aboutsummaryrefslogtreecommitdiff
path: root/drivers/pwm/sysfs.c
diff options
context:
space:
mode:
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/pwm/sysfs.c
downloadlinux-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/pwm/sysfs.c')
-rw-r--r--drivers/pwm/sysfs.c529
1 files changed, 529 insertions, 0 deletions
diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
new file mode 100644
index 000000000..e7db8e450
--- /dev/null
+++ b/drivers/pwm/sysfs.c
@@ -0,0 +1,529 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * A simple sysfs interface for the generic PWM framework
+ *
+ * Copyright (C) 2013 H Hartley Sweeten <hsweeten@visionengravers.com>
+ *
+ * Based on previous work by Lars Poeschel <poeschel@lemonage.de>
+ */
+
+#include <linux/device.h>
+#include <linux/mutex.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/kdev_t.h>
+#include <linux/pwm.h>
+
+struct pwm_export {
+ struct device child;
+ struct pwm_device *pwm;
+ struct mutex lock;
+ struct pwm_state suspend;
+};
+
+static struct pwm_export *child_to_pwm_export(struct device *child)
+{
+ return container_of(child, struct pwm_export, child);
+}
+
+static struct pwm_device *child_to_pwm_device(struct device *child)
+{
+ struct pwm_export *export = child_to_pwm_export(child);
+
+ return export->pwm;
+}
+
+static ssize_t period_show(struct device *child,
+ struct device_attribute *attr,
+ char *buf)
+{
+ const struct pwm_device *pwm = child_to_pwm_device(child);
+ struct pwm_state state;
+
+ pwm_get_state(pwm, &state);
+
+ return sysfs_emit(buf, "%llu\n", state.period);
+}
+
+static ssize_t period_store(struct device *child,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ struct pwm_export *export = child_to_pwm_export(child);
+ struct pwm_device *pwm = export->pwm;
+ struct pwm_state state;
+ u64 val;
+ int ret;
+
+ ret = kstrtou64(buf, 0, &val);
+ if (ret)
+ return ret;
+
+ mutex_lock(&export->lock);
+ pwm_get_state(pwm, &state);
+ state.period = val;
+ ret = pwm_apply_state(pwm, &state);
+ mutex_unlock(&export->lock);
+
+ return ret ? : size;
+}
+
+static ssize_t duty_cycle_show(struct device *child,
+ struct device_attribute *attr,
+ char *buf)
+{
+ const struct pwm_device *pwm = child_to_pwm_device(child);
+ struct pwm_state state;
+
+ pwm_get_state(pwm, &state);
+
+ return sysfs_emit(buf, "%llu\n", state.duty_cycle);
+}
+
+static ssize_t duty_cycle_store(struct device *child,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ struct pwm_export *export = child_to_pwm_export(child);
+ struct pwm_device *pwm = export->pwm;
+ struct pwm_state state;
+ u64 val;
+ int ret;
+
+ ret = kstrtou64(buf, 0, &val);
+ if (ret)
+ return ret;
+
+ mutex_lock(&export->lock);
+ pwm_get_state(pwm, &state);
+ state.duty_cycle = val;
+ ret = pwm_apply_state(pwm, &state);
+ mutex_unlock(&export->lock);
+
+ return ret ? : size;
+}
+
+static ssize_t enable_show(struct device *child,
+ struct device_attribute *attr,
+ char *buf)
+{
+ const struct pwm_device *pwm = child_to_pwm_device(child);
+ struct pwm_state state;
+
+ pwm_get_state(pwm, &state);
+
+ return sysfs_emit(buf, "%d\n", state.enabled);
+}
+
+static ssize_t enable_store(struct device *child,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ struct pwm_export *export = child_to_pwm_export(child);
+ struct pwm_device *pwm = export->pwm;
+ struct pwm_state state;
+ int val, ret;
+
+ ret = kstrtoint(buf, 0, &val);
+ if (ret)
+ return ret;
+
+ mutex_lock(&export->lock);
+
+ pwm_get_state(pwm, &state);
+
+ switch (val) {
+ case 0:
+ state.enabled = false;
+ break;
+ case 1:
+ state.enabled = true;
+ break;
+ default:
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ ret = pwm_apply_state(pwm, &state);
+
+unlock:
+ mutex_unlock(&export->lock);
+ return ret ? : size;
+}
+
+static ssize_t polarity_show(struct device *child,
+ struct device_attribute *attr,
+ char *buf)
+{
+ const struct pwm_device *pwm = child_to_pwm_device(child);
+ const char *polarity = "unknown";
+ struct pwm_state state;
+
+ pwm_get_state(pwm, &state);
+
+ switch (state.polarity) {
+ case PWM_POLARITY_NORMAL:
+ polarity = "normal";
+ break;
+
+ case PWM_POLARITY_INVERSED:
+ polarity = "inversed";
+ break;
+ }
+
+ return sysfs_emit(buf, "%s\n", polarity);
+}
+
+static ssize_t polarity_store(struct device *child,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ struct pwm_export *export = child_to_pwm_export(child);
+ struct pwm_device *pwm = export->pwm;
+ enum pwm_polarity polarity;
+ struct pwm_state state;
+ int ret;
+
+ if (sysfs_streq(buf, "normal"))
+ polarity = PWM_POLARITY_NORMAL;
+ else if (sysfs_streq(buf, "inversed"))
+ polarity = PWM_POLARITY_INVERSED;
+ else
+ return -EINVAL;
+
+ mutex_lock(&export->lock);
+ pwm_get_state(pwm, &state);
+ state.polarity = polarity;
+ ret = pwm_apply_state(pwm, &state);
+ mutex_unlock(&export->lock);
+
+ return ret ? : size;
+}
+
+static ssize_t capture_show(struct device *child,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct pwm_device *pwm = child_to_pwm_device(child);
+ struct pwm_capture result;
+ int ret;
+
+ ret = pwm_capture(pwm, &result, jiffies_to_msecs(HZ));
+ if (ret)
+ return ret;
+
+ return sysfs_emit(buf, "%u %u\n", result.period, result.duty_cycle);
+}
+
+static DEVICE_ATTR_RW(period);
+static DEVICE_ATTR_RW(duty_cycle);
+static DEVICE_ATTR_RW(enable);
+static DEVICE_ATTR_RW(polarity);
+static DEVICE_ATTR_RO(capture);
+
+static struct attribute *pwm_attrs[] = {
+ &dev_attr_period.attr,
+ &dev_attr_duty_cycle.attr,
+ &dev_attr_enable.attr,
+ &dev_attr_polarity.attr,
+ &dev_attr_capture.attr,
+ NULL
+};
+ATTRIBUTE_GROUPS(pwm);
+
+static void pwm_export_release(struct device *child)
+{
+ struct pwm_export *export = child_to_pwm_export(child);
+
+ kfree(export);
+}
+
+static int pwm_export_child(struct device *parent, struct pwm_device *pwm)
+{
+ struct pwm_export *export;
+ char *pwm_prop[2];
+ int ret;
+
+ if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
+ return -EBUSY;
+
+ export = kzalloc(sizeof(*export), GFP_KERNEL);
+ if (!export) {
+ clear_bit(PWMF_EXPORTED, &pwm->flags);
+ return -ENOMEM;
+ }
+
+ export->pwm = pwm;
+ mutex_init(&export->lock);
+
+ export->child.release = pwm_export_release;
+ export->child.parent = parent;
+ export->child.devt = MKDEV(0, 0);
+ export->child.groups = pwm_groups;
+ dev_set_name(&export->child, "pwm%u", pwm->hwpwm);
+
+ ret = device_register(&export->child);
+ if (ret) {
+ clear_bit(PWMF_EXPORTED, &pwm->flags);
+ put_device(&export->child);
+ export = NULL;
+ return ret;
+ }
+ pwm_prop[0] = kasprintf(GFP_KERNEL, "EXPORT=pwm%u", pwm->hwpwm);
+ pwm_prop[1] = NULL;
+ kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop);
+ kfree(pwm_prop[0]);
+
+ return 0;
+}
+
+static int pwm_unexport_match(struct device *child, void *data)
+{
+ return child_to_pwm_device(child) == data;
+}
+
+static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm)
+{
+ struct device *child;
+ char *pwm_prop[2];
+
+ if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
+ return -ENODEV;
+
+ child = device_find_child(parent, pwm, pwm_unexport_match);
+ if (!child)
+ return -ENODEV;
+
+ pwm_prop[0] = kasprintf(GFP_KERNEL, "UNEXPORT=pwm%u", pwm->hwpwm);
+ pwm_prop[1] = NULL;
+ kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop);
+ kfree(pwm_prop[0]);
+
+ /* for device_find_child() */
+ put_device(child);
+ device_unregister(child);
+ pwm_put(pwm);
+
+ return 0;
+}
+
+static ssize_t export_store(struct device *parent,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct pwm_chip *chip = dev_get_drvdata(parent);
+ struct pwm_device *pwm;
+ unsigned int hwpwm;
+ int ret;
+
+ ret = kstrtouint(buf, 0, &hwpwm);
+ if (ret < 0)
+ return ret;
+
+ if (hwpwm >= chip->npwm)
+ return -ENODEV;
+
+ pwm = pwm_request_from_chip(chip, hwpwm, "sysfs");
+ if (IS_ERR(pwm))
+ return PTR_ERR(pwm);
+
+ ret = pwm_export_child(parent, pwm);
+ if (ret < 0)
+ pwm_put(pwm);
+
+ return ret ? : len;
+}
+static DEVICE_ATTR_WO(export);
+
+static ssize_t unexport_store(struct device *parent,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct pwm_chip *chip = dev_get_drvdata(parent);
+ unsigned int hwpwm;
+ int ret;
+
+ ret = kstrtouint(buf, 0, &hwpwm);
