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author | 2023-02-21 18:24:12 -0800 | |
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committer | 2023-02-21 18:24:12 -0800 | |
commit | 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch) | |
tree | cc5c2d0a898769fd59549594fedb3ee6f84e59a0 /drivers/i2c/muxes/i2c-mux-pca9541.c | |
download | linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip |
Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
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().
...
Diffstat (limited to 'drivers/i2c/muxes/i2c-mux-pca9541.c')
-rw-r--r-- | drivers/i2c/muxes/i2c-mux-pca9541.c | 348 |
1 files changed, 348 insertions, 0 deletions
diff --git a/drivers/i2c/muxes/i2c-mux-pca9541.c b/drivers/i2c/muxes/i2c-mux-pca9541.c new file mode 100644 index 000000000..09d1d9e67 --- /dev/null +++ b/drivers/i2c/muxes/i2c-mux-pca9541.c @@ -0,0 +1,348 @@ +/* + * I2C multiplexer driver for PCA9541 bus master selector + * + * Copyright (c) 2010 Ericsson AB. + * + * Author: Guenter Roeck <linux@roeck-us.net> + * + * Derived from: + * pca954x.c + * + * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it> + * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it> + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#include <linux/bitops.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/i2c.h> +#include <linux/i2c-mux.h> +#include <linux/jiffies.h> +#include <linux/module.h> +#include <linux/slab.h> + +/* + * The PCA9541 is a bus master selector. It supports two I2C masters connected + * to a single slave bus. + * + * Before each bus transaction, a master has to acquire bus ownership. After the + * transaction is complete, bus ownership has to be released. This fits well + * into the I2C multiplexer framework, which provides select and release + * functions for this purpose. For this reason, this driver is modeled as + * single-channel I2C bus multiplexer. + * + * This driver assumes that the two bus masters are controlled by two different + * hosts. If a single host controls both masters, platform code has to ensure + * that only one of the masters is instantiated at any given time. + */ + +#define PCA9541_CONTROL 0x01 +#define PCA9541_ISTAT 0x02 + +#define PCA9541_CTL_MYBUS BIT(0) +#define PCA9541_CTL_NMYBUS BIT(1) +#define PCA9541_CTL_BUSON BIT(2) +#define PCA9541_CTL_NBUSON BIT(3) +#define PCA9541_CTL_BUSINIT BIT(4) +#define PCA9541_CTL_TESTON BIT(6) +#define PCA9541_CTL_NTESTON BIT(7) + +#define PCA9541_ISTAT_INTIN BIT(0) +#define PCA9541_ISTAT_BUSINIT BIT(1) +#define PCA9541_ISTAT_BUSOK BIT(2) +#define PCA9541_ISTAT_BUSLOST BIT(3) +#define PCA9541_ISTAT_MYTEST BIT(6) +#define PCA9541_ISTAT_NMYTEST BIT(7) + +#define BUSON (PCA9541_CTL_BUSON | PCA9541_CTL_NBUSON) +#define MYBUS (PCA9541_CTL_MYBUS | PCA9541_CTL_NMYBUS) +#define mybus(x) (!((x) & MYBUS) || ((x) & MYBUS) == MYBUS) +#define busoff(x) (!((x) & BUSON) || ((x) & BUSON) == BUSON) + +/* arbitration timeouts, in jiffies */ +#define ARB_TIMEOUT (HZ / 8) /* 125 ms until forcing bus ownership */ +#define ARB2_TIMEOUT (HZ / 4) /* 250 ms until acquisition failure */ + +/* arbitration retry delays, in us */ +#define SELECT_DELAY_SHORT 50 +#define SELECT_DELAY_LONG 1000 + +struct pca9541 { + struct i2c_client *client; + unsigned long select_timeout; + unsigned long arb_timeout; +}; + +static const struct i2c_device_id pca9541_id[] = { + {"pca9541", 0}, + {} +}; + +MODULE_DEVICE_TABLE(i2c, pca9541_id); + +#ifdef