &data->ctrl_byte[channel], + }; + + status = i2c_transfer(client->adapter, &msg, 1); + if (status != 1) + return status; + + return 0; +} + +static int max127_read_channel(struct max127_data *data, int channel, u16 *vin) +{ + int status; + u8 i2c_data[2]; + struct i2c_client *client = data->client; + struct i2c_msg msg = { + .addr = client->addr, + .flags = I2C_M_RD, + .len = 2, + .buf = i2c_data, + }; + + status = i2c_transfer(client->adapter, &msg, 1); + if (status != 1) + return status; + + *vin = ((i2c_data[0] << 8) | i2c_data[1]) >> MAX127_DATA1_SHIFT; + return 0; +} + +static ssize_t max127_input_show(struct device *dev, + struct device_attribute *dev_attr, + char *buf) +{ + u16 vin; + int status; + struct max127_data *data = dev_get_drvdata(dev); + struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr); + + if (mutex_lock_interruptible(&data->lock)) + return -ERESTARTSYS; + + status = max127_select_channel(data, attr->index); + if (status) + goto exit; + + status = max127_read_channel(data, attr->index, &vin); + if (status) + goto exit; + + status = sprintf(buf, "%u", vin); + +exit: + mutex_unlock(&data->lock); + return status; +} + +static ssize_t max127_range_show(struct device *dev, + struct device_attribute *dev_attr, + char *buf) +{ + u8 ctrl, rng_bip; + struct max127_data *data = dev_get_drvdata(dev); + struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(dev_attr); + int rng_type = attr->nr; /* 0 for min, 1 for max */ + int channel = attr->index; + int full = data->input_limit; + int half = full / 2; + int range_table[4][2] = { + [0] = {0, half}, /* RNG=0, BIP=0 */ + [1] = {-half, half}, /* RNG=0, BIP=1 */ + [2] = {0, full}, /* RNG=1, BIP=0 */ + [3] = {-full, full}, /* RNG=1, BIP=1 */ + }; + + if (mutex_lock_interruptible(&data->lock)) + return -ERESTARTSYS; + ctrl = data->ctrl_byte[channel]; + mutex_unlock(&data->lock); + + rng_bip = (ctrl >> 2) & 3; + return sprintf(buf, "%d", range_table[rng_bip][rng_type]); +} + +static void max127_set_range(struct max127_data *data, int channel) +{ + data->ctrl_byte[channel] |= MAX127_CTRL_RNG; +} + +static void max127_clear_range(struct max127_data *data, int channel) +{ + data->ctrl_byte[channel] &= ~MAX127_CTRL_RNG; +} + +static void max127_set_polarity(struct max127_data *data, int channel) +{ + data->ctrl_byte[channel] |= MAX127_CTRL_BIP; +} + +static void max127_clear_polarity(struct max127_data *data, int channel) +{ + data->ctrl_byte[channel] &= ~MAX127_CTRL_BIP; +} + +static ssize_t max127_range_store(struct device *dev, + struct device_attribute *devattr, + const char *buf, + size_t count) +{ + struct max127_data *data = dev_get_drvdata(dev); + struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr); + int rng_type = attr->nr; /* 0 for min, 1 for max */ + int channel = attr->index; + int full = data->input_limit; + int half = full / 2; + long input, output; + + if (kstrtol(buf, 0, &input)) + return -EINVAL; + + if (rng_type == 0) { /* min input */ + if (input <= -full) + output = -full; + else if (input < 0) + output = -half; + else + output = 0; + } else { /* max input */ + output = (input >= full) ? full : half; + } + + if (mutex_lock_interruptible(&data->lock)) + return -ERESTARTSYS; + + if (output == -full) { + max127_set_polarity(data, channel); + max127_set_range(data, channel); + } else if (output == -half) { + max127_set_polarity(data, channel); + max127_clear_range(data, channel); + } else if (output == 0) { + max127_clear_polarity(data, channel); + } else if (output == half) { + max127_clear_range(data, channel); + } else { + max127_set_range(data, channel); + } + + mutex_unlock(&data->lock); + + return count; +} + +#define MAX127_SENSOR_DEV_ATTR_DEF(ch) \ + static SENSOR_DEVICE_ATTR_RO(in##ch##_input, max127_input, ch); \ + static SENSOR_DEVICE_ATTR_2_RW(in##ch##_min, max127_range, 0, ch); \ + static SENSOR_DEVICE_ATTR_2_RW(in##ch##_max, max127_range, 1, ch) + +MAX127_SENSOR_DEV_ATTR_DEF(0); +MAX127_SENSOR_DEV_ATTR_DEF(1); +MAX127_SENSOR_DEV_ATTR_DEF(2); +MAX127_SENSOR_DEV_ATTR_DEF(3); +MAX127_SENSOR_DEV_ATTR_DEF(4); +MAX127_SENSOR_DEV_ATTR_DEF(5); +MAX127_SENSOR_DEV_ATTR_DEF(6); +MAX127_SENSOR_DEV_ATTR_DEF(7); + +#define MAX127_SENSOR_DEVICE_ATTR(ch) \ + &sensor_dev_attr_in##ch##_input.dev_attr.attr, \ + &sensor_dev_attr_in##ch##_min.dev_attr.attr, \ + &sensor_dev_attr_in##ch##_max.dev_attr.attr + +static struct attribute *max127_attrs[] = { + MAX127_SENSOR_DEVICE_ATTR(0), + MAX127_SENSOR_DEVICE_ATTR(1), + MAX127_SENSOR_DEVICE_ATTR(2), + MAX127_SENSOR_DEVICE_ATTR(3), + MAX127_SENSOR_DEVICE_ATTR(4), + MAX127_SENSOR_DEVICE_ATTR(5), + MAX127_SENSOR_DEVICE_ATTR(6), + MAX127_SENSOR_DEVICE_ATTR(7), + NULL, +}; + +ATTRIBUTE_GROUPS(max127); + +static const struct attribute_group max127_attr_groups = { + .attrs = max127_attrs, +}; + +static int max127_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + int i; + struct device *hwmon_dev; + struct max127_data *data; + struct device *dev = &client->dev; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->client = client; + mutex_init(&data->lock); + data->input_limit = MAX127_INPUT_LIMIT; + for (i = 0; i < ARRAY_SIZE(data->ctrl_byte); i++) + data->ctrl_byte[i] = (MAX127_CTRL_START | + MAX127_SET_CHANNEL(i)); + + hwmon_dev = devm_hwmon_device_register_with_groups(dev, + client->name, data, max127_groups); + + return PTR_ERR_OR_ZERO(hwmon_dev); +} + +static const struct i2c_device_id max127_id[] = { + { "max127", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, max127_id); + +static struct i2c_driver max127_driver = { + .class = I2C_CLASS_HWMON, + .driver = { + .name = "max127", + }, + .probe = max127_probe, + .id_table = max127_id, +}; + +module_i2c_driver(max127_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Mike Choi <mikechoi@fb.com>"); +MODULE_AUTHOR("Tao Ren <rentao.bupt@gmail.com>"); +MODULE_DESCRIPTION("MAX127 Hardware Monitoring driver");