From 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 21 Feb 2023 18:24:12 -0800 Subject: Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next Pull networking updates from Jakub Kicinski: "Core: - Add dedicated kmem_cache for typical/small skb->head, avoid having to access struct page at kfree time, and improve memory use. - Introduce sysctl to set default RPS configuration for new netdevs. - Define Netlink protocol specification format which can be used to describe messages used by each family and auto-generate parsers. Add tools for generating kernel data structures and uAPI headers. - Expose all net/core sysctls inside netns. - Remove 4s sleep in netpoll if carrier is instantly detected on boot. - Add configurable limit of MDB entries per port, and port-vlan. - Continue populating drop reasons throughout the stack. - Retire a handful of legacy Qdiscs and classifiers. Protocols: - Support IPv4 big TCP (TSO frames larger than 64kB). - Add IP_LOCAL_PORT_RANGE socket option, to control local port range on socket by socket basis. - Track and report in procfs number of MPTCP sockets used. - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path manager. - IPv6: don't check net.ipv6.route.max_size and rely on garbage collection to free memory (similarly to IPv4). - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986). - ICMP: add per-rate limit counters. - Add support for user scanning requests in ieee802154. - Remove static WEP support. - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate reporting. - WiFi 7 EHT channel puncturing support (client & AP). BPF: - Add a rbtree data structure following the "next-gen data structure" precedent set by recently added linked list, that is, by using kfunc + kptr instead of adding a new BPF map type. - Expose XDP hints via kfuncs with initial support for RX hash and timestamp metadata. - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata. - Improve x86 JIT's codegen for PROBE_MEM runtime error checks. - Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers. - Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case. - Significantly reduce the search time for module symbols by livepatch and BPF. - Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals. - Add support for BPF trampoline on s390x and riscv64. - Add capability to export the XDP features supported by the NIC. - Add __bpf_kfunc tag for marking kernel functions as kfuncs. - Add cgroup.memory=nobpf kernel parameter option to disable BPF memory accounting for container environments. Netfilter: - Remove the CLUSTERIP target. It has been marked as obsolete for years, and we still have WARN splats wrt races of the out-of-band /proc interface installed by this target. - Add 'destroy' commands to nf_tables. They are identical to the existing 'delete' commands, but do not return an error if the referenced object (set, chain, rule...) did not exist. Driver API: - Improve cpumask_local_spread() locality to help NICs set the right IRQ affinity on AMD platforms. - Separate C22 and C45 MDIO bus transactions more clearly. - Introduce new DCB table to control DSCP rewrite on egress. - Support configuration of Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of shared medium Ethernet. - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing preemption of low priority frames by high priority frames. - Add support for controlling MACSec offload using netlink SET. - Rework devlink instance refcounts to allow registration and de-registration under the instance lock. Split the code into multiple files, drop some of the unnecessarily granular locks and factor out common parts of netlink operation handling. - Add TX frame aggregation parameters (for USB drivers). - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning messages with notifications for debug. - Allow offloading of UDP NEW connections via act_ct. - Add support for per action HW stats in TC. - Support hardware miss to TC action (continue processing in SW from a specific point in the action chain). - Warn if old Wireless Extension user space interface is used with modern cfg80211/mac80211 drivers. Do not support Wireless Extensions for Wi-Fi 7 devices at all. Everyone should switch to using nl80211 interface instead. - Improve the CAN bit timing configuration. Use extack to return error messages directly to user