CONFIG_OF +static const struct of_device_id pca9541_of_match[] = { + { .compatible = "nxp,pca9541" }, + {} +}; +MODULE_DEVICE_TABLE(of, pca9541_of_match); +#endif + +/* + * Write to chip register. Don't use i2c_transfer()/i2c_smbus_xfer() + * as they will try to lock the adapter a second time. + */ +static int pca9541_reg_write(struct i2c_client *client, u8 command, u8 val) +{ + struct i2c_adapter *adap = client->adapter; + union i2c_smbus_data data = { .byte = val }; + + return __i2c_smbus_xfer(adap, client->addr, client->flags, + I2C_SMBUS_WRITE, command, + I2C_SMBUS_BYTE_DATA, &data); +} + +/* + * Read from chip register. Don't use i2c_transfer()/i2c_smbus_xfer() + * as they will try to lock adapter a second time. + */ +static int pca9541_reg_read(struct i2c_client *client, u8 command) +{ + struct i2c_adapter *adap = client->adapter; + union i2c_smbus_data data; + int ret; + + ret = __i2c_smbus_xfer(adap, client->addr, client->flags, + I2C_SMBUS_READ, command, + I2C_SMBUS_BYTE_DATA, &data); + + return ret ?: data.byte; +} + +/* + * Arbitration management functions + */ + +/* Release bus. Also reset NTESTON and BUSINIT if it was set. */ +static void pca9541_release_bus(struct i2c_client *client) +{ + int reg; + + reg = pca9541_reg_read(client, PCA9541_CONTROL); + if (reg >= 0 && !busoff(reg) && mybus(reg)) + pca9541_reg_write(client, PCA9541_CONTROL, + (reg & PCA9541_CTL_NBUSON) >> 1); +} + +/* + * Arbitration is defined as a two-step process. A bus master can only activate + * the slave bus if it owns it; otherwise it has to request ownership first. + * This multi-step process ensures that access contention is resolved + * gracefully. + * + * Bus Ownership Other master Action + * state requested access + * ---------------------------------------------------- + * off - yes wait for arbitration timeout or + * for other master to drop request + * off no no take ownership + * off yes no turn on bus + * on yes - done + * on no - wait for arbitration timeout or + * for other master to release bus + * + * The main contention point occurs if the slave bus is off and both masters + * request ownership at the same time. In this case, one master will turn on + * the slave bus, believing that it owns it. The other master will request + * bus ownership. Result is that the bus is turned on, and master which did + * _not_ own the slave bus before ends up owning it. + */ + +/* Control commands per PCA9541 datasheet */ +static const u8 pca9541_control[16] = { + 4, 0, 1, 5, 4, 4, 5, 5, 0, 0, 1, 1, 0, 4, 5, 1 +}; + +/* + * Channel arbitration + * + * Return values: + * <0: error + * 0 : bus not acquired + * 1 : bus acquired + */ +static int pca9541_arbitrate(struct i2c_client *client) +{ + struct i2c_mux_core *muxc = i2c_get_clientdata(client); + struct pca9541 *data = i2c_mux_priv(muxc); + int reg; + + reg = pca9541_reg_read(client, PCA9541_CONTROL); + if (reg < 0) + return reg; + + if (busoff(reg)) { + int istat; + /* + * Bus is off. Request ownership or turn it on unless + * other master requested ownership. + */ + istat = pca9541_reg_read(client, PCA9541_ISTAT); + if (!