Hi,
This patch series adds a new GNSS driver for the Mediatek-based GNSS receivers.
These receivers transmits NMEA output sequence after boot.
Power management can be done via the main supply and optional backup supply
as defined in the device tree.
The driver has been tested using a GlobalTop pa6h chipset on a Libretech-cc
board using the expansion header. Changes made in the board device tree can
be found below for reference and testing.
Loys
Version 3 changes:
- driver: Removed "mediatek,mt3339" compatible
- driver: moved gnss_types_names string diff in the GNSS_TYPE patch
- driver: edited [patch 3/4] commit message to remove ref to vendor protocol
- driver: retained the original copyright
- dt: removed interfaces that are not available on the globaltop SoC
- dt: Added missing pins documentation
- dt: added optional properties pin names
Version 2 changes:
- driver: Renamed driver from Globaltop/gtop to Mediatek/mtk
- driver: Added "mediatek,mt3339" compatible
- dt: Renamed bindings from Globaltop to Mediatek
- dt: Moved the current-speed property as optional
- dt: removed the status line in example
- cover-letter: removed the alias that is not needed anymore
Loys Ollivier (4):
dt-bindings: Add vendor prefix for "GlobalTop Technology, Inc."
dt-bindings: gnss: add mediatek binding
gnss: add mtk receiver type support
gnss: add driver for mediatek receivers
.../devicetree/bindings/gnss/mediatek.txt | 37 +++++
.../devicetree/bindings/vendor-prefixes.txt | 1 +
drivers/gnss/Kconfig | 13 ++
drivers/gnss/Makefile | 3 +
drivers/gnss/core.c | 1 +
drivers/gnss/mtk.c | 152 +++++++++++++++++++++
include/linux/gnss.h | 1 +
7 files changed, 208 insertions(+)
create mode 100644 Documentation/devicetree/bindings/gnss/mediatek.txt
create mode 100644 drivers/gnss/mtk.c
---
diff --git a/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-libretech-cc.dts b/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-libretech-cc.dts
index 90a56af967a7..3b3d4dcc47aa 100644
--- a/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-libretech-cc.dts
+++ b/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-libretech-cc.dts
@@ -17,6 +17,7 @@
aliases {
serial0 = &uart_AO;
ethernet0 = ðmac;
};
@@ -269,7 +270,20 @@
pinctrl-names = "default";
};
+/* This is brought out on the UART_A_TX (8) and UART_A_RX (10) pins: */
+&uart_A {
+ status = "okay";
+ pinctrl-0 = <&uart_a_pins>;
+ pinctrl-names = "default";
+
+ gnss {
+ compatible = "globaltop,pa6h";
+ v-bckp-supply = <&vcc_3v3>;
+ vcc-supply = <&vcc_3v3>;
+ current-speed = <9600>;
+ };
+};
+
&usb0 {
status = "okay";
};
--
2.7.4
Add driver for serial-connected Mediatek-based GNSS receivers.
These devices typically boot transmitting vendor specific NMEA output
sequences. The serial port bit rate is read from the device tree
"current-speed".
Note that the driver uses the generic GNSS serial implementation and
therefore essentially only manages power abstracted into three power
states: ACTIVE, STANDBY, and OFF.
For mediatek receivers with a main supply and no enable-gpios, this simply
means that the main supply is disabled in STANDBY and OFF (the optional
backup supply is kept enabled while the driver is bound).
Note that the timepulse-support is left unimplemented.
Signed-off-by: Loys Ollivier <[email protected]>
---
v3:
Sorted the Kconfig and Makefile
Retained the original Copyright
Removed "mediatek,mt3339" compatible.
v2:
Renamed from gtop/Globaltop to mtk/Mediatek.
