[PATCH v3 3/6] counter: new TI eQEP driver
From: David Lechner
Date: Sun Sep 01 2019 - 18:59:04 EST
This adds a new counter driver for the Texas Instruments Enhanced
Quadrature Encoder Pulse (eQEP) module.
Only very basic functionality is currently implemented - only enough to
be able to read the position. The actual device has many more features
which can be added to the driver on an as-needed basis.
It is not possible to read the QEPA/B signal values in hardware, so
that feature is omitted.
The TI_PWMSS kernel option is selected in Kconfig to enable the parent
bus, which is needed for power management.
Signed-off-by: David Lechner <david@xxxxxxxxxxxxxx>
---
v3 changes:
- Fixed ordering of pm runtime disable
- Added comment explaining where pm runtime is handled
- Dropped initialization of .action in ti_eqep_position_synapses
v2 changes:
- Dropped unused index and strobe signals
- Added synapses and actions
- Fixed base in of kstrtouint()
- Clarifications in commit message
MAINTAINERS | 6 +
drivers/bus/Kconfig | 2 +-
drivers/counter/Kconfig | 11 +
drivers/counter/Makefile | 1 +
drivers/counter/ti-eqep.c | 473 ++++++++++++++++++++++++++++++++++++++
5 files changed, 492 insertions(+), 1 deletion(-)
create mode 100644 drivers/counter/ti-eqep.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 783569e3c4b4..53c28d52964c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16014,6 +16014,12 @@ S: Maintained
F: drivers/media/platform/davinci/
F: include/media/davinci/
+TI ENHANCED QUADRATURE ENCODER PULSE (eQEP) DRIVER
+R: David Lechner <david@xxxxxxxxxxxxxx>
+L: linux-iio@xxxxxxxxxxxxxxx
+F: Documentation/devicetree/bindings/counter/ti-eqep.yaml
+F: drivers/counter/ti-eqep.c
+
TI ETHERNET SWITCH DRIVER (CPSW)
R: Grygorii Strashko <grygorii.strashko@xxxxxx>
L: linux-omap@xxxxxxxxxxxxxxx
diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
index 4eeb15839ce0..04db7fce4604 100644
--- a/drivers/bus/Kconfig
+++ b/drivers/bus/Kconfig
@@ -142,7 +142,7 @@ config TEGRA_GMI
config TI_PWMSS
bool
- default y if (ARCH_OMAP2PLUS) && (PWM_TIECAP || PWM_TIEHRPWM)
+ default y if (ARCH_OMAP2PLUS) && (PWM_TIECAP || PWM_TIEHRPWM || TI_EQEP)
help
PWM Subsystem driver support for AM33xx SOC.
diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
index 2967d0a9ff91..c80fa76bb531 100644
--- a/drivers/counter/Kconfig
+++ b/drivers/counter/Kconfig
@@ -49,6 +49,17 @@ config STM32_LPTIMER_CNT
To compile this driver as a module, choose M here: the
module will be called stm32-lptimer-cnt.
+config TI_EQEP
+ tristate "TI eQEP counter driver"
+ depends on (SOC_AM33XX || COMPILE_TEST)
+ select REGMAP_MMIO
+ help
+ Select this option to enable the Texas Instruments Enhanced Quadrature
+ Encoder Pulse (eQEP) counter driver.
+
+ To compile this driver as a module, choose M here: the module will be
+ called ti-eqep.
