--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Arcx Anybus-S Controller 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/mutex.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regmap.h>
+
+/* move to <linux/anybuss-controller.h> when taking this out of staging */
+#include "anybuss-controller.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 controller_priv {
+ struct device *class_dev;
+ bool common_reset;
+ struct gpio_desc *reset_gpiod;
+ void __iomem *cpld_base;
+ struct mutex ctrl_lock; /* protects CONTROL register */
+ u8 control_reg;
+ char version[3];
+ u16 design_no;
+};
+
+static void do_reset(struct controller_priv *cd, u8 rst_bit, bool reset)
+{
+ mutex_lock(&cd->ctrl_lock);
+ /*
+ * 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)
+ usleep_range(100, 200);
+ mutex_unlock(&cd->ctrl_lock);
+}
+
+static int anybuss_reset(struct controller_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 void export_reset_0(struct device *dev, bool assert)
+{
+ struct controller_priv *cd = dev_get_drvdata(dev);
+
+ anybuss_reset(cd, 0, assert);
+}
+
+static void export_reset_1(struct device *dev, bool assert)
+{
+ struct controller_priv *cd = dev_get_drvdata(dev);
+
+ anybuss_reset(cd, 1, assert);
+}
+
+/*
+ * parallel bus limitation:
+ *
+ * the anybus is 8-bit wide. we can't assume that the hardware will translate
+ * word accesses on the parallel bus to multiple byte-accesses on the anybus.
+ *
+ * the imx WEIM bus does not provide this type of translation.
+ *
+ * to be safe, we will limit parallel bus accesses to a single byte
+ * at a time for now.
+ */
+
+static int read_reg_bus(void *context, unsigned int reg,
+ unsigned int *val)
+{
+ void __iomem *base = context;
+
+ *val = readb(base + reg);
+ return 0;
+}
+
+static int write_reg_bus(void *context, unsigned int reg,
+ unsigned int val)
+{
+ void __iomem *base = context;
+
+ writeb(val, base + reg);
+ return 0;
+}
+
+static struct regmap *create_parallel_regmap(struct platform_device *pdev,
+ int idx)
+{
+ struct regmap_config regmap_cfg = {
+ .reg_bits = 11,
+ .val_bits = 8,
+ /*
+ * single-byte parallel bus accesses are atomic, so don't
+ * require any synchronization.
+ */
+ .disable_locking = true,
+ .reg_read = read_reg_bus,
+ .reg_write = write_reg_bus,
+ };
+ struct resource *res;
+ void __iomem *base;
+ struct device *dev = &pdev->dev;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, idx + 1);
+ if (resource_size(res) < (1 << regmap_cfg.reg_bits))
+ return ERR_PTR(-EINVAL);
+ base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(base))
+ return ERR_CAST(base);
+ return devm_regmap_init(dev, NULL, base, ®map_cfg);
+}
+
+static struct anybuss_host *
+create_anybus_host(struct platform_device *pdev, int idx)
+{
+ struct anybuss_ops ops = {};
+
+ switch (idx) {
+ case 0:
+ ops.reset = export_reset_0;
+ break;
+ case 1:
+ ops.reset = export_reset_1;
+ break;
+ default:
+ return ERR_PTR(-EINVAL);
+ }
+ ops.host_idx = idx;
+ ops.regmap = create_parallel_regmap(pdev, idx);
+ if (IS_ERR(ops.regmap))
+ return ERR_CAST(ops.regmap);
+ ops.irq = platform_get_irq(pdev, idx);
+ if (ops.irq <= 0)
+ return ERR_PTR(-EINVAL);
+ return devm_anybuss_host_common_probe(&pdev->dev, &ops);
+}
+
+static ssize_t version_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct controller_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 controller_priv *cd = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%d\n", cd->design_no);
+}
+static DEVICE_ATTR_RO(design_number);
+
+static struct attribute *controller_attributes[] = {
+ &dev_attr_version.attr,
