Add a driver for the Arcx anybus bridge.
This chip embeds up to two Anybus-S application connectors
(slots), and connects to the SoC via a parallel memory bus.
There is also a CAN power readout, unrelated to the Anybus,
modelled as a regulator.
Signed-off-by: Sven Van Asbroeck <svendev@xxxxxxxx>
---
drivers/fieldbus/Kconfig | 10 +
drivers/fieldbus/Makefile | 1 +
drivers/fieldbus/anybus-bridge.c | 321 +++++++++++++++++++++++++++++++
3 files changed, 332 insertions(+)
create mode 100644 drivers/fieldbus/anybus-bridge.c
diff --git a/drivers/fieldbus/Kconfig b/drivers/fieldbus/Kconfig
index 1d1929ba7e27..fc2e20b59b38 100644
--- a/drivers/fieldbus/Kconfig
+++ b/drivers/fieldbus/Kconfig
@@ -16,4 +16,14 @@ menuconfig FIELDBUS_DEV
if FIELDBUS_DEV
+config ARCX_ANYBUS_BRIDGE
+ tristate "Arcx Anybus-S Bridge"
+ depends on OF && GPIOLIB
+ help
+ Select this to get support for the Arcx Anybus bridge.
+ It connects to the SoC via a parallel memory bus, and
+ embeds up to two Anybus-S application connectors (slots).
+ There is also a CAN power readout, unrelated to the Anybus,
+ modelled as a regulator.
+
endif
diff --git a/drivers/fieldbus/Makefile b/drivers/fieldbus/Makefile
index 768a116fc9c6..a623722aace6 100644
--- a/drivers/fieldbus/Makefile
+++ b/drivers/fieldbus/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_FIELDBUS_DEV) += fieldbus_dev_core.o
fieldbus_dev_core-y := dev_core.o
# Devices
+obj-$(CONFIG_ARCX_ANYBUS_BRIDGE) += anybus-bridge.o
diff --git a/drivers/fieldbus/anybus-bridge.c b/drivers/fieldbus/anybus-bridge.c
new file mode 100644
index 000000000000..9eee39efc3aa
--- /dev/null
+++ b/drivers/fieldbus/anybus-bridge.c
@@ -0,0 +1,321 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Arcx Anybus Bridge driver
+ *
+ * Copyright (C) 2018 Arcx Inc
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/delay.h>
+#include <linux/idr.h>
+#include <linux/spinlock.h>
+#include <linux/reset-controller.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+
+#define CPLD_STATUS1 0x80
+#define CPLD_CONTROL 0x80
+#define CPLD_CONTROL_CRST 0x40
+#define CPLD_CONTROL_RST1 0x04
+#define CPLD_CONTROL_RST2 0x80
+#define CPLD_STATUS1_AB 0x02
+#define CPLD_STATUS1_CAN_POWER 0x01
+#define CPLD_DESIGN_LO 0x81
+#define CPLD_DESIGN_HI 0x82
+#define CPLD_CAP 0x83
+#define CPLD_CAP_COMPAT 0x01
+#define CPLD_CAP_SEP_RESETS 0x02
+
+struct bridge_priv {
+ struct device *class_dev;
+ struct reset_controller_dev rcdev;
+ bool common_reset;
+ struct gpio_desc *reset_gpiod;
+ void __iomem *cpld_base;
+ spinlock_t regs_lock;
+ u8 control_reg;
+ char version[3];
+ u16 design_no;
+};
+
+static void do_reset(struct bridge_priv *cd, u8 rst_bit, bool reset)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&cd->regs_lock, flags);
+ /*
+ * CPLD_CONTROL is write-only, so cache its value in
+ * cd->control_reg
+ */
+ if (reset)
+ cd->control_reg &= ~rst_bit;
+ else
+ cd->control_reg |= rst_bit;
+ writeb(cd->control_reg, cd->cpld_base + CPLD_CONTROL);
+ /*
+ * h/w work-around:
+ * the hardware is 'too fast', so a reset followed by an immediate
+ * not-reset will _not_ change the anybus reset line in any way,
+ * losing the reset. to prevent this from happening, introduce
+ * a minimum reset duration.
+ * Verified minimum safe duration required using a scope
+ * on 14-June-2018: 100 us.