Added "mediatek,mt3339" compatible.
drivers/gnss/Kconfig | 13 +++++
drivers/gnss/Makefile | 3 +
drivers/gnss/mtk.c | 152 ++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 168 insertions(+)
create mode 100644 drivers/gnss/mtk.c
diff --git a/drivers/gnss/Kconfig b/drivers/gnss/Kconfig
index 6abc88514512..6d8c8027e1cd 100644
--- a/drivers/gnss/Kconfig
+++ b/drivers/gnss/Kconfig
@@ -15,6 +15,19 @@ if GNSS
config GNSS_SERIAL
tristate
+config GNSS_MTK_SERIAL
+ tristate "Mediatek GNSS receiver support"
+ depends on SERIAL_DEV_BUS
+ select GNSS_SERIAL
+ help
+ Say Y here if you have a Mediatek-based GNSS receiver which uses a
+ serial interface.
+
+ To compile this driver as a module, choose M here: the module will
+ be called gnss-mtk.
+
+ If unsure, say N.
+
config GNSS_SIRF_SERIAL
tristate "SiRFstar GNSS receiver support"
depends on SERIAL_DEV_BUS
diff --git a/drivers/gnss/Makefile b/drivers/gnss/Makefile
index 5cf0ebe0330a..451f11401ecc 100644
--- a/drivers/gnss/Makefile
+++ b/drivers/gnss/Makefile
@@ -9,6 +9,9 @@ gnss-y := core.o
obj-$(CONFIG_GNSS_SERIAL) += gnss-serial.o
gnss-serial-y := serial.o
+obj-$(CONFIG_GNSS_MTK_SERIAL) += gnss-mtk.o
+gnss-mtk-y := mtk.o
+
obj-$(CONFIG_GNSS_SIRF_SERIAL) += gnss-sirf.o
gnss-sirf-y := sirf.o
diff --git a/drivers/gnss/mtk.c b/drivers/gnss/mtk.c
new file mode 100644
index 000000000000..a5aad08fb9d7
--- /dev/null
+++ b/drivers/gnss/mtk.c
@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Mediatek GNSS receiver driver
+ *
+ * Copyright (C) 2018 Johan Hovold <[email protected]>
+ */
+
+#include <linux/errno.h>
+#include <linux/gnss.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regulator/consumer.h>
+#include <linux/serdev.h>
+
+#include "serial.h"
+
+struct mtk_data {
+ struct regulator *v_bckp;
+ struct regulator *vcc;
+};
+
+static int mtk_set_active(struct gnss_serial *gserial)
+{
+ struct mtk_data *data = gnss_serial_get_drvdata(gserial);
+ int ret;
+
+ ret = regulator_enable(data->vcc);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int mtk_set_standby(struct gnss_serial *gserial)
+{
+ struct mtk_data *data = gnss_serial_get_drvdata(gserial);
+ int ret;
+
+ ret = regulator_disable(data->vcc);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int mtk_set_power(struct gnss_serial *gserial,
+ enum gnss_serial_pm_state state)
+{
+ switch (state) {
+ case GNSS_SERIAL_ACTIVE:
+ return mtk_set_active(gserial);
+ case GNSS_SERIAL_OFF:
+ case GNSS_SERIAL_STANDBY:
+ return mtk_set_standby(gserial);
+ }
+
+ return -EINVAL;
+}
+
+static const struct gnss_serial_ops mtk_gserial_ops = {
+ .set_power = mtk_set_power,
+};
+
+static int mtk_probe(struct serdev_device *serdev)
+{
+ struct gnss_serial *gserial;
+ struct mtk_data *data;
+ int ret;
+
+ gserial = gnss_serial_allocate(serdev, sizeof(*data));
+ if (IS_ERR(gserial)) {
+ ret = PTR_ERR(gserial);
+ return ret;
+ }
+
+ gserial->ops = &mtk_gserial_ops;
+
+ gserial->gdev->type = GNSS_TYPE_MTK;
+
+ data = gnss_serial_get_drvdata(gserial);
+
+ data->vcc = devm_regulator_get(&serdev->dev, "vcc");
+ if (IS_ERR(data->vcc)) {
+ ret = PTR_ERR(data->vcc);
+ goto err_free_gserial;
+ }
+
+ data->v_bckp = devm_regulator_get_optional(&serdev->dev, "v-bckp");
