[PATCH V2 3/9] dt-bindings: Tegra186 tachometer device tree bindings
Supply Device tree binding documentation for the NVIDIA
Tegra186 SoC's Tachometer Controller
Signed-off-by: Rajkumar Rampelli <rr...@nvidia.com>
---
V2: Renamed compatible string to "nvidia,tegra186-pwm-tachometer"
Renamed dt property values of clock-names and reset-names to "tachometer"
from "tach"
.../bindings/pwm/pwm-tegra-tachometer.txt | 31 ++
1 file changed, 31 insertions(+)
create mode 100644
Documentation/devicetree/bindings/pwm/pwm-tegra-tachometer.txt
diff --git a/Documentation/devicetree/bindings/pwm/pwm-tegra-tachometer.txt
b/Documentation/devicetree/bindings/pwm/pwm-tegra-tachometer.txt
new file mode 100644
index 000..4a7ead4
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/pwm-tegra-tachometer.txt
@@ -0,0 +1,31 @@
+Bindings for a PWM based Tachometer driver
+
+Required properties:
+- compatible: Must be "nvidia,tegra186-pwm-tachometer"
+- reg: physical base addresses of the controller and length of
+ memory mapped region.
+- #pwm-cells: should be 2. See pwm.txt in this directory for a
+ description of the cells format.
+- clocks: phandle list of tachometer clocks
+- clock-names: should be "tachometer". See clock-bindings.txt in documentations
+- resets: phandle to the reset controller for the Tachometer IP
+- reset-names: should be "tachometer". See reset.txt in documentations
+- nvidia,pulse-per-rev: Integer, pulses per revolution of a Fan. This value
+ obtained from Fan specification document.
+- nvidia,capture-window-len: Integer, window of the Fan Tach monitor, it
indicates
+ that how many period of the input fan tach signal will the FAN TACH logic
+ monitor. Valid values are 1, 2, 4 and 8 only.
+
+Example:
+ tegra_tachometer: tachometer@39c {
+ compatible = "nvidia,tegra186-pwm-tachometer";
+ reg = <0x0 0x039c 0x0 0x10>;
+ #pwm-cells = <2>;
+ clocks = <_car TEGRA186_CLK_TACH>;
+ clock-names = "tachometer";
+ resets = <_car TEGRA186_RESET_TACH>;
+ reset-names = "tachometer";
+ nvidia,pulse-per-rev = <2>;
+ nvidia,capture-window-len = <2>;
+ status = "disabled";
+ };
--
2.1.4
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[PATCH V2 5/9] pwm: tegra: Add PWM based Tachometer driver
PWM Tachometer driver capture the PWM signal which is output of FAN
in general and provide the period of PWM signal which is converted to
RPM by SW.
Add Tegra Tachometer driver which implements the pwm-capture to
measure period.
Signed-off-by: Rajkumar Rampelli <rr...@nvidia.com>
Signed-off-by: Laxman Dewangan <ldewan...@nvidia.com>
---
V2: Renamed compatible string to "nvidia-tegra186-pwm-tachometer"
Renamed arguments of reset and clk apis to "tachometer" from "tach"
drivers/pwm/Kconfig| 10 ++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-tegra-tachometer.c | 303 +
3 files changed, 314 insertions(+)
create mode 100644 drivers/pwm/pwm-tegra-tachometer.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 763ee50..29aeeeb 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -454,6 +454,16 @@ config PWM_TEGRA
To compile this driver as a module, choose M here: the module
will be called pwm-tegra.
+config PWM_TEGRA_TACHOMETER
+ tristate "NVIDIA Tegra Tachometer PWM driver"
+ depends on ARCH_TEGRA
+ help
+ NVIDIA Tegra Tachometer reads the PWM signal and reports the PWM
+ signal periods. This helps in measuring the fan speed where Fan
+ output for speed is PWM signal.
+
+ This driver support the Tachometer driver in PWM framework.