+
config FTM_QUADDEC
tristate "Flex Timer Module Quadrature decoder driver"
depends on HAS_IOMEM && OF
diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile
index 40d35522937d..55142d1f4c43 100644
--- a/drivers/counter/Makefile
+++ b/drivers/counter/Makefile
@@ -8,4 +8,5 @@ obj-$(CONFIG_COUNTER) += counter.o
obj-$(CONFIG_104_QUAD_8) += 104-quad-8.o
obj-$(CONFIG_STM32_TIMER_CNT) += stm32-timer-cnt.o
obj-$(CONFIG_STM32_LPTIMER_CNT) += stm32-lptimer-cnt.o
+obj-$(CONFIG_TI_EQEP) += ti-eqep.o
obj-$(CONFIG_FTM_QUADDEC) += ftm-quaddec.o
diff --git a/drivers/counter/ti-eqep.c b/drivers/counter/ti-eqep.c
new file mode 100644
index 000000000000..4b3ef2449c06
--- /dev/null
+++ b/drivers/counter/ti-eqep.c
@@ -0,0 +1,473 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2019 David Lechner <david@xxxxxxxxxxxxxx>
+ *
+ * Counter driver for Texas Instruments Enhanced Quadrature Encoder Pulse (eQEP)
+ */
+
+#include <linux/bitops.h>
+#include <linux/counter.h>
+#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+
+/* 32-bit registers */
+#define QPOSCNT 0x0
+#define QPOSINIT 0x4
+#define QPOSMAX 0x8
+#define QPOSCMP 0xc
+#define QPOSILAT 0x10
+#define QPOSSLAT 0x14
+#define QPOSLAT 0x18
+#define QUTMR 0x1c
+#define QUPRD 0x20
+
+/* 16-bit registers */
+#define QWDTMR 0x0 /* 0x24 */
+#define QWDPRD 0x2 /* 0x26 */
+#define QDECCTL 0x4 /* 0x28 */
+#define QEPCTL 0x6 /* 0x2a */
+#define QCAPCTL 0x8 /* 0x2c */
+#define QPOSCTL 0xa /* 0x2e */
+#define QEINT 0xc /* 0x30 */
+#define QFLG 0xe /* 0x32 */
+#define QCLR 0x10 /* 0x34 */
+#define QFRC 0x12 /* 0x36 */
+#define QEPSTS 0x14 /* 0x38 */
+#define QCTMR 0x16 /* 0x3a */
+#define QCPRD 0x18 /* 0x3c */
+#define QCTMRLAT 0x1a /* 0x3e */
+#define QCPRDLAT 0x1c /* 0x40 */
+
+#define QDECCTL_QSRC_SHIFT 14
+#define QDECCTL_QSRC GENMASK(15, 14)
+#define QDECCTL_SOEN BIT(13)
+#define QDECCTL_SPSEL BIT(12)
+#define QDECCTL_XCR BIT(11)
+#define QDECCTL_SWAP BIT(10)
+#define QDECCTL_IGATE BIT(9)
+#define QDECCTL_QAP BIT(8)
+#define QDECCTL_QBP BIT(7)
+#define QDECCTL_QIP BIT(6)
+#define QDECCTL_QSP BIT(5)
+
+#define QEPCTL_FREE_SOFT GENMASK(15, 14)
+#define QEPCTL_PCRM GENMASK(13, 12)
+#define QEPCTL_SEI GENMASK(11, 10)
+#define QEPCTL_IEI GENMASK(9, 8)
+#define QEPCTL_SWI BIT(7)
+#define QEPCTL_SEL BIT(6)
+#define QEPCTL_IEL GENMASK(5, 4)
+#define QEPCTL_PHEN BIT(3)
+#define QEPCTL_QCLM BIT(2)
+#define QEPCTL_UTE BIT(1)
+#define QEPCTL_WDE BIT(0)
+
+/* EQEP Inputs */
+enum {
+ TI_EQEP_SIGNAL_QEPA, /* QEPA/XCLK */
+ TI_EQEP_SIGNAL_QEPB, /* QEPB/XDIR */
+};
+
+/* Position Counter Input Modes */
+enum {
+ TI_EQEP_COUNT_FUNC_QUAD_COUNT,
+ TI_EQEP_COUNT_FUNC_DIR_COUNT,
+ TI_EQEP_COUNT_FUNC_UP_COUNT,
