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Message-Id: <20200429133320.140458-1-akira215corp@gmail.com>
Date: Wed, 29 Apr 2020 15:33:20 +0200
From: Akira Shimahara <akira215corp@...il.com>
To: greg@...ah.com
Cc: zbr@...emap.net, linux-kernel@...r.kernel.org,
Akira Shimahara <akira215corp@...il.com>
Subject: [PATCH v3 3/5] w1_therm: Optimizing read timing by checking device resolution. Updating documentation
Patch for enhacement of w1_therm module. Added features :
- Optimized conversion time regarding to device resolution
- Dedicated sysfs entry for, resolution set/get, eeprom save/restore,
and additionnal temperature entry to ease user data collect.
- Code optimization to mitigate bus traffic
The status of each device (power status and resolution if supported)
is stored in a dedicated structure in the driver, so that device are not
interrogated during temperature conversion process. The status is
evaluated as soon as a device is connected on the bus, and re evaluated
when user either set values either by get them, using the corresponding
sysfs entry.
A dedicated EEPROM sysfs entry allow the user to save or restore device
registers from/to device EEPROM.
Updating Documentation/ABI/testing/sysfs-driver-w1_therm accordingly
with w1_therm_add_slavenew sysfs entries
Signed-off-by: Akira Shimahara <akira215corp@...il.com>
---
.../ABI/testing/sysfs-driver-w1_therm | 43 +
drivers/w1/slaves/w1_therm.c | 785 +++++++++++++-----
drivers/w1/slaves/w1_therm.h | 168 +++-
3 files changed, 760 insertions(+), 236 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-driver-w1_therm b/Documentation/ABI/testing/sysfs-driver-w1_therm
index 9aaf625..279e13d 100644
--- a/Documentation/ABI/testing/sysfs-driver-w1_therm
+++ b/Documentation/ABI/testing/sysfs-driver-w1_therm
@@ -1,3 +1,17 @@
+What: /sys/bus/w1/devices/.../eeprom
+Date: Apr 2020
+Contact: Akira Shimahara <akira215corp@...il.com>
+Description:
+ (WO) writing that file will either trigger a save of the
+ device data to its embedded EEPROM, either restore data
+ embedded in device EEPROM. Be aware that devices support
+ limited EEPROM writing cycles (typical 50k)
+ * `save`: save device RAM to EEPROM
+ * `restore`: restore EEPROM data in device RAM
+Users: any user space application which wants to communicate with
+ w1_term device
+
+
What: /sys/bus/w1/devices/.../ext_power
Date: Apr 2020
Contact: Akira Shimahara <akira215corp@...il.com>
@@ -10,6 +24,35 @@ Users: any user space application which wants to communicate with
w1_term device
+What: /sys/bus/w1/devices/.../resolution
+Date: Apr 2020
+Contact: Akira Shimahara <akira215corp@...il.com>
+Description:
+ (RW) get or set the device resolution (on supported devices,
+ if not, this entry is not present). Note that the resolution
+ will be changed only in device RAM, so it will be cleared when
+ power is lost. Trigger a `save` to EEPROM command to keep
+ values after power-on. Read or write are :
+ * `9..12`: device resolution in bit
+ or resolution to set in bit
+ * `-xx`: xx is kernel error when reading the resolution
+ * Anything else: do nothing
+Users: any user space application which wants to communicate with
+ w1_term device
+
+
+What: /sys/bus/w1/devices/.../temperature
+Date: Apr 2020
+Contact: Akira Shimahara <akira215corp@...il.com>
+Description:
+ (RO) return the temperature in 1/1000 degC.
+ Note that the conversion duration depend on the resolution (if
+ device support this feature). It takes 94ms in 9bits
+ resolution, 750ms for 12bits.
+Users: any user space application which wants to communicate with
+ w1_term device
+
+
What: /sys/bus/w1/devices/.../w1_slave
Date: Apr 2020
Contact: Akira Shimahara <akira215corp@...il.com>
diff --git a/drivers/w1/slaves/w1_therm.c b/drivers/w1/slaves/w1_therm.c
index a530853..3ddf2b1 100644
--- a/drivers/w1/slaves/w1_therm.c
+++ b/drivers/w1/slaves/w1_therm.c
@@ -37,23 +37,77 @@
static int w1_strong_pullup = 1;
module_param_named(strong_pullup, w1_strong_pullup, int, 0);
+/*
+ * sysfile interface:
+ * w1_slave (RW) : Old driver way, kept for compatibility
+ * read :
+ * return 2 lines with the hexa output of the device
+ * return the CRC check
+ * return temperature in 1/1000°
+ * write :
+ * .0 :save the 2 or 3 bytes to the device EEPROM
+ * (i.e. TH, TL and config register)
+ * .9..12: set the device resolution in RAM (if supported)
+ * .Else : do nothing
+ *
+ * temperature (RO):
+ * . temperature in 1/1000°
+ *
+ * ext_power (RO):
+ * . -xx : xx is kernel error refer to /usr/include/asm/errno.h
+ * . 0 : device parasite powered
+ * . 1 : device externally powered
+ *
+ * resolution (RW):
+ * . -xx : xx is kernel error refer to /usr/include/asm/errno.h
+ * . 9..12 : resolution set in bit (or resolution to set in bit)
+ *
+ * eeprom (WO): be aware that eeprom writing cycles count is limited
+ * . 'save' : save device RAM to EEPROM
+ * . 'restore' : restore EEPROM data in device RAM
+ * (device do that automatically on power-up)
+ *
+ *
+ */
+
+/*
+ * struct attribute for each device type