+
config PWM_TIECAP
tristate "ECAP PWM support"
depends on ARCH_OMAP2PLUS || ARCH_DAVINCI_DA8XX || ARCH_KEYSTONE
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 0258a74..14c183e 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -45,6 +45,7 @@ obj-$(CONFIG_PWM_STM32_LP)+= pwm-stm32-lp.o
obj-$(CONFIG_PWM_STMPE)+= pwm-stmpe.o
obj-$(CONFIG_PWM_SUN4I)+= pwm-sun4i.o
obj-$(CONFIG_PWM_TEGRA)+= pwm-tegra.o
+obj-$(CONFIG_PWM_TEGRA_TACHOMETER) += pwm-tegra-tachometer.o
obj-$(CONFIG_PWM_TIECAP) += pwm-tiecap.o
obj-$(CONFIG_PWM_TIEHRPWM) += pwm-tiehrpwm.o
obj-$(CONFIG_PWM_TIPWMSS) += pwm-tipwmss.o
diff --git a/drivers/pwm/pwm-tegra-tachometer.c
b/drivers/pwm/pwm-tegra-tachometer.c
new file mode 100644
index 000..bcc44ce
--- /dev/null
+++ b/drivers/pwm/pwm-tegra-tachometer.c
@@ -0,0 +1,303 @@
+/*
+ * Tegra Tachometer Pulse-Width-Modulation driver
+ *
+ * Copyright (c) 2017-2018, NVIDIA CORPORATION. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+
+/* Since oscillator clock (38.4MHz) serves as a clock source for
+ * the tach input controller, 1.0105263MHz (i.e. 38.4/38) has to be
+ * used as a clock value in the RPM calculations
+ */
+#define TACH_COUNTER_CLK 1010526
+
+#define TACH_FAN_TACH0 0x0
+#define TACH_FAN_TACH0_PERIOD_MASK 0x7
+#define TACH_FAN_TACH0_PERIOD_MAX 0x7
+#define TACH_FAN_TACH0_PERIOD_MIN 0x0
+#define TACH_FAN_TACH0_WIN_LENGTH_SHIFT25
+#define TACH_FAN_TACH0_WIN_LENGTH_MASK 0x3
+#define TACH_FAN_TACH0_OVERFLOW_MASK BIT(24)
+
+#define TACH_FAN_TACH1 0x4
+#define TACH_FAN_TACH1_HI_MASK 0x7
+/*
+ * struct pwm_tegra_tach - Tegra tachometer object
+ * @dev: device providing the Tachometer
+ * @pulse_per_rev: Pulses per revolution of a Fan
+ * @capture_window_len: Defines the window of the FAN TACH monitor
+ * @regs: physical base addresses of the controller
+ * @clk: phandle list of tachometer clocks
+ * @rst: phandle to reset the controller
+ * @chip: PWM chip providing this PWM device
+ */
+struct pwm_tegra_tach {
+ struct device *dev;
+ void __iomem*regs;
+ struct clk *clk;
+ struct reset_control*rst;
+ u32 pulse_per_rev;
+ u32 capture_window_len;
+ struct pwm_chip chip;
+};
+
+static struct pwm_tegra_tach *to_tegra_pwm_chip(struct pwm_chip *chip)
+{
+ return container_of(chip, struct pwm_tegra_tach, chip);
+}
+
+static u32 tachometer_readl(struct pwm_tegra_tach *ptt, unsigned long reg)
+{
+ return readl(ptt->regs + reg);
+}
+
+static inline void tachometer_writel(struct pwm_tegra_tach *ptt, u32 val,
+unsigned long reg)
+{
+ write
[PATCH V2 8/9] arm64: defconfig: enable Nvidia Tegra Tachometer as a module
Tegra Tachometer driver implements PWM capture to measure period. Enable this driver as a module in the ARM64 defconfig. Signed-off-by: Rajkumar Rampelli <rr...@nvidia.com> --- V2: No changes in this patch arch/arm64/configs/defconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig index 634b373..8b2bda7 100644 --- a/arch/arm64/configs/defconfig +++ b/arch/arm64/configs/defconfig @@ -550,6 +550,7 @@ CONFIG_PWM_MESON=m CONFIG_PWM_ROCKCHIP=y CONFIG_PWM_SAMSUNG=y CONFIG_PWM_TEGRA=m +CONFIG_PWM_TEGRA_TACHOMETER=m CONFIG_PHY_RCAR_GEN3_USB2=y CONFIG_PHY_HI6220_USB=y CONFIG_PHY_QCOM_USB_HS=y -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH V2 1/9] pwm: core: Add support for PWM HW driver with pwm capture only
Add support for pwm HW driver which has only capture functionality.
This helps to implement the PWM based Tachometer driver which reads
the PWM output signals from electronic fans.
PWM Tachometer captures the period and duty cycle of the PWM signal
Add conditional checks for callabacks enable(), disable(), config()
to check if they are supported by the client driver or not. Skip these
callbacks if they are not supported.
Signed-off-by: Rajkumar Rampelli <rr...@nvidia.com>
---
V2: Added if conditional checks for pwm callbacks since drivers may
implements only pwm capture functionality.
drivers/pwm/core.c | 21 +++--
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 1581f6a..f70fe68 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -246,6 +246,10 @@ static bool pwm_ops_check(const struct pwm_ops *ops)
if (ops->apply)
return true;
+ /* driver supports capture operation */
+ if (ops->capture)
+ return true;
+
return false;
}
@@ -495,7 +499,8 @@ int pwm_apply_state(struct pwm_device *pwm, struct
pwm_state *state)
* ->apply().