+ TI_EQEP_COUNT_FUNC_DOWN_COUNT,
+};
+
+enum {
+ TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES,
+ TI_EQEP_SYNAPSE_ACTION_RISING_EDGE,
+ TI_EQEP_SYNAPSE_ACTION_NONE,
+};
+
+struct ti_eqep_cnt {
+ struct counter_device counter;
+ struct regmap *regmap32;
+ struct regmap *regmap16;
+};
+
+static int ti_eqep_count_read(struct counter_device *counter,
+ struct counter_count *count,
+ struct counter_count_read_value *val)
+{
+ struct ti_eqep_cnt *priv = counter->priv;
+ u32 cnt;
+
+ regmap_read(priv->regmap32, QPOSCNT, &cnt);
+ counter_count_read_value_set(val, COUNTER_COUNT_POSITION, &cnt);
+
+ return 0;
+}
+
+static int ti_eqep_count_write(struct counter_device *counter,
+ struct counter_count *count,
+ struct counter_count_write_value *val)
+{
+ struct ti_eqep_cnt *priv = counter->priv;
+ u32 cnt, max;
+ int err;
+
+ err = counter_count_write_value_get(&cnt, COUNTER_COUNT_POSITION, val);
+ if (err)
+ return err;
+
+ regmap_read(priv->regmap32, QPOSMAX, &max);
+ if (cnt > max)
+ return -EINVAL;
+
+ return regmap_write(priv->regmap32, QPOSCNT, cnt);
+}
+
+static int ti_eqep_function_get(struct counter_device *counter,
+ struct counter_count *count, size_t *function)
+{
+ struct ti_eqep_cnt *priv = counter->priv;
+ u32 qdecctl;
+
+ regmap_read(priv->regmap16, QDECCTL, &qdecctl);
+ *function = (qdecctl & QDECCTL_QSRC) >> QDECCTL_QSRC_SHIFT;
+
+ return 0;
+}
+
+static int ti_eqep_function_set(struct counter_device *counter,
+ struct counter_count *count, size_t function)
+{
+ struct ti_eqep_cnt *priv = counter->priv;
+
+ return regmap_write_bits(priv->regmap16, QDECCTL, QDECCTL_QSRC,
+ function << QDECCTL_QSRC_SHIFT);
+}
+
+static int ti_eqep_action_get(struct counter_device *counter,
+ struct counter_count *count,
+ struct counter_synapse *synapse, size_t *action)
+{
+ struct ti_eqep_cnt *priv = counter->priv;
+ size_t function;
+ u32 qdecctl;
+ int err;
+
+ err = ti_eqep_function_get(counter, count, &function);
+ if (err)
+ return err;
+
+ switch (function) {
+ case TI_EQEP_COUNT_FUNC_QUAD_COUNT:
+ /* In quadrature mode, the rising and falling edge of both
+ * QEPA and QEPB trigger QCLK.
+ */
+ *action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
+ break;
+ case TI_EQEP_COUNT_FUNC_DIR_COUNT:
+ /* In direction-count mode only rising edge of QEPA is counted
+ * and QEPB gives direction.
+ */
+ switch (synapse->signal->id) {
+ case TI_EQEP_SIGNAL_QEPA:
+ *action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
+ break;
+ default:
+ *action = TI_EQEP_SYNAPSE_ACTION_NONE;
+ break;
+ }
+ break;
+ case TI_EQEP_COUNT_FUNC_UP_COUNT:
+ case TI_EQEP_COUNT_FUNC_DOWN_COUNT:
+ /* In up/down-count modes only QEPA is counted and QEPB is not
+ * used.
