--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel Quadrature Encoder Peripheral driver
+ *
+ * Copyright (C) 2019-2021 Intel Corporation
+ *
+ * Author: Felipe Balbi (Intel)
+ * Author: Jarkko Nikula <jarkko.nikula@linux.intel.com>
+ * Author: Raymond Tan <raymond.tan@intel.com>
+ */
+#include <linux/bitops.h>
+#include <linux/counter.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/pci.h>
+#include <linux/pm_runtime.h>
+
+#define INTEL_QEPCON 0x00
+#define INTEL_QEPFLT 0x04
+#define INTEL_QEPCOUNT 0x08
+#define INTEL_QEPMAX 0x0c
+#define INTEL_QEPWDT 0x10
+#define INTEL_QEPCAPDIV 0x14
+#define INTEL_QEPCNTR 0x18
+#define INTEL_QEPCAPBUF 0x1c
+#define INTEL_QEPINT_STAT 0x20
+#define INTEL_QEPINT_MASK 0x24
+
+/* QEPCON */
+#define INTEL_QEPCON_EN BIT(0)
+#define INTEL_QEPCON_FLT_EN BIT(1)
+#define INTEL_QEPCON_EDGE_A BIT(2)
+#define INTEL_QEPCON_EDGE_B BIT(3)
+#define INTEL_QEPCON_EDGE_INDX BIT(4)
+#define INTEL_QEPCON_SWPAB BIT(5)
+#define INTEL_QEPCON_OP_MODE BIT(6)
+#define INTEL_QEPCON_PH_ERR BIT(7)
+#define INTEL_QEPCON_COUNT_RST_MODE BIT(8)
+#define INTEL_QEPCON_INDX_GATING_MASK GENMASK(10, 9)
+#define INTEL_QEPCON_INDX_GATING(n) (((n) & 3) << 9)
+#define INTEL_QEPCON_INDX_PAL_PBL INTEL_QEPCON_INDX_GATING(0)
+#define INTEL_QEPCON_INDX_PAL_PBH INTEL_QEPCON_INDX_GATING(1)
+#define INTEL_QEPCON_INDX_PAH_PBL INTEL_QEPCON_INDX_GATING(2)
+#define INTEL_QEPCON_INDX_PAH_PBH INTEL_QEPCON_INDX_GATING(3)
+#define INTEL_QEPCON_CAP_MODE BIT(11)
+#define INTEL_QEPCON_FIFO_THRE_MASK GENMASK(14, 12)
+#define INTEL_QEPCON_FIFO_THRE(n) ((((n) - 1) & 7) << 12)
+#define INTEL_QEPCON_FIFO_EMPTY BIT(15)
+
+/* QEPFLT */
+#define INTEL_QEPFLT_MAX_COUNT(n) ((n) & 0x1fffff)
+
+/* QEPINT */
+#define INTEL_QEPINT_FIFOCRIT BIT(5)
+#define INTEL_QEPINT_FIFOENTRY BIT(4)
+#define INTEL_QEPINT_QEPDIR BIT(3)
+#define INTEL_QEPINT_QEPRST_UP BIT(2)
+#define INTEL_QEPINT_QEPRST_DOWN BIT(1)
+#define INTEL_QEPINT_WDT BIT(0)
+
+#define INTEL_QEPINT_MASK_ALL GENMASK(5, 0)
+
+#define INTEL_QEP_CLK_PERIOD_NS 10
+
+#define INTEL_QEP_COUNTER_EXT_RW(_name) \
+{ \
+ .name = #_name, \
+ .read = _name##_read, \
+ .write = _name##_write, \
+}
+
+struct intel_qep {
+ struct counter_device counter;
+ struct mutex lock;
+ struct device *dev;
+ void __iomem *regs;
+ bool enabled;
+ /* Context save registers */
+ u32 qepcon;
+ u32 qepflt;
+ u32 qepmax;
+};
+
+static inline u32 intel_qep_readl(struct intel_qep *qep, u32 offset)
+{
+ return readl(qep->regs + offset);
+}
+
+static inline void intel_qep_writel(struct intel_qep *qep,
+ u32 offset, u32 value)
+{
+ writel(value, qep->regs + offset);
+}
+