+ if (IS_ERR(data->v_bckp)) {
+ ret = PTR_ERR(data->v_bckp);
+ if (ret == -ENODEV)
+ data->v_bckp = NULL;
+ else
+ goto err_free_gserial;
+ }
+
+ if (data->v_bckp) {
+ ret = regulator_enable(data->v_bckp);
+ if (ret)
+ goto err_free_gserial;
+ }
+
+ ret = gnss_serial_register(gserial);
+ if (ret)
+ goto err_disable_v_bckp;
+
+ return 0;
+
+err_disable_v_bckp:
+ if (data->v_bckp)
+ regulator_disable(data->v_bckp);
+err_free_gserial:
+ gnss_serial_free(gserial);
+
+ return ret;
+}
+
+static void mtk_remove(struct serdev_device *serdev)
+{
+ struct gnss_serial *gserial = serdev_device_get_drvdata(serdev);
+ struct mtk_data *data = gnss_serial_get_drvdata(gserial);
+
+ gnss_serial_deregister(gserial);
+ if (data->v_bckp)
+ regulator_disable(data->v_bckp);
+ gnss_serial_free(gserial);
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id mtk_of_match[] = {
+ { .compatible = "globaltop,pa6h" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, mtk_of_match);
+#endif
+
+static struct serdev_device_driver mtk_driver = {
+ .driver = {
+ .name = "gnss-mtk",
+ .of_match_table = of_match_ptr(mtk_of_match),
+ .pm = &gnss_serial_pm_ops,
+ },
+ .probe = mtk_probe,
+ .remove = mtk_remove,
+};
+module_serdev_device_driver(mtk_driver);
+
+MODULE_AUTHOR("Loys Ollivier <[email protected]>");
+MODULE_DESCRIPTION("Mediatek GNSS receiver driver");
+MODULE_LICENSE("GPL v2");
--
2.7.4
Add binding for Mediatek-based GNSS receivers.
Signed-off-by: Loys Ollivier <[email protected]>
---
v3:
Removed the I2C and SPI interfaces references.
Removed the "mediatek,mt3339" compatible line.
Added the optional propertied (reset, fix)
Added the pin names for the optional properties.
v2:
Renamed bindings from Globaltop/gtop to Mediatek/mtk.
Moved current-speed as an optional propertie.
Removed the status line in the example.
Added "mediatek,mt3339" compatible.
.../devicetree/bindings/gnss/mediatek.txt | 37 ++++++++++++++++++++++
1 file changed, 37 insertions(+)
create mode 100644 Documentation/devicetree/bindings/gnss/mediatek.txt
diff --git a/Documentation/devicetree/bindings/gnss/mediatek.txt b/Documentation/devicetree/bindings/gnss/mediatek.txt
new file mode 100644
index 000000000000..00650d81c5c8
--- /dev/null
+++ b/Documentation/devicetree/bindings/gnss/mediatek.txt
@@ -0,0 +1,37 @@
+Mediatek-based GNSS Receiver DT binding
+
+Mediatek chipsets are used in GNSS-receiver modules produced by several
+vendors and can use an UART interface.
+
+Please see Documentation/devicetree/bindings/gnss/gnss.txt for generic
+properties.
+
+Required properties:
+
+- compatible : Must be
+
+ "globaltop,pa6h"
+
+- vcc-supply : Main voltage regulator (pin name: VCC)
+
+Optional properties:
+
+- gtop,reset-gpios : GPIO used to reset the device
+ (pin name: RESET, NRESET)
+- gtop,fix-gpios : GPIO used to determine device position fix state
+ (pin name: FIX, 3D_FIX)
+- timepulse-gpios : Time pulse GPIO (pin name: PPS1, 1PPS)
+- v-bckp-supply : Backup voltage regulator
+ (pin name: VBAT, VBACKUP)
+- current-speed : Default UART baud rate
+
+Example:
+
+serial@1234 {
+ compatible = "ns16550a";
+
+ gnss {
+ compatible = "globaltop,pa6h";
+ vcc-supply = <&vcc_3v3>;
+ };
+};
--
2.7.4
Add globaltop vendor definition.