+ */
+ if (reset)
+ udelay(100);
+ spin_unlock_irqrestore(&cd->regs_lock, flags);
+}
+
+static int anybuss_reset(struct bridge_priv *cd,
+ unsigned long id, bool reset)
+{
+ if (id >= 2)
+ return -EINVAL;
+ if (cd->common_reset)
+ do_reset(cd, CPLD_CONTROL_CRST, reset);
+ else
+ do_reset(cd, id ? CPLD_CONTROL_RST2 : CPLD_CONTROL_RST1, reset);
+ return 0;
+}
+
+static int anybuss_reset_assert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct bridge_priv *cd = container_of(rcdev, struct bridge_priv, rcdev);
+
+ return anybuss_reset(cd, id, true);
+}
+
+static int anybuss_reset_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct bridge_priv *cd = container_of(rcdev, struct bridge_priv, rcdev);
+
+ return anybuss_reset(cd, id, false);
+}
+
+static const struct reset_control_ops anybuss_reset_ops = {
+ .assert = anybuss_reset_assert,
+ .deassert = anybuss_reset_deassert,
+};
+
+static ssize_t version_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct bridge_priv *cd = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%s\n", cd->version);
+}
+static DEVICE_ATTR_RO(version);
+
+static ssize_t design_number_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct bridge_priv *cd = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%d\n", cd->design_no);
+}
+static DEVICE_ATTR_RO(design_number);
+
+static struct attribute *bridge_attributes[] = {
+ &dev_attr_version.attr,
+ &dev_attr_design_number.attr,
+ NULL,
+};
+
+static struct attribute_group bridge_attribute_group = {
+ .attrs = bridge_attributes,
+};
+
+static const struct attribute_group *bridge_attribute_groups[] = {
+ &bridge_attribute_group,
+ NULL,
+};
+
+static void bridge_device_release(struct device *dev)
+{
+ kfree(dev);
+}
+
+static int can_power_is_enabled(struct regulator_dev *rdev)
+{
+ struct bridge_priv *cd = rdev_get_drvdata(rdev);
+
+ return !(readb(cd->cpld_base + CPLD_STATUS1) & CPLD_STATUS1_CAN_POWER);
+}
+
+static struct regulator_ops can_power_ops = {
+ .is_enabled = can_power_is_enabled,
+};
+
+static const struct regulator_desc can_power_desc = {
+ .name = "regulator-can-power",
+ .id = -1,
+ .type = REGULATOR_VOLTAGE,
+ .owner = THIS_MODULE,
+ .ops = &can_power_ops,
+};
+
+static struct class *bridge_class;
+static DEFINE_IDA(bridge_index_ida);
+
+static int bridge_probe(struct platform_device *pdev)
+{
+ struct bridge_priv *cd;
+ struct device *dev = &pdev->dev;
+ struct regulator_config config = { };
+ struct regulator_dev *regulator;
+ int err, id;
+ struct resource *res;
+ u8 status1, cap;
+
+ cd = devm_kzalloc(dev, sizeof(*cd), GFP_KERNEL);
+ if (!cd)
+ return -ENOMEM;
+ dev_set_drvdata(dev, cd);
+ spin_lock_init(&cd->regs_lock);
+ cd->reset_gpiod = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
+ if (IS_ERR(cd->reset_gpiod))
+ return PTR_ERR(cd->reset_gpiod);
+
+ /* CPLD control memory, sits at index 0 */
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ cd->cpld_base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(cd->cpld_base)) {
+ dev_err(dev,
+ "failed to map cpld base address\n");
+ err = PTR_ERR(cd->cpld_base);
+ goto out_reset;
+ }
+
+ /* identify cpld */
+ status1 = readb(cd->cpld_base + CPLD_STATUS1);
+ cd->design_no = (readb(cd->cpld_base + CPLD_DESIGN_HI) << 8) |
+ readb(cd->cpld_base + CPLD_DESIGN_LO);
+ snprintf(cd->version, sizeof(cd->version), "%c%d",
+ 'A' + ((status1>>5) & 0x7),
+ (status1>>2) & 0x7);
+ dev_info(dev, "Bridge is design number %d, revision %s\n",
+ cd->design_no,
+ cd->version);
+ cap = readb(cd->cpld_base + CPLD_CAP);
+ if (!(cap & CPLD_CAP_COMPAT)) {
+ dev_err(dev, "unsupported bridge [cap=0x%02X]", cap);
+ err = -ENODEV;
+ goto out_reset;
+ }
+
+ if (status1 & CPLD_STATUS1_AB) {
+ dev_info(dev, "Bridge has anybus-S slot(s)");
+ cd->common_reset = !(cap & CPLD_CAP_SEP_RESETS);
+ dev_info(dev, "Bridge supports %s", cd->common_reset ?
+ "a common reset" : "separate resets");
+ cd->rcdev.owner = THIS_MODULE;
+ cd->rcdev.nr_resets = 2;
+ cd->rcdev.ops = &anybuss_reset_ops;
+ cd->rcdev.of_node = dev->of_node;
+ err = devm_reset_controller_register(dev, &cd->rcdev);
+ if (err)
+ goto out_reset;
+ }
+
+ id = ida_simple_get(&bridge_index_ida, 0, 0, GFP_KERNEL);
+ if (id < 0) {
+ err = id;
+ goto out_reset;
+ }
+ /* export can power readout as a regulator */
+ config.dev = dev;
+ config.driver_data = cd;
+ regulator = devm_regulator_register(dev, &can_power_desc, &config);
+ if (IS_ERR(regulator)) {
+ err = PTR_ERR(regulator);
+ goto out_reset;
+ }
+ /* make bridge info visible to userspace */
+ cd->class_dev = kzalloc(sizeof(*cd->class_dev), GFP_KERNEL);
+ if (!cd->class_dev) {
+ err = -ENOMEM;
+ goto out_ida;
+ }
+ cd->class_dev->class = bridge_class;
+ cd->class_dev->groups = bridge_attribute_groups;
+ cd->class_dev->parent = dev;
+ cd->class_dev->id = id;
+ cd->class_dev->release = bridge_device_release;
+ dev_set_name(cd->class_dev, "bridge%d", cd->class_dev->id);
+ dev_set_drvdata(cd->class_dev, cd);
+ err = device_register(cd->class_dev);
+ if (err)
+ goto out_dev;
+ return 0;
+out_dev:
+ put_device(cd->class_dev);
+out_ida:
+ ida_simple_remove(&bridge_index_ida, id);
+out_reset:
+ gpiod_set_value_cansleep(cd->reset_gpiod, 1);
+ return err;
+}
+
+static int bridge_remove(struct platform_device *pdev)
+{
+ struct bridge_priv *cd = platform_get_drvdata(pdev);
+ int id = cd->class_dev->id;
+
+ device_unregister(cd->class_dev);
+ ida_simple_remove(&bridge_index_ida, id);
+ gpiod_set_value_cansleep(cd->reset_gpiod, 1);
+ return 0;
+}
+
+static const struct of_device_id bridge_of_match[] = {
+ { .compatible = "arcx,anybus-bridge" },
+ { }
+};
+
+MODULE_DEVICE_TABLE(of, bridge_of_match);
+
+static struct platform_driver bridge_driver = {
+ .probe = bridge_probe,
+ .remove = bridge_remove,
+ .driver = {
+ .name = "arcx-anybus-bridge",
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(bridge_of_match),
+ },
+};
+
+static int __init bridge_init(void)
+{
+ int err;
+
+ bridge_class = class_create(THIS_MODULE, "arcx_anybus_bridge");
+ if (!IS_ERR(bridge_class)) {
+ err = platform_driver_register(&bridge_driver);
+ if (err)
+ class_destroy(bridge_class);
+ } else
+ err = PTR_ERR(bridge_class);
+ return err;
+}
+
+static void __exit bridge_exit(void)
+{
+ platform_driver_unregister(&bridge_driver);
+ class_destroy(bridge_class);
+}
+
+module_init(bridge_init);
+module_exit(bridge_exit);
+
+MODULE_DESCRIPTION("Arcx Anybus Bridge driver");
+MODULE_AUTHOR("Sven Van Asbroeck <svendev@xxxxxxxx>");
+MODULE_LICENSE("GPL v2");
--
2.17.1