(istat & PCA9541_ISTAT_NMYTEST) + || time_is_before_eq_jiffies(data->arb_timeout)) { + /* + * Other master did not request ownership, + * or arbitration timeout expired. Take the bus. + */ + pca9541_reg_write(client, + PCA9541_CONTROL, + pca9541_control[reg & 0x0f] + | PCA9541_CTL_NTESTON); + data->select_timeout = SELECT_DELAY_SHORT; + } else { + /* + * Other master requested ownership. + * Set extra long timeout to give it time to acquire it. + */ + data->select_timeout = SELECT_DELAY_LONG * 2; + } + } else if (mybus(reg)) { + /* + * Bus is on, and we own it. We are done with acquisition. + * Reset NTESTON and BUSINIT, then return success. + */ + if (reg & (PCA9541_CTL_NTESTON | PCA9541_CTL_BUSINIT)) + pca9541_reg_write(client, + PCA9541_CONTROL, + reg & ~(PCA9541_CTL_NTESTON + | PCA9541_CTL_BUSINIT)); + return 1; + } else { + /* + * Other master owns the bus. + * If arbitration timeout has expired, force ownership. + * Otherwise request it. + */ + data->select_timeout = SELECT_DELAY_LONG; + if (time_is_before_eq_jiffies(data->arb_timeout)) { + /* Time is up, take the bus and reset it. */ + pca9541_reg_write(client, + PCA9541_CONTROL, + pca9541_control[reg & 0x0f] + | PCA9541_CTL_BUSINIT + | PCA9541_CTL_NTESTON); + } else { + /* Request bus ownership if needed */ + if (!(reg & PCA9541_CTL_NTESTON)) + pca9541_reg_write(client, + PCA9541_CONTROL, + reg | PCA9541_CTL_NTESTON); + } + } + return 0; +} + +static int pca9541_select_chan(struct i2c_mux_core *muxc, u32 chan) +{ + struct pca9541 *data = i2c_mux_priv(muxc); + struct i2c_client *client = data->client; + int ret; + unsigned long timeout = jiffies + ARB2_TIMEOUT; + /* give up after this time */ + + data->arb_timeout = jiffies + ARB_TIMEOUT; + /* force bus ownership after this time */ + + do { + ret = pca9541_arbitrate(client); + if (ret) + return ret < 0 ? ret : 0; + + if (data->select_timeout == SELECT_DELAY_SHORT) + udelay(data->select_timeout); + else + msleep(data->select_timeout / 1000); + } while (time_is_after_eq_jiffies(timeout)); + + return -ETIMEDOUT; +} + +static int pca9541_release_chan(struct i2c_mux_core *muxc, u32 chan) +{ + struct pca9541 *data = i2c_mux_priv(muxc); + struct i2c_client *client = data->client; + + pca9541_release_bus(client); + return 0; +} + +/* + * I2C init/probing/exit functions + */ +static int pca9541_probe(struct i2c_client *client) +{ + struct i2c_adapter *adap = client->adapter; + struct i2c_mux_core *muxc; + struct pca9541 *data; + int ret; + + if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE_DATA)) + return -ENODEV; + + /* + * I2C accesses are unprotected here. + * We have to lock the I2C segment before releasing the bus. + */ + i2c_lock_bus(adap, I2C_LOCK_SEGMENT); + pca9541_release_bus(client); + i2c_unlock_bus(adap, I2C_LOCK_SEGMENT); + + /* Create mux adapter */ + + muxc = i2c_mux_alloc(adap, &client->dev, 1, sizeof(*data), + I2C_MUX_ARBITRATOR, + pca9541_select_chan, pca9541_release_chan); + if (!muxc) + return -ENOMEM; + + data = i2c_mux_priv(muxc); + data->client = client; + + i2c_set_clientdata(client, muxc); + + ret = i2c_mux_add_adapter(muxc, 0, 0, 0); + if (ret) + return ret; + + dev_info(&client->dev, "registered master selector for I2C %s\n", + client->name); + + return 0; +} + +static void pca9541_remove(struct i2c_client *client) +{ + struct i2c_mux_core *muxc = i2c_get_clientdata(client); + + i2c_mux_del_adapters(muxc); +} + +static struct i2c_driver pca9541_driver = { + .driver = { + .name = "pca9541", + .of_match_table = of_match_ptr(pca9541_of_match), + }, + .probe_new = pca9541_probe, + .remove = pca9541_remove, + .id_table = pca9541_id, +}; + +module_i2c_driver(pca9541_driver); + +MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>"); +MODULE_DESCRIPTION("PCA9541 I2C master selector driver"); +MODULE_LICENSE("GPL v2"); |