+ * This will enable entry in sysfs, it should match device capability
+ */
+
static struct attribute *w1_therm_attrs[] = {
&dev_attr_w1_slave.attr,
+ &dev_attr_temperature.attr,
+ &dev_attr_ext_power.attr,
+ &dev_attr_resolution.attr,
+ &dev_attr_eeprom.attr,
+ NULL,
+};
+
+static struct attribute *w1_ds18s20_attrs[] = {
+ &dev_attr_w1_slave.attr,
+ &dev_attr_temperature.attr,
&dev_attr_ext_power.attr,
+ &dev_attr_eeprom.attr,
NULL,
};
static struct attribute *w1_ds28ea00_attrs[] = {
&dev_attr_w1_slave.attr,
&dev_attr_w1_seq.attr,
+ &dev_attr_temperature.attr,
&dev_attr_ext_power.attr,
+ &dev_attr_resolution.attr,
+ &dev_attr_eeprom.attr,
NULL,
};
/*------------------------------attribute groups----------------------------*/
ATTRIBUTE_GROUPS(w1_therm);
+ATTRIBUTE_GROUPS(w1_ds18s20);
ATTRIBUTE_GROUPS(w1_ds28ea00);
+
#if IS_REACHABLE(CONFIG_HWMON)
static int w1_read_temp(struct device *dev, u32 attr, int channel,
long *val);
@@ -112,6 +166,13 @@ static struct w1_family_ops w1_therm_fops = {
.chip_info = W1_CHIPINFO,
};
+static struct w1_family_ops w1_ds18s20_fops = {
+ .add_slave = w1_therm_add_slave,
+ .remove_slave = w1_therm_remove_slave,
+ .groups = w1_ds18s20_groups,
+ .chip_info = W1_CHIPINFO,
+};
+
static struct w1_family_ops w1_ds28ea00_fops = {
.add_slave = w1_therm_add_slave,
.remove_slave = w1_therm_remove_slave,
@@ -122,7 +183,7 @@ static struct w1_family_ops w1_ds28ea00_fops = {
/*--------------------family binding on operations struct-------------------*/
static struct w1_family w1_therm_family_DS18S20 = {
.fid = W1_THERM_DS18S20,
- .fops = &w1_therm_fops,
+ .fops = &w1_ds18s20_fops,
};
static struct w1_family w1_therm_family_DS18B20 = {
@@ -148,127 +209,144 @@ static struct w1_family w1_therm_family_DS1825 = {
/*----------------------Device capability description-----------------------*/
static struct w1_therm_family_converter w1_therm_families[] = {
{
- .f = &w1_therm_family_DS18S20,
- .convert = w1_DS18S20_convert_temp,
- .precision = w1_DS18S20_precision,
- .eeprom = w1_therm_eeprom
+ .f = &w1_therm_family_DS18S20,
+ .convert = w1_DS18S20_convert_temp,
+ .get_conversion_time = w1_DS18S20_convert_time,
+ .set_resolution = NULL, // no config register
+ .get_resolution = NULL, // no config register
+ .write_data = w1_DS18S20_write_data,
},
{
- .f = &w1_therm_family_DS1822,
- .convert = w1_DS18B20_convert_temp,
- .precision = w1_DS18S20_precision,
- .eeprom = w1_therm_eeprom
+ .f = &w1_therm_family_DS1822,
+ .convert = w1_DS18B20_convert_temp,
+ .get_conversion_time = w1_DS18B20_convert_time,
+ .set_resolution = w1_DS18B20_set_resolution,
+ .get_resolution = w1_DS18B20_get_resolution,
+ .write_data = w1_DS18B20_write_data,
},
{
- .f = &w1_therm_family_DS18B20,
- .convert = w1_DS18B20_convert_temp,
- .precision = w1_DS18B20_precision,
- .eeprom = w1_therm_eeprom
+ .f = &w1_therm_family_DS18B20,
+ .convert = w1_DS18B20_convert_temp,
+ .get_conversion_time = w1_DS18B20_convert_time,
+ .set_resolution = w1_DS18B20_set_resolution,
+ .get_resolution = w1_DS18B20_get_resolution,
+ .write_data = w1_DS18B20_write_data,
},
{
- .f = &w1_therm_family_DS28EA00,
- .convert = w1_DS18B20_convert_temp,
- .precision = w1_DS18S20_precision,
- .eeprom = w1_therm_eeprom
+ .f = &w1_therm_family_DS28EA00,
+ .convert = w1_DS18B20_convert_temp,
+ .get_conversion_time = w1_DS18B20_convert_time,
+ .set_resolution = w1_DS18B20_set_resolution,
+ .get_resolution = w1_DS18B20_get_resolution,
+ .write_data = w1_DS18B20_write_data,
},
{
- .f = &w1_therm_family_DS1825,
- .convert = w1_DS18B20_convert_temp,
- .precision = w1_DS18S20_precision,
- .eeprom = w1_therm_eeprom
+ .f = &w1_therm_family_DS1825,
+ .convert = w1_DS18B20_convert_temp,
+ .get_conversion_time = w1_DS18B20_convert_time,
+ .set_resolution = w1_DS18B20_set_resolution,
+ .get_resolution = w1_DS18B20_get_resolution,
+ .write_data = w1_DS18B20_write_data,
}
};
/*------------------------ Device dependent func---------------------------*/
-/* DS18S20 does not feature configuration register */
-static inline int w1_DS18S20_precision(struct device *device, int val)
+static inline int w1_DS18B20_convert_time(struct w1_slave *sl)
{
- return 0;
-}
-
-static inline int w1_DS18B20_precision(struct device *device, int val)
-{
- struct w1_slave *sl = dev_to_w1_slave(device);
- struct w1_master *dev = sl->master;
- u8 rom[9], crc;
- int ret, max_trying = 10;
- u8 *family_data = sl->family_data;
- uint8_t precision_bits;
- uint8_t mask = 0x60;
-
- if (val > 12 || val < 9) {
- pr_warn("Unsupported precision\n");
- ret = -EINVAL;
- goto error;
- }
-
- if (!sl->family_data) {
- ret = -ENODEV;
- goto error;
- }
-
- /* prevent the slave from going away in sleep */
- atomic_inc(THERM_REFCNT(family_data));
-
- ret = mutex_lock_interruptible(&dev->bus_mutex);
- if (ret != 0)
- goto dec_refcnt;
+ int ret;
- memset(rom, 0, sizeof(rom));
+ if (!sl->family_data)
+ return -ENODEV; /* device unknown */
- /* translate precision to bitmask (see datasheet page 9) */
- switch (val) {
+ /* return time in ms for conversion operation */
+ switch (SLAVE_RESOLUTION(sl)) {
case 9:
- precision_bits = 0x00;
+ ret = 95;
break;
case 10:
- precision_bits = 0x20;
+ ret = 190;
break;
case 11:
- precision_bits = 0x40;
+ ret = 375;
break;
case 12:
default:
- precision_bits = 0x60;
- break;
+ ret = 750;
}
+ return ret;
+}
- while (max_trying--) {
- crc = 0;
+static inline int w1_DS18S20_convert_time(struct w1_slave *sl)
+{
+ (void)(sl);
+ return 750; /* always 750ms for DS18S20 */
+}
- if (!reset_select_slave(sl)) {
- int count = 0;
+static inline int w1_DS18B20_write_data(struct w1_slave *sl,
+ const u8 *data)
+{
+ return write_scratchpad(sl, data, 3);
+}
- /* read values to only alter precision bits */
- w1_write_8(dev, W1_READ_SCRATCHPAD);
- count = w1_read_block(dev, rom, 9);
- if (count != 9)
- dev_warn(device, "w1_read_block() returned %u instead of 9.\n", count);
+static inline int w1_DS18S20_write_data(struct w1_slave *sl,
+ const u8 *data)
+{
+ /* No config register */
+ return write_scratchpad(sl, data, 2);
+}
- crc = w1_calc_crc8(rom, 8);
- if (rom[8] == crc) {
- rom[4] = (rom[4] & ~mask) | (precision_bits & mask);
+static inline int w1_DS18B20_set_resolution(struct w1_slave *sl, int val)
+{
+ int ret = -ENODEV;
+ u8 new_config_register[3]; /* array of data to be written */
+ struct therm_info info;
- if (!reset_select_slave(sl)) {
- w1_write_8(dev, W1_WRITE_SCRATCHPAD);
- w1_write_8(dev, rom[2]);
- w1_write_8(dev, rom[3]);
- w1_write_8(dev, rom[4]);
+ /* resolution of DS18B20 is in the range [9..12] bits */
+ if (val < 9 || val > 12)
+ return -EINVAL;
+
+ val -= 9; /* soustract 9 the lowest resolution in bit */
+ val = (val << 5); /* shift to position bit 5 & bit 6 */
+
+ /* Read the scratchpad to change only the required bits
+ * (bit5 & bit 6 from byte 4)
+ */
+ ret = read_scratchpad(sl, &info);
+ if (!ret) {
+ new_config_register[0] = info.rom[2];
+ new_config_register[1] = info.rom[3];
+ /* config register is byte 4 & mask 0b10011111*/
+ new_config_register[2] = (info.rom[4] & 0x9F) |
+ (u8) val;
+ } else
+ return ret;
- break;
- }
- }
- }
- }
+ /* Write data in the device RAM */
+ ret = w1_DS18B20_write_data(sl, new_config_register);
- mutex_unlock(&dev->bus_mutex);
-dec_refcnt:
- atomic_dec(THERM_REFCNT(family_data));
-error:
return ret;
}
+static inline int w1_DS18B20_get_resolution(struct w1_slave *sl)
+{
+ int ret = -ENODEV;
+ u8 config_register;
+ struct therm_info info;
+
+ ret = read_scratchpad(sl, &info);
+
+ if (!ret) {
+ config_register = info.rom[4]; // config register is byte 4
+ config_register &= 0x60; // 0b01100000 keep only bit 5 & 6
+ config_register = (config_register >> 5); // shift
+ config_register += 9; // add 9 the lowest resolution in bit
+ ret = (int) config_register;
+ }
+ return ret;
+}
+
+
static inline int w1_DS18B20_convert_temp(u8 rom[9])
{
s16 t = le16_to_cpup((__le16 *)rom);
@@ -280,8 +358,10 @@ static inline int w1_DS18S20_convert_temp(u8 rom[9])
{
int t, h;
- if (!rom[7])
+ if (!rom[7]) {
+ pr_debug("%s: Invalid argument for conversion\n", __func__);
return 0;
+ }
if (rom[1] == 0)
t = ((s32)rom[0] >> 1)*1000;
@@ -298,6 +378,20 @@ static inline int w1_DS18S20_convert_temp(u8 rom[9])
/*------------------------ Helpers Functions----------------------------*/
+static struct w1_therm_family_converter *device_family(struct w1_slave *sl)
+{
+ struct w1_therm_family_converter *ret = NULL;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
+ if (w1_therm_families[i].f->fid == sl->family->fid) {
+ ret = &w1_therm_families[i];
+ break;
+ }
+ }
+ return ret;
+}
+
static inline bool bus_mutex_lock(struct mutex *lock)
{
int max_trying = W1_THERM_MAX_TRY;
@@ -316,15 +410,55 @@ static inline bool bus_mutex_lock(struct mutex *lock)
return true;
}
+static inline int conversion_time(struct w1_slave *sl)
+{
+ if (SLAVE_SPECIFIC_FUNC(sl))
+ return SLAVE_SPECIFIC_FUNC(sl)->get_conversion_time(sl);
+
+ dev_info(&sl->dev,
+ "%s: Device not supported by the driver\n", __func__);
+
+ return -ENODEV; /* No device family */
+}
+
+static inline int temperature_from_RAM(struct w1_slave *sl, u8 rom[9])
+{
+ if (SLAVE_SPECIFIC_FUNC(sl))
+ return SLAVE_SPECIFIC_FUNC(sl)->convert(rom);
+
+ dev_info(&sl->dev,
+ "%s: Device not supported by the driver\n", __func__);
+
+ return 0; /* No device family */
+}
+
+static inline s8 int_to_short(int i)
+{
+ /* Prepare to cast to short by eliminating out of range values */
+ i = i > MAX_TEMP ? MAX_TEMP : i;
+ i = i < MIN_TEMP ? MIN_TEMP : i;
+ return (s8) i;
+}
/*-------------------------Interface Functions------------------------------*/
+
static int w1_therm_add_slave(struct w1_slave *sl)
{
+ struct w1_therm_family_converter *sl_family_conv;
+
+ /* Allocate memory*/
sl->family_data = kzalloc(sizeof(struct w1_therm_family_data),
GFP_KERNEL);
if (!sl->family_data)
return -ENOMEM;
atomic_set(THERM_REFCNT(sl->family_data), 1);
+ /* Get a pointer to the device specific function struct */
+ sl_family_conv = device_family(sl);
+ if (!sl_family_conv) {
+ kfree(sl->family_data);
+ return -ENODEV;
+ }
+ SLAVE_SPECIFIC_FUNC(sl) = sl_family_conv;
/* Getting the power mode of the device {external, parasite}*/