Signed-off-by: Loys Ollivier <[email protected]>
---
v3: No changes
v2: Alphabetical order
Documentation/devicetree/bindings/vendor-prefixes.txt | 1 +
1 file changed, 1 insertion(+)
diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt
index 389508584f48..d80a70343b36 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.txt
+++ b/Documentation/devicetree/bindings/vendor-prefixes.txt
@@ -150,6 +150,7 @@ geniatech Geniatech, Inc.
giantec Giantec Semiconductor, Inc.
giantplus Giantplus Technology Co., Ltd.
globalscale Globalscale Technologies, Inc.
+globaltop GlobalTop Technology, Inc.
gmt Global Mixed-mode Technology, Inc.
goodix Shenzhen Huiding Technology Co., Ltd.
google Google, Inc.
--
2.7.4
Add an MTK (Mediatek) type to the "GNSS_TYPE" attribute.
Note that MTK receivers support a subset of NMEA 0183 with vendor
extensions.
Signed-off-by: Loys Ollivier <[email protected]>
---
v3:
Moved the gnss_type_names string addition to this patch.
Edited the commit message to remove the reference to a vendor protocol.
v2: renamed from GTOP to MTK.
drivers/gnss/core.c | 1 +
include/linux/gnss.h | 1 +
2 files changed, 2 insertions(+)
diff --git a/drivers/gnss/core.c b/drivers/gnss/core.c
index 4291a0dd22aa..320cfca80d5f 100644
--- a/drivers/gnss/core.c
+++ b/drivers/gnss/core.c
@@ -334,6 +334,7 @@ static const char * const gnss_type_names[GNSS_TYPE_COUNT] = {
[GNSS_TYPE_NMEA] = "NMEA",
[GNSS_TYPE_SIRF] = "SiRF",
[GNSS_TYPE_UBX] = "UBX",
+ [GNSS_TYPE_MTK] = "MTK",
};
static const char *gnss_type_name(struct gnss_device *gdev)
diff --git a/include/linux/gnss.h b/include/linux/gnss.h
index 43546977098c..36968a0f33e8 100644
--- a/include/linux/gnss.h
+++ b/include/linux/gnss.h
@@ -22,6 +22,7 @@ enum gnss_type {
GNSS_TYPE_NMEA = 0,
GNSS_TYPE_SIRF,
GNSS_TYPE_UBX,
+ GNSS_TYPE_MTK,
GNSS_TYPE_COUNT
};
--
2.7.4
On Mon, 28 Jan 2019 17:37:58 +0100, Loys Ollivier wrote:
> Add globaltop vendor definition.
>
> Signed-off-by: Loys Ollivier <[email protected]>
> ---
>
> v3: No changes
>
> v2: Alphabetical order
>
> Documentation/devicetree/bindings/vendor-prefixes.txt | 1 +
> 1 file changed, 1 insertion(+)
>
Please add Acked-by/Reviewed-by tags when posting new versions. However,
there's no need to repost patches *only* to add the tags. The upstream
maintainer will do that for acks received on the version they apply.
If a tag was not added on purpose, please state why and what changed.
On Mon, Jan 28, 2019 at 05:37:59PM +0100, Loys Ollivier wrote:
> Add binding for Mediatek-based GNSS receivers.
>
> Signed-off-by: Loys Ollivier <[email protected]>
> ---
>
> v3:
> Removed the I2C and SPI interfaces references.
> Removed the "mediatek,mt3339" compatible line.
> Added the optional propertied (reset, fix)
> Added the pin names for the optional properties.
>
> v2:
> Renamed bindings from Globaltop/gtop to Mediatek/mtk.
