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counter: Add support for Intel Quadrature Encoder Peripheral

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Add support for Intel Quadrature Encoder Peripheral found on Intel
Elkhart Lake platform.

Initial implementation was done by Felipe Balbi while he was working at
Intel with later changes from Raymond Tan and me.

Co-developed-by: Felipe Balbi (Intel) <balbi@kernel.org>
Signed-off-by: Felipe Balbi (Intel) <balbi@kernel.org>
Co-developed-by: Raymond Tan <raymond.tan@intel.com>
Signed-off-by: Raymond Tan <raymond.tan@intel.com>
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Link: https://lore.kernel.org/r/20210602113259.158674-1-jarkko.nikula@linux.intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Jarkko Nikula 2021-06-02 14:32:59 +03:00 committed by Jonathan Cameron
parent 6a7e4b04df
commit b711f687a1
5 changed files with 571 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

9
Documentation/ABI/testing/sysfs-bus-counter
View file

@ -193,6 +193,15 @@ Description:
both edges:
Any state transition.
What: /sys/bus/counter/devices/counterX/countY/spike_filter_ns
KernelVersion: 5.14
Contact: linux-iio@vger.kernel.org
Description:
If the counter device supports programmable spike filter this
attribute indicates the value in nanoseconds where noise pulses
shorter or equal to configured value are ignored. Value 0 means
filter is disabled.
What: /sys/bus/counter/devices/counterX/name
KernelVersion: 5.2
Contact: linux-iio@vger.kernel.org

5
MAINTAINERS
View file

@ -9364,6 +9364,11 @@ L: linux-pm@vger.kernel.org
S: Supported
F: drivers/cpufreq/intel_pstate.c
INTEL QUADRATURE ENCODER PERIPHERAL DRIVER
M: Jarkko Nikula <jarkko.nikula@linux.intel.com>
L: linux-iio@vger.kernel.org
F: drivers/counter/intel-qep.c
INTEL RDMA RNIC DRIVER
M: Faisal Latif <faisal.latif@intel.com>
M: Shiraz Saleem <shiraz.saleem@intel.com>

10
drivers/counter/Kconfig
View file

@ -91,4 +91,14 @@ config MICROCHIP_TCB_CAPTURE
To compile this driver as a module, choose M here: the
module will be called microchip-tcb-capture.
config INTEL_QEP
tristate "Intel Quadrature Encoder Peripheral driver"
depends on PCI
help
Select this option to enable the Intel Quadrature Encoder Peripheral
driver.
To compile this driver as a module, choose M here: the module
will be called intel-qep.
endif # COUNTER

1
drivers/counter/Makefile
View file

@ -12,3 +12,4 @@ obj-$(CONFIG_STM32_LPTIMER_CNT) += stm32-lptimer-cnt.o
obj-$(CONFIG_TI_EQEP) += ti-eqep.o
obj-$(CONFIG_FTM_QUADDEC) += ftm-quaddec.o
obj-$(CONFIG_MICROCHIP_TCB_CAPTURE) += microchip-tcb-capture.o
obj-$(CONFIG_INTEL_QEP) += intel-qep.o

546
drivers/counter/intel-qep.c Normal file
View file

@ -0,0 +1,546 @@
// 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");