SLAVE_POWERMODE(sl) = read_powermode(sl);
@@ -334,6 +468,19 @@ static int w1_therm_add_slave(struct w1_slave *sl)
"%s: Device has been added, but power_mode may be corrupted. err=%d\n",
__func__, SLAVE_POWERMODE(sl));
}
+
+ /* Getting the resolution of the device */
+ if (SLAVE_SPECIFIC_FUNC(sl)->get_resolution) {
+ SLAVE_RESOLUTION(sl) =
+ SLAVE_SPECIFIC_FUNC(sl)->get_resolution(sl);
+ if (SLAVE_RESOLUTION(sl) < 0) {
+ /* no error returned as device has been added */
+ dev_warn(&sl->dev,
+ "%s:Device has been added, but resolution may be corrupted. err=%d\n",
+ __func__, SLAVE_RESOLUTION(sl));
+ }
+ }
+
return 0;
}
@@ -347,6 +494,7 @@ static void w1_therm_remove_slave(struct w1_slave *sl)
}
kfree(sl->family_data);
sl->family_data = NULL;
+
}
/*------------------------Hardware Functions--------------------------*/
@@ -366,180 +514,254 @@ static int reset_select_slave(struct w1_slave *sl)
return 0;
}
-static inline int w1_convert_temp(u8 rom[9], u8 fid)
+static int convert_t(struct w1_slave *sl, struct therm_info *info)
{
- int i;
+ struct w1_master *dev_master = sl->master;
+ int max_trying = W1_THERM_MAX_TRY;
+ int t_conv;
+ int ret = -ENODEV;
+ bool strong_pullup;
- for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
- if (w1_therm_families[i].f->fid == fid)
- return w1_therm_families[i].convert(rom);
+ if (!sl->family_data)
+ goto error;
- return 0;
-}
+ strong_pullup = (w1_strong_pullup == 2 ||
+ (!SLAVE_POWERMODE(sl) &&
+ w1_strong_pullup));
-static ssize_t read_therm(struct device *device,
- struct w1_slave *sl, struct therm_info *info)
-{
- struct w1_master *dev = sl->master;
- u8 external_power;
- int ret, max_trying = 10;
- u8 *family_data = sl->family_data;
+ /* get conversion duration device and id dependent */
+ t_conv = conversion_time(sl);
- if (!family_data) {
- ret = -ENODEV;
- goto error;
- }
+ memset(info->rom, 0, sizeof(info->rom));
- /* prevent the slave from going away in sleep */
- atomic_inc(THERM_REFCNT(family_data));
+ // prevent the slave from going away in sleep
+ atomic_inc(THERM_REFCNT(sl->family_data));
- ret = mutex_lock_interruptible(&dev->bus_mutex);
- if (ret != 0)
+ if (!bus_mutex_lock(&dev_master->bus_mutex)) {
+ ret = -EAGAIN; // Didn't acquire the mutex
goto dec_refcnt;
+ }
- memset(info->rom, 0, sizeof(info->rom));
-
- while (max_trying--) {
+ while (max_trying-- && ret) { /* ret should be 0 */
info->verdict = 0;
info->crc = 0;
-
+ /* safe version to select slave */
if (!reset_select_slave(sl)) {
- int count = 0;
- unsigned int tm = 750;
unsigned long sleep_rem;
- w1_write_8(dev, W1_READ_PSUPPLY);
- external_power = w1_read_8(dev);
-
- if (reset_select_slave(sl))
- continue;
-
/* 750ms strong pullup (or delay) after the convert */
- if (w1_strong_pullup == 2 ||
- (!external_power && w1_strong_pullup))
- w1_next_pullup(dev, tm);
-
- w1_write_8(dev, W1_CONVERT_TEMP);
+ if (strong_pullup)
+ w1_next_pullup(dev_master, t_conv);
- if (external_power) {
- mutex_unlock(&dev->bus_mutex);
+ w1_write_8(dev_master, W1_CONVERT_TEMP);
- sleep_rem = msleep_interruptible(tm);
+ if (strong_pullup) { /*some device need pullup */
+ sleep_rem = msleep_interruptible(t_conv);
if (sleep_rem != 0) {
ret = -EINTR;
- goto dec_refcnt;
+ goto mt_unlock;
}
+ mutex_unlock(&dev_master->bus_mutex);
+ } else { /*no device need pullup */
+ mutex_unlock(&dev_master->bus_mutex);
- ret = mutex_lock_interruptible(&dev->bus_mutex);
- if (ret != 0)
- goto dec_refcnt;
- } else if (!w1_strong_pullup) {
- sleep_rem = msleep_interruptible(tm);
+ sleep_rem = msleep_interruptible(t_conv);
if (sleep_rem != 0) {
ret = -EINTR;
- goto mt_unlock;
+ goto dec_refcnt;
}
}
+ ret = read_scratchpad(sl, info);
+ goto dec_refcnt;
+ }
- if (!reset_select_slave(sl)) {
+ }
- w1_write_8(dev, W1_READ_SCRATCHPAD);
- count = w1_read_block(dev, info->rom, 9);
- if (count != 9) {
- dev_warn(device, "w1_read_block() "
- "returned %u instead of 9.\n",
- count);
- }
+mt_unlock:
+ mutex_unlock(&dev_master->bus_mutex);
+dec_refcnt:
+ atomic_dec(THERM_REFCNT(sl->family_data));
+error:
+ return ret;
+}
+
+
+static int read_scratchpad(struct w1_slave *sl, struct therm_info *info)
+{
+ struct w1_master *dev_master = sl->master;
+ int max_trying = W1_THERM_MAX_TRY;
+ int ret = -ENODEV;
+
+ info->verdict = 0;
+
+ if (!sl->family_data)
+ goto error;
+
+ memset(info->rom, 0, sizeof(info->rom));
+
+ /* prevent the slave from going away in sleep */
+ atomic_inc(THERM_REFCNT(sl->family_data));
+
+ if (!bus_mutex_lock(&dev_master->bus_mutex)) {
+ ret = -EAGAIN; // Didn't acquire the mutex
+ goto dec_refcnt;
+ }
+
+ while (max_trying-- && ret) { /* ret should be 0 */
+ /* safe version to select slave */
+ if (!reset_select_slave(sl)) {
+ u8 nb_bytes_read;
- info->crc = w1_calc_crc8(info->rom, 8);
+ w1_write_8(dev_master, W1_READ_SCRATCHPAD);
- if (info->rom[8] == info->crc)
- info->verdict = 1;
+ nb_bytes_read = w1_read_block(dev_master, info->rom, 9);
+ if (nb_bytes_read != 9) {
+ dev_warn(&sl->dev,
+ "w1_read_block(): returned %u instead of 9.\n",
+ nb_bytes_read);
+ ret = -EIO;
}
+