> Moved current-speed as an optional propertie.
> Removed the status line in the example.
> Added "mediatek,mt3339" compatible.
>
> .../devicetree/bindings/gnss/mediatek.txt | 37 ++++++++++++++++++++++
> 1 file changed, 37 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/gnss/mediatek.txt
>
> diff --git a/Documentation/devicetree/bindings/gnss/mediatek.txt b/Documentation/devicetree/bindings/gnss/mediatek.txt
> new file mode 100644
> index 000000000000..00650d81c5c8
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gnss/mediatek.txt
> @@ -0,0 +1,37 @@
> +Mediatek-based GNSS Receiver DT binding
> +
> +Mediatek chipsets are used in GNSS-receiver modules produced by several
> +vendors and can use an UART interface.
> +
> +Please see Documentation/devicetree/bindings/gnss/gnss.txt for generic
> +properties.
> +
> +Required properties:
> +
> +- compatible : Must be
> +
> + "globaltop,pa6h"
> +
> +- vcc-supply : Main voltage regulator (pin name: VCC)
> +
> +Optional properties:
> +
> +- gtop,reset-gpios : GPIO used to reset the device
> + (pin name: RESET, NRESET)
reset-gpios is the standard name.
> +- gtop,fix-gpios : GPIO used to determine device position fix state
> + (pin name: FIX, 3D_FIX)
> +- timepulse-gpios : Time pulse GPIO (pin name: PPS1, 1PPS)
> +- v-bckp-supply : Backup voltage regulator
> + (pin name: VBAT, VBACKUP)
> +- current-speed : Default UART baud rate
> +
> +Example:
> +
> +serial@1234 {
> + compatible = "ns16550a";
> +
> + gnss {
> + compatible = "globaltop,pa6h";
> + vcc-supply = <&vcc_3v3>;
> + };
> +};
> --
> 2.7.4
>
On Wed 30 Jan 2019 at 15:48, Rob Herring <[email protected]> wrote:
> On Mon, 28 Jan 2019 17:37:58 +0100, Loys Ollivier wrote:
>> Add globaltop vendor definition.
>>
>> Signed-off-by: Loys Ollivier <[email protected]>
>> ---
>>
>> v3: No changes
>>
>> v2: Alphabetical order
>>
>> Documentation/devicetree/bindings/vendor-prefixes.txt | 1 +
>> 1 file changed, 1 insertion(+)
>>
>
> Please add Acked-by/Reviewed-by tags when posting new versions. However,
> there's no need to repost patches *only* to add the tags. The upstream
> maintainer will do that for acks received on the version they apply.
>
> If a tag was not added on purpose, please state why and what changed.
Oops apologies. I'll remember that for future submissions.
--
-L
On Wed, Jan 30, 2019 at 09:50:16AM -0600, Rob Herring wrote:
> On Mon, Jan 28, 2019 at 05:37:59PM +0100, Loys Ollivier wrote:
> > Add binding for Mediatek-based GNSS receivers.
> >
> > Signed-off-by: Loys Ollivier <[email protected]>
> > ---
> >
> > v3:
> > Removed the I2C and SPI interfaces references.
> > Removed the "mediatek,mt3339" compatible line.
> > Added the optional propertied (reset, fix)
> > Added the pin names for the optional properties.
> >
> > v2:
> > Renamed bindings from Globaltop/gtop to Mediatek/mtk.
> > Moved current-speed as an optional propertie.
> > Removed the status line in the example.
> > Added "mediatek,mt3339" compatible.
> >
> > .../devicetree/bindings/gnss/mediatek.txt | 37 ++++++++++++++++++++++
> > 1 file changed, 37 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/gnss/mediatek.txt
> >
> > diff --git a/Documentation/devicetree/bindings/gnss/mediatek.txt b/Documentation/devicetree/bindings/gnss/mediatek.txt
> > new file mode 100644
> > index 000000000000..00650d81c5c8
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/gnss/mediatek.txt
> > @@ -0,0 +1,37 @@
> > +Mediatek-based GNSS Receiver DT binding
> > +
> > +Mediatek chipsets are used in GNSS-receiver modules produced by several
> > +vendors and can use an UART interface.
s/an/a/
> > +
> > +Please see Documentation/devicetree/bindings/gnss/gnss.txt for generic
> > +properties.