*/
if (pwm->state.enabled) {
- pwm->chip->ops->disable(pwm->chip, pwm);
+ if (pwm->chip->ops->disable)
+ pwm->chip->ops->disable(pwm->chip, pwm);
pwm->state.enabled = false;
}
@@ -509,22 +514,26 @@ int pwm_apply_state(struct pwm_device *pwm, struct
pwm_state *state)
if (state->period != pwm->state.period ||
state->duty_cycle != pwm->state.duty_cycle) {
- err = pwm->chip->ops->config(pwm->chip, pwm,
+ if (pwm->chip->ops->config) {
+ err = pwm->chip->ops->config(pwm->chip, pwm,
state->duty_cycle,
state->period);
- if (err)
- return err;
+ if (err)
+ return err;
+ }
pwm->state.duty_cycle = state->duty_cycle;
pwm->state.period = state->period;
}
if (state->enabled != pwm->state.enabled) {
- if (state->enabled) {
+ if (state->enabled && pwm->chip->ops->enable) {
err = pwm->chip->ops->enable(pwm->chip, pwm);
if (err)
return err;
- } else {
+ }
+
+ if (!state->enabled && pwm->chip->ops->disable) {
pwm->chip->ops->disable(pwm->chip, pwm);
}
--
2.1.4
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Re: [PATCH 05/10] hwmon: generic-pwm-tachometer: Add generic PWM based tachometer
On Wednesday 28 February 2018 07:59 PM, Guenter Roeck wrote:
On 02/27/2018 11:03 PM, Mikko Perttunen wrote:
On 02/28/2018 08:12 AM, Rajkumar Rampelli wrote:
On Wednesday 28 February 2018 11:28 AM, Guenter Roeck wrote:
On 02/27/2018 09:38 PM, Rajkumar Rampelli wrote:
On Wednesday 21 February 2018 08:20 PM, Guenter Roeck wrote:
On 02/20/2018 10:58 PM, Rajkumar Rampelli wrote:
Add generic PWM based tachometer driver via HWMON interface
to report the RPM of motor. This drivers get the period/duty
cycle from PWM IP which captures the motor PWM output.
This driver implements a simple interface for monitoring the
speed of
a fan and exposes it in roatations per minute (RPM) to the user
space
by using the hwmon's sysfs interface
Signed-off-by: Rajkumar Rampelli <rr...@nvidia.com>
---
Documentation/hwmon/generic-pwm-tachometer | 17 +
drivers/hwmon/Kconfig | 10 +++
drivers/hwmon/Makefile | 1 +
drivers/hwmon/generic-pwm-tachometer.c | 112
+
4 files changed, 140 insertions(+)
create mode 100644 Documentation/hwmon/generic-pwm-tachometer
create mode 100644 drivers/hwmon/generic-pwm-tachometer.c
diff --git a/Documentation/hwmon/generic-pwm-tachometer
b/Documentation/hwmon/generic-pwm-tachometer
new file mode 100644
index 000..e0713ee
--- /dev/null
+++ b/Documentation/hwmon/generic-pwm-tachometer
@@ -0,0 +1,17 @@
+Kernel driver generic-pwm-tachometer
+
+
+This driver enables the use of a PWM module to monitor a fan.
It uses the
+generic PWM interface and can be used on SoCs as along as the
SoC supports
+Tachometer controller that moniors the Fan speed in periods.
+
+Author: Rajkumar Rampelli <rr...@nvidia.com>
+
+Description
+---
+
+The driver implements a simple interface for monitoring the Fan
speed using
+PWM module and Tachometer controller. It requests period value
through PWM
+capture interface to Tachometer and measures the Rotations per
minute using
+received period value. It exposes the Fan speed in RPM to the
user space by
+using the hwmon's sysfs interface.
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index ef23553..8912dcb 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1878,6 +1878,16 @@ config SENSORS_XGENE
If you say yes here you get support for the temperature
and power sensors for APM X-Gene SoC.
+config GENERIC_PWM_TACHOMETER
+tristate "Generic PWM based tachometer driver"
+depends on PWM
+help
+ Enables a driver to use PWM signal from motor to use
+ for measuring the motor speed. The RPM is captured by
+ PWM modules which has PWM capture capability and this
+ drivers reads the captured data from PWM IP to convert
+ it to speed in RPM.