+ info->crc = w1_calc_crc8(info->rom, 8);
+
+ if (info->rom[8] == info->crc) {
+ info->verdict = 1;
+ ret = 0;
+ } else
+ ret = -EIO; /* CRC not checked */
}
- if (info->verdict)
- break;
}
+ mutex_unlock(&dev_master->bus_mutex);
-mt_unlock:
- mutex_unlock(&dev->bus_mutex);
dec_refcnt:
- atomic_dec(THERM_REFCNT(family_data));
+ atomic_dec(THERM_REFCNT(sl->family_data));
error:
return ret;
}
-static inline int w1_therm_eeprom(struct device *device)
+static int write_scratchpad(struct w1_slave *sl, const u8 *data, u8 nb_bytes)
{
- struct w1_slave *sl = dev_to_w1_slave(device);
- struct w1_master *dev = sl->master;
- u8 rom[9], external_power;
- int ret, max_trying = 10;
- u8 *family_data = sl->family_data;
+ struct w1_master *dev_master = sl->master;
+ int max_trying = W1_THERM_MAX_TRY;
+ int ret = -ENODEV;
- if (!sl->family_data) {
- ret = -ENODEV;
+ if (!sl->family_data)
goto error;
- }
/* prevent the slave from going away in sleep */
- atomic_inc(THERM_REFCNT(family_data));
+ atomic_inc(THERM_REFCNT(sl->family_data));
- ret = mutex_lock_interruptible(&dev->bus_mutex);
- if (ret != 0)
+ if (!bus_mutex_lock(&dev_master->bus_mutex)) {
+ ret = -EAGAIN; // Didn't acquire the mutex
goto dec_refcnt;
+ }
- memset(rom, 0, sizeof(rom));
-
- while (max_trying--) {
+ while (max_trying-- && ret) { /* ret should be 0 */
+ /* safe version to select slave */
if (!reset_select_slave(sl)) {
- unsigned int tm = 10;
- unsigned long sleep_rem;
+ w1_write_8(dev_master, W1_WRITE_SCRATCHPAD);
+ w1_write_block(dev_master, data, nb_bytes);
+ ret = 0;
+ }
+ }
+ mutex_unlock(&dev_master->bus_mutex);
- /* check if in parasite mode */
- w1_write_8(dev, W1_READ_PSUPPLY);
- external_power = w1_read_8(dev);
+dec_refcnt:
+ atomic_dec(THERM_REFCNT(sl->family_data));
+error:
+ return ret;
+}
- if (reset_select_slave(sl))
- continue;
+static int copy_scratchpad(struct w1_slave *sl)
+{
+ struct w1_master *dev_master = sl->master;
+ int max_trying = W1_THERM_MAX_TRY;
+ int t_write, ret = -ENODEV;
+ bool strong_pullup;
- /* 10ms strong pullup/delay after the copy command */
- if (w1_strong_pullup == 2 ||
- (!external_power && w1_strong_pullup))
- w1_next_pullup(dev, tm);
+ if (!sl->family_data)
+ goto error;
- w1_write_8(dev, W1_COPY_SCRATCHPAD);
+ t_write = W1_THERM_EEPROM_WRITE_DELAY;
+ strong_pullup = (w1_strong_pullup == 2 ||
+ (!SLAVE_POWERMODE(sl) &&
+ w1_strong_pullup));
- if (external_power) {
- mutex_unlock(&dev->bus_mutex);
+ // prevent the slave from going away in sleep
+ atomic_inc(THERM_REFCNT(sl->family_data));
- sleep_rem = msleep_interruptible(tm);
- if (sleep_rem != 0) {
- ret = -EINTR;
- goto dec_refcnt;
- }
+ if (!bus_mutex_lock(&dev_master->bus_mutex)) {
+ ret = -EAGAIN; // Didn't acquire the mutex
+ goto dec_refcnt;
+ }
- ret = mutex_lock_interruptible(&dev->bus_mutex);
- if (ret != 0)
- goto dec_refcnt;
- } else if (!w1_strong_pullup) {
- sleep_rem = msleep_interruptible(tm);
+ while (max_trying-- && ret) { /* ret should be 0 */
+ /* safe version to select slave */
+ if (!reset_select_slave(sl)) {
+ unsigned long sleep_rem;
+
+ /* 10ms strong pullup (or delay) after the convert */
+ if (strong_pullup)
+ w1_next_pullup(dev_master, t_write);
+
+ w1_write_8(dev_master, W1_COPY_SCRATCHPAD);
+
+ if (strong_pullup) {
+ sleep_rem = msleep_interruptible(t_write);
if (sleep_rem != 0) {
ret = -EINTR;
goto mt_unlock;
}
}
-
- break;
+ ret = 0;
}
+
}
mt_unlock:
- mutex_unlock(&dev->bus_mutex);
+ mutex_unlock(&dev_master->bus_mutex);
dec_refcnt:
- atomic_dec(THERM_REFCNT(family_data));
+ atomic_dec(THERM_REFCNT(sl->family_data));
+error:
+ return ret;
+}
+
+static int recall_eeprom(struct w1_slave *sl)
+{
+ struct w1_master *dev_master = sl->master;
+ int max_trying = W1_THERM_MAX_TRY;
+ int ret = -ENODEV;
+
+ if (!sl->family_data)
+ goto error;
+
+ // prevent the slave from going away in sleep
+ atomic_inc(THERM_REFCNT(sl->family_data));
+
+ if (!bus_mutex_lock(&dev_master->bus_mutex)) {
+ ret = -EAGAIN; // Didn't acquire the mutex
+ goto dec_refcnt;
+ }
+
+ while (max_trying-- && ret) { /* ret should be 0 */
+ /* safe version to select slave */
+ if (!reset_select_slave(sl)) {
+
+ w1_write_8(dev_master, W1_RECALL_EEPROM);
+
+ ret = 1; /* Slave will pull line to 0 */
+ while (ret)
+ ret = 1 - w1_touch_bit(dev_master, 1);
+ }
+
+ }
+
+ mutex_unlock(&dev_master->bus_mutex);
+
+dec_refcnt:
+ atomic_dec(THERM_REFCNT(sl->family_data));
error:
return ret;
}
@@ -591,27 +813,33 @@ static ssize_t w1_slave_show(struct device *device,
u8 *family_data = sl->family_data;
int ret, i;
ssize_t c = PAGE_SIZE;
- u8 fid = sl->family->fid;
- ret = read_therm(device, sl, &info);
- if (ret)
- return ret;
+ ret = convert_t(sl, &info);
+
+ if (ret < 0) {
+ dev_dbg(device,
+ "%s: Temperature data may be corrupted. err=%d\n",
+ __func__, ret);
+ return 0;
+ }
for (i = 0; i < 9; ++i)
c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", info.rom[i]);
c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n",
info.crc, (info.verdict) ? "YES" : "NO");
+
if (info.verdict)
memcpy(family_data, info.rom, sizeof(info.rom));
else