> > +
> > +Required properties:
> > +
> > +- compatible : Must be
> > +
> > + "globaltop,pa6h"
> > +
> > +- vcc-supply : Main voltage regulator (pin name: VCC)
> > +
> > +Optional properties:
> > +
> > +- gtop,reset-gpios : GPIO used to reset the device
> > + (pin name: RESET, NRESET)
>
> reset-gpios is the standard name.
>
> > +- gtop,fix-gpios : GPIO used to determine device position fix state
> > + (pin name: FIX, 3D_FIX)
I'm thinking we might need a standard name for fix-gpios as well. This
isn't a feature that is globaltop (or mediatek) specific, and other
manufacturers provide similar functionality through pins named UI_FIX,
or even LCKIND (lock indicator).
The pin is typically used to drive an indicator LED AFAIU, but the
characteristics of the signal varies from device to device (fw to fw),
for example, pulse when no lock and low otherwise, or pulse when a 2d or
3d-fix is acquired, etc.
I'm not sure how useful the pulsing would be for software, but someone
might find a use for it in some form.
Rob, is this something we want to keep in the binding, and if so, how
about using a generic name such as "gnss-fix-gpios"?
Johan
On Mon 11 Feb 2019 at 09:22, Johan Hovold <[email protected]> wrote:
> On Wed, Jan 30, 2019 at 09:50:16AM -0600, Rob Herring wrote:
>> On Mon, Jan 28, 2019 at 05:37:59PM +0100, Loys Ollivier wrote:
>> > Add binding for Mediatek-based GNSS receivers.
>> >
>> > Signed-off-by: Loys Ollivier <[email protected]>
>> > ---
>> >
>> > v3:
>> > Removed the I2C and SPI interfaces references.
>> > Removed the "mediatek,mt3339" compatible line.
>> > Added the optional propertied (reset, fix)
>> > Added the pin names for the optional properties.
>> >
>> > v2:
>> > Renamed bindings from Globaltop/gtop to Mediatek/mtk.
>> > Moved current-speed as an optional propertie.
>> > Removed the status line in the example.
>> > Added "mediatek,mt3339" compatible.
>> >
>> > .../devicetree/bindings/gnss/mediatek.txt | 37 ++++++++++++++++++++++
>> > 1 file changed, 37 insertions(+)
>> > create mode 100644 Documentation/devicetree/bindings/gnss/mediatek.txt
>> >
>> > diff --git a/Documentation/devicetree/bindings/gnss/mediatek.txt b/Documentation/devicetree/bindings/gnss/mediatek.txt
>> > new file mode 100644
>> > index 000000000000..00650d81c5c8
>> > --- /dev/null
>> > +++ b/Documentation/devicetree/bindings/gnss/mediatek.txt
>> > @@ -0,0 +1,37 @@
>> > +Mediatek-based GNSS Receiver DT binding
>> > +
>> > +Mediatek chipsets are used in GNSS-receiver modules produced by several
>> > +vendors and can use an UART interface.
>
> s/an/a/
>
ok
>> > +
>> > +Please see Documentation/devicetree/bindings/gnss/gnss.txt for generic
>> > +properties.
>> > +
>> > +Required properties:
>> > +
>> > +- compatible : Must be
>> > +
>> > + "globaltop,pa6h"
>> > +
>> > +- vcc-supply : Main voltage regulator (pin name: VCC)
>> > +
>> > +Optional properties:
>> > +
>> > +- gtop,reset-gpios : GPIO used to reset the device
>> > + (pin name: RESET, NRESET)
>>
>> reset-gpios is the standard name.