+
if ACPI
comment "ACPI drivers"
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index f814b4a..9dcc374 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -175,6 +175,7 @@ obj-$(CONFIG_SENSORS_WM8350)+=
wm8350-hwmon.o
obj-$(CONFIG_SENSORS_XGENE)+= xgene-hwmon.o
obj-$(CONFIG_PMBUS)+= pmbus/
+obj-$(CONFIG_GENERIC_PWM_TACHOMETER) += generic-pwm-tachometer.o
ccflags-$(CONFIG_HWMON_DEBUG_CHIP) := -DDEBUG
diff --git a/drivers/hwmon/generic-pwm-tachometer.c
b/drivers/hwmon/generic-pwm-tachometer.c
new file mode 100644
index 000..9354d43
--- /dev/null
+++ b/drivers/hwmon/generic-pwm-tachometer.c
@@ -0,0 +1,112 @@
+/*
+ * Copyright (c) 2017-2018, NVIDIA CORPORATION. All rights
reserved.
+ *
+ * This program is free software; you can redistribute it
and/or modify it
+ * under the terms and conditions of the GNU General Public
License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful,
but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
Public License for
+ * more details.
+ *
+ */
+
+#include
+#include
+#include
+#include
+#include
+#include
+
+struct pwm_hwmon_tach {
+struct device*dev;
+struct pwm_device*pwm;
+struct device*hwmon;
+};
+
+static ssize_t show_rpm(struct device *dev, struct
device_attribute *attr,
+char *buf)
+{
+struct pwm_hwmon_tach *ptt = dev_get_drvdata(dev);
+struct pwm_device *pwm = ptt->pwm;
+struct pwm_capture result;
+int err;
+unsigned int rpm = 0;
+
+err = pwm_capture(pwm, , 0);
+if (err < 0) {
+dev_err(ptt->dev, "Failed to capture PWM: %d\n", err);
+return err;
+}
+
+if (result.period)
+rpm = DIV_ROUND_CLOSEST_ULL(60ULL * NSEC_PER_SEC,
+result.period);
+
+return sprintf(buf, "%u\n", rpm);
+}
+
+static SENSOR_DEVICE_ATTR(rpm, 0444, s
Re: [PATCH 05/10] hwmon: generic-pwm-tachometer: Add generic PWM based tachometer
On Wednesday 28 February 2018 11:28 AM, Guenter Roeck wrote:
On 02/27/2018 09:38 PM, Rajkumar Rampelli wrote:
On Wednesday 21 February 2018 08:20 PM, Guenter Roeck wrote:
On 02/20/2018 10:58 PM, Rajkumar Rampelli wrote:
Add generic PWM based tachometer driver via HWMON interface
to report the RPM of motor. This drivers get the period/duty
cycle from PWM IP which captures the motor PWM output.
This driver implements a simple interface for monitoring the speed of
a fan and exposes it in roatations per minute (RPM) to the user space
by using the hwmon's sysfs interface
Signed-off-by: Rajkumar Rampelli <rr...@nvidia.com>
---
Documentation/hwmon/generic-pwm-tachometer | 17 +
drivers/hwmon/Kconfig | 10 +++
drivers/hwmon/Makefile | 1 +
drivers/hwmon/generic-pwm-tachometer.c | 112
+
4 files changed, 140 insertions(+)
create mode 100644 Documentation/hwmon/generic-pwm-tachometer
create mode 100644 drivers/hwmon/generic-pwm-tachometer.c
diff --git a/Documentation/hwmon/generic-pwm-tachometer
b/Documentation/hwmon/generic-pwm-tachometer
new file mode 100644
index 000..e0713ee
--- /dev/null
+++ b/Documentation/hwmon/generic-pwm-tachometer
@@ -0,0 +1,17 @@
+Kernel driver generic-pwm-tachometer
+
+
+This driver enables the use of a PWM module to monitor a fan. It
uses the
+generic PWM interface and can be used on SoCs as along as the SoC
supports
+Tachometer controller that moniors the Fan speed in periods.
+
+Author: Rajkumar Rampelli <rr...@nvidia.com>
+
+Description
+---
+
+The driver implements a simple interface for monitoring the Fan
speed using
+PWM module and Tachometer controller. It requests period value
through PWM
+capture interface to Tachometer and measures the Rotations per
minute using
+received period value. It exposes the Fan speed in RPM to the user
space by
+using the hwmon's sysfs interface.
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index ef23553..8912dcb 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1878,6 +1878,16 @@ config SENSORS_XGENE
If you say yes here you get support for the temperature
and power sensors for APM X-Gene SoC.
+config GENERIC_PWM_TACHOMETER
+tristate "Generic PWM based tachometer driver"
+depends on PWM
+help
+ Enables a driver to use PWM signal from motor to use
+ for measuring the motor speed. The RPM is captured by
+ PWM modules which has PWM capture capability and this
+ drivers reads the captured data from PWM IP to convert
+ it to speed in RPM.