space, update the SJW handling, including the definition of a new default value that will benefit CAN-FD controllers, by increasing their oscillator tolerance. New hardware / drivers: - Ethernet: - nVidia BlueField-3 support (control traffic driver) - Ethernet support for imx93 SoCs - Motorcomm yt8531 gigabit Ethernet PHY - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA) - Microchip LAN8841 PHY (incl. cable diagnostics and PTP) - Amlogic gxl MDIO mux - WiFi: - RealTek RTL8188EU (rtl8xxxu) - Qualcomm Wi-Fi 7 devices (ath12k) - CAN: - Renesas R-Car V4H Drivers: - Bluetooth: - Set Per Platform Antenna Gain (PPAG) for Intel controllers. - Ethernet NICs: - Intel (1G, igc): - support TSN / Qbv / packet scheduling features of i226 model - Intel (100G, ice): - use GNSS subsystem instead of TTY - multi-buffer XDP support - extend support for GPIO pins to E823 devices - nVidia/Mellanox: - update the shared buffer configuration on PFC commands - implement PTP adjphase function for HW offset control - TC support for Geneve and GRE with VF tunnel offload - more efficient crypto key management method - multi-port eswitch support - Netronome/Corigine: - add DCB IEEE support - support IPsec offloading for NFP3800 - Freescale/NXP (enetc): - support XDP_REDIRECT for XDP non-linear buffers - improve reconfig, avoid link flap and waiting for idle - support MAC Merge layer - Other NICs: - sfc/ef100: add basic devlink support for ef100 - ionic: rx_push mode operation (writing descriptors via MMIO) - bnxt: use the auxiliary bus abstraction for RDMA - r8169: disable ASPM and reset bus in case of tx timeout - cpsw: support QSGMII mode for J721e CPSW9G - cpts: support pulse-per-second output - ngbe: add an mdio bus driver - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing - r8152: handle devices with FW with NCM support - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation - virtio-net: support multi buffer XDP - virtio/vsock: replace virtio_vsock_pkt with sk_buff - tsnep: XDP support - Ethernet high-speed switches: - nVidia/Mellanox (mlxsw): - add support for latency TLV (in FW control messages) - Microchip (sparx5): - separate explicit and implicit traffic forwarding rules, make the implicit rules always active - add support for egress DSCP rewrite - IS0 VCAP support (Ingress Classification) - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.) - ES2 VCAP support (Egress Access Control) - support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1) - Ethernet embedded switches: - Marvell (mv88e6xxx): - add MAB (port auth) offload support - enable PTP receive for mv88e6390 - NXP (ocelot): - support MAC Merge layer - support for the the vsc7512 internal copper phys - Microchip: - lan9303: convert to PHYLINK - lan966x: support TC flower filter statistics - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x - lan937x: support Credit Based Shaper configuration - ksz9477: support Energy Efficient Ethernet - other: - qca8k: convert to regmap read/write API, use bulk operations - rswitch: Improve TX timestamp accuracy - Intel WiFi (iwlwifi): - EHT (Wi-Fi 7) rate reporting - STEP equalizer support: transfer some STEP (connection to radio on platforms with integrated wifi) related parameters from the BIOS to the firmware. - Qualcomm 802.11ax WiFi (ath11k): - IPQ5018 support - Fine Timing Measurement (FTM) responder role support - channel 177 support - MediaTek WiFi (mt76): - per-PHY LED support - mt7996: EHT (Wi-Fi 7) support - Wireless Ethernet Dispatch (WED) reset support - switch to using page pool allocator - RealTek WiFi (rtw89): - support new version of Bluetooth co-existance - Mobile: - rmnet: support TX aggregation" * tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits) page_pool: add a comment explaining the fragment counter usage net: ethtool: fix __ethtool_dev_mm_supported() implementation ethtool: pse-pd: Fix double word in comments xsk: add linux/vmalloc.h to xsk.c sefltests: netdevsim: wait for devlink instance after netns removal selftest: fib_tests: Always cleanup before exit net/mlx5e: Align IPsec ASO result memory to be as required by hardware net/mlx5e: TC, Set CT miss to the specific ct action instance net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG net/mlx5: Refactor tc miss handling to a single function net/mlx5: Kconfig: Make tc offload depend on tc skb extension