* [PATCH v7 1/2] dt-bindings: bus: Add documentation for the Technologic Systems NBUS
@ 2017-11-01 17:14 Sebastien Bourdelin
2017-11-01 17:14 ` Sebastien Bourdelin
0 siblings, 1 reply; 11+ messages in thread
From: Sebastien Bourdelin @ 2017-11-01 17:14 UTC (permalink / raw)
To: linux-kernel, kernel, robh, linus.walleij, devicetree, linux,
fabio.estevam
Cc: mark, kris, Sebastien Bourdelin
Add binding documentation for the Technologic Systems NBUS that is used
to interface with peripherals in the FPGA of the TS-4600 SoM.
Signed-off-by: Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
---
Changes v6 -> v7:
- rebase on master
- add missing ack from Rob Herring on v4 (no changes done since)
Changes v5 -> v6:
- rebase on master
- split the previous patch series into series by subsystem
- add ack by Linus Walleij
Changes v4 -> v5:
- fix missing signed off
Changes v3 -> v4:
- rebase on master
- fix vendor prefixes for dts properties (suggested by Rob Herring)
- v3 was acked by Linus Walleij
Changes v2 -> v3:
- rebase on master
- fix typo (suggested by Rob Herring)
Changes v1 -> v2:
- rebase on master
- remove the simple-bus compatibility as the root node will now
populate child nodes (suggested by Rob Herring)
- use the ts vendor prefix for gpios (suggested by Rob Herring)
---
Documentation/devicetree/bindings/bus/ts-nbus.txt | 50 +++++++++++++++++++++++
1 file changed, 50 insertions(+)
create mode 100644 Documentation/devicetree/bindings/bus/ts-nbus.txt
diff --git a/Documentation/devicetree/bindings/bus/ts-nbus.txt b/Documentation/devicetree/bindings/bus/ts-nbus.txt
new file mode 100644
index 000000000000..2a10d065b9fa
--- /dev/null
+++ b/Documentation/devicetree/bindings/bus/ts-nbus.txt
@@ -0,0 +1,50 @@
+Technologic Systems NBUS
+
+The NBUS is a bus used to interface with peripherals in the Technologic
+Systems FPGA on the TS-4600 SoM.
+
+Required properties :
+ - compatible : "technologic,ts-nbus"
+ - #address-cells : must be 1
+ - #size-cells : must be 0
+ - pwms : The PWM bound to the FPGA
+ - ts,data-gpios : The 8 GPIO pins connected to the data lines on the FPGA
+ - ts,csn-gpios : The GPIO pin connected to the csn line on the FPGA
+ - ts,txrx-gpios : The GPIO pin connected to the txrx line on the FPGA
+ - ts,strobe-gpios : The GPIO pin connected to the stobe line on the FPGA
+ - ts,ale-gpios : The GPIO pin connected to the ale line on the FPGA
+ - ts,rdy-gpios : The GPIO pin connected to the rdy line on the FPGA
+
+Child nodes:
+
+The NBUS node can contain zero or more child nodes representing peripherals
+on the bus.
+
+Example:
+
+ nbus {
+ compatible = "technologic,ts-nbus";
+ pinctrl-0 = <&nbus_pins>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+ pwms = <&pwm 2 83>;
+ ts,data-gpios = <&gpio0 0 GPIO_ACTIVE_HIGH
+ &gpio0 1 GPIO_ACTIVE_HIGH
+ &gpio0 2 GPIO_ACTIVE_HIGH
+ &gpio0 3 GPIO_ACTIVE_HIGH
+ &gpio0 4 GPIO_ACTIVE_HIGH
+ &gpio0 5 GPIO_ACTIVE_HIGH
+ &gpio0 6 GPIO_ACTIVE_HIGH
+ &gpio0 7 GPIO_ACTIVE_HIGH>;
+ ts,csn-gpios = <&gpio0 16 GPIO_ACTIVE_HIGH>;
+ ts,txrx-gpios = <&gpio0 24 GPIO_ACTIVE_HIGH>;
+ ts,strobe-gpios = <&gpio0 25 GPIO_ACTIVE_HIGH>;
+ ts,ale-gpios = <&gpio0 26 GPIO_ACTIVE_HIGH>;
+ ts,rdy-gpios = <&gpio0 21 GPIO_ACTIVE_HIGH>;
+
+ watchdog@2a {
+ compatible = "...";
+
+ /* ... */
+ };
+ };
--
2.13.4
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH v7 2/2] bus: add driver for the Technologic Systems NBUS
@ 2017-11-01 17:14 ` Sebastien Bourdelin
0 siblings, 0 replies; 11+ messages in thread
From: Sebastien Bourdelin @ 2017-11-01 17:14 UTC (permalink / raw)
To: linux-kernel, kernel, robh, linus.walleij, devicetree, linux,
fabio.estevam
Cc: mark, kris, Sebastien Bourdelin
This driver implements a GPIOs bit-banged bus, called the NBUS by
Technologic Systems. It is used to communicate with the peripherals in
the FPGA on the TS-4600 SoM.
Signed-off-by: Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
---
Changes v6 -> v7:
- rebase on master
Changes v5 -> v6:
- rebase on master
- split the previous patch series into series by subsystem
- add ack by Linux Walleij
Changes v4 -> v5:
- fix missing signed off
Changes v3 -> v4:
- rebase on master
- fix vendor prefixes for dts properties (suggested by Rob Herring)
- v3 was acked by Linus Walleij
Changes v2 -> v3:
- rebase on master
- remove all call to the "inline" keyword in functions to let the
compiler decide when required (suggested by Linus Walleij)
- move the struct ts_nbus to the driver code instead of its header
file (suggested by Linus Walleij)
- use the bitops header and the BIT macro (suggested by Linus Walleij)
- move the mutex to the struct ts_nbus instead to have it statically
declared in the driver code (suggested by Linus Walleij)
- remove the ts_nbus_set_mode function to simplify the logic
(suggested by Linus Walleij)
- the nbus will always need 8 data lines, remove the use of the
ndescs when dealing with the data gpios and hardcode the value for
simplicity instead (suggested by Linus Walleij)
- add more comments (suggested by Linus Walleij)
- rework all the ts_nbus_read_... functions to propagate the
gpiod_get_value_... errno code (suggested by Linus Walleij)
- few typos and code reformating for lisibility
Changes v1 -> v2:
- rebase on master
- the driver now populate its child nodes
- remove the 'default y' option from the Kconfig
- rework the driver to not use singleton anymore (suggested by Linus
Walleij)
- replace the use of the legacy GPIO API with gpiod (suggested by
Linus Walleij)
- use the ts vendor prefix for gpios (suggested by Rob Herring)
---
drivers/bus/Kconfig | 8 ++
drivers/bus/Makefile | 1 +
drivers/bus/ts-nbus.c | 375 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/ts-nbus.h | 18 +++
4 files changed, 402 insertions(+)
create mode 100644 drivers/bus/ts-nbus.c
create mode 100644 include/linux/ts-nbus.h
diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
index ae3d8f3444b9..854348e646b3 100644
--- a/drivers/bus/Kconfig
+++ b/drivers/bus/Kconfig
@@ -157,6 +157,14 @@ config TEGRA_GMI
Driver for the Tegra Generic Memory Interface bus which can be used
to attach devices such as NOR, UART, FPGA and more.
+config TS_NBUS
+ tristate "Technologic Systems NBUS Driver"
+ depends on SOC_IMX28
+ depends on OF_GPIO && PWM
+ help
+ Driver for the Technologic Systems NBUS which is used to interface
+ with the peripherals in the FPGA of the TS-4600 SoM.
+
config UNIPHIER_SYSTEM_BUS
tristate "UniPhier System Bus driver"
depends on ARCH_UNIPHIER && OF
diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile
index cc6364bec054..72377f77651c 100644
--- a/drivers/bus/Makefile
+++ b/drivers/bus/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_SUNXI_RSB) += sunxi-rsb.o
obj-$(CONFIG_SIMPLE_PM_BUS) += simple-pm-bus.o
obj-$(CONFIG_TEGRA_ACONNECT) += tegra-aconnect.o
obj-$(CONFIG_TEGRA_GMI) += tegra-gmi.o
+obj-$(CONFIG_TS_NBUS) += ts-nbus.o
obj-$(CONFIG_UNIPHIER_SYSTEM_BUS) += uniphier-system-bus.o
obj-$(CONFIG_VEXPRESS_CONFIG) += vexpress-config.o
diff --git a/drivers/bus/ts-nbus.c b/drivers/bus/ts-nbus.c
new file mode 100644
index 000000000000..073fd9011154
--- /dev/null
+++ b/drivers/bus/ts-nbus.c
@@ -0,0 +1,375 @@
+/*
+ * NBUS driver for TS-4600 based boards
+ *
+ * Copyright (c) 2016 - Savoir-faire Linux
+ * Author: Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ *
+ * This driver implements a GPIOs bit-banged bus, called the NBUS by Technologic
+ * Systems. It is used to communicate with the peripherals in the FPGA on the
+ * TS-4600 SoM.