- dev_warn(device, "Read failed CRC check\n");
+ dev_warn(device, "%s:Read failed CRC check\n", __func__);
for (i = 0; i < 9; ++i)
c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ",
((u8 *)family_data)[i]);
c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n",
- w1_convert_temp(info.rom, fid));
+ temperature_from_RAM(sl, info.rom));
+
ret = PAGE_SIZE - c;
return ret;
}
@@ -621,24 +849,62 @@ static ssize_t w1_slave_store(struct device *device,
size_t size)
{
struct w1_slave *sl = dev_to_w1_slave(device);
- int val, ret, i;
+ int val, ret = 0;
- ret = kstrtoint(buf, 10, &val);
- if (ret)
- return ret;
+ ret = kstrtoint(buf, 10, &val); /* converting user entry to int */
- for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
- if (w1_therm_families[i].f->fid == sl->family->fid) {
- /* zero value indicates to write current configuration to eeprom */
- if (val == 0)
- ret = w1_therm_families[i].eeprom(device);
- else
- ret = w1_therm_families[i].precision(device,
- val);
- break;
- }
+ if (ret) { /* conversion error */
+ dev_info(device,
+ "%s: conversion error. err= %d\n", __func__, ret);
+ return size; /* return size to avoid call back again*/
+ }
+
+ if ((!sl->family_data) || (!SLAVE_SPECIFIC_FUNC(sl))) {
+ dev_info(device,
+ "%s: Device not supported by the driver\n", __func__);
+ return size; /* No device family */
+ }
+
+ if (val == 0) /* val=0 : trigger a EEPROM save */
+ ret = copy_scratchpad(sl);
+ else {
+ if (SLAVE_SPECIFIC_FUNC(sl)->set_resolution)
+ ret = SLAVE_SPECIFIC_FUNC(sl)->set_resolution(sl, val);
+ }
+
+ if (ret) {
+ dev_info(device,
+ "%s: writing error %d\n", __func__, ret);
+ /* return size to avoid call back again*/
+ } else
+ SLAVE_RESOLUTION(sl) = val;
+
+ return size; /* always return size to avoid infinite calling */
+}
+
+static ssize_t temperature_show(struct device *device,
+ struct device_attribute *attr, char *buf)
+{
+ struct w1_slave *sl = dev_to_w1_slave(device);
+ struct therm_info info;
+ int ret = 0;
+
+ if ((!sl->family_data) || (!SLAVE_SPECIFIC_FUNC(sl))) {
+ dev_info(device,
+ "%s: Device not supported by the driver\n", __func__);
+ return 0; /* No device family */
+ }
+
+ ret = convert_t(sl, &info);
+
+ if (ret < 0) {
+ dev_dbg(device,
+ "%s: Temperature data may be corrupted. err=%d\n",
+ __func__, ret);
+ return 0;
}
- return ret ? : size;
+
+ return sprintf(buf, "%d\n", temperature_from_RAM(sl, info.rom));
}
static ssize_t ext_power_show(struct device *device,
@@ -663,18 +929,97 @@ static ssize_t ext_power_show(struct device *device,
return sprintf(buf, "%d\n", SLAVE_POWERMODE(sl));
}
+static ssize_t resolution_show(struct device *device,
+ struct device_attribute *attr, char *buf)
+{
+ struct w1_slave *sl = dev_to_w1_slave(device);
+
+ if ((!sl->family_data) || (!SLAVE_SPECIFIC_FUNC(sl))) {
+ dev_info(device,
+ "%s: Device not supported by the driver\n", __func__);
+ return 0; /* No device family */
+ }
+
+ /* get the correct function depending on the device */
+ SLAVE_RESOLUTION(sl) = SLAVE_SPECIFIC_FUNC(sl)->get_resolution(sl);
+ if (SLAVE_RESOLUTION(sl) < 0) {
+ dev_dbg(device,
+ "%s: Resolution may be corrupted. err=%d\n",
+ __func__, SLAVE_RESOLUTION(sl));
+ }
+
+ return sprintf(buf, "%d\n", SLAVE_RESOLUTION(sl));
+}
+
+static ssize_t resolution_store(struct device *device,
+ struct device_attribute *attr, const char *buf, size_t size)
+{
+ struct w1_slave *sl = dev_to_w1_slave(device);
+ int val;
+ int ret = 0;
+
+ ret = kstrtoint(buf, 10, &val); /* converting user entry to int */
+
+ if (ret) { /* conversion error */
+ dev_info(device,
+ "%s: conversion error. err= %d\n", __func__, ret);
+ return size; /* return size to avoid call back again*/
+ }
+
+ if ((!sl->family_data) || (!SLAVE_SPECIFIC_FUNC(sl))) {
+ dev_info(device,
+ "%s: Device not supported by the driver\n", __func__);
+ return size; /* No device family */
+ }
+
+ /* Don't deal with the val enterd by user,
+ * only device knows what is correct or not
+ */
+
+ /* get the correct function depending on the device */
+ ret = SLAVE_SPECIFIC_FUNC(sl)->set_resolution(sl, val);
+
+ if (ret) {
+ dev_info(device,
+ "%s: writing error %d\n", __func__, ret);
+ /* return size to avoid call back again*/
+ } else
+ SLAVE_RESOLUTION(sl) = val;
+
+ return size;
+}
+
+static ssize_t eeprom_store(struct device *device,
+ struct device_attribute *attr, const char *buf, size_t size)
+{
+ struct w1_slave *sl = dev_to_w1_slave(device);
+ int ret = -EINVAL; // Invalid argument
+
+ if (size == sizeof(EEPROM_CMD_WRITE)) {
+ if (!strncmp(buf, EEPROM_CMD_WRITE, sizeof(EEPROM_CMD_WRITE)-1))
+ ret = copy_scratchpad(sl);
+ } else if (size == sizeof(EEPROM_CMD_READ)) {
+ if (!strncmp(buf, EEPROM_CMD_READ, sizeof(EEPROM_CMD_READ)-1))
+ ret = recall_eeprom(sl);
+ }
+
+ if (ret)
+ dev_info(device, "%s: error in process %d\n", __func__, ret);
+
+ return size;
+}
+
#if IS_REACHABLE(CONFIG_HWMON)
static int w1_read_temp(struct device *device, u32 attr, int channel,
long *val)
{
struct w1_slave *sl = dev_get_drvdata(device);
struct therm_info info;
- u8 fid = sl->family->fid;
int ret;
