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-rw-r--r--drivers/bus/arm-integrator-lm.c129
1 files changed, 129 insertions, 0 deletions
diff --git a/drivers/bus/arm-integrator-lm.c b/drivers/bus/arm-integrator-lm.c
new file mode 100644
index 000000000..2344d560b
--- /dev/null
+++ b/drivers/bus/arm-integrator-lm.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ARM Integrator Logical Module bus driver
+ * Copyright (C) 2020 Linaro Ltd.
+ * Author: Linus Walleij <linus.walleij@linaro.org>
+ *
+ * See the device tree bindings for this block for more details on the
+ * hardware.
+ */
+
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/bitops.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+
+/* All information about the connected logic modules are in here */
+#define INTEGRATOR_SC_DEC_OFFSET 0x10
+
+/* Base address for the expansion modules */
+#define INTEGRATOR_AP_EXP_BASE 0xc0000000
+#define INTEGRATOR_AP_EXP_STRIDE 0x10000000
+
+static int integrator_lm_populate(int num, struct device *dev)
+{
+ struct device_node *np = dev->of_node;
+ struct device_node *child;
+ u32 base;
+ int ret;
+
+ base = INTEGRATOR_AP_EXP_BASE + (num * INTEGRATOR_AP_EXP_STRIDE);
+
+ /* Walk over the child nodes and see what chipselects we use */
+ for_each_available_child_of_node(np, child) {
+ struct resource res;
+
+ ret = of_address_to_resource(child, 0, &res);
+ if (ret) {
+ dev_info(dev, "no valid address on child\n");
+ continue;
+ }
+
+ /* First populate the syscon then any devices */
+ if (res.start == base) {
+ dev_info(dev, "populate module @0x%08x from DT\n",
+ base);
+ ret = of_platform_default_populate(child, NULL, dev);
+ if (ret) {
+ dev_err(dev, "failed to populate module\n");
+ of_node_put(child);
+ return ret;
+ }
+ }
+ }
+
+ return 0;
+}
+
+static const struct of_device_id integrator_ap_syscon_match[] = {
+ { .compatible = "arm,integrator-ap-syscon"},
+ { },
+};
+
+static int integrator_ap_lm_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *syscon;
+ static struct regmap *map;
+ u32 val;
+ int ret;
+ int i;
+
+ /* Look up the system controller */
+ syscon = of_find_matching_node(NULL, integrator_ap_syscon_match);
+ if (!syscon) {
+ dev_err(dev,
+ "could not find Integrator/AP system controller\n");
+ return -ENODEV;
+ }
+ map = syscon_node_to_regmap(syscon);
+ if (IS_ERR(map)) {
+ dev_err(dev,
+ "could not find Integrator/AP system controller\n");
+ return PTR_ERR(map);
+ }
+
+ ret = regmap_read(map, INTEGRATOR_SC_DEC_OFFSET, &val);
+ if (ret) {
+ dev_err(dev, "could not read from Integrator/AP syscon\n");
+ return ret;
+ }
+
+ /* Loop over the connected modules */
+ for (i = 0; i < 4; i++) {
+ if (!(val & BIT(4 + i)))
+ continue;
+
+ dev_info(dev, "detected module in slot %d\n", i);
+ ret = integrator_lm_populate(i, dev);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static const struct of_device_id integrator_ap_lm_match[] = {
+ { .compatible = "arm,integrator-ap-lm"},
+ { },
+};
+
+static struct platform_driver integrator_ap_lm_driver = {
+ .probe = integrator_ap_lm_probe,
+ .driver = {
+ .name = "integratorap-lm",
+ .of_match_table = integrator_ap_lm_match,
+ },
+};
+module_platform_driver(integrator_ap_lm_driver);
+MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
+MODULE_DESCRIPTION("Integrator AP Logical Module driver");
+MODULE_LICENSE("GPL v2");