+static void intel_qep_init(struct intel_qep *qep)
+{
+ u32 reg;
+
+ reg = intel_qep_readl(qep, INTEL_QEPCON);
+ reg &= ~INTEL_QEPCON_EN;
+ intel_qep_writel(qep, INTEL_QEPCON, reg);
+ qep->enabled = false;
+ /*
+ * Make sure peripheral is disabled by flushing the write with
+ * a dummy read
+ */
+ reg = intel_qep_readl(qep, INTEL_QEPCON);
+
+ reg &= ~(INTEL_QEPCON_OP_MODE | INTEL_QEPCON_FLT_EN);
+ reg |= INTEL_QEPCON_EDGE_A | INTEL_QEPCON_EDGE_B |
+ INTEL_QEPCON_EDGE_INDX | INTEL_QEPCON_COUNT_RST_MODE;
+ intel_qep_writel(qep, INTEL_QEPCON, reg);
+ intel_qep_writel(qep, INTEL_QEPINT_MASK, INTEL_QEPINT_MASK_ALL);
+}
+
+static int intel_qep_count_read(struct counter_device *counter,
+ struct counter_count *count,
+ unsigned long *val)
+{
+ struct intel_qep *const qep = counter->priv;
+
+ pm_runtime_get_sync(qep->dev);
+ *val = intel_qep_readl(qep, INTEL_QEPCOUNT);
+ pm_runtime_put(qep->dev);
+
+ return 0;
+}
+
+static const enum counter_count_function intel_qep_count_functions[] = {
+ COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
+};
+
+static int intel_qep_function_get(struct counter_device *counter,
+ struct counter_count *count,
+ size_t *function)
+{
+ *function = 0;
+
+ return 0;
+}
+
+static const enum counter_synapse_action intel_qep_synapse_actions[] = {
+ COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
+};
+
+static int intel_qep_action_get(struct counter_device *counter,
+ struct counter_count *count,
+ struct counter_synapse *synapse,
+ size_t *action)
+{
+ *action = 0;
+ return 0;
+}
+
+static const struct counter_ops intel_qep_counter_ops = {
+ .count_read = intel_qep_count_read,
+ .function_get = intel_qep_function_get,
+ .action_get = intel_qep_action_get,
+};
+
+#define INTEL_QEP_SIGNAL(_id, _name) { \
+ .id = (_id), \
+ .name = (_name), \
+}
+
+static struct counter_signal intel_qep_signals[] = {
+ INTEL_QEP_SIGNAL(0, "Phase A"),
+ INTEL_QEP_SIGNAL(1, "Phase B"),
+ INTEL_QEP_SIGNAL(2, "Index"),
+};
+
+#define INTEL_QEP_SYNAPSE(_signal_id) { \
+ .actions_list = intel_qep_synapse_actions, \
+ .num_actions = ARRAY_SIZE(intel_qep_synapse_actions), \
+ .signal = &intel_qep_signals[(_signal_id)], \
+}
+
+static struct counter_synapse intel_qep_count_synapses[] = {
+ INTEL_QEP_SYNAPSE(0),
+ INTEL_QEP_SYNAPSE(1),
+ INTEL_QEP_SYNAPSE(2),
+};
+
+static ssize_t ceiling_read(struct counter_device *counter,
+ struct counter_count *count,
+ void *priv, char *buf)
+{
+ struct intel_qep *qep = counter->priv;
+ u32 reg;
+
+ pm_runtime_get_sync(qep->dev);
+ reg = intel_qep_readl(qep, INTEL_QEPMAX);
+ pm_runtime_put(qep->dev);
+
+ return sysfs_emit(buf, "%u\n", reg);
+}
+