net/sched: flower: Support hardware miss to tc action net/sched: flower: Move filter handle initialization earlier net/sched: cls_api: Support hardware miss to tc action net/sched: Rename user cookie and act cookie sfc: fix builds without CONFIG_RTC_LIB sfc: clean up some inconsistent indentings net/mlx4_en: Introduce flexible array to silence overflow warning net: lan966x: Fix possible deadlock inside PTP net/ulp: Remove redundant ->clone() test in inet_clone_ulp(). ... --- Documentation/hwmon/lm90.rst | 641 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 641 insertions(+) create mode 100644 Documentation/hwmon/lm90.rst (limited to 'Documentation/hwmon/lm90.rst') diff --git a/Documentation/hwmon/lm90.rst b/Documentation/hwmon/lm90.rst new file mode 100644 index 000000000..23af17a0a --- /dev/null +++ b/Documentation/hwmon/lm90.rst @@ -0,0 +1,641 @@ +Kernel driver lm90 +================== + +Supported chips: + + * National Semiconductor LM84 + + Prefix: 'lm84' + + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + + Datasheet: Publicly available at the National Semiconductor website + + * National Semiconductor LM90 + + Prefix: 'lm90' + + Addresses scanned: I2C 0x4c + + Datasheet: Publicly available at the National Semiconductor website + + http://www.national.com/pf/LM/LM90.html + + * National Semiconductor LM89 + + Prefix: 'lm89' (no auto-detection) + + Addresses scanned: I2C 0x4c and 0x4d + + Datasheet: Publicly available at the National Semiconductor website + + http://www.national.com/mpf/LM/LM89.html + + * National Semiconductor LM99 + + Prefix: 'lm99' + + Addresses scanned: I2C 0x4c and 0x4d + + Datasheet: Publicly available at the National Semiconductor website + + http://www.national.com/pf/LM/LM99.html + + * National Semiconductor LM86 + + Prefix: 'lm86' + + Addresses scanned: I2C 0x4c + + Datasheet: Publicly available at the National Semiconductor website + + http://www.national.com/mpf/LM/LM86.html + + * Analog Devices ADM1020 + + Prefix: 'adm1020' + + Addresses scanned: I2C 0x4c - 0x4e + + Datasheet: Publicly available at the Analog Devices website + + * Analog Devices ADM1021 + + Prefix: 'adm1021' + + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + + Datasheet: Publicly available at the Analog Devices website + + * Analog Devices ADM1021A/ADM1023 + + Prefix: 'adm1023' + + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + + Datasheet: Publicly available at the Analog Devices website + + * Analog Devices ADM1032 + + Prefix: 'adm1032' + + Addresses scanned: I2C 0x4c and 0x4d + + Datasheet: Publicly available at the ON Semiconductor website + + https://www.onsemi.com/PowerSolutions/product.do?id=ADM1032 + + * Analog Devices ADT7461 + + Prefix: 'adt7461' + + Addresses scanned: I2C 0x4c and 0x4d + + Datasheet: Publicly available at the ON Semiconductor website + + https://www.onsemi.com/PowerSolutions/product.do?id=ADT7461 + + * Analog Devices ADT7461A + + Prefix: 'adt7461a' + + Addresses scanned: I2C 0x4c and 0x4d + + Datasheet: Publicly available at the ON Semiconductor website + + https://www.onsemi.com/PowerSolutions/product.do?id=ADT7461A + + * Analog Devices ADT7481 + + Prefix: 'adt7481' + + Addresses scanned: I2C 0x4b and 0x4c + + Datasheet: Publicly available at the ON Semiconductor website + + https://www.onsemi.com/PowerSolutions/product.do?id=ADT7481 + + * Analog Devices ADT7482 + + Prefix: 'adt7482' + + Addresses scanned: I2C 0x4c + + Datasheet: Publicly available at the ON Semiconductor website + + https://www.onsemi.com/PowerSolutions/product.do?id=ADT7482 + + * Analog Devices ADT7483A + + Prefix: 'adt7483a' + + Addresses scanned: I2C 0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x4c, 0x4d, 0x4e + + Datasheet: Publicly available at the ON Semiconductor website + + https://www.onsemi.com/PowerSolutions/product.do?id=ADT7483A + + * ON Semiconductor NCT1008 + + Prefix: 'nct1008' + + Addresses scanned: I2C 0x4c and 0x4d + + Datasheet: Publicly available at the ON Semiconductor website + + https://www.onsemi.com/PowerSolutions/product.do?id=NCT1008 + + * ON Semiconductor NCT210 + + Prefix: 'adm1021' + + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + + Datasheet: Publicly available at the ON Semiconductor website + + https://www.onsemi.com/PowerSolutions/product.do?id=NCT210 + + * ON Semiconductor NCT214 + + Prefix: 