+ */
+
+#include <linux/bitops.h>
+#include <linux/gpio/consumer.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/ts-nbus.h>
+
+#define TS_NBUS_DIRECTION_IN 0
+#define TS_NBUS_DIRECTION_OUT 1
+#define TS_NBUS_WRITE_ADR 0
+#define TS_NBUS_WRITE_VAL 1
+
+struct ts_nbus {
+ struct pwm_device *pwm;
+ struct gpio_descs *data;
+ struct gpio_desc *csn;
+ struct gpio_desc *txrx;
+ struct gpio_desc *strobe;
+ struct gpio_desc *ale;
+ struct gpio_desc *rdy;
+ struct mutex lock;
+};
+
+/*
+ * request all gpios required by the bus.
+ */
+static int ts_nbus_init_pdata(struct platform_device *pdev, struct ts_nbus
+ *ts_nbus)
+{
+ ts_nbus->data = devm_gpiod_get_array(&pdev->dev, "ts,data",
+ GPIOD_OUT_HIGH);
+ if (IS_ERR(ts_nbus->data)) {
+ dev_err(&pdev->dev, "failed to retrieve ts,data-gpio from dts\n");
+ return PTR_ERR(ts_nbus->data);
+ }
+
+ ts_nbus->csn = devm_gpiod_get(&pdev->dev, "ts,csn", GPIOD_OUT_HIGH);
+ if (IS_ERR(ts_nbus->csn)) {
+ dev_err(&pdev->dev, "failed to retrieve ts,csn-gpio from dts\n");
+ return PTR_ERR(ts_nbus->csn);
+ }
+
+ ts_nbus->txrx = devm_gpiod_get(&pdev->dev, "ts,txrx", GPIOD_OUT_HIGH);
+ if (IS_ERR(ts_nbus->txrx)) {
+ dev_err(&pdev->dev, "failed to retrieve ts,txrx-gpio from dts\n");
+ return PTR_ERR(ts_nbus->txrx);
+ }
+
+ ts_nbus->strobe = devm_gpiod_get(&pdev->dev, "ts,strobe", GPIOD_OUT_HIGH);
+ if (IS_ERR(ts_nbus->strobe)) {
+ dev_err(&pdev->dev, "failed to retrieve ts,strobe-gpio from dts\n");
+ return PTR_ERR(ts_nbus->strobe);
+ }
+
+ ts_nbus->ale = devm_gpiod_get(&pdev->dev, "ts,ale", GPIOD_OUT_HIGH);
+ if (IS_ERR(ts_nbus->ale)) {
+ dev_err(&pdev->dev, "failed to retrieve ts,ale-gpio from dts\n");
+ return PTR_ERR(ts_nbus->ale);
+ }
+
+ ts_nbus->rdy = devm_gpiod_get(&pdev->dev, "ts,rdy", GPIOD_IN);
+ if (IS_ERR(ts_nbus->rdy)) {
+ dev_err(&pdev->dev, "failed to retrieve ts,rdy-gpio from dts\n");
+ return PTR_ERR(ts_nbus->rdy);
+ }
+
+ return 0;
+}
+
+/*
+ * the data gpios are used for reading and writing values, their directions
+ * should be adjusted accordingly.
+ */
+static void ts_nbus_set_direction(struct ts_nbus *ts_nbus, int direction)
+{
+ int i;
+
+ for (i = 0; i < 8; i++) {
+ if (direction == TS_NBUS_DIRECTION_IN)
+ gpiod_direction_input(ts_nbus->data->desc[i]);
+ else
+ /* when used as output the default state of the data
+ * lines are set to high */
+ gpiod_direction_output(ts_nbus->data->desc[i], 1);
+ }
+}
+
+/*
+ * reset the bus in its initial state.
+ * The data, csn, strobe and ale lines must be zero'ed to let the FPGA knows a
+ * new transaction can be process.
+ */
+static void ts_nbus_reset_bus(struct ts_nbus *ts_nbus)
+{
+ int i;
+ int values[8];
+
+ for (i = 0; i < 8; i++)
+ values[i] = 0;
+
+ gpiod_set_array_value_cansleep(8, ts_nbus->data->desc, values);
+ gpiod_set_value_cansleep(ts_nbus->csn, 0);
+ gpiod_set_value_cansleep(ts_nbus->strobe, 0);
+ gpiod_set_value_cansleep(ts_nbus->ale, 0);
+}
+
+/*
+ * let the FPGA knows it can process.
+ */
+static void ts_nbus_start_transaction(struct ts_nbus *ts_nbus)
+{
+ gpiod_set_value_cansleep(ts_nbus->strobe, 1);
+}
+
+/*
+ * read a byte value from the data gpios.
+ * return 0 on success or negative errno on failure.
+ */
+static int ts_nbus_read_byte(struct ts_nbus *ts_nbus, u8 *val)
+{
+ struct gpio_descs *gpios = ts_nbus->data;
+ int ret, i;
+
+ *val = 0;
+ for (i = 0; i < 8; i++) {
+ ret = gpiod_get_value_cansleep(gpios->desc[i]);
+ if (ret < 0)
+ return ret;
+ if (ret)
+ *val |= BIT(i);
+ }
+
+ return 0;
+}
+
+/*
+ * set the data gpios accordingly to the byte value.
+ */
+static void ts_nbus_write_byte(struct ts_nbus *ts_nbus, u8 byte)
+{
+ struct gpio_descs *gpios = ts_nbus->data;
+ int i;
+ int values[8];
+
+ for (i = 0; i < 8; i++)
+ if (byte & BIT(i))
+ values[i] = 1;
+ else
+ values[i] = 0;
+
+ gpiod_set_array_value_cansleep(8, gpios->desc, values);
+}
+
+/*
+ * reading the bus consists of resetting the bus, then notifying the FPGA to
+ * send the data in the data gpios and return the read value.
+ * return 0 on success or negative errno on failure.
+ */
+static int ts_nbus_read_bus(struct ts_nbus *ts_nbus, u8 *val)
+{
+ ts_nbus_reset_bus(ts_nbus);
+ ts_nbus_start_transaction(ts_nbus);
+
+ return ts_nbus_read_byte(ts_nbus, val);
+}
+
+/*
+ * writing to the bus consists of resetting the bus, then define the type of
+ * command (address/value), write the data and notify the FPGA to retrieve the
+ * value in the data gpios.
+ */
+static void ts_nbus_write_bus(struct ts_nbus *ts_nbus, int cmd, u8 val)
+{
+ ts_nbus_reset_bus(ts_nbus);
+
+ if (cmd == TS_NBUS_WRITE_ADR)
+ gpiod_set_value_cansleep(ts_nbus->ale, 1);
+
+ ts_nbus_write_byte(ts_nbus, val);
+ ts_nbus_start_transaction(ts_nbus);
+}
+
+/*
+ * read the value in the FPGA register at the given address.
+ * return 0 on success or negative errno on failure.
+ */
+int ts_nbus_read(struct ts_nbus *ts_nbus, u8 adr, u16 *val)
+{
+ int ret, i;
+ u8 byte;
+
+ /* bus access must be atomic */
+ mutex_lock(&ts_nbus->lock);
+
+ /* set the bus in read mode */
+ gpiod_set_value_cansleep(ts_nbus->txrx, 0);
+
+ /* write address */
+ ts_nbus_write_bus(ts_nbus, TS_NBUS_WRITE_ADR, adr);
+
+ /* set the data gpios direction as input before reading */
+ ts_nbus_set_direction(ts_nbus, TS_NBUS_DIRECTION_IN);
+
+ /* reading value MSB first */
+ do {
+ *val = 0;
+ byte = 0;
+ for (i = 1; i >= 0; i--) {
+ /* read a byte from the bus, leave on error */
+ ret = ts_nbus_read_bus(ts_nbus, &byte);
+ if (ret < 0)
+ goto err;
+
+ /* append the byte read to the final value */
+ *val |= byte << (i * 8);
+ }
+ gpiod_set_value_cansleep(ts_nbus->csn, 1);
+ ret = gpiod_get_value_cansleep(ts_nbus->rdy);
+ } while (ret);
+
+err:
+ /* restore the data gpios direction as output after reading */
+ ts_nbus_set_direction(ts_nbus, TS_NBUS_DIRECTION_OUT);
+
+ mutex_unlock(&ts_nbus->lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ts_nbus_read);
+
+/*
+ * write the desired value in the FPGA register at the given address.
