ARM: SoC driver updates for v4.15

This branch contains platform-related driver updates for ARM and ARM64,
 these are the areas that bring the changes:
 
 New drivers:
  - Driver support for Renesas R-Car V3M (R8A77970)
  - Power management support for Amlogic GX
  - A new driver for the Tegra BPMP thermal sensor
  - A new bus driver for Technologic Systems NBUS
 
 Changes for subsystems that prefer to merge through arm-soc:
  - The usual updates for reset controller drivers from Philipp Zabel,
    with five added drivers for SoCs in the arc, meson, socfpa, uniphier
    and mediatek families.
  - Updates to the ARM SCPI and PSCI frameworks, from Sudeep Holla,
    Heiner Kallweit and Lorenzo Pieralisi.
 
 Changes specific to some ARM-based SoC
  - The Freescale/NXP DPAA QBMan drivers from PowerPC can now work
    on ARM as well.
  - Several changes for power management on Broadcom SoCs
  - Various improvements on Qualcomm, Broadcom, Amlogic, Atmel, Mediatek
  - Minor Cleanups for Samsung, TI OMAP SoCs
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Merge tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc

Pull ARM SoC driver updates from Arnd Bergmann:
 "This branch contains platform-related driver updates for ARM and
  ARM64, these are the areas that bring the changes:

  New drivers:

   - driver support for Renesas R-Car V3M (R8A77970)

   - power management support for Amlogic GX

   - a new driver for the Tegra BPMP thermal sensor

   - a new bus driver for Technologic Systems NBUS

  Changes for subsystems that prefer to merge through arm-soc:

   - the usual updates for reset controller drivers from Philipp Zabel,
     with five added drivers for SoCs in the arc, meson, socfpa,
     uniphier and mediatek families

   - updates to the ARM SCPI and PSCI frameworks, from Sudeep Holla,
     Heiner Kallweit and Lorenzo Pieralisi

  Changes specific to some ARM-based SoC

   - the Freescale/NXP DPAA QBMan drivers from PowerPC can now work on
     ARM as well

   - several changes for power management on Broadcom SoCs

   - various improvements on Qualcomm, Broadcom, Amlogic, Atmel,
     Mediatek

   - minor Cleanups for Samsung, TI OMAP SoCs"

[ NOTE! This doesn't work without the previous ARM SoC device-tree pull,
  because the R8A77970 driver is missing a header file that came from
  that pull.

  The fact that this got merged afterwards only fixes it at this point,
  and bisection of that driver will fail if/when you walk into the
  history of that driver.           - Linus ]

* tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (96 commits)
  soc: amlogic: meson-gx-pwrc-vpu: fix power-off when powered by bootloader
  bus: add driver for the Technologic Systems NBUS
  memory: omap-gpmc: Remove deprecated gpmc_update_nand_reg()
  soc: qcom: remove unused label
  soc: amlogic: gx pm domain: add PM and OF dependencies
  drivers/firmware: psci_checker: Add missing destroy_timer_on_stack()
  dt-bindings: power: add amlogic meson power domain bindings
  soc: amlogic: add Meson GX VPU Domains driver
  soc: qcom: Remote filesystem memory driver
  dt-binding: soc: qcom: Add binding for rmtfs memory
  of: reserved_mem: Accessor for acquiring reserved_mem
  of/platform: Generalize /reserved-memory handling
  soc: mediatek: pwrap: fix fatal compiler error
  soc: mediatek: pwrap: fix compiler errors
  arm64: mediatek: cleanup message for platform selection
  soc: Allow test-building of MediaTek drivers
  soc: mediatek: place Kconfig for all SoC drivers under menu
  soc: mediatek: pwrap: add support for MT7622 SoC
  soc: mediatek: pwrap: add common way for setup CS timing extenstion
  soc: mediatek: pwrap: add MediaTek MT6380 as one slave of pwrap
  ..

drivers/bus/Kconfig

@@ -165,6 +165,14 @@ 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

drivers/bus/Makefile

@@ -22,6 +22,7 @@ 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
 

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 <[email protected]>");
+MODULE_DESCRIPTION("Technologic Systems NBUS");
+MODULE_LICENSE("GPL v2");