+ if (ret < 0)
+ return ret;
+
+ if (hwpwm >= chip->npwm)
+ return -ENODEV;
+
+ ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]);
+
+ return ret ? : len;
+}
+static DEVICE_ATTR_WO(unexport);
+
+static ssize_t npwm_show(struct device *parent, struct device_attribute *attr,
+ char *buf)
+{
+ const struct pwm_chip *chip = dev_get_drvdata(parent);
+
+ return sysfs_emit(buf, "%u\n", chip->npwm);
+}
+static DEVICE_ATTR_RO(npwm);
+
+static struct attribute *pwm_chip_attrs[] = {
+ &dev_attr_export.attr,
+ &dev_attr_unexport.attr,
+ &dev_attr_npwm.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(pwm_chip);
+
+/* takes export->lock on success */
+static struct pwm_export *pwm_class_get_state(struct device *parent,
+ struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+ struct device *child;
+ struct pwm_export *export;
+
+ if (!test_bit(PWMF_EXPORTED, &pwm->flags))
+ return NULL;
+
+ child = device_find_child(parent, pwm, pwm_unexport_match);
+ if (!child)
+ return NULL;
+
+ export = child_to_pwm_export(child);
+ put_device(child); /* for device_find_child() */
+
+ mutex_lock(&export->lock);
+ pwm_get_state(pwm, state);
+
+ return export;
+}
+
+static int pwm_class_apply_state(struct pwm_export *export,
+ struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+ int ret = pwm_apply_state(pwm, state);
+
+ /* release lock taken in pwm_class_get_state */
+ mutex_unlock(&export->lock);
+
+ return ret;
+}
+
+static int pwm_class_resume_npwm(struct device *parent, unsigned int npwm)
+{
+ struct pwm_chip *chip = dev_get_drvdata(parent);
+ unsigned int i;
+ int ret = 0;
+
+ for (i = 0; i < npwm; i++) {
+ struct pwm_device *pwm = &chip->pwms[i];
+ struct pwm_state state;
+ struct pwm_export *export;
+
+ export = pwm_class_get_state(parent, pwm, &state);
+ if (!export)
+ continue;
+
+ state.enabled = export->suspend.enabled;
+ ret = pwm_class_apply_state(export, pwm, &state);
+ if (ret < 0)
+ break;
+ }
+
+ return ret;
+}
+
+static int pwm_class_suspend(struct device *parent)
+{
+ struct pwm_chip *chip = dev_get_drvdata(parent);
+ unsigned int i;
+ int ret = 0;
+
+ for (i = 0; i < chip->npwm; i++) {
+ struct pwm_device *pwm = &chip->pwms[i];
+ struct pwm_state state;
+ struct pwm_export *export;
+
+ export = pwm_class_get_state(parent, pwm, &state);
+ if (!export)
+ continue;
+
+ export->suspend = state;
+ state.enabled = false;
+ ret = pwm_class_apply_state(export, pwm, &state);
+ if (ret < 0) {
+ /*
+ * roll back the PWM devices that were disabled by
+ * this suspend function.
+ */
+ pwm_class_resume_npwm(parent, i);
+ break;
+ }
+ }
+
+ return ret;
+}
+
+static int pwm_class_resume(struct device *parent)
+{
+ struct pwm_chip *chip = dev_get_drvdata(parent);
+
+ return pwm_class_resume_npwm(parent, chip->npwm);
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(pwm_class_pm_ops, pwm_class_suspend, pwm_class_resume);
+
+static struct class pwm_class = {
+ .name = "pwm",
+ .owner = THIS_MODULE,
+ .dev_groups = pwm_chip_groups,
+ .pm = pm_sleep_ptr(&pwm_class_pm_ops),
+};
+
+static int pwmchip_sysfs_match(struct device *parent, const void *data)
+{
+ return dev_get_drvdata(parent) == data;
+}
+
+void pwmchip_sysfs_export(struct pwm_chip *chip)
+{
+ struct device *parent;
+
+ /*
+ * If device_create() fails the pwm_chip is still usable by
+ * the kernel it's just not exported.
+ */
+ parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip,
+ "pwmchip%d", chip->base);
+ if (IS_ERR(parent)) {
+ dev_warn(chip->dev,
+ "device_create failed for pwm_chip sysfs export\n");
+ }
+}
+
+void pwmchip_sysfs_unexport(struct pwm_chip *chip)
+{
+ struct device *parent;
+ unsigned int i;
+
+ parent = class_find_device(&pwm_class, NULL, chip,
+ pwmchip_sysfs_match);
+ if (!parent)
+ return;
+
+ for (i = 0; i < chip->npwm; i++) {
+ struct pwm_device *pwm = &chip->pwms[i];
+
+ if (test_bit(PWMF_EXPORTED, &pwm->flags))
+ pwm_unexport_child(parent, pwm);
+ }
+
+ put_device(parent);
+ device_unregister(parent);
+}
+
+static int __init pwm_sysfs_init(void)
+{
+ return class_register(&pwm_class);
+}
+subsys_initcall(pwm_sysfs_init);