mtd: hyperbus: Add driver for TI's HyperBus memory controller

Add driver for HyperBus memory controller on TI's AM654 SoC. Programming
IP is pretty simple and provides direct memory mapped access to
connected Flash devices.

Add basic support for the IP without DMA. Second chipSelect is not
supported for now.

Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>

drivers/mtd/hyperbus/Kconfig

@@ -9,3 +9,15 @@ menuconfig MTD_HYPERBUS
 	  the HyperBus Controller driver to communicate with
 	  HyperFlash. See Cypress HyperBus specification for more
 	  details
+
+if MTD_HYPERBUS
+
+config HBMC_AM654
+	tristate "HyperBus controller driver for AM65x SoC"
+	select MULTIPLEXER
+	select MUX_MMIO
+	help
+	 This is the driver for HyperBus controller on TI's AM65x and
+	 other SoCs
+
+endif # MTD_HYPERBUS

drivers/mtd/hyperbus/Makefile

@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_MTD_HYPERBUS)	+= hyperbus-core.o
+obj-$(CONFIG_HBMC_AM654)	+= hbmc-am654.o

drivers/mtd/hyperbus/hbmc-am654.c

@@ -0,0 +1,141 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/
+// Author: Vignesh Raghavendra <vigneshr@ti.com>
+
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mtd/cfi.h>
+#include <linux/mtd/hyperbus.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mux/consumer.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/types.h>
+
+#define AM654_HBMC_CALIB_COUNT 25
+
+struct am654_hbmc_priv {
+	struct hyperbus_ctlr ctlr;
+	struct hyperbus_device hbdev;
+};
+
+static int am654_hbmc_calibrate(struct hyperbus_device *hbdev)
+{
+	struct map_info *map = &hbdev->map;
+	struct cfi_private cfi;
+	int count = AM654_HBMC_CALIB_COUNT;
+	int pass_count = 0;
+	int ret;
+
+	cfi.interleave = 1;
+	cfi.device_type = CFI_DEVICETYPE_X16;
+	cfi_send_gen_cmd(0xF0, 0, 0, map, &cfi, cfi.device_type, NULL);
+	cfi_send_gen_cmd(0x98, 0x55, 0, map, &cfi, cfi.device_type, NULL);
+
+	while (count--) {
+		ret = cfi_qry_present(map, 0, &cfi);
+		if (ret)
+			pass_count++;
+		else
+			pass_count = 0;
+		if (pass_count == 5)
+			break;
+	}
+
+	cfi_qry_mode_off(0, map, &cfi);
+
+	return ret;
+}
+
+static const struct hyperbus_ops am654_hbmc_ops = {
+	.calibrate = am654_hbmc_calibrate,
+};
+
+static int am654_hbmc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct am654_hbmc_priv *priv;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, priv);
+
+	if (of_property_read_bool(dev->of_node, "mux-controls")) {
+		struct mux_control *control = devm_mux_control_get(dev, NULL);
+
+		if (IS_ERR(control))
+			return PTR_ERR(control);
+
+		ret = mux_control_select(control, 1);
+		if (ret) {
+			dev_err(dev, "Failed to select HBMC mux\n");
+			return ret;
+		}
+	}
+
+	pm_runtime_enable(dev);
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		pm_runtime_put_noidle(dev);
+		goto disable_pm;
+	}
+
+	priv->ctlr.dev = dev;
+	priv->ctlr.ops = &am654_hbmc_ops;
+	priv->hbdev.ctlr = &priv->ctlr;
+	priv->hbdev.np = of_get_next_child(dev->of_node, NULL);
+	ret = hyperbus_register_device(&priv->hbdev);
+	if (ret) {
+		dev_err(dev, "failed to register controller\n");
+		pm_runtime_put_sync(&pdev->dev);
+		goto disable_pm;
+	}
+
+	return 0;
+disable_pm:
+	pm_runtime_disable(dev);
+	return ret;
+}
+
+static int am654_hbmc_remove(struct platform_device *pdev)
+{
+	struct am654_