'nct214' + + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + + Datasheet: Publicly available at the ON Semiconductor website + + https://www.onsemi.com/PowerSolutions/product.do?id=NCT214 + + * ON Semiconductor NCT218 + + Prefix: 'nct218' + + Addresses scanned: I2C 0x4c - 0x4d + + Datasheet: Publicly available at the ON Semiconductor website + + https://www.onsemi.com/PowerSolutions/product.do?id=NCT218 + + * ON Semiconductor NCT72 + + Prefix: 'nct72' + + Addresses scanned: I2C 0x4c - 0x4d + + Datasheet: Publicly available at the ON Semiconductor website + + https://www.onsemi.com/PowerSolutions/product.do?id=NCT72 + + * Maxim MAX1617 + + Prefix: 'max1617' + + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + + Datasheet: Publicly available at the Maxim website + + * Maxim MAX1617A + + Prefix: 'max1617a' + + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + + Datasheet: Publicly available at the Maxim website + + * Maxim MAX6642 + + Prefix: 'max6642' + + Addresses scanned: I2C 0x48-0x4f + + Datasheet: Publicly available at the Maxim website + + http://datasheets.maxim-ic.com/en/ds/MAX6642.pdf + + * Maxim MAX6646 + + Prefix: 'max6646' + + Addresses scanned: I2C 0x4d + + Datasheet: Publicly available at the Maxim website + + http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3497 + + * Maxim MAX6647 + + Prefix: 'max6646' + + Addresses scanned: I2C 0x4e + + Datasheet: Publicly available at the Maxim website + + http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3497 + + * Maxim MAX6648 + + Prefix: 'max6648' + + Addresses scanned: I2C 0x4c + + Datasheet: Publicly available at the Maxim website + + http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3500 + + * Maxim MAX6649 + + Prefix: 'max6646' + + Addresses scanned: I2C 0x4c + + Datasheet: Publicly available at the Maxim website + + http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3497 + + * Maxim MAX6654 + + Prefix: 'max6654' + + Addresses scanned: I2C 0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, + + 0x4c, 0x4d and 0x4e + + Datasheet: Publicly available at the Maxim website + + https://www.maximintegrated.com/en/products/sensors/MAX6654.html + + * Maxim MAX6657 + + Prefix: 'max6657' + + Addresses scanned: I2C 0x4c + + Datasheet: Publicly available at the Maxim website + + http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2578 + + * Maxim MAX6658 + + Prefix: 'max6657' + + Addresses scanned: I2C 0x4c + + Datasheet: Publicly available at the Maxim website + + http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2578 + + * Maxim MAX6659 + + Prefix: 'max6659' + + Addresses scanned: I2C 0x4c, 0x4d, 0x4e + + Datasheet: Publicly available at the Maxim website + + http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2578 + + * Maxim MAX6680 + + Prefix: 'max6680' + + Addresses scanned: I2C 0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, + + 0x4c, 0x4d and 0x4e + + Datasheet: Publicly available at the Maxim website + + http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3370 + + * Maxim MAX6681 + + Prefix: 'max6680' + + Addresses scanned: I2C 0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, + + 0x4c, 0x4d and 0x4e + + Datasheet: Publicly available at the Maxim website + + http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3370 + + * Maxim MAX6692 + + Prefix: 'max6648' + + Addresses scanned: I2C 0x4c + + Datasheet: Publicly available at the Maxim website + + http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3500 + + * Maxim MAX6695 + + Prefix: 'max6695' + + Addresses scanned: I2C 0x18 + + Datasheet: Publicly available at the Maxim website + + http://www.maxim-ic.com/datasheet/index.mvp/id/4199 + + * Maxim MAX6696 + + Prefix: 'max6695' + + Addresses scanned: I2C 0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, + + 0x4c, 0x4d and 0x4e + + Datasheet: Publicly available at the Maxim website + + http://www.maxim-ic.com/datasheet/index.mvp/id/4199 + + * Winbond/Nuvoton W83L771W/G + + Prefix: 'w83l771' + + Addresses scanned: I2C 0x4c + + Datasheet: No longer available + + * Winbond/Nuvoton W83L771AWG/ASG + + Prefix: 'w83l771' + + Addresses scanned: I2C 0x4c + + Datasheet: Not publicly available, can be requested from Nuvoton + + * Philips/NXP SA56004X + + Prefix: 'sa56004' + + Addresses scanned: I2C 0x48 through 0x4F + + Datasheet: Publicly available at NXP website + + http://ics.nxp.com/products/interface/datasheet/sa56004x.pdf + + * GMT G781 + + Prefix: 'g781' + + Addresses scanned: I2C 0x4c, 0x4d + + Datasheet: Not publicly available from GMT + + * Texas Instruments TMP451 + + Prefix: 'tmp451' + + Addresses scanned: I2C 0x4c + + Datasheet: Publicly available at TI website + + https://www.ti.com/litv/pdf/sbos686 + + * Texas Instruments TMP461 + + Prefix: 'tmp461' + + Addresses scanned: I2C 0x48 through 0x4F + + Datasheet: Publicly available at TI website + + https://www.ti.com/lit/gpn/tmp461 + + * Philips NE1617, NE1617A + + Prefix: 'max1617' (probably detected as a max1617) + + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + + Datasheets: Publicly available at the Philips website + + * Philips NE1618 + + Prefix: 'ne1618' + + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + + Datasheets: Publicly available at the Philips website + + * Genesys Logic GL523SM + + Prefix: 'gl523sm' + + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + + Datasheet: + + * TI THMC10 + + Prefix: 'thmc10' + + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + + Datasheet: Publicly available at the TI website + + * Onsemi MC1066 + + Prefix: 'mc1066' + + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + + Datasheet: Publicly available at the Onsemi website + +Author: Jean Delvare + + +Description +----------- + +The LM90 is a digital temperature sensor. It senses its own temperature as +well as the temperature of up to one external diode. It is compatible +with many other devices, many of which are supported by this driver. + +The family of chips supported by this driver is derived from MAX1617. +This chip as well as various compatible chips support a local and a remote +temperature sensor with 8 bit accuracy. Later chips provide improved accuracy +and other additional features such as hysteresis and temperature offset +registers. + +Note that there is no easy way to differentiate between the MAX6657, +MAX6658 and MAX6659 variants. The extra features of the MAX6659 are only +supported by this driver if the chip is located at address 0x4d or 0x4e, +or if the chip type is explicitly selected as max6659. +The MAX6680 and MAX6681 only differ in their pinout, therefore they obviously +can't (and don't need to) be distinguished. + +The different chipsets of the family are not strictly identical, although +very similar. For reference, here comes a non-exhaustive list of specific +features: + +LM84: + * 8 bit sensor resolution + +ADM1020, ADM1021, GL523SM, MAX1617, NE1617, NE1617A, THMC10: + * 8 bit sensor resolution + * Low temperature limits + +NCT210, NE1618: + * 11 bit sensor resolution for remote temperature sensor + * Low temperature limits + +ADM1021A, ADM1023: + * Temperature offset register for remote temperature sensor + * 11 bit resolution for remote temperature sensor + * Low temperature limits + +LM90: + * 11 bit resolution for remote temperature sensor + * Temperature offset register for remote temperature sensor + * Low and critical temperature limits + * Configurable conversion rate + * Filter and alert configuration register at 0xBF. + * ALERT is triggered by temperatures over critical limits. + +LM86 and LM89: + * Same as LM90 + * Better external channel accuracy + +LM99: + * Same as LM89 + * External temperature shifted by 16 degrees down + +ADM1032: + * Consecutive alert register at 0x22. + * Conversion averaging. + * Up to 64 conversions/s. + * ALERT is triggered by open remote sensor. + * SMBus PEC support for Write Byte and Receive Byte transactions. + +ADT7461, ADT7461A, NCT1008: + * Extended temperature range (breaks compatibility) + * Lower resolution for remote temperature + * SMBus PEC support for Write Byte and Receive Byte transactions. + * 10 bit temperature resolution + +ADT7481, ADT7482, ADT7483: + * Temperature offset register + * SMBus PEC support + * 10 bit temperature resolution for external sensors + * Two remote sensors + * Selectable address (ADT7483) + +MAX6642: + * No critical limit register + * Conversion rate not configurable + * Better local resolution (10 bit) + * 10 bit external sensor resolution + +MAX6646, MAX6647, MAX6649: + * Better local resolution + * Extended range unsigned external temperature + +MAX6648, MAX6692: + * Better local resolution + * Unsigned temperature + +MAX6654, MAX6690: + * Better local