+static ssize_t ceiling_write(struct counter_device *counter,
+ struct counter_count *count,
+ void *priv, const char *buf, size_t len)
+{
+ struct intel_qep *qep = counter->priv;
+ u32 max;
+ int ret;
+
+ ret = kstrtou32(buf, 0, &max);
+ if (ret < 0)
+ return ret;
+
+ mutex_lock(&qep->lock);
+ if (qep->enabled) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ pm_runtime_get_sync(qep->dev);
+ intel_qep_writel(qep, INTEL_QEPMAX, max);
+ pm_runtime_put(qep->dev);
+ ret = len;
+
+out:
+ mutex_unlock(&qep->lock);
+ return ret;
+}
+
+static ssize_t enable_read(struct counter_device *counter,
+ struct counter_count *count,
+ void *priv, char *buf)
+{
+ struct intel_qep *qep = counter->priv;
+
+ return sysfs_emit(buf, "%u\n", qep->enabled);
+}
+
+static ssize_t enable_write(struct counter_device *counter,
+ struct counter_count *count,
+ void *priv, const char *buf, size_t len)
+{
+ struct intel_qep *qep = counter->priv;
+ u32 reg;
+ bool val, changed;
+ int ret;
+
+ ret = kstrtobool(buf, &val);
+ if (ret)
+ return ret;
+
+ mutex_lock(&qep->lock);
+ changed = val ^ qep->enabled;
+ if (!changed)
+ goto out;
+
+ pm_runtime_get_sync(qep->dev);
+ reg = intel_qep_readl(qep, INTEL_QEPCON);
+ if (val) {
+ /* Enable peripheral and keep runtime PM always on */
+ reg |= INTEL_QEPCON_EN;
+ pm_runtime_get_noresume(qep->dev);
+ } else {
+ /* Let runtime PM be idle and disable peripheral */
+ pm_runtime_put_noidle(qep->dev);
+ reg &= ~INTEL_QEPCON_EN;
+ }
+ intel_qep_writel(qep, INTEL_QEPCON, reg);
+ pm_runtime_put(qep->dev);
+ qep->enabled = val;
+
+out:
+ mutex_unlock(&qep->lock);
+ return len;
+}
+
+static ssize_t spike_filter_ns_read(struct counter_device *counter,
+ struct counter_count *count,
+ void *priv, char *buf)
+{
+ struct intel_qep *qep = counter->priv;
+ u32 reg;
+
+ pm_runtime_get_sync(qep->dev);
+ reg = intel_qep_readl(qep, INTEL_QEPCON);
+ if (!(reg & INTEL_QEPCON_FLT_EN)) {
+ pm_runtime_put(qep->dev);
+ return sysfs_emit(buf, "0\n");
+ }
+ reg = INTEL_QEPFLT_MAX_COUNT(intel_qep_readl(qep, INTEL_QEPFLT));
+ pm_runtime_put(qep->dev);
+
+ return sysfs_emit(buf, "%u\n", (reg + 2) * INTEL_QEP_CLK_PERIOD_NS);
+}
+
+static ssize_t spike_filter_ns_write(struct counter_device *counter,
+ struct counter_count *count,
+ void *priv, const char *buf, size_t len)
+{
+ struct intel_qep *qep = counter->priv;
+ u32 reg, length;
+ bool enable;
+ int ret;
+
+ ret = kstrtou32(buf, 0, &length);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * Spike filter length is (MAX_COUNT + 2) clock periods.
+ * Disable filter when userspace writes 0, enable for valid
+ * nanoseconds values and error out otherwise.