+ */
+int ts_nbus_write(struct ts_nbus *ts_nbus, u8 adr, u16 val)
+{
+ int i;
+
+ /* bus access must be atomic */
+ mutex_lock(&ts_nbus->lock);
+
+ /* set the bus in write mode */
+ gpiod_set_value_cansleep(ts_nbus->txrx, 1);
+
+ /* write address */
+ ts_nbus_write_bus(ts_nbus, TS_NBUS_WRITE_ADR, adr);
+
+ /* writing value MSB first */
+ for (i = 1; i >= 0; i--)
+ ts_nbus_write_bus(ts_nbus, TS_NBUS_WRITE_VAL, (u8)(val >> (i * 8)));
+
+ /* wait for completion */
+ gpiod_set_value_cansleep(ts_nbus->csn, 1);
+ while (gpiod_get_value_cansleep(ts_nbus->rdy) != 0) {
+ gpiod_set_value_cansleep(ts_nbus->csn, 0);
+ gpiod_set_value_cansleep(ts_nbus->csn, 1);
+ }
+
+ mutex_unlock(&ts_nbus->lock);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(ts_nbus_write);
+
+static int ts_nbus_probe(struct platform_device *pdev)
+{
+ struct pwm_device *pwm;
+ struct pwm_args pargs;
+ struct device *dev = &pdev->dev;
+ struct ts_nbus *ts_nbus;
+ int ret;
+
+ ts_nbus = devm_kzalloc(dev, sizeof(*ts_nbus), GFP_KERNEL);
+ if (!ts_nbus)
+ return -ENOMEM;
+
+ mutex_init(&ts_nbus->lock);
+
+ ret = ts_nbus_init_pdata(pdev, ts_nbus);
+ if (ret < 0)
+ return ret;
+
+ pwm = devm_pwm_get(dev, NULL);
+ if (IS_ERR(pwm)) {
+ ret = PTR_ERR(pwm);
+ if (ret != -EPROBE_DEFER)
+ dev_err(dev, "unable to request PWM\n");
+ return ret;
+ }
+
+ pwm_get_args(pwm, &pargs);
+ if (!pargs.period) {
+ dev_err(&pdev->dev, "invalid PWM period\n");
+ return -EINVAL;
+ }
+
+ /*
+ * FIXME: pwm_apply_args() should be removed when switching to
+ * the atomic PWM API.
+ */
+ pwm_apply_args(pwm);
+ ret = pwm_config(pwm, pargs.period, pargs.period);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * we can now start the FPGA and populate the peripherals.
+ */
+ pwm_enable(pwm);
+ ts_nbus->pwm = pwm;
+
+ /*
+ * let the child nodes retrieve this instance of the ts-nbus.
+ */
+ dev_set_drvdata(dev, ts_nbus);
+
+ ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
+ if (ret < 0)
+ return ret;
+
+ dev_info(dev, "initialized\n");
+
+ return 0;
+}
+
+static int ts_nbus_remove(struct platform_device *pdev)
+{
+ struct ts_nbus *ts_nbus = dev_get_drvdata(&pdev->dev);
+
+ /* shutdown the FPGA */
+ mutex_lock(&ts_nbus->lock);
+ pwm_disable(ts_nbus->pwm);
+ mutex_unlock(&ts_nbus->lock);
+
+ return 0;
+}
+
+static const struct of_device_id ts_nbus_of_match[] = {
+ { .compatible = "technologic,ts-nbus", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, ts_nbus_of_match);
+
+static struct platform_driver ts_nbus_driver = {
+ .probe = ts_nbus_probe,
+ .remove = ts_nbus_remove,
+ .driver = {
+ .name = "ts_nbus",
+ .of_match_table = ts_nbus_of_match,
+ },
+};
+
+module_platform_driver(ts_nbus_driver);
+
+MODULE_ALIAS("platform:ts_nbus");
+MODULE_AUTHOR("Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>");
+MODULE_DESCRIPTION("Technologic Systems NBUS");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/ts-nbus.h b/include/linux/ts-nbus.h
new file mode 100644
index 000000000000..5bd4c822f7cf
--- /dev/null
+++ b/include/linux/ts-nbus.h
@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2016 - Savoir-faire Linux
+ * Author: Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#ifndef _TS_NBUS_H
+#define _TS_NBUS_H
+
+struct ts_nbus;
+
+extern int ts_nbus_read(struct ts_nbus *ts_nbus, u8 adr, u16 *val);
+extern int ts_nbus_write(struct ts_nbus *ts_nbus, u8 adr, u16 val);
+
+#endif /* _TS_NBUS_H */
--
2.13.4
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH v7 2/2] bus: add driver for the Technologic Systems NBUS
@ 2017-11-01 17:14 ` Sebastien Bourdelin
0 siblings, 0 replies; 11+ messages in thread
From: Sebastien Bourdelin @ 2017-11-01 17:14 UTC (permalink / raw)
To: linux-kernel-u79uwXL29TY76Z2rM5mHXA,
kernel-4ysUXcep3aM1wj+D4I0NRVaTQe2KTcn/,
robh-DgEjT+Ai2ygdnm+yROfE0A,
linus.walleij-QSEj5FYQhm4dnm+yROfE0A,
devicetree-u79uwXL29TY76Z2rM5mHXA, linux-0h96xk9xTtrk1uMJSBkQmQ,
fabio.estevam-3arQi8VN3Tc
Cc: mark-L1vi/lXTdtvnC/t2CciAbw, kris-L1vi/lXTdtvnC/t2CciAbw,
Sebastien Bourdelin
This driver implements a GPIOs bit-banged bus, called the NBUS by
Technologic Systems. It is used to communicate with the peripherals in
the FPGA on the TS-4600 SoM.
Signed-off-by: Sebastien Bourdelin <sebastien.bourdelin-4ysUXcep3aM1wj+D4I0NRVaTQe2KTcn/@public.gmane.org>
Acked-by: Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
Changes v6 -> v7:
- rebase on master
Changes v5 -> v6:
- rebase on master
- split the previous patch series into series by subsystem
- add ack by Linux Walleij
Changes v4 -> v5:
- fix missing signed off
Changes v3 -> v4:
- rebase on master
- fix vendor prefixes for dts properties (suggested by Rob Herring)
- v3 was acked by Linus Walleij
Changes v2 -> v3:
- rebase on master
- remove all call to the "inline" keyword in functions to let the
compiler decide when required (suggested by Linus Walleij)
- move the struct ts_nbus to the driver code instead of its header
file (suggested by Linus Walleij)
- use the bitops header and the BIT macro (suggested by Linus Walleij)
- move the mutex to the struct ts_nbus instead to have it statically
declared in the driver code (suggested by Linus Walleij)
- remove the ts_nbus_set_mode function to simplify the logic
(suggested by Linus Walleij)
- the nbus will always need 8 data lines, remove the use of the
ndescs when dealing with the data gpios and hardcode the value for
simplicity instead (suggested by Linus Walleij)
- add more comments (suggested by Linus Walleij)
- rework all the ts_nbus_read_... functions to propagate the
gpiod_get_value_... errno code (suggested by Linus Walleij)
- few typos and code reformating for lisibility
Changes v1 -> v2:
- rebase on master
- the driver now populate its child nodes
- remove the 'default y' option from the Kconfig
- rework the driver to not use singleton anymore (suggested by Linus
Walleij)
- replace the use of the legacy GPIO API with gpiod (suggested by
Linus Walleij)
- use the ts vendor prefix for gpios (suggested by Rob Herring)
---
drivers/bus/Kconfig | 8 ++
drivers/bus/Makefile | 1 +
drivers/bus/ts-nbus.c | 375 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/ts-nbus.h | 18 +++
4 files changed, 402 insertions(+)
create mode 100644 drivers/bus/ts-nbus.c
create mode 100644 include/linux/ts-nbus.h
diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
index ae3d8f3444b9..854348e646b3 100644
--- a/drivers/bus/Kconfig
+++ b/drivers/bus/Kconfig
@@ -157,6 +157,14 @@ config TEGRA_GMI
Driver for the Tegra Generic Memory Interface bus which can be used
to attach devices such as NOR, UART, FPGA and more.
+config TS_NBUS
+ tristate "Technologic Systems NBUS Driver"
+ depends on SOC_IMX28
+ depends on OF_GPIO && PWM
+ help
+ Driver for the Technologic Systems NBUS which is used to interface
+ with the peripherals in the FPGA of the TS-4600 SoM.