+
if ACPI
comment "ACPI drivers"
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index f814b4a..9dcc374 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -175,6 +175,7 @@ obj-$(CONFIG_SENSORS_WM8350)+= wm8350-hwmon.o
obj-$(CONFIG_SENSORS_XGENE)+= xgene-hwmon.o
obj-$(CONFIG_PMBUS)+= pmbus/
+obj-$(CONFIG_GENERIC_PWM_TACHOMETER) += generic-pwm-tachometer.o
ccflags-$(CONFIG_HWMON_DEBUG_CHIP) := -DDEBUG
diff --git a/drivers/hwmon/generic-pwm-tachometer.c
b/drivers/hwmon/generic-pwm-tachometer.c
new file mode 100644
index 000..9354d43
--- /dev/null
+++ b/drivers/hwmon/generic-pwm-tachometer.c
@@ -0,0 +1,112 @@
+/*
+ * Copyright (c) 2017-2018, NVIDIA CORPORATION. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but
WITHOUT
+ * ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
License for
+ * more details.
+ *
+ */
+
+#include
+#include
+#include
+#include
+#include
+#include
+
+struct pwm_hwmon_tach {
+struct device*dev;
+struct pwm_device*pwm;
+struct device*hwmon;
+};
+
+static ssize_t show_rpm(struct device *dev, struct
device_attribute *attr,
+char *buf)
+{
+struct pwm_hwmon_tach *ptt = dev_get_drvdata(dev);
+struct pwm_device *pwm = ptt->pwm;
+struct pwm_capture result;
+int err;
+unsigned int rpm = 0;
+
+err = pwm_capture(pwm, , 0);
+if (err < 0) {
+dev_err(ptt->dev, "Failed to capture PWM: %d\n", err);
+return err;
+}
+
+if (result.period)
+rpm = DIV_ROUND_CLOSEST_ULL(60ULL * NSEC_PER_SEC,
+result.period);
+
+return sprintf(buf, "%u\n", rpm);
+}
+
+static SENSOR_DEVICE_ATTR(rpm, 0444, show_rpm, NULL, 0);
+
+static struct attribute *pwm_tach_attrs[] = {
+_dev_attr_rpm.dev_attr.attr,
+NULL,
+};
"rpm" is not a standard hwmon sysfs attribute. If you don't
Re: [PATCH 05/10] hwmon: generic-pwm-tachometer: Add generic PWM based tachometer
On Wednesday 21 February 2018 08:20 PM, Guenter Roeck wrote:
On 02/20/2018 10:58 PM, Rajkumar Rampelli wrote:
Add generic PWM based tachometer driver via HWMON interface
to report the RPM of motor. This drivers get the period/duty
cycle from PWM IP which captures the motor PWM output.
This driver implements a simple interface for monitoring the speed of
a fan and exposes it in roatations per minute (RPM) to the user space
by using the hwmon's sysfs interface
Signed-off-by: Rajkumar Rampelli <rr...@nvidia.com>
---
Documentation/hwmon/generic-pwm-tachometer | 17 +
drivers/hwmon/Kconfig | 10 +++
drivers/hwmon/Makefile | 1 +
drivers/hwmon/generic-pwm-tachometer.c | 112
+
4 files changed, 140 insertions(+)
create mode 100644 Documentation/hwmon/generic-pwm-tachometer
create mode 100644 drivers/hwmon/generic-pwm-tachometer.c
diff --git a/Documentation/hwmon/generic-pwm-tachometer
b/Documentation/hwmon/generic-pwm-tachometer
new file mode 100644
index 000..e0713ee
--- /dev/null
+++ b/Documentation/hwmon/generic-pwm-tachometer
@@ -0,0 +1,17 @@
+Kernel driver generic-pwm-tachometer
+
+
+This driver enables the use of a PWM module to monitor a fan. It
uses the
+generic PWM interface and can be used on SoCs as along as the SoC
supports
+Tachometer controller that moniors the Fan speed in periods.
+
+Author: Rajkumar Rampelli <rr...@nvidia.com>
+
+Description
+---
+
+The driver implements a simple interface for monitoring the Fan
speed using
+PWM module and Tachometer controller. It requests period value
through PWM
+capture interface to Tachometer and measures the Rotations per
minute using
+received period value. It exposes the Fan speed in RPM to the user
space by
+using the hwmon's sysfs interface.
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index ef23553..8912dcb 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1878,6 +1878,16 @@ config SENSORS_XGENE
If you say yes here you get support for the temperature
and power sensors for APM X-Gene SoC.
+config GENERIC_PWM_TACHOMETER
+tristate "Generic PWM based tachometer driver"
+depends on PWM
+help
+ Enables a driver to use PWM signal from motor to use
+ for measuring the motor speed. The RPM is captured by
+ PWM modules which has PWM capture capability and this
+ drivers reads the captured data from PWM IP to convert
+ it to speed in RPM.