+ */
+ length /= INTEL_QEP_CLK_PERIOD_NS;
+ if (length == 0) {
+ enable = false;
+ length = 0;
+ } else if (length >= 2) {
+ enable = true;
+ length -= 2;
+ } else {
+ return -EINVAL;
+ }
+
+ if (length > INTEL_QEPFLT_MAX_COUNT(length))
+ return -EINVAL;
+
+ mutex_lock(&qep->lock);
+ if (qep->enabled) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ pm_runtime_get_sync(qep->dev);
+ reg = intel_qep_readl(qep, INTEL_QEPCON);
+ if (enable)
+ reg |= INTEL_QEPCON_FLT_EN;
+ else
+ reg &= ~INTEL_QEPCON_FLT_EN;
+ intel_qep_writel(qep, INTEL_QEPFLT, length);
+ intel_qep_writel(qep, INTEL_QEPCON, reg);
+ pm_runtime_put(qep->dev);
+ ret = len;
+
+out:
+ mutex_unlock(&qep->lock);
+ return ret;
+}
+
+static ssize_t preset_enable_read(struct counter_device *counter,
+ struct counter_count *count,
+ void *priv, char *buf)
+{
+ struct intel_qep *qep = counter->priv;
+ u32 reg;
+
+ pm_runtime_get_sync(qep->dev);
+ reg = intel_qep_readl(qep, INTEL_QEPCON);
+ pm_runtime_put(qep->dev);
+ return sysfs_emit(buf, "%u\n", !(reg & INTEL_QEPCON_COUNT_RST_MODE));
+}
+
+static ssize_t preset_enable_write(struct counter_device *counter,
+ struct counter_count *count,
+ void *priv, const char *buf, size_t len)
+{
+ struct intel_qep *qep = counter->priv;
+ u32 reg;
+ bool val;
+ int ret;
+
+ ret = kstrtobool(buf, &val);
+ if (ret)
+ return ret;
+
+ mutex_lock(&qep->lock);
+ if (qep->enabled) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ pm_runtime_get_sync(qep->dev);
+ reg = intel_qep_readl(qep, INTEL_QEPCON);
+ if (val)
+ reg &= ~INTEL_QEPCON_COUNT_RST_MODE;
+ else
+ reg |= INTEL_QEPCON_COUNT_RST_MODE;
+
+ intel_qep_writel(qep, INTEL_QEPCON, reg);
+ pm_runtime_put(qep->dev);
+ ret = len;
+
+out:
+ mutex_unlock(&qep->lock);
+
+ return ret;
+}
+
+static const struct counter_count_ext intel_qep_count_ext[] = {
+ INTEL_QEP_COUNTER_EXT_RW(ceiling),
+ INTEL_QEP_COUNTER_EXT_RW(enable),
+ INTEL_QEP_COUNTER_EXT_RW(spike_filter_ns),
+ INTEL_QEP_COUNTER_EXT_RW(preset_enable)
+};
+
+static struct counter_count intel_qep_counter_count[] = {
+ {
+ .id = 0,
+ .name = "Channel 1 Count",
+ .functions_list = intel_qep_count_functions,
+ .num_functions = ARRAY_SIZE(intel_qep_count_functions),
+ .synapses = intel_qep_count_synapses,
+ .num_synapses = ARRAY_SIZE(intel_qep_count_synapses),
+ .ext = intel_qep_count_ext,
+ .num_ext = ARRAY_SIZE(intel_qep_count_ext),
+ },
+};
+
+static int intel_qep_probe(struct pci_dev *pci, const struct pci_device_id *id)
+{
+ struct intel_qep *qep;
+ struct device *dev = &pci->dev;
+ void __iomem *regs;
+ int ret;
+
+ qep = devm_kzalloc(dev, sizeof(*qep), GFP_KERNEL);
+ if (!qep)
+ return -ENOMEM;
+
+ ret = pcim_enable_device(pci);
+ if (ret)
+ return ret;
+
+ pci_set_master(pci);
+
+ ret = pcim_iomap_regions(pci, BIT(0), pci_name(pci));
+ if (ret)
+ return ret;
+
+ regs = pcim_iomap_table(pci)[0];
+ if (!regs)
+ return -ENOMEM;
+
+ qep->dev = dev;
+ qep->regs = regs;
+ mutex_init(&qep->lock);
+
+ intel_qep_init(qep);