+
config UNIPHIER_SYSTEM_BUS
tristate "UniPhier System Bus driver"
depends on ARCH_UNIPHIER && OF
diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile
index cc6364bec054..72377f77651c 100644
--- a/drivers/bus/Makefile
+++ b/drivers/bus/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_SUNXI_RSB) += sunxi-rsb.o
obj-$(CONFIG_SIMPLE_PM_BUS) += simple-pm-bus.o
obj-$(CONFIG_TEGRA_ACONNECT) += tegra-aconnect.o
obj-$(CONFIG_TEGRA_GMI) += tegra-gmi.o
+obj-$(CONFIG_TS_NBUS) += ts-nbus.o
obj-$(CONFIG_UNIPHIER_SYSTEM_BUS) += uniphier-system-bus.o
obj-$(CONFIG_VEXPRESS_CONFIG) += vexpress-config.o
diff --git a/drivers/bus/ts-nbus.c b/drivers/bus/ts-nbus.c
new file mode 100644
index 000000000000..073fd9011154
--- /dev/null
+++ b/drivers/bus/ts-nbus.c
@@ -0,0 +1,375 @@
+/*
+ * NBUS driver for TS-4600 based boards
+ *
+ * Copyright (c) 2016 - Savoir-faire Linux
+ * Author: Sebastien Bourdelin <sebastien.bourdelin-4ysUXcep3aM1wj+D4I0NRVaTQe2KTcn/@public.gmane.org>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ *
+ * This driver implements a GPIOs bit-banged bus, called the NBUS by Technologic
+ * Systems. It is used to communicate with the peripherals in the FPGA on the
+ * TS-4600 SoM.
+ */
+
+#include <linux/bitops.h>
+#include <linux/gpio/consumer.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/ts-nbus.h>
+
+#define TS_NBUS_DIRECTION_IN 0
+#define TS_NBUS_DIRECTION_OUT 1
+#define TS_NBUS_WRITE_ADR 0
+#define TS_NBUS_WRITE_VAL 1
+
+struct ts_nbus {
+ struct pwm_device *pwm;
+ struct gpio_descs *data;
+ struct gpio_desc *csn;
+ struct gpio_desc *txrx;
+ struct gpio_desc *strobe;
+ struct gpio_desc *ale;
+ struct gpio_desc *rdy;
+ struct mutex lock;
+};
+
+/*
+ * request all gpios required by the bus.
+ */
+static int ts_nbus_init_pdata(struct platform_device *pdev, struct ts_nbus
+ *ts_nbus)
+{
+ ts_nbus->data = devm_gpiod_get_array(&pdev->dev, "ts,data",
+ GPIOD_OUT_HIGH);
+ if (IS_ERR(ts_nbus->data)) {
+ dev_err(&pdev->dev, "failed to retrieve ts,data-gpio from dts\n");
+ return PTR_ERR(ts_nbus->data);
+ }
+
+ ts_nbus->csn = devm_gpiod_get(&pdev->dev, "ts,csn", GPIOD_OUT_HIGH);
+ if (IS_ERR(ts_nbus->csn)) {
+ dev_err(&pdev->dev, "failed to retrieve ts,csn-gpio from dts\n");
+ return PTR_ERR(ts_nbus->csn);
+ }
+
+ ts_nbus->txrx = devm_gpiod_get(&pdev->dev, "ts,txrx", GPIOD_OUT_HIGH);
+ if (IS_ERR(ts_nbus->txrx)) {
+ dev_err(&pdev->dev, "failed to retrieve ts,txrx-gpio from dts\n");
+ return PTR_ERR(ts_nbus->txrx);
+ }
+
+ ts_nbus->strobe = devm_gpiod_get(&pdev->dev, "ts,strobe", GPIOD_OUT_HIGH);
+ if (IS_ERR(ts_nbus->strobe)) {
+ dev_err(&pdev->dev, "failed to retrieve ts,strobe-gpio from dts\n");
+ return PTR_ERR(ts_nbus->strobe);
+ }
+
+ ts_nbus->ale = devm_gpiod_get(&pdev->dev, "ts,ale", GPIOD_OUT_HIGH);
+ if (IS_ERR(ts_nbus->ale)) {
+ dev_err(&pdev->dev, "failed to retrieve ts,ale-gpio from dts\n");
+ return PTR_ERR(ts_nbus->ale);
+ }
+
+ ts_nbus->rdy = devm_gpiod_get(&pdev->dev, "ts,rdy", GPIOD_IN);
+ if (IS_ERR(ts_nbus->rdy)) {
+ dev_err(&pdev->dev, "failed to retrieve ts,rdy-gpio from dts\n");
+ return PTR_ERR(ts_nbus->rdy);
+ }
+
+ return 0;
+}
+
+/*
+ * the data gpios are used for reading and writing values, their directions
+ * should be adjusted accordingly.
+ */
+static void ts_nbus_set_direction(struct ts_nbus *ts_nbus, int direction)
+{
+ int i;
+
+ for (i = 0; i < 8; i++) {
+ if (direction == TS_NBUS_DIRECTION_IN)
+ gpiod_direction_input(ts_nbus->data->desc[i]);
+ else
+ /* when used as output the default state of the data
+ * lines are set to high */
+ gpiod_direction_output(ts_nbus->data->desc[i], 1);
+ }
+}
+
+/*
+ * reset the bus in its initial state.
+ * The data, csn, strobe and ale lines must be zero'ed to let the FPGA knows a
+ * new transaction can be process.
+ */
+static void ts_nbus_reset_bus(struct ts_nbus *ts_nbus)
+{
+ int i;
+ int values[8];
+
+ for (i = 0; i < 8; i++)
+ values[i] = 0;
+
+ gpiod_set_array_value_cansleep(8, ts_nbus->data->desc, values);
+ gpiod_set_value_cansleep(ts_nbus->csn, 0);
+ gpiod_set_value_cansleep(ts_nbus->strobe, 0);
+ gpiod_set_value_cansleep(ts_nbus->ale, 0);
+}
+
+/*
+ * let the FPGA knows it can process.
+ */
+static void ts_nbus_start_transaction(struct ts_nbus *ts_nbus)
+{
+ gpiod_set_value_cansleep(ts_nbus->strobe, 1);
+}
+
+/*
+ * read a byte value from the data gpios.
+ * return 0 on success or negative errno on failure.
+ */
+static int ts_nbus_read_byte(struct ts_nbus *ts_nbus, u8 *val)
+{
+ struct gpio_descs *gpios = ts_nbus->data;
+ int ret, i;
+
+ *val = 0;
+ for (i = 0; i < 8; i++) {
+ ret = gpiod_get_value_cansleep(gpios->desc[i]);
+ if (ret < 0)
+ return ret;
+ if (ret)
+ *val |= BIT(i);
+ }
+
+ return 0;
+}
+
+/*
+ * set the data gpios accordingly to the byte value.
+ */
+static void ts_nbus_write_byte(struct ts_nbus *ts_nbus, u8 byte)
+{
+ struct gpio_descs *gpios = ts_nbus->data;
+ int i;
+ int values[8];
+
+ for (i = 0; i < 8; i++)
+ if (byte & BIT(i))
+ values[i] = 1;
+ else
+ values[i] = 0;
+
+ gpiod_set_array_value_cansleep(8, gpios->desc, values);
+}
+
+/*
+ * reading the bus consists of resetting the bus, then notifying the FPGA to
+ * send the data in the data gpios and return the read value.
+ * return 0 on success or negative errno on failure.
+ */
+static int ts_nbus_read_bus(struct ts_nbus *ts_nbus, u8 *val)
+{
+ ts_nbus_reset_bus(ts_nbus);
+ ts_nbus_start_transaction(ts_nbus);
+
+ return ts_nbus_read_byte(ts_nbus, val);
+}
+
+/*
+ * writing to the bus consists of resetting the bus, then define the type of
+ * command (address/value), write the data and notify the FPGA to retrieve the
+ * value in the data gpios.
+ */
+static void ts_nbus_write_bus(struct ts_nbus *ts_nbus, int cmd, u8 val)
+{
+ ts_nbus_reset_bus(ts_nbus);
+
+ if (cmd == TS_NBUS_WRITE_ADR)
+ gpiod_set_value_cansleep(ts_nbus->ale, 1);
+
+ ts_nbus_write_byte(ts_nbus, val);
+ ts_nbus_start_transaction(ts_nbus);
+}
+
+/*
+ * read the value in the FPGA register at the given address.
+ * return 0 on success or negative errno on failure.
