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authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /drivers/i2c/muxes/i2c-mux-pca9541.c
downloadlinux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz
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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.c348
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");