switch (attr) {
case hwmon_temp_input:
- ret = read_therm(device, sl, &info);
+ ret = convert_t(sl, &info);
if (ret)
return ret;
@@ -683,7 +1028,7 @@ static int w1_read_temp(struct device *device, u32 attr, int channel,
return ret;
}
- *val = w1_convert_temp(info.rom, fid);
+ *val = temperature_from_RAM(sl, info.rom);
ret = 0;
break;
default:
diff --git a/drivers/w1/slaves/w1_therm.h b/drivers/w1/slaves/w1_therm.h
index 2f975a4..487156f 100644
--- a/drivers/w1/slaves/w1_therm.h
+++ b/drivers/w1/slaves/w1_therm.h
@@ -26,11 +26,25 @@
#include <linux/w1.h>
/*----------------------------------Defines---------------------------------*/
+/* This command should be in public header w1.h but is not */
+#define W1_RECALL_EEPROM 0xB8
+
/* Nb of try for an operation */
#define W1_THERM_MAX_TRY 5
/* ms delay to retry bus mutex */
#define W1_THERM_RETRY_DELAY 20
+
+/* delay in ms to write in EEPROM */
+#define W1_THERM_EEPROM_WRITE_DELAY 10
+
+#define EEPROM_CMD_WRITE "save" /* cmd for write eeprom sysfs */
+#define EEPROM_CMD_READ "restore" /* cmd for read eeprom sysfs */
+#define BULK_TRIGGER_CMD "trigger" /* cmd to trigger a bulk read */
+
+#define MIN_TEMP -55 /* min temperature that can be mesured */
+#define MAX_TEMP 125 /* max temperature that can be mesured */
+
/*----------------------------------Structs---------------------------------*/
/**
@@ -41,12 +55,14 @@
* see helper : device_family()
*/
struct w1_therm_family_converter {
- u8 broken;
- u16 reserved;
+ u8 broken;
+ u16 reserved;
struct w1_family *f;
- int (*convert)(u8 rom[9]);
- int (*precision)(struct device *device, int val);
- int (*eeprom)(struct device *device);
+ int (*convert)(u8 rom[9]);
+ int (*get_conversion_time)(struct w1_slave *sl);
+ int (*set_resolution)(struct w1_slave *sl, int val);
+ int (*get_resolution)(struct w1_slave *sl);
+ int (*write_data)(struct w1_slave *sl, const u8 *data);
};
/**
@@ -57,11 +73,14 @@ struct w1_therm_family_converter {
* 1 device powered externally,
* 0 device parasite powered,
* -x error or undefined
+ * @param resolution resolution in bit of the device, <O kernel error code
*/
struct w1_therm_family_data {
uint8_t rom[9];
atomic_t refcnt;
int external_powered;
+ int resolution;
+ struct w1_therm_family_converter *specific_functions;
};
/**
@@ -79,36 +98,78 @@ struct therm_info {
/*-----------------------Device specific functions-------------------------*/
-/* write configuration to eeprom */
-static inline int w1_therm_eeprom(struct device *device);
-
-/* Set precision for conversion */
-static inline int w1_DS18B20_precision(struct device *device, int val);
-static inline int w1_DS18S20_precision(struct device *device, int val);
-
-/* The return value is millidegrees Centigrade. */
static inline int w1_DS18B20_convert_temp(u8 rom[9]);
static inline int w1_DS18S20_convert_temp(u8 rom[9]);
+static inline int w1_DS18B20_convert_time(struct w1_slave *sl);
+static inline int w1_DS18S20_convert_time(struct w1_slave *sl);
+
+static inline int w1_DS18B20_write_data(struct w1_slave *sl, const u8 *data);
+static inline int w1_DS18S20_write_data(struct w1_slave *sl, const u8 *data);
+
+static inline int w1_DS18B20_set_resolution(struct w1_slave *sl, int val);
+static inline int w1_DS18B20_get_resolution(struct w1_slave *sl);
+
/*-------------------------------Macros--------------------------------------*/
+
+/* return a pointer on the slave w1_therm_family_converter struct:
+ * always test family data existence before
+ */
+#define SLAVE_SPECIFIC_FUNC(sl) \
+ (((struct w1_therm_family_data *)(sl->family_data))->specific_functions)
+
/* return the power mode of the sl slave : 1-ext, 0-parasite, <0 unknown
* always test family data existence before
*/
#define SLAVE_POWERMODE(sl) \
(((struct w1_therm_family_data *)(sl->family_data))->external_powered)
+/* return the resolution in bit of the sl slave : <0 unknown
+ * always test family data existence before
+ */
+#define SLAVE_RESOLUTION(sl) \
+ (((struct w1_therm_family_data *)(sl->family_data))->resolution)
/* return the address of the refcnt in the family data */
#define THERM_REFCNT(family_data) \
(&((struct w1_therm_family_data *)family_data)->refcnt)
/*-------------------------- Helpers Functions------------------------------*/
+/** device_family()
+ * @brief Helper function that provide a pointer
+ * on the w1_therm_family_converter struct
+ * @param sl represents the device
+ * @return pointer to the slaves's family converter, NULL if not known
+ */
+static struct w1_therm_family_converter *device_family(struct w1_slave *sl);
+
/** bus_mutex_lock() get the mutex & retry
* @param lock w1 bus mutex to get
* @return value true is mutex is acquired and lock, false otherwise
*/
static inline bool bus_mutex_lock(struct mutex *lock);
+/** conversion_time() get the Tconv fo the device
+ * @param sl device to get the conversion time
+ * @return conversion time in ms, negative values kernel error code
+ */
+static inline int conversion_time(struct w1_slave *sl);
+
+/** temperature_from_RAM() return the temperature in 1/100°