>>
>> > +- gtop,fix-gpios : GPIO used to determine device position fix state
>> > + (pin name: FIX, 3D_FIX)
>
> I'm thinking we might need a standard name for fix-gpios as well. This
> isn't a feature that is globaltop (or mediatek) specific, and other
> manufacturers provide similar functionality through pins named UI_FIX,
> or even LCKIND (lock indicator).
>
> The pin is typically used to drive an indicator LED AFAIU, but the
> characteristics of the signal varies from device to device (fw to fw),
> for example, pulse when no lock and low otherwise, or pulse when a 2d or
> 3d-fix is acquired, etc.
>
Yes most GNSS recevivers provide a similar feature even if behavior of
the line differs.
> I'm not sure how useful the pulsing would be for software, but someone
> might find a use for it in some form.
>
Well it is useful to know when you start acquiring "valid" positionning
data. I'm using this as a trigger to start recording position.
> Rob, is this something we want to keep in the binding, and if so, how
> about using a generic name such as "gnss-fix-gpios"?
>
Name "gnss-fix-gpios" sounds good to me.
Loys
> Johan
--
-L
On Mon, Feb 11, 2019 at 3:23 AM Johan Hovold <[email protected]> wrote:
>
> On Wed, Jan 30, 2019 at 09:50:16AM -0600, Rob Herring wrote:
> > On Mon, Jan 28, 2019 at 05:37:59PM +0100, Loys Ollivier wrote:
> > > Add binding for Mediatek-based GNSS receivers.
> > >
> > > Signed-off-by: Loys Ollivier <[email protected]>
> > > ---
> > >
> > > v3:
> > > Removed the I2C and SPI interfaces references.
> > > Removed the "mediatek,mt3339" compatible line.
> > > Added the optional propertied (reset, fix)
> > > Added the pin names for the optional properties.
> > >
> > > v2:
> > > Renamed bindings from Globaltop/gtop to Mediatek/mtk.
> > > Moved current-speed as an optional propertie.
> > > Removed the status line in the example.
> > > Added "mediatek,mt3339" compatible.
> > >
> > > .../devicetree/bindings/gnss/mediatek.txt | 37 ++++++++++++++++++++++
> > > 1 file changed, 37 insertions(+)
> > > create mode 100644 Documentation/devicetree/bindings/gnss/mediatek.txt
> > >
> > > diff --git a/Documentation/devicetree/bindings/gnss/mediatek.txt b/Documentation/devicetree/bindings/gnss/mediatek.txt
> > > new file mode 100644
> > > index 000000000000..00650d81c5c8
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/gnss/mediatek.txt
> > > @@ -0,0 +1,37 @@
> > > +Mediatek-based GNSS Receiver DT binding
> > > +
> > > +Mediatek chipsets are used in GNSS-receiver modules produced by several
> > > +vendors and can use an UART interface.
>
> s/an/a/
>
> > > +
> > > +Please see Documentation/devicetree/bindings/gnss/gnss.txt for generic
> > > +properties.
> > > +
> > > +Required properties:
> > > +
> > > +- compatible : Must be
> > > +
> > > + "globaltop,pa6h"
> > > +
> > > +- vcc-supply : Main voltage regulator (pin name: VCC)
> > > +
> > > +Optional properties:
> > > +
> > > +- gtop,reset-gpios : GPIO used to reset the device
> > > + (pin name: RESET, NRESET)
> >
> > reset-gpios is the standard name.
> >
> > > +- gtop,fix-gpios : GPIO used to determine device position fix state
> > > + (pin name: FIX, 3D_FIX)
>
> I'm thinking we might need a standard name for fix-gpios as well. This
> isn't a feature that is globaltop (or mediatek) specific, and other
> manufacturers provide similar functionality through pins named UI_FIX,
> or even LCKIND (lock indicator).
>
> The pin is typically used to drive an indicator LED AFAIU, but the
> characteristics of the signal varies from device to device (fw to fw),
> for example, pulse when no lock and low otherwise, or pulse when a 2d or
> 3d-fix is acquired, etc.