+
if ACPI
comment "ACPI drivers"
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index f814b4a..9dcc374 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -175,6 +175,7 @@ obj-$(CONFIG_SENSORS_WM8350)+= wm8350-hwmon.o
obj-$(CONFIG_SENSORS_XGENE)+= xgene-hwmon.o
obj-$(CONFIG_PMBUS)+= pmbus/
+obj-$(CONFIG_GENERIC_PWM_TACHOMETER) += generic-pwm-tachometer.o
ccflags-$(CONFIG_HWMON_DEBUG_CHIP) := -DDEBUG
diff --git a/drivers/hwmon/generic-pwm-tachometer.c
b/drivers/hwmon/generic-pwm-tachometer.c
new file mode 100644
index 000..9354d43
--- /dev/null
+++ b/drivers/hwmon/generic-pwm-tachometer.c
@@ -0,0 +1,112 @@
+/*
+ * Copyright (c) 2017-2018, NVIDIA CORPORATION. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but
WITHOUT
+ * ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
License for
+ * more details.
+ *
+ */
+
+#include
+#include
+#include
+#include
+#include
+#include
+
+struct pwm_hwmon_tach {
+struct device*dev;
+struct pwm_device*pwm;
+struct device*hwmon;
+};
+
+static ssize_t show_rpm(struct device *dev, struct device_attribute
*attr,
+char *buf)
+{
+struct pwm_hwmon_tach *ptt = dev_get_drvdata(dev);
+struct pwm_device *pwm = ptt->pwm;
+struct pwm_capture result;
+int err;
+unsigned int rpm = 0;
+
+err = pwm_capture(pwm, , 0);
+if (err < 0) {
+dev_err(ptt->dev, "Failed to capture PWM: %d\n", err);
+return err;
+}
+
+if (result.period)
+rpm = DIV_ROUND_CLOSEST_ULL(60ULL * NSEC_PER_SEC,
+result.period);
+
+return sprintf(buf, "%u\n", rpm);
+}
+
+static SENSOR_DEVICE_ATTR(rpm, 0444, show_rpm, NULL, 0);
+
+static struct attribute *pwm_tach_attrs[] = {
+_dev_attr_rpm.dev_attr.attr,
+NULL,
+};
"rpm" is not a standard hwmon sysfs attribute. If you don't provide
a single standard hwmon sysfs attribute, having a hwmon driver is
pointless.
Guenter Roeck,
I will defin
[PATCH 01/10] pwm: core: Add support for PWM HW driver with pwm capture only
Add support for pwm HW driver which has only capture functionality. This helps to implement the PWM based Tachometer driver which reads the PWM output signals from electronic fans. PWM Tachometer captures the period and duty cycle of the PWM signal Signed-off-by: Rajkumar Rampelli <rr...@nvidia.com> --- drivers/pwm/core.c | 4 1 file changed, 4 insertions(+) diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 1581f6a..87d14c9 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -246,6 +246,10 @@ static bool pwm_ops_check(const struct pwm_ops *ops) if (ops->apply) return true; + /* driver supports capture operation */ + if (ops->capture) + return true; + return false; } -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH 04/10] hwmon: generic-pwm-tachometer: Add DT binding details
Add DT binding details for the PWM based generic tachometer
driver which gets the period of the PWM tach-output from Fan
via PWM IP having capability of capturing the signal.
Signed-off-by: Rajkumar Rampelli <rr...@nvidia.com>
---
.../bindings/hwmon/generic-pwm-tachometer.txt | 25 ++
1 file changed, 25 insertions(+)
create mode 100644
Documentation/devicetree/bindings/hwmon/generic-pwm-tachometer.txt
diff --git a/Documentation/devicetree/bindings/hwmon/generic-pwm-tachometer.txt
b/Documentation/devicetree/bindings/hwmon/generic-pwm-tachometer.txt
new file mode 100644
index 000..3541fe5
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/generic-pwm-tachometer.txt
@@ -0,0 +1,25 @@
+Device tree bindings for fan tach output connected to PWM controller with
+PWM capture capability.
+
+Required properties:
+- compatible : Should be "generic-pwm-tachometer"
+- pwms : PWM handle. Please refer pwm.txt DT binding for more details.