resolution + * Selectable address + * Remote sensor type selection + * Extended temperature range + * Extended resolution only available when conversion rate <= 1 Hz + +MAX6657 and MAX6658: + * Better local resolution + * Remote sensor type selection + +MAX6659: + * Better local resolution + * Selectable address + * Second critical temperature limit + * Remote sensor type selection + +MAX6680 and MAX6681: + * Selectable address + * Remote sensor type selection + +MAX6695 and MAX6696: + * Better local resolution + * Selectable address (max6696) + * Second critical temperature limit + * Two remote sensors + +W83L771W/G + * The G variant is lead-free, otherwise similar to the W. + * Filter and alert configuration register at 0xBF + * Moving average (depending on conversion rate) + +W83L771AWG/ASG + * Successor of the W83L771W/G, same features. + * The AWG and ASG variants only differ in package format. + * Diode ideality factor configuration (remote sensor) at 0xE3 + +SA56004X: + * Better local resolution + +All temperature values are given in degrees Celsius. Resolution +is 1.0 degree for the local temperature, 0.125 degree for the remote +temperature, except for the MAX6654, MAX6657, MAX6658 and MAX6659 which have +a resolution of 0.125 degree for both temperatures. + +Each sensor has its own high and low limits, plus a critical limit. +Additionally, there is a relative hysteresis value common to both critical +values. To make life easier to user-space applications, two absolute values +are exported, one for each channel, but these values are of course linked. +Only the local hysteresis can be set from user-space, and the same delta +applies to the remote hysteresis. + +The lm90 driver will not update its values more frequently than configured with +the update_interval attribute; reading them more often will do no harm, but will +return 'old' values. + +SMBus Alert Support +------------------- + +This driver has basic support for SMBus alert. When an alert is received, +the status register is read and the faulty temperature channel is logged. + +The Analog Devices chips (ADM1032, ADT7461 and ADT7461A) and ON +Semiconductor chips (NCT1008) do not implement the SMBus alert protocol +properly so additional care is needed: the ALERT output is disabled when +an alert is received, and is re-enabled only when the alarm is gone. +Otherwise the chip would block alerts from other chips in the bus as long +as the alarm is active. + +PEC Support +----------- + +The ADM1032 is the only chip of the family which supports PEC. It does +not support PEC on all transactions though, so some care must be taken. + +When reading a register value, the PEC byte is computed and sent by the +ADM1032 chip. However, in the case of a combined transaction (SMBus Read +Byte), the ADM1032 computes the CRC value over only the second half of +the message rather than its entirety, because it thinks the first half +of the message belongs to a different transaction. As a result, the CRC +value differs from what the SMBus master expects, and all reads fail. + +For this reason, the lm90 driver will enable PEC for the ADM1032 only if +the bus supports the SMBus Send Byte and Receive Byte transaction types. +These transactions will be used to read register values, instead of +SMBus Read Byte, and PEC will work properly. + +Additionally, the ADM1032 doesn't support SMBus Send Byte with PEC. +Instead, it will try to write the PEC value to the register (because the +SMBus Send Byte transaction with PEC is similar to a Write Byte transaction +without PEC), which is not what we want. Thus, PEC is explicitly disabled +on SMBus Send Byte transactions in the lm90 driver. + +PEC on byte data transactions represents a significant increase in bandwidth +usage (+33% for writes, +25% for reads) in normal conditions. With the need +to use two SMBus transaction for reads, this overhead jumps to +50%. Worse, +two transactions will typically mean twice as much delay waiting for +transaction completion, effectively doubling the register cache refresh time. +I guess reliability comes at a price, but it's quite expensive this time. + +So, as not everyone might enjoy the slowdown, PEC is disabled by default and +can be enabled through sysfs. Just write 1 to the "pec" file and PEC will be +enabled. Write 0 to that file to disable PEC again. -- cgit v1.2.3