+ &dev_attr_design_number.attr,
+ NULL,
+};
+
+static struct attribute_group controller_attribute_group = {
+ .attrs = controller_attributes,
+};
+
+static const struct attribute_group *controller_attribute_groups[] = {
+ &controller_attribute_group,
+ NULL,
+};
+
+static void controller_device_release(struct device *dev)
+{
+ kfree(dev);
+}
+
+static int can_power_is_enabled(struct regulator_dev *rdev)
+{
+ struct controller_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 *controller_class;
+static DEFINE_IDA(controller_index_ida);
+
+static int controller_probe(struct platform_device *pdev)
+{
+ struct controller_priv *cd;
+ struct device *dev = &pdev->dev;
+ struct regulator_config config = { };
+ struct regulator_dev *regulator;
+ int err, id;
+ struct resource *res;
+ struct anybuss_host *host;
+ u8 status1, cap;
+
+ cd = devm_kzalloc(dev, sizeof(*cd), GFP_KERNEL);
+ if (!cd)
+ return -ENOMEM;
+ dev_set_drvdata(dev, cd);
+ mutex_init(&cd->ctrl_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, "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 controller [cap=0x%02X]", cap);
+ err = -ENODEV;
+ goto out_reset;
+ }
+
+ if (status1 & CPLD_STATUS1_AB) {
+ dev_info(dev, "has anybus-S slot(s)");
+ cd->common_reset = !(cap & CPLD_CAP_SEP_RESETS);
+ dev_info(dev, "supports %s", cd->common_reset ?
+ "a common reset" : "separate resets");
+ for (id = 0; id < 2; id++) {
+ host = create_anybus_host(pdev, id);
+ if (!IS_ERR(host))
+ continue;
+ err = PTR_ERR(host);
+ /* -ENODEV is fine, it just means no card detected */
+ if (err != -ENODEV)
+ goto out_reset;
+ }
+ }
+
+ id = ida_simple_get(&controller_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 controller 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 = controller_class;
+ cd->class_dev->groups = controller_attribute_groups;
+ cd->class_dev->parent = dev;
+ cd->class_dev->id = id;
+ cd->class_dev->release = controller_device_release;
+ dev_set_name(cd->class_dev, "%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(&controller_index_ida, id);
+out_reset:
+ gpiod_set_value_cansleep(cd->reset_gpiod, 1);
+ return err;
+}
+
+static int controller_remove(struct platform_device *pdev)
+{
+ struct controller_priv *cd = platform_get_drvdata(pdev);
+ int id = cd->class_dev->id;
+
+ device_unregister(cd->class_dev);
+ ida_simple_remove(&controller_index_ida, id);
+ gpiod_set_value_cansleep(cd->reset_gpiod, 1);
+ return 0;
+}
+
+static const struct of_device_id controller_of_match[] = {
+ { .compatible = "arcx,anybus-controller" },
+ { }
+};
+
+MODULE_DEVICE_TABLE(of, controller_of_match);
+
+static struct platform_driver controller_driver = {
+ .probe = controller_probe,
+ .remove = controller_remove,
+ .driver = {
+ .name = "arcx-anybus-controller",
+ .of_match_table = of_match_ptr(controller_of_match),
+ },
+};
+
+static int __init controller_init(void)
+{
+ int err;
+
+ controller_class = class_create(THIS_MODULE, "arcx_anybus_controller");
+ if (IS_ERR(controller_class))
+ return PTR_ERR(controller_class);
+ err = platform_driver_register(&controller_driver);
+ if (err)
+ class_destroy(controller_class);
+
+ return err;
+}
+
+static void __exit controller_exit(void)
+{
+ platform_driver_unregister(&controller_driver);
+ class_destroy(controller_class);
+ ida_destroy(&controller_index_ida);
+}
+
+module_init(controller_init);
+module_exit(controller_exit);
+
+MODULE_DESCRIPTION("Arcx Anybus-S Controller driver");
+MODULE_AUTHOR("Sven Van Asbroeck <TheSven73@gmail.com>");
+MODULE_LICENSE("GPL v2");
projects / linux-2.6-microblaze.git / commitdiff