+ */
+int ts_nbus_read(struct ts_nbus *ts_nbus, u8 adr, u16 *val)
+{
+ int ret, i;
+ u8 byte;
+
+ /* bus access must be atomic */
+ mutex_lock(&ts_nbus->lock);
+
+ /* set the bus in read mode */
+ gpiod_set_value_cansleep(ts_nbus->txrx, 0);
+
+ /* write address */
+ ts_nbus_write_bus(ts_nbus, TS_NBUS_WRITE_ADR, adr);
+
+ /* set the data gpios direction as input before reading */
+ ts_nbus_set_direction(ts_nbus, TS_NBUS_DIRECTION_IN);
+
+ /* reading value MSB first */
+ do {
+ *val = 0;
+ byte = 0;
+ for (i = 1; i >= 0; i--) {
+ /* read a byte from the bus, leave on error */
+ ret = ts_nbus_read_bus(ts_nbus, &byte);
+ if (ret < 0)
+ goto err;
+
+ /* append the byte read to the final value */
+ *val |= byte << (i * 8);
+ }
+ gpiod_set_value_cansleep(ts_nbus->csn, 1);
+ ret = gpiod_get_value_cansleep(ts_nbus->rdy);
+ } while (ret);
+
+err:
+ /* restore the data gpios direction as output after reading */
+ ts_nbus_set_direction(ts_nbus, TS_NBUS_DIRECTION_OUT);
+
+ mutex_unlock(&ts_nbus->lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ts_nbus_read);
+
+/*
+ * write the desired value in the FPGA register at the given address.
+ */
+int ts_nbus_write(struct ts_nbus *ts_nbus, u8 adr, u16 val)
+{
+ int i;
+
+ /* bus access must be atomic */
+ mutex_lock(&ts_nbus->lock);
+
+ /* set the bus in write mode */
+ gpiod_set_value_cansleep(ts_nbus->txrx, 1);
+
+ /* write address */
+ ts_nbus_write_bus(ts_nbus, TS_NBUS_WRITE_ADR, adr);
+
+ /* writing value MSB first */
+ for (i = 1; i >= 0; i--)
+ ts_nbus_write_bus(ts_nbus, TS_NBUS_WRITE_VAL, (u8)(val >> (i * 8)));
+
+ /* wait for completion */
+ gpiod_set_value_cansleep(ts_nbus->csn, 1);
+ while (gpiod_get_value_cansleep(ts_nbus->rdy) != 0) {
+ gpiod_set_value_cansleep(ts_nbus->csn, 0);
+ gpiod_set_value_cansleep(ts_nbus->csn, 1);
+ }
+
+ mutex_unlock(&ts_nbus->lock);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(ts_nbus_write);
+
+static int ts_nbus_probe(struct platform_device *pdev)
+{
+ struct pwm_device *pwm;
+ struct pwm_args pargs;
+ struct device *dev = &pdev->dev;
+ struct ts_nbus *ts_nbus;
+ int ret;
+
+ ts_nbus = devm_kzalloc(dev, sizeof(*ts_nbus), GFP_KERNEL);
+ if (!ts_nbus)
+ return -ENOMEM;
+
+ mutex_init(&ts_nbus->lock);
+
+ ret = ts_nbus_init_pdata(pdev, ts_nbus);
+ if (ret < 0)
+ return ret;
+
+ pwm = devm_pwm_get(dev, NULL);
+ if (IS_ERR(pwm)) {
+ ret = PTR_ERR(pwm);
+ if (ret != -EPROBE_DEFER)
+ dev_err(dev, "unable to request PWM\n");
+ return ret;
+ }
+
+ pwm_get_args(pwm, &pargs);
+ if (!pargs.period) {
+ dev_err(&pdev->dev, "invalid PWM period\n");
+ return -EINVAL;
+ }
+
+ /*
+ * FIXME: pwm_apply_args() should be removed when switching to
+ * the atomic PWM API.
+ */
+ pwm_apply_args(pwm);
+ ret = pwm_config(pwm, pargs.period, pargs.period);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * we can now start the FPGA and populate the peripherals.
+ */
+ pwm_enable(pwm);
+ ts_nbus->pwm = pwm;
+
+ /*
+ * let the child nodes retrieve this instance of the ts-nbus.
+ */
+ dev_set_drvdata(dev, ts_nbus);
+
+ ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
+ if (ret < 0)
+ return ret;
+
+ dev_info(dev, "initialized\n");
+
+ return 0;
+}
+
+static int ts_nbus_remove(struct platform_device *pdev)
+{
+ struct ts_nbus *ts_nbus = dev_get_drvdata(&pdev->dev);
+
+ /* shutdown the FPGA */
+ mutex_lock(&ts_nbus->lock);
+ pwm_disable(ts_nbus->pwm);
+ mutex_unlock(&ts_nbus->lock);
+
+ return 0;
+}
+
+static const struct of_device_id ts_nbus_of_match[] = {
+ { .compatible = "technologic,ts-nbus", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, ts_nbus_of_match);
+
+static struct platform_driver ts_nbus_driver = {
+ .probe = ts_nbus_probe,
+ .remove = ts_nbus_remove,
+ .driver = {
+ .name = "ts_nbus",
+ .of_match_table = ts_nbus_of_match,
+ },
+};
+
+module_platform_driver(ts_nbus_driver);
+
+MODULE_ALIAS("platform:ts_nbus");
+MODULE_AUTHOR("Sebastien Bourdelin <sebastien.bourdelin-4ysUXcep3aM1wj+D4I0NRVaTQe2KTcn/@public.gmane.org>");
+MODULE_DESCRIPTION("Technologic Systems NBUS");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/ts-nbus.h b/include/linux/ts-nbus.h
new file mode 100644
index 000000000000..5bd4c822f7cf
--- /dev/null
+++ b/include/linux/ts-nbus.h
@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2016 - Savoir-faire Linux
+ * Author: Sebastien Bourdelin <sebastien.bourdelin-4ysUXcep3aM1wj+D4I0NRVaTQe2KTcn/@public.gmane.org>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#ifndef _TS_NBUS_H
+#define _TS_NBUS_H
+
+struct ts_nbus;
+
+extern int ts_nbus_read(struct ts_nbus *ts_nbus, u8 adr, u16 *val);
+extern int ts_nbus_write(struct ts_nbus *ts_nbus, u8 adr, u16 val);
+
+#endif /* _TS_NBUS_H */
--
2.13.4
--
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^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [PATCH v7 2/2] bus: add driver for the Technologic Systems NBUS
2017-11-01 17:14 ` Sebastien Bourdelin
(?)
@ 2017-11-02 14:22 ` Linus Walleij
2017-11-02 14:37 ` Sebastien Bourdelin
-1 siblings, 1 reply; 11+ messages in thread
From: Linus Walleij @ 2017-11-02 14:22 UTC (permalink / raw)
To: Sebastien Bourdelin
Cc: linux-kernel, kernel, Rob Herring, devicetree, Guenter Roeck,
Fabio Estevam, Mark Featherston, kris
On Wed, Nov 1, 2017 at 6:14 PM, Sebastien Bourdelin
<sebastien.bourdelin@savoirfairelinux.com> wrote:
> This driver implements a GPIOs bit-banged bus, called the NBUS by
> Technologic Systems. It is used to communicate with the peripherals in
> the FPGA on the TS-4600 SoM.
>
> Signed-off-by: Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>
> Acked-by: Linus Walleij <linus.walleij@linaro.org>
This is still a very nice driver.
If you are working on supplemental patches: from the next merge window
we will have:
+ int gpiod_get_array_value_cansleep(unsigned int array_size,
+ struct gpio_desc **desc_array,
+ int *value_array);
See:
https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio.git/commit/?h=devel&id=eec1d566cdf94b57e8f5ba9fe60eea214929bcfc
If your GPIO controller also has .get_multiple() implemented it just
becomes one register read if you're lucky.
BTW do you have a way upstream for this patch? ARM SoC?
Yours,
Linus Walleij
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v7 2/2] bus: add driver for the Technologic Systems NBUS
2017-11-02 14:22 ` Linus Walleij
@ 2017-11-02 14:37 ` Sebastien Bourdelin
2017-11-02 15:57 ` Linus Walleij
0 siblings, 1 reply; 11+ messages in thread
From: Sebastien Bourdelin @ 2017-11-02 14:37 UTC (permalink / raw)
To: Linus Walleij
Cc: linux-kernel, kernel, Rob Herring, devicetree, Guenter Roeck,
Fabio Estevam, Mark Featherston, kris
Hi Linus,
On 11/02/2017 10:22 AM, Linus Walleij wrote:
> On Wed, Nov 1, 2017 at 6:14 PM, Sebastien Bourdelin
> <sebastien.bourdelin@savoirfairelinux.com> wrote:
>
>> This driver implements a GPIOs bit-banged bus, called the NBUS by
>> Technologic Systems. It is used to communicate with the peripherals in
>> the FPGA on the TS-4600 SoM.
