[PATCH] bus: ts-nbus: remove bus driver without user

* [PATCH] bus: ts-nbus: remove bus driver without user
@ 2019-01-07 19:45 Uwe Kleine-König
  2019-01-11 12:52 ` Linus Walleij
  0 siblings, 1 reply; 9+ messages in thread
From: Uwe Kleine-König @ 2019-01-07 19:45 UTC (permalink / raw)
  To: Arnd Bergmann
  Cc: Linus Walleij, kernel, kernel, linux-arm-kernel,
	Jérôme OUFELLA

Since the ts-nbus driver was introduced in 2017 it only saw some reworking
changes. There is no user in the tree, neither a machine that has this
bus nor a driver for a device on that bus. Also the email address of the
author doesn't exist any more.

So remove this bus.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
Hello,

I'm not sure where to send this patch to. There was a patch set on the
arm-kernel list but I didn't find the final version in my archive. Arnd
applied the patch (5b143d2a6ede ("bus: add driver for the Technologic
Systems NBUS")) so I send it to him :-)

Best regards
Uwe

 .../devicetree/bindings/bus/ts-nbus.txt       |  50 ---
 drivers/bus/Kconfig                           |   8 -
 drivers/bus/Makefile                          |   1 -
 drivers/bus/ts-nbus.c                         | 369 ------------------
 include/linux/ts-nbus.h                       |  18 -
 5 files changed, 446 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/bus/ts-nbus.txt
 delete mode 100644 drivers/bus/ts-nbus.c
 delete mode 100644 include/linux/ts-nbus.h

diff --git a/Documentation/devicetree/bindings/bus/ts-nbus.txt b/Documentation/devicetree/bindings/bus/ts-nbus.txt
deleted file mode 100644
index 2a10d065b9fa..000000000000
--- a/Documentation/devicetree/bindings/bus/ts-nbus.txt
+++ /dev/null
@@ -1,50 +0,0 @@
-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 = "...";
-
-			/* ... */
-		};
-	};
diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
index 1851112ccc29..275402198537 100644
--- a/drivers/bus/Kconfig
+++ b/drivers/bus/Kconfig
@@ -147,14 +147,6 @@ config TI_SYSC
 	  Generic driver for Texas Instruments interconnect target module
 	  found on many TI SoCs.
 
-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 ca300b1914ce..1cb001b6fc4f 100644
--- a/drivers/bus/Makefile
+++ b/drivers/bus/Makefile
@@ -27,7 +27,6 @@ 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_TI_SYSC)		+= ti-sysc.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
deleted file mode 100644
index 9989ce904a37..000000000000
--- a/drivers/bus/ts-nbus.c
+++ /dev/null
@@ -1,369 +0,0 @@
-/*
- * 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)
-{
-	DECLARE_BITMAP(values, 8);
-
-	values[0] = 0;
-
-	gpiod_set_array_value_cansleep(8, ts_nbus->data->desc,
-				       ts_nbus->data->info, 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;
-	DECLARE_BITMAP(values, 8);
-
-	values[0] = byte;
-
-	gpiod_set_array_value_cansleep(8, gpios->desc, gpios->info, 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
deleted file mode 100644
index 5bd4c822f7cf..000000000000
--- a/include/linux/ts-nbus.h
+++ /dev/null
@@ -1,18 +0,0 @@
-/*
- * 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 */
-- 
2.20.1


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