>
> I'm not sure how useful the pulsing would be for software, but someone
> might find a use for it in some form.
>
> Rob, is this something we want to keep in the binding, and if so, how
> about using a generic name such as "gnss-fix-gpios"?
Sure. As long as details like being a pulse and when the pulse occurs
are implied by compatible string. So we don't get an endless addition
of properties to describe those.
Rob
On Tue, Feb 12, 2019 at 03:18:46PM -0600, Rob Herring wrote:
> On Mon, Feb 11, 2019 at 3:23 AM Johan Hovold <[email protected]> wrote:
> >
> > On Wed, Jan 30, 2019 at 09:50:16AM -0600, Rob Herring wrote:
> > > On Mon, Jan 28, 2019 at 05:37:59PM +0100, Loys Ollivier wrote:
> > > > Add binding for Mediatek-based GNSS receivers.
> > > >
> > > > Signed-off-by: Loys Ollivier <[email protected]>
> > > > +- gtop,fix-gpios : GPIO used to determine device position fix state
> > > > + (pin name: FIX, 3D_FIX)
> >
> > I'm thinking we might need a standard name for fix-gpios as well. This
> > isn't a feature that is globaltop (or mediatek) specific, and other
> > manufacturers provide similar functionality through pins named UI_FIX,
> > or even LCKIND (lock indicator).
> >
> > The pin is typically used to drive an indicator LED AFAIU, but the
> > characteristics of the signal varies from device to device (fw to fw),
> > for example, pulse when no lock and low otherwise, or pulse when a 2d or
> > 3d-fix is acquired, etc.
> >
> > I'm not sure how useful the pulsing would be for software, but someone
> > might find a use for it in some form.
> >
> > Rob, is this something we want to keep in the binding, and if so, how
> > about using a generic name such as "gnss-fix-gpios"?
>
> Sure. As long as details like being a pulse and when the pulse occurs
> are implied by compatible string. So we don't get an endless addition
> of properties to describe those.
Agreed, thanks.
Johan
On Mon, Feb 11, 2019 at 03:06:50PM +0100, Loys Ollivier wrote:
>
> On Mon 11 Feb 2019 at 09:22, Johan Hovold <[email protected]> wrote:
>
> > On Wed, Jan 30, 2019 at 09:50:16AM -0600, Rob Herring wrote:
> >> On Mon, Jan 28, 2019 at 05:37:59PM +0100, Loys Ollivier wrote:
> >> > Add binding for Mediatek-based GNSS receivers.
> >> >
> >> > Signed-off-by: Loys Ollivier <[email protected]>
> >> reset-gpios is the standard name.
> >>
> >> > +- gtop,fix-gpios : GPIO used to determine device position fix state
> >> > + (pin name: FIX, 3D_FIX)
> >
> > I'm thinking we might need a standard name for fix-gpios as well. This
> > isn't a feature that is globaltop (or mediatek) specific, and other
> > manufacturers provide similar functionality through pins named UI_FIX,
> > or even LCKIND (lock indicator).
> >
> > The pin is typically used to drive an indicator LED AFAIU, but the
> > characteristics of the signal varies from device to device (fw to fw),
> > for example, pulse when no lock and low otherwise, or pulse when a 2d or
> > 3d-fix is acquired, etc.
> >
>
> Yes most GNSS recevivers provide a similar feature even if behavior of
> the line differs.
>
> > I'm not sure how useful the pulsing would be for software, but someone
> > might find a use for it in some form.
> >
>
> Well it is useful to know when you start acquiring "valid" positionning
> data. I'm using this as a trigger to start recording position.
Sure, but a non-pulsing signal might have been easier to deal with if it
was meant to be used by software.
> > Rob, is this something we want to keep in the binding, and if so, how
> > about using a generic name such as "gnss-fix-gpios"?
>
> Name "gnss-fix-gpios" sounds good to me.
Let's go with that then.
Johan