>>
>> Signed-off-by: Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>
>> Acked-by: Linus Walleij <linus.walleij@linaro.org>
>
> This is still a very nice driver.
Thanks that's very kind and greatly appreciate.
>
> If you are working on supplemental patches: from the next merge window
> we will have:
>
> + int gpiod_get_array_value_cansleep(unsigned int array_size,
> + struct gpio_desc **desc_array,
> + int *value_array);
>
> See:
> https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio.git/commit/?h=devel&id=eec1d566cdf94b57e8f5ba9fe60eea214929bcfc
>
> If your GPIO controller also has .get_multiple() implemented it just
> becomes one register read if you're lucky.
>
Ok, i guess i will not if this is fine like that, i'll see if someone
suggested some changes.
> BTW do you have a way upstream for this patch? ARM SoC?
Honestly i have no idea, do you have a recommandation for this kind of
bus driver? should i re-submit just this patch to a specific tree?
>
> Yours,
> Linus Walleij
>
Thanks again for your inputs.
Best regards,
Sebastien Bourdelin.
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v7 2/2] bus: add driver for the Technologic Systems NBUS
2017-11-02 14:37 ` Sebastien Bourdelin
@ 2017-11-02 15:57 ` Linus Walleij
2017-11-02 16:10 ` Sebastien Bourdelin
0 siblings, 1 reply; 11+ messages in thread
From: Linus Walleij @ 2017-11-02 15:57 UTC (permalink / raw)
To: Sebastien Bourdelin
Cc: linux-kernel, kernel, Rob Herring, devicetree, Guenter Roeck,
Fabio Estevam, Mark Featherston, kris
On Thu, Nov 2, 2017 at 3:37 PM, Sebastien Bourdelin
<sebastien.bourdelin@savoirfairelinux.com> wrote:
>> BTW do you have a way upstream for this patch? ARM SoC?
>
> Honestly i have no idea, do you have a recommandation for this kind of
> bus driver? should i re-submit just this patch to a specific tree?
If this is for an ARM system I would suggest that you just sent
the patches to arm@kernel.org with CC to the linux-arm-kernel
mailing list and ask the ARM SoC maintainers to apply them directly
for the upstream kernel.
Yours,
Linus Walleij
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v7 2/2] bus: add driver for the Technologic Systems NBUS
@ 2017-11-02 16:10 ` Sebastien Bourdelin
0 siblings, 0 replies; 11+ messages in thread
From: Sebastien Bourdelin @ 2017-11-02 16:10 UTC (permalink / raw)
To: Linus Walleij
Cc: linux-kernel, kernel, Rob Herring, devicetree, Guenter Roeck,
Fabio Estevam, Mark Featherston, kris
On 11/02/2017 11:57 AM, Linus Walleij wrote:
> On Thu, Nov 2, 2017 at 3:37 PM, Sebastien Bourdelin
> <sebastien.bourdelin@savoirfairelinux.com> wrote:
>
>>> BTW do you have a way upstream for this patch? ARM SoC?
>>
>> Honestly i have no idea, do you have a recommandation for this kind of
>> bus driver? should i re-submit just this patch to a specific tree?
>
> If this is for an ARM system I would suggest that you just sent
> the patches to arm@kernel.org with CC to the linux-arm-kernel
> mailing list and ask the ARM SoC maintainers to apply them directly
> for the upstream kernel.
>
Ok, i will, thanks again!
> Yours,
> Linus Walleij
>
Best Regards,
Sebastien Bourdelin.
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v7 2/2] bus: add driver for the Technologic Systems NBUS
@ 2017-11-02 16:10 ` Sebastien Bourdelin
0 siblings, 0 replies; 11+ messages in thread
From: Sebastien Bourdelin @ 2017-11-02 16:10 UTC (permalink / raw)
To: Linus Walleij
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA, kernel, Rob Herring,
devicetree-u79uwXL29TY76Z2rM5mHXA, Guenter Roeck, Fabio Estevam,
Mark Featherston, kris-L1vi/lXTdtvnC/t2CciAbw
On 11/02/2017 11:57 AM, Linus Walleij wrote:
> On Thu, Nov 2, 2017 at 3:37 PM, Sebastien Bourdelin
> <sebastien.bourdelin-4ysUXcep3aM1wj+D4I0NRVaTQe2KTcn/@public.gmane.org> wrote:
>
>>> BTW do you have a way upstream for this patch? ARM SoC?
>>
>> Honestly i have no idea, do you have a recommandation for this kind of
>> bus driver? should i re-submit just this patch to a specific tree?
>
> If this is for an ARM system I would suggest that you just sent
> the patches to arm-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org with CC to the linux-arm-kernel
> mailing list and ask the ARM SoC maintainers to apply them directly
> for the upstream kernel.
>
Ok, i will, thanks again!
> Yours,
> Linus Walleij
>
Best Regards,
Sebastien Bourdelin.
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^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v7 2/2] bus: add driver for the Technologic Systems NBUS
@ 2017-11-07 15:29 ` Arnd Bergmann
0 siblings, 0 replies; 11+ messages in thread
From: Arnd Bergmann @ 2017-11-07 15:29 UTC (permalink / raw)
To: Sebastien Bourdelin
Cc: Linux Kernel Mailing List, kernel, Rob Herring, Linus Walleij,
DTML, Guenter Roeck, Fabio Estevam, mark, kris
On Wed, Nov 1, 2017 at 6:14 PM, Sebastien Bourdelin
<sebastien.bourdelin@savoirfairelinux.com> wrote:
> This driver implements a GPIOs bit-banged bus, called the NBUS by
> Technologic Systems. It is used to communicate with the peripherals in
> the FPGA on the TS-4600 SoM.
>
> Signed-off-by: Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>
> Acked-by: Linus Walleij <linus.walleij@linaro.org>
Applied to next/drivers, thanks!
Arnd
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v7 2/2] bus: add driver for the Technologic Systems NBUS
@ 2017-11-07 15:29 ` Arnd Bergmann
0 siblings, 0 replies; 11+ messages in thread
From: Arnd Bergmann @ 2017-11-07 15:29 UTC (permalink / raw)
To: Sebastien Bourdelin
Cc: Linux Kernel Mailing List,
kernel-4ysUXcep3aM1wj+D4I0NRVaTQe2KTcn/,
Rob Herring, Linus Walleij, DTML, Guenter Roeck, Fabio Estevam,
mark-L1vi/lXTdtvnC/t2CciAbw, kris-L1vi/lXTdtvnC/t2CciAbw
On Wed, Nov 1, 2017 at 6:14 PM, Sebastien Bourdelin
<sebastien.bourdelin-4ysUXcep3aM1wj+D4I0NRVaTQe2KTcn/@public.gmane.org> wrote:
> This driver implements a GPIOs bit-banged bus, called the NBUS by
> Technologic Systems. It is used to communicate with the peripherals in
> the FPGA on the TS-4600 SoM.
>
> Signed-off-by: Sebastien Bourdelin <sebastien.bourdelin-4ysUXcep3aM1wj+D4I0NRVaTQe2KTcn/@public.gmane.org>
> Acked-by: Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Applied to next/drivers, thanks!
Arnd
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^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH v7 2/2] bus: add driver for the Technologic Systems NBUS
2017-11-02 18:17 [PATCH v7 0/2] add support " Sebastien Bourdelin
@ 2017-11-02 18:17 ` Sebastien Bourdelin
0 siblings, 0 replies; 11+ messages in thread
From: Sebastien Bourdelin @ 2017-11-02 18:17 UTC (permalink / raw)
To: linux-arm-kernel
This driver implements a GPIOs bit-banged bus, called the NBUS by
Technologic Systems. It is used to communicate with the peripherals in
the FPGA on the TS-4600 SoM.