+ * @brief Device dependent, it will select the correct computation method
+ * @param sl device that sent the RAM data
+ * @param rom ram read value
+ * @return temperature in 1/1000°
+ */
+static inline int temperature_from_RAM(struct w1_slave *sl, u8 rom[9]);
+
+/** int_to_short() safe casting of int to short
+ * min/max values are defined by macro
+ * @param i integer to be converted to short
+ * @return a short in the range of min/max value
+ */
+static inline s8 int_to_short(int i);
+
/*---------------------------Hardware Functions-----------------------------*/
/**
@@ -124,13 +185,41 @@ static inline bool bus_mutex_lock(struct mutex *lock);
*/
static int reset_select_slave(struct w1_slave *sl);
-/** read_therm()
+/** convert_t()
* @param sl pointer to the slave to read
* @param info pointer to a structure to store the read results
* @return 0 if success, -kernel error code otherwise
*/
-static ssize_t read_therm(struct device *device,
- struct w1_slave *sl, struct therm_info *info);
+static int convert_t(struct w1_slave *sl, struct therm_info *info);
+
+/** read_scratchpad()
+ * @param sl pointer to the slave to read
+ * @param info pointer to a structure to store the read results
+ * @return 0 if success, -kernel error code otherwise
+ */
+static int read_scratchpad(struct w1_slave *sl, struct therm_info *info);
+
+/** write_data()
+ * @param sl pointer to the slave to read
+ * @param data pointer to an array of 3 bytes, as 3 bytes MUST be written
+ * @param nb_bytes Nb bytes to be written (2 for DS18S20, 3 for other devices)
+ * @return 0 if success, -kernel error code otherwise
+ */
+static int write_scratchpad(struct w1_slave *sl, const u8 *data, u8 nb_bytes);
+
+/** copy_scratchpad() - Copy the content of scratchpad in device EEPROM
+ * @param sl slave involved
+ * @return 0 if success, -kernel error code otherwise
+ */
+static int copy_scratchpad(struct w1_slave *sl);
+
+/** recall_eeprom()
+ * @brief retrieve EEPROM data to device RAM
+ * @param sl slave involved
+ * @return 0 if success, -kernel error code otherwise
+ */
+static int recall_eeprom(struct w1_slave *sl);
+
/** read_powermode()
* @brief ask the device to get its power mode {external, parasite}
* @param sl slave to be interrogated
@@ -158,6 +247,16 @@ static ssize_t w1_slave_store(struct device *device,
static ssize_t w1_seq_show(struct device *device,
struct device_attribute *attr, char *buf);
+
+/** @brief A callback function to output the temperature
+ * Main differences with w1_slave :
+ * No hardware check (just read the stored device infos)
+ * No formatting
+ * @return temperature (1/1000°)
+ */
+static ssize_t temperature_show(struct device *device,
+ struct device_attribute *attr, char *buf);
+
/** @brief A callback function to output the power mode of the device
* Once done, it is stored in the sl->family_data to avoid doing the test
* during data read
@@ -167,11 +266,35 @@ static ssize_t w1_seq_show(struct device *device,
*/
static ssize_t ext_power_show(struct device *device,
struct device_attribute *attr, char *buf);
+
+/** @brief A callback function to output the resolution of the device
+ * Once done, it is stored in the sl->family_data to avoid doing the test
+ * during data read
+ * @return current resolution of the device in bit
+ */
+static ssize_t resolution_show(struct device *device,
+ struct device_attribute *attr, char *buf);
+
+/** @brief A callback function to store the user resolution in the device RAM
+ * @param resolution in bit to be set
+ */
+static ssize_t resolution_store(struct device *device,
+ struct device_attribute *attr, const char *buf, size_t size);
+
+/** @brief A callback function to let the user read/write device EEPROM
+ * @param check EEPROM_CMD_WRITE & EEPROM_CMD_READ macros
+ */
+static ssize_t eeprom_store(struct device *device,
+ struct device_attribute *attr, const char *buf, size_t size);
+
/*-----------------------------Attributes declarations----------------------*/
static DEVICE_ATTR_RW(w1_slave);
static DEVICE_ATTR_RO(w1_seq);
+static DEVICE_ATTR_RO(temperature);
static DEVICE_ATTR_RO(ext_power);
+static DEVICE_ATTR_RW(resolution);
+static DEVICE_ATTR_WO(eeprom);
/*--------------------------Interface Functions-----------------------------*/
@@ -188,4 +311,17 @@ static int w1_therm_add_slave(struct w1_slave *sl);
*/
static void w1_therm_remove_slave(struct w1_slave *sl);
+/** w1_DS18B20_set_resolution() write new resolution to the RAM device
+ * @param sl device to set the resolution
+ * @param val new resolution in bit [9..12]
+ * @return 0 if success, negative kernel error code otherwise
+ */
+static inline int w1_DS18B20_set_resolution(struct w1_slave *sl, int val);
+
+/** w1_DS18B20_get_resolution() read the device RAM to get current resolution
+ * @param sl slave to get the resolution form
+ * @return resolution in bit [9..12] or negative kernel error code
+ */
+static inline int w1_DS18B20_get_resolution(struct w1_slave *sl);
+
#endif /* __W1_THERM_H */
\ No newline at end of file
--
2.25.4
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