+ pci_set_drvdata(pci, qep);
+
+ qep->counter.name = pci_name(pci);
+ qep->counter.parent = dev;
+ qep->counter.ops = &intel_qep_counter_ops;
+ qep->counter.counts = intel_qep_counter_count;
+ qep->counter.num_counts = ARRAY_SIZE(intel_qep_counter_count);
+ qep->counter.signals = intel_qep_signals;
+ qep->counter.num_signals = ARRAY_SIZE(intel_qep_signals);
+ qep->counter.priv = qep;
+ qep->enabled = false;
+
+ pm_runtime_put(dev);
+ pm_runtime_allow(dev);
+
+ return devm_counter_register(&pci->dev, &qep->counter);
+}
+
+static void intel_qep_remove(struct pci_dev *pci)
+{
+ struct intel_qep *qep = pci_get_drvdata(pci);
+ struct device *dev = &pci->dev;
+
+ pm_runtime_forbid(dev);
+ if (!qep->enabled)
+ pm_runtime_get(dev);
+
+ intel_qep_writel(qep, INTEL_QEPCON, 0);
+}
+
+#ifdef CONFIG_PM
+static int intel_qep_suspend(struct device *dev)
+{
+ struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
+ struct intel_qep *qep = pci_get_drvdata(pdev);
+
+ qep->qepcon = intel_qep_readl(qep, INTEL_QEPCON);
+ qep->qepflt = intel_qep_readl(qep, INTEL_QEPFLT);
+ qep->qepmax = intel_qep_readl(qep, INTEL_QEPMAX);
+
+ return 0;
+}
+
+static int intel_qep_resume(struct device *dev)
+{
+ struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
+ struct intel_qep *qep = pci_get_drvdata(pdev);
+
+ /*
+ * Make sure peripheral is disabled when restoring registers and
+ * control register bits that are writable only when the peripheral
+ * is disabled
+ */
+ intel_qep_writel(qep, INTEL_QEPCON, 0);
+ intel_qep_readl(qep, INTEL_QEPCON);
+
+ intel_qep_writel(qep, INTEL_QEPFLT, qep->qepflt);
+ intel_qep_writel(qep, INTEL_QEPMAX, qep->qepmax);
+ intel_qep_writel(qep, INTEL_QEPINT_MASK, INTEL_QEPINT_MASK_ALL);
+
+ /* Restore all other control register bits except enable status */
+ intel_qep_writel(qep, INTEL_QEPCON, qep->qepcon & ~INTEL_QEPCON_EN);
+ intel_qep_readl(qep, INTEL_QEPCON);
+
+ /* Restore enable status */
+ intel_qep_writel(qep, INTEL_QEPCON, qep->qepcon);
+
+ return 0;
+}
+#endif
+
+static UNIVERSAL_DEV_PM_OPS(intel_qep_pm_ops,
+ intel_qep_suspend, intel_qep_resume, NULL);
+
+static const struct pci_device_id intel_qep_id_table[] = {
+ /* EHL */
+ { PCI_VDEVICE(INTEL, 0x4bc3), },
+ { PCI_VDEVICE(INTEL, 0x4b81), },
+ { PCI_VDEVICE(INTEL, 0x4b82), },
+ { PCI_VDEVICE(INTEL, 0x4b83), },
+ { } /* Terminating Entry */
+};
+MODULE_DEVICE_TABLE(pci, intel_qep_id_table);
+
+static struct pci_driver intel_qep_driver = {
+ .name = "intel-qep",
+ .id_table = intel_qep_id_table,
+ .probe = intel_qep_probe,
+ .remove = intel_qep_remove,
+ .driver = {
+ .pm = &intel_qep_pm_ops,
+ }
+};
+
+module_pci_driver(intel_qep_driver);
+
+MODULE_AUTHOR("Felipe Balbi (Intel)");
+MODULE_AUTHOR("Jarkko Nikula <jarkko.nikula@linux.intel.com>");
+MODULE_AUTHOR("Raymond Tan <raymond.tan@intel.com>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Intel Quadrature Encoder Peripheral driver");
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