Signed-off-by: Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
---
Changes v6 -> v7:
- rebase on master
Changes v5 -> v6:
- rebase on master
- split the previous patch series into series by subsystem
- add ack by Linux Walleij
Changes v4 -> v5:
- fix missing signed off
Changes v3 -> v4:
- rebase on master
- fix vendor prefixes for dts properties (suggested by Rob Herring)
- v3 was acked by Linus Walleij
Changes v2 -> v3:
- rebase on master
- remove all call to the "inline" keyword in functions to let the
compiler decide when required (suggested by Linus Walleij)
- move the struct ts_nbus to the driver code instead of its header
file (suggested by Linus Walleij)
- use the bitops header and the BIT macro (suggested by Linus Walleij)
- move the mutex to the struct ts_nbus instead to have it statically
declared in the driver code (suggested by Linus Walleij)
- remove the ts_nbus_set_mode function to simplify the logic
(suggested by Linus Walleij)
- the nbus will always need 8 data lines, remove the use of the
ndescs when dealing with the data gpios and hardcode the value for
simplicity instead (suggested by Linus Walleij)
- add more comments (suggested by Linus Walleij)
- rework all the ts_nbus_read_... functions to propagate the
gpiod_get_value_... errno code (suggested by Linus Walleij)
- few typos and code reformating for lisibility
Changes v1 -> v2:
- rebase on master
- the driver now populate its child nodes
- remove the 'default y' option from the Kconfig
- rework the driver to not use singleton anymore (suggested by Linus
Walleij)
- replace the use of the legacy GPIO API with gpiod (suggested by
Linus Walleij)
- use the ts vendor prefix for gpios (suggested by Rob Herring)
---
drivers/bus/Kconfig | 8 ++
drivers/bus/Makefile | 1 +
drivers/bus/ts-nbus.c | 375 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/ts-nbus.h | 18 +++
4 files changed, 402 insertions(+)
create mode 100644 drivers/bus/ts-nbus.c
create mode 100644 include/linux/ts-nbus.h
diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
index ae3d8f3444b9..854348e646b3 100644
--- a/drivers/bus/Kconfig
+++ b/drivers/bus/Kconfig
@@ -157,6 +157,14 @@ config TEGRA_GMI
Driver for the Tegra Generic Memory Interface bus which can be used
to attach devices such as NOR, UART, FPGA and more.
+config TS_NBUS
+ tristate "Technologic Systems NBUS Driver"
+ depends on SOC_IMX28
+ depends on OF_GPIO && PWM
+ help
+ Driver for the Technologic Systems NBUS which is used to interface
+ with the peripherals in the FPGA of the TS-4600 SoM.
+
config UNIPHIER_SYSTEM_BUS
tristate "UniPhier System Bus driver"
depends on ARCH_UNIPHIER && OF
diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile
index cc6364bec054..72377f77651c 100644
--- a/drivers/bus/Makefile
+++ b/drivers/bus/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_SUNXI_RSB) += sunxi-rsb.o
obj-$(CONFIG_SIMPLE_PM_BUS) += simple-pm-bus.o
obj-$(CONFIG_TEGRA_ACONNECT) += tegra-aconnect.o
obj-$(CONFIG_TEGRA_GMI) += tegra-gmi.o
+obj-$(CONFIG_TS_NBUS) += ts-nbus.o
obj-$(CONFIG_UNIPHIER_SYSTEM_BUS) += uniphier-system-bus.o
obj-$(CONFIG_VEXPRESS_CONFIG) += vexpress-config.o
diff --git a/drivers/bus/ts-nbus.c b/drivers/bus/ts-nbus.c
new file mode 100644
index 000000000000..073fd9011154
--- /dev/null
+++ b/drivers/bus/ts-nbus.c
@@ -0,0 +1,375 @@
+/*
+ * NBUS driver for TS-4600 based boards
+ *
+ * Copyright (c) 2016 - Savoir-faire Linux
+ * Author: Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ *
+ * This driver implements a GPIOs bit-banged bus, called the NBUS by Technologic
+ * Systems. It is used to communicate with the peripherals in the FPGA on the
+ * TS-4600 SoM.
+ */
+
+#include <linux/bitops.h>
+#include <linux/gpio/consumer.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/ts-nbus.h>
+
+#define TS_NBUS_DIRECTION_IN 0
+#define TS_NBUS_DIRECTION_OUT 1
+#define TS_NBUS_WRITE_ADR 0
+#define TS_NBUS_WRITE_VAL 1
+
+struct ts_nbus {
+ struct pwm_device *pwm;
+ struct gpio_descs *data;
+ struct gpio_desc *csn;
+ struct gpio_desc *txrx;
+ struct gpio_desc *strobe;
+ struct gpio_desc *ale;
+ struct gpio_desc *rdy;
+ struct mutex lock;
+};
+
+/*
+ * request all gpios required by the bus.
+ */
+static int ts_nbus_init_pdata(struct platform_device *pdev, struct ts_nbus
+ *ts_nbus)
+{
+ ts_nbus->data = devm_gpiod_get_array(&pdev->dev, "ts,data",
+ GPIOD_OUT_HIGH);
+ if (IS_ERR(ts_nbus->data)) {
+ dev_err(&pdev->dev, "failed to retrieve ts,data-gpio from dts\n");
+ return PTR_ERR(ts_nbus->data);
+ }
+
+ ts_nbus->csn = devm_gpiod_get(&pdev->dev, "ts,csn", GPIOD_OUT_HIGH);
+ if (IS_ERR(ts_nbus->csn)) {
+ dev_err(&pdev->dev, "failed to retrieve ts,csn-gpio from dts\n");
+ return PTR_ERR(ts_nbus->csn);
+ }
+
+ ts_nbus->txrx = devm_gpiod_get(&pdev->dev, "ts,txrx", GPIOD_OUT_HIGH);
+ if (IS_ERR(ts_nbus->txrx)) {
+ dev_err(&pdev->dev, "failed to retrieve ts,txrx-gpio from dts\n");
+ return PTR_ERR(ts_nbus->txrx);
+ }
+
+ ts_nbus->strobe = devm_gpiod_get(&pdev->dev, "ts,strobe", GPIOD_OUT_HIGH);
+ if (IS_ERR(ts_nbus->strobe)) {
+ dev_err(&pdev->dev, "failed to retrieve ts,strobe-gpio from dts\n");
+ return PTR_ERR(ts_nbus->strobe);
+ }
+
+ ts_nbus->ale = devm_gpiod_get(&pdev->dev, "ts,ale", GPIOD_OUT_HIGH);
+ if (IS_ERR(ts_nbus->ale)) {
+ dev_err(&pdev->dev, "failed to retrieve ts,ale-gpio from dts\n");
+ return PTR_ERR(ts_nbus->ale);
+ }
+
+ ts_nbus->rdy = devm_gpiod_get(&pdev->dev, "ts,rdy", GPIOD_IN);
+ if (IS_ERR(ts_nbus->rdy)) {
+ dev_err(&pdev->dev, "failed to retrieve ts,rdy-gpio from dts\n");
+ return PTR_ERR(ts_nbus->rdy);
+ }
+
+ return 0;
+}
+
+/*
+ * the data gpios are used for reading and writing values, their directions
+ * should be adjusted accordingly.
+ */
+static void ts_nbus_set_direction(struct ts_nbus *ts_nbus, int direction)
+{
+ int i;
+
+ for (i = 0; i < 8; i++) {
+ if (direction == TS_NBUS_DIRECTION_IN)
+ gpiod_direction_input(ts_nbus->data->desc[i]);
+ else
+ /* when used as output the default state of the data
+ * lines are set to high */
+ gpiod_direction_output(ts_nbus->data->desc[i], 1);
+ }
+}
+
+/*
+ * reset the bus in its initial state.
+ * The data, csn, strobe and ale lines must be zero'ed to let the FPGA knows a
+ * new transaction can be process.
+ */
+static void ts_nbus_reset_bus(struct ts_nbus *ts_nbus)
+{
+ int i;
+ int values[8];
+
+ for (i = 0; i < 8; i++)
+ values[i] = 0;
+
+ gpiod_set_array_value_cansleep(8, ts_nbus->data->desc, values);
+ gpiod_set_value_cansleep(ts_nbus->csn, 0);
+ gpiod_set_value_cansleep(ts_nbus->strobe, 0);
+ gpiod_set_value_cansleep(ts_nbus->ale, 0);
+}
+
+/*
+ * let the FPGA knows it can process.
+ */
+static void ts_nbus_start_transaction(struct ts_nbus *ts_nbus)
+{
+ gpiod_set_value_cansleep(ts_nbus->strobe, 1);
+}
+
+/*
+ * read a byte value from the data gpios.
+ * return 0 on success or negative errno on failure.
+ */
+static int ts_nbus_read_byte(struct ts_nbus *ts_nbus, u8 *val)
+{
+ struct gpio_descs *gpios = ts_nbus->data;
+ int ret, i;
+
+ *val = 0;
+ for (i = 0; i < 8; i++) {
+ ret = gpiod_get_value_cansleep(gpios->desc[i]);
+ if (ret < 0)
+ return ret;
+ if (ret)
+ *val |= BIT(i);
+ }
+
+ return 0;
+}
+
+/*
+ * set the data gpios accordingly to the byte value.