+ */
+ switch (synapse->signal->id) {
+ case TI_EQEP_SIGNAL_QEPA:
+ err = regmap_read(priv->regmap16, QDECCTL, &qdecctl);
+ if (err)
+ return err;
+
+ if (qdecctl & QDECCTL_XCR)
+ *action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
+ else
+ *action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
+ break;
+ default:
+ *action = TI_EQEP_SYNAPSE_ACTION_NONE;
+ break;
+ }
+ break;
+ }
+
+ return 0;
+}
+
+static const struct counter_ops ti_eqep_counter_ops = {
+ .count_read = ti_eqep_count_read,
+ .count_write = ti_eqep_count_write,
+ .function_get = ti_eqep_function_get,
+ .function_set = ti_eqep_function_set,
+ .action_get = ti_eqep_action_get,
+};
+
+static ssize_t ti_eqep_position_ceiling_read(struct counter_device *counter,
+ struct counter_count *count,
+ void *ext_priv, char *buf)
+{
+ struct ti_eqep_cnt *priv = counter->priv;
+ u32 qposmax;
+
+ regmap_read(priv->regmap32, QPOSMAX, &qposmax);
+
+ return sprintf(buf, "%u\n", qposmax);
+}
+
+static ssize_t ti_eqep_position_ceiling_write(struct counter_device *counter,
+ struct counter_count *count,
+ void *ext_priv, const char *buf,
+ size_t len)
+{
+ struct ti_eqep_cnt *priv = counter->priv;
+ int err;
+ u32 res;
+
+ err = kstrtouint(buf, 0, &res);
+ if (err < 0)
+ return err;
+
+ regmap_write(priv->regmap32, QPOSMAX, res);
+
+ return len;
+}
+
+static ssize_t ti_eqep_position_floor_read(struct counter_device *counter,
+ struct counter_count *count,
+ void *ext_priv, char *buf)
+{
+ struct ti_eqep_cnt *priv = counter->priv;
+ u32 qposinit;
+
+ regmap_read(priv->regmap32, QPOSINIT, &qposinit);
+
+ return sprintf(buf, "%u\n", qposinit);
+}
+
+static ssize_t ti_eqep_position_floor_write(struct counter_device *counter,
+ struct counter_count *count,
+ void *ext_priv, const char *buf,
+ size_t len)
+{
+ struct ti_eqep_cnt *priv = counter->priv;
+ int err;
+ u32 res;
+
+ err = kstrtouint(buf, 0, &res);
+ if (err < 0)
+ return err;
+
+ regmap_write(priv->regmap32, QPOSINIT, res);
+
+ return len;
+}
+
+static ssize_t ti_eqep_position_enable_read(struct counter_device *counter,
+ struct counter_count *count,
+ void *ext_priv, char *buf)
+{
+ struct ti_eqep_cnt *priv = counter->priv;
+ u32 qepctl;
+
+ regmap_read(priv->regmap16, QEPCTL, &qepctl);
+
+ return sprintf(buf, "%u\n", !!(qepctl & QEPCTL_PHEN));
+}
+
+static ssize_t ti_eqep_position_enable_write(struct counter_device *counter,
+ struct counter_count *count,
+ void *ext_priv, const char *buf,
+ size_t len)
+{
+ struct ti_eqep_cnt *priv = counter->priv;
+ int err;
+ bool res;
+
+ err = kstrtobool(buf, &res);
+ if (err < 0)
+ return err;
+
+ regmap_write_bits(priv->regmap16, QEPCTL, QEPCTL_PHEN, res ? -1 : 0);
+
+ return len;
+}
+
+static struct counter_count_ext ti_eqep_position_ext[] = {
+ {
+ .name = "ceiling",
+ .read = ti_eqep_position_ceiling_read,
+ .write = ti_eqep_position_ceiling_write,
+ },
+ {
+ .name = "floor",
+ .read = ti_eqep_position_floor_read,
+ .write = ti_eqep_position_floor_write,
+ },
+ {
+ .name = "enable",
+ .read = ti_eqep_position_enable_read,
+ .write = ti_eqep_position_enable_write,
+ },
+};
+
+static struct counter_signal ti_eqep_signals[] = {
+ [TI_EQEP_SIGNAL_QEPA] = {
+ .id = TI_EQEP_SIGNAL_QEPA,
+ .name = "QEPA"
+ },
+ [TI_EQEP_SIGNAL_QEPB] = {
+ .id = TI_EQEP_SIGNAL_QEPB,
+ .name = "QEPB"
+ },
+};
+
+static const enum counter_count_function ti_eqep_position_functions[] = {
+ [TI_EQEP_COUNT_FUNC_QUAD_COUNT] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
+ [TI_EQEP_COUNT_FUNC_DIR_COUNT] = COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
+ [TI_EQEP_COUNT_FUNC_UP_COUNT] = COUNTER_COUNT_FUNCTION_INCREASE,
+ [TI_EQEP_COUNT_FUNC_DOWN_COUNT] = COUNTER_COUNT_FUNCTION_DECREASE,
+};
+
+static const enum counter_synapse_action ti_eqep_position_synapse_actions[] = {
+ [TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
+ [TI_EQEP_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
+ [TI_EQEP_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
+};
+
+static struct counter_synapse ti_eqep_position_synapses[] = {
+ {
+ .actions_list = ti_eqep_position_synapse_actions,
+ .num_actions = ARRAY_SIZE(ti_eqep_position_synapse_actions),
+ .signal = &ti_eqep_signals[TI_EQEP_SIGNAL_QEPA],
+ },
+ {
+ .actions_list = ti_eqep_position_synapse_actions,
+ .num_actions = ARRAY_SIZE(ti_eqep_position_synapse_actions),
+ .signal = &ti_eqep_signals[TI_EQEP_SIGNAL_QEPB],
+ },
+};
+
+static struct counter_count ti_eqep_counts[] = {
+ {
+ .id = 0,
+ .name = "QPOSCNT",
+ .functions_list = ti_eqep_position_functions,
+ .num_functions = ARRAY_SIZE(ti_eqep_position_functions),
+ .synapses = ti_eqep_position_synapses,
+ .num_synapses = ARRAY_SIZE(ti_eqep_position_synapses),
+ .ext = ti_eqep_position_ext,
+ .num_ext = ARRAY_SIZE(ti_eqep_position_ext),
+ },
+};
+
+static const struct regmap_config ti_eqep_regmap32_config = {
+ .name = "32-bit",
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = 4,
+ .max_register = 0x24,
+};
+
+static const struct regmap_config ti_eqep_regmap16_config = {
+ .name = "16-bit",
+ .reg_bits = 16,
+ .val_bits = 16,
+ .reg_stride = 2,
+ .max_register = 0x1e,
+};
+
+static int ti_eqep_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct ti_eqep_cnt *priv;
+ void __iomem *base;
+ int err;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(base))
+ return PTR_ERR(base);
+
+ priv->regmap32 = devm_regmap_init_mmio(dev, base,
+ &ti_eqep_regmap32_config);
+ if (IS_ERR(priv->regmap32))
+ return PTR_ERR(priv->regmap32);
+
+ priv->regmap16 = devm_regmap_init_mmio(dev, base + 0x24,
+ &ti_eqep_regmap16_config);
+ if (IS_ERR(priv->regmap16))
+ return PTR_ERR(priv->regmap16);
+
+ priv->counter.name = dev_name(dev);
+ priv->counter.parent = dev;
+ priv->counter.ops = &ti_eqep_counter_ops;
+ priv->counter.counts = ti_eqep_counts;
+ priv->counter.num_counts = ARRAY_SIZE(ti_eqep_counts);
+ priv->counter.signals = ti_eqep_signals;
+ priv->counter.num_signals = ARRAY_SIZE(ti_eqep_signals);
+ priv->counter.priv = priv;
+
+ platform_set_drvdata(pdev, priv);
+
+ /*
+ * Need to make sure power is turned on. On AM33xx, this comes from the
+ * parent PWMSS bus driver. On AM17xx, this comes from the PSC power
+ * domain.
+ */
+ pm_runtime_enable(dev);
+ pm_runtime_get_sync(dev);
+
+ err = counter_register(&priv->counter);
+ if (err < 0) {
+ pm_runtime_put_sync(dev);
+ pm_runtime_disable(dev);
+ return err;
+ }
+
+ return 0;
+}
+
+static int ti_eqep_remove(struct platform_device *pdev)
+{
+ struct ti_eqep_cnt *priv = platform_get_drvdata(pdev);
+ struct device *dev = &pdev->dev;
+
+ counter_unregister(&priv->counter);
+ pm_runtime_put_sync(dev),
+ pm_runtime_disable(dev);
+
+ return 0;
+}
+
+static const struct of_device_id ti_eqep_of_match[] = {
+ { .compatible = "ti,am3352-eqep", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, ti_eqep_of_match);
+
+static struct platform_driver ti_eqep_driver = {
+ .probe = ti_eqep_probe,
+ .remove = ti_eqep_remove,
+ .driver = {
+ .name = "ti-eqep-cnt",
+ .of_match_table = ti_eqep_of_match,
+ },
+};
+module_platform_driver(ti_eqep_driver);
+
+MODULE_AUTHOR("David Lechner <david@xxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("TI eQEP counter driver");
+MODULE_LICENSE("GPL v2");
--
2.17.1