+
+Example:
+ tegra_tachometer: tachometer@39c {
+ compatible = "nvidia,tegra186-pwm-tachometer";
+ reg = <0x0 0x039c 0x0 0x10>;
+ clocks = <_clks TEGRA194_CLK_TACH>;
+ clock-names = "tachometer";
+ resets = <_resets TEGRA194_RESET_TACH>;
+ reset-names = "tachometer";
+ nvidia,pulse-per-rev = <2>;
+ nvidia,sampling-window = <2>;
+ status = "okay";
+ };
+
+ generic_pwm_tachometer {
+ compatible = "generic-pwm-tachometer";
+ pwms = <_tachometer 0 100>;
+ status = "okay";
+ };
--
2.1.4
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[PATCH 07/10] arm64: tegra: Add PWM based Tachometer support on Tegra186
Add PWM based Tachometer support on Tegra186 to measure
number of rotations of a Fan per minute by using PWM
capture interface
Signed-off-by: Rajkumar Rampelli <rr...@nvidia.com>
---
arch/arm64/boot/dts/nvidia/tegra186.dtsi | 6 ++
1 file changed, 6 insertions(+)
diff --git a/arch/arm64/boot/dts/nvidia/tegra186.dtsi
b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
index 8f2d598..37149e9 100644
--- a/arch/arm64/boot/dts/nvidia/tegra186.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
@@ -1042,4 +1042,10 @@
reset-names = "tachometer";
status = "disabled";
};
+
+ generic_pwm_tachometer {
+ compatible = "generic-pwm-tachometer";
+ pwms = <_tachometer 0 100>;
+ status = "disabled";
+ };
};
--
2.1.4
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[PATCH 06/10] arm64: tegra: Add Tachometer Controller on Tegra186
The NVIDIA Tegra186 SoC has a Tachometer Controller that analyzes the
PWM signal of a Fan and reports the period value through pwm interface.
Signed-off-by: Rajkumar Rampelli <rr...@nvidia.com>
---
arch/arm64/boot/dts/nvidia/tegra186-p2771-.dts | 5 +
arch/arm64/boot/dts/nvidia/tegra186.dtsi | 11 +++
2 files changed, 16 insertions(+)
diff --git a/arch/arm64/boot/dts/nvidia/tegra186-p2771-.dts
b/arch/arm64/boot/dts/nvidia/tegra186-p2771-.dts
index bd5305a..13c3e59 100644
--- a/arch/arm64/boot/dts/nvidia/tegra186-p2771-.dts
+++ b/arch/arm64/boot/dts/nvidia/tegra186-p2771-.dts
@@ -172,4 +172,9 @@
vin-supply = <_5v0_sys>;
};
};
+
+ tachometer@39c {
+ nvidia,pulse-per-rev = <2>;
+ nvidia,capture-window-len = <2>;
+ };
};
diff --git a/arch/arm64/boot/dts/nvidia/tegra186.dtsi
b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
index b762227..8f2d598 100644
--- a/arch/arm64/boot/dts/nvidia/tegra186.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
@@ -1031,4 +1031,15 @@
(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>;
interrupt-parent = <>;
};
+
+ tegra_tachometer: tachometer@39c {
+ compatible = "nvidia,tegra186-pwm-tachometer";
+ reg = <0x0 0x039c 0x0 0x10>;
+ #pwm-cells = <2>;
+ clocks = < TEGRA186_CLK_TACH>;
+ clock-names = "tachometer";
+ resets = < TEGRA186_RESET_TACH>;
+ reset-names = "tachometer";
+ status = "disabled";
+ };
};
--
2.1.4
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[PATCH 10/10] arm64: tegra: Add PWM controller on Tegra186 soc
The NVIDIA Tegra186 SoC has a PWM controller which is
used in FAN control use case.
Signed-off-by: Rajkumar Rampelli <rr...@nvidia.com>
---
arch/arm64/boot/dts/nvidia/tegra186.dtsi | 11 +++
1 file changed, 11 insertions(+)
diff --git a/arch/arm64/boot/dts/nvidia/tegra186.dtsi
b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
index 37149e9..c6f154e 100644
--- a/arch/arm64/boot/dts/nvidia/tegra186.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
@@ -1032,6 +1032,17 @@
interrupt-parent = <>;
};
+ pwm@c34 {
+ compatible = "nvidia,tegra186-pwm";
+ reg = <0x0 0xc34 0x0 0x1>;
+ clocks = < TEGRA186_CLK_PWM4>;
+ clock-names = "pwm";
+ #pwm-cells = <2>;
+ resets = < TEGRA186_RESET_PWM4>;
+ reset-names = "pwm";
+ status = "disabled";
+ };
+
tegra_tachometer: tachometer@39c {
compatible = "nvidia,tegra186-pwm-tachometer";
reg = <0x0 0x039c 0x0 0x10>;
--
2.1.4
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[PATCH 09/10] arm64: defconfig: Enable Generic PWM based Tachometer driver