+ */
+static void ts_nbus_write_byte(struct ts_nbus *ts_nbus, u8 byte)
+{
+ struct gpio_descs *gpios = ts_nbus->data;
+ int i;
+ int values[8];
+
+ for (i = 0; i < 8; i++)
+ if (byte & BIT(i))
+ values[i] = 1;
+ else
+ values[i] = 0;
+
+ gpiod_set_array_value_cansleep(8, gpios->desc, values);
+}
+
+/*
+ * reading the bus consists of resetting the bus, then notifying the FPGA to
+ * send the data in the data gpios and return the read value.
+ * return 0 on success or negative errno on failure.
+ */
+static int ts_nbus_read_bus(struct ts_nbus *ts_nbus, u8 *val)
+{
+ ts_nbus_reset_bus(ts_nbus);
+ ts_nbus_start_transaction(ts_nbus);
+
+ return ts_nbus_read_byte(ts_nbus, val);
+}
+
+/*
+ * writing to the bus consists of resetting the bus, then define the type of
+ * command (address/value), write the data and notify the FPGA to retrieve the
+ * value in the data gpios.
+ */
+static void ts_nbus_write_bus(struct ts_nbus *ts_nbus, int cmd, u8 val)
+{
+ ts_nbus_reset_bus(ts_nbus);
+
+ if (cmd == TS_NBUS_WRITE_ADR)
+ gpiod_set_value_cansleep(ts_nbus->ale, 1);
+
+ ts_nbus_write_byte(ts_nbus, val);
+ ts_nbus_start_transaction(ts_nbus);
+}
+
+/*
+ * read the value in the FPGA register at the given address.
+ * return 0 on success or negative errno on failure.
+ */
+int ts_nbus_read(struct ts_nbus *ts_nbus, u8 adr, u16 *val)
+{
+ int ret, i;
+ u8 byte;
+
+ /* bus access must be atomic */
+ mutex_lock(&ts_nbus->lock);
+
+ /* set the bus in read mode */
+ gpiod_set_value_cansleep(ts_nbus->txrx, 0);
+
+ /* write address */
+ ts_nbus_write_bus(ts_nbus, TS_NBUS_WRITE_ADR, adr);
+
+ /* set the data gpios direction as input before reading */
+ ts_nbus_set_direction(ts_nbus, TS_NBUS_DIRECTION_IN);
+
+ /* reading value MSB first */
+ do {
+ *val = 0;
+ byte = 0;
+ for (i = 1; i >= 0; i--) {
+ /* read a byte from the bus, leave on error */
+ ret = ts_nbus_read_bus(ts_nbus, &byte);
+ if (ret < 0)
+ goto err;
+
+ /* append the byte read to the final value */
+ *val |= byte << (i * 8);
+ }
+ gpiod_set_value_cansleep(ts_nbus->csn, 1);
+ ret = gpiod_get_value_cansleep(ts_nbus->rdy);
+ } while (ret);
+
+err:
+ /* restore the data gpios direction as output after reading */
+ ts_nbus_set_direction(ts_nbus, TS_NBUS_DIRECTION_OUT);
+
+ mutex_unlock(&ts_nbus->lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ts_nbus_read);
+
+/*
+ * write the desired value in the FPGA register at the given address.
+ */
+int ts_nbus_write(struct ts_nbus *ts_nbus, u8 adr, u16 val)
+{
+ int i;
+
+ /* bus access must be atomic */
+ mutex_lock(&ts_nbus->lock);
+
+ /* set the bus in write mode */
+ gpiod_set_value_cansleep(ts_nbus->txrx, 1);
+
+ /* write address */
+ ts_nbus_write_bus(ts_nbus, TS_NBUS_WRITE_ADR, adr);
+
+ /* writing value MSB first */
+ for (i = 1; i >= 0; i--)
+ ts_nbus_write_bus(ts_nbus, TS_NBUS_WRITE_VAL, (u8)(val >> (i * 8)));
+
+ /* wait for completion */
+ gpiod_set_value_cansleep(ts_nbus->csn, 1);
+ while (gpiod_get_value_cansleep(ts_nbus->rdy) != 0) {
+ gpiod_set_value_cansleep(ts_nbus->csn, 0);
+ gpiod_set_value_cansleep(ts_nbus->csn, 1);
+ }
+
+ mutex_unlock(&ts_nbus->lock);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(ts_nbus_write);
+
+static int ts_nbus_probe(struct platform_device *pdev)
+{
+ struct pwm_device *pwm;
+ struct pwm_args pargs;
+ struct device *dev = &pdev->dev;
+ struct ts_nbus *ts_nbus;
+ int ret;
+
+ ts_nbus = devm_kzalloc(dev, sizeof(*ts_nbus), GFP_KERNEL);
+ if (!ts_nbus)
+ return -ENOMEM;
+
+ mutex_init(&ts_nbus->lock);
+
+ ret = ts_nbus_init_pdata(pdev, ts_nbus);
+ if (ret < 0)
+ return ret;
+
+ pwm = devm_pwm_get(dev, NULL);
+ if (IS_ERR(pwm)) {
+ ret = PTR_ERR(pwm);
+ if (ret != -EPROBE_DEFER)
+ dev_err(dev, "unable to request PWM\n");
+ return ret;
+ }
+
+ pwm_get_args(pwm, &pargs);
+ if (!pargs.period) {
+ dev_err(&pdev->dev, "invalid PWM period\n");
+ return -EINVAL;
+ }
+
+ /*
+ * FIXME: pwm_apply_args() should be removed when switching to
+ * the atomic PWM API.
+ */
+ pwm_apply_args(pwm);
+ ret = pwm_config(pwm, pargs.period, pargs.period);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * we can now start the FPGA and populate the peripherals.
+ */
+ pwm_enable(pwm);
+ ts_nbus->pwm = pwm;
+
+ /*
+ * let the child nodes retrieve this instance of the ts-nbus.
+ */
+ dev_set_drvdata(dev, ts_nbus);
+
+ ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
+ if (ret < 0)
+ return ret;
+
+ dev_info(dev, "initialized\n");
+
+ return 0;
+}
+
+static int ts_nbus_remove(struct platform_device *pdev)
+{
+ struct ts_nbus *ts_nbus = dev_get_drvdata(&pdev->dev);
+
+ /* shutdown the FPGA */
+ mutex_lock(&ts_nbus->lock);
+ pwm_disable(ts_nbus->pwm);
+ mutex_unlock(&ts_nbus->lock);
+
+ return 0;
+}
+
+static const struct of_device_id ts_nbus_of_match[] = {
+ { .compatible = "technologic,ts-nbus", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, ts_nbus_of_match);
+
+static struct platform_driver ts_nbus_driver = {
+ .probe = ts_nbus_probe,
+ .remove = ts_nbus_remove,
+ .driver = {
+ .name = "ts_nbus",
+ .of_match_table = ts_nbus_of_match,
+ },
+};
+
+module_platform_driver(ts_nbus_driver);
+
+MODULE_ALIAS("platform:ts_nbus");
+MODULE_AUTHOR("Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>");
+MODULE_DESCRIPTION("Technologic Systems NBUS");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/ts-nbus.h b/include/linux/ts-nbus.h
new file mode 100644
index 000000000000..5bd4c822f7cf
--- /dev/null
+++ b/include/linux/ts-nbus.h
@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2016 - Savoir-faire Linux
+ * Author: Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#ifndef _TS_NBUS_H
+#define _TS_NBUS_H
+
+struct ts_nbus;
+
+extern int ts_nbus_read(struct ts_nbus *ts_nbus, u8 adr, u16 *val);
+extern int ts_nbus_write(struct ts_nbus *ts_nbus, u8 adr, u16 val);
+
+#endif /* _TS_NBUS_H */
--
2.15.0
^ permalink raw reply related [flat|nested] 11+ messages in thread
end of thread, other threads:[~2017-11-07 15:29 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-11-01 17:14 [PATCH v7 1/2] dt-bindings: bus: Add documentation for the Technologic Systems NBUS Sebastien Bourdelin
2017-11-01 17:14 ` [PATCH v7 2/2] bus: add driver " Sebastien Bourdelin
2017-11-01 17:14 ` Sebastien Bourdelin
2017-11-02 14:22 ` Linus Walleij
2017-11-02 14:37 ` Sebastien Bourdelin
2017-11-02 15:57 ` Linus Walleij
2017-11-02 16:10 ` Sebastien Bourdelin
2017-11-02 16:10 ` Sebastien Bourdelin
2017-11-07 15:29 ` Arnd Bergmann
2017-11-07 15:29 ` Arnd Bergmann
2017-11-02 18:17 [PATCH v7 0/2] add support " Sebastien Bourdelin
2017-11-02 18:17 ` [PATCH v7 2/2] bus: add driver " Sebastien Bourdelin
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