Enable Generic PWM based Tachometer driver which implements a simple interface for monitoring the speed of a fan in roatations per minute, and exposes it to the user space by using the hwmon's sysfs interface. Enable this driver as a module in the ARM64 defconfig. Signed-off-by: Rajkumar Rampelli <rr...@nvidia.com> --- arch/arm64/configs/defconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig index 8b2bda7..1b29109 100644 --- a/arch/arm64/configs/defconfig +++ b/arch/arm64/configs/defconfig @@ -321,6 +321,7 @@ CONFIG_BATTERY_BQ27XXX=y CONFIG_SENSORS_ARM_SCPI=y CONFIG_SENSORS_LM90=m CONFIG_SENSORS_INA2XX=m +CONFIG_GENERIC_PWM_TACHOMETER=m CONFIG_THERMAL_GOV_POWER_ALLOCATOR=y CONFIG_CPU_THERMAL=y CONFIG_THERMAL_EMULATION=y -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH 00/10] Implementation of Tegra Tachometer driver
The following patches adds support for PWM based Tegra Tachometer driver which implements PWM capture interface to analyze the PWM signal of a electronic fan and reports it in periods and duty cycles. Generic PWM Tachometer implemented to monitor the speed of fan in rpms using PWM interface. RPM of Fan will be exposed to user interface through HWMON sysfs interface avialable at below location /sys/devices/platform/generic_pwm_tachometer/hwmon/hwmon0/rpm Steps to validate Tachometer: A. push modules pwm-tegra.ko, pwm-tegra-tachometer.ko and generic-pwm-tachometer.ko to linux device using scp command. scp build/tegra186/drivers/pwm/pwm-tegra.ko ubuntu@10.19.65.176:/tmp/ scp build/tegra186/drivers/pwm/pwm-tegra-tachometer.ko ubuntu@10.19.65.176:/tmp/ scp build/tegra186/drivers/hwmon/generic-pwm-tachometer.ko ubuntu@10.19.65.176:/tmp/ B. On Linux device console, insert these modules using insmod command. insmod /tmp/pwm-tegra.ko insmod /tmp/pwm-tegra-tachometer.ko insmod /tmp/generic-pwm-tachometer.ko C. Read RPM value at below sysfs node cat /sys/devices/platform/generic_pwm_tachometer/hwmon/hwmon0/rpm D. Change the FAN speed using PWM sysfs interface. Follow below steps for the same: a. cd /sys/class/pwm/pwmchip0 b. ls -la (make sure pwm controller is c34.pwm) Output should be: device -> ../../../c34.pwm c. echo 0 > export d. cd pwmchip0:0 e. echo 8000 > period f. echo 1 > enable g. echo 7000 > duty_cycle # change duty_cycles from 0 to 7000 and see FAN speed h. cat /sys/devices/platform/generic_pwm_tachometer/hwmon/hwmon0/rpm i. echo 4000 > duty_cycle h. cat /sys/devices/platform/generic_pwm_tachometer/hwmon/hwmon0/rpm i. echo 2000 > duty_cycle h. cat /sys/devices/platform/generic_pwm_tachometer/hwmon/hwmon0/rpm i. echo 0 > duty_cycle h. cat /sys/devices/platform/generic_pwm_tachometer/hwmon/hwmon0/rpm Rajkumar Rampelli (10): pwm: core: Add support for PWM HW driver with pwm capture only dt-bindings: Tegra186 tachometer device tree bindings pwm: tegra: Add PWM based Tachometer driver hwmon: generic-pwm-tachometer: Add DT binding details hwmon: generic-pwm-tachometer: Add generic PWM based tachometer arm64: tegra: Add Tachometer Controller on Tegra186 arm64: tegra: Add PWM based Tachometer support on Tegra186 arm64: defconfig: enable Nvidia Tegra Tachometer as a module arm64: defconfig: Enable Generic PWM based Tachometer driver arm64: tegra: Add PWM controller on Tegra186 soc .../bindings/hwmon/generic-pwm-tachometer.txt | 25 ++ .../bindings/pwm/pwm-tegra-tachometer.txt | 31 +++ Documentation/hwmon/generic-pwm-tachometer | 17 ++ arch/arm64/boot/dts/nvidia/tegra186-p2771-.dts | 5 + arch/arm64/boot/dts/nvidia/tegra186.dtsi | 28 ++ arch/arm64/configs/defconfig | 2 + drivers/hwmon/Kconfig | 10 + drivers/hwmon/Makefile | 1 + drivers/hwmon/generic-pwm-tachometer.c | 112 drivers/pwm/Kconfig| 10 + drivers/pwm/Makefile | 1 + drivers/pwm/core.c | 4 + drivers/pwm/pwm-tegra-tachometer.c | 303 + 13 files changed, 549 insertions(+) create mode 100644 Documentation/devicetree/bindings/hwmon/generic-pwm-tachometer.txt create mode 100644 Documentation/devicetree/bindings/pwm/pwm-tegra-tachometer.txt create mode 100644 Documentation/hwmon/generic-pwm-tachometer create mode 100644 drivers/hwmon/generic-pwm-tachometer.c create mode 100644 drivers/pwm/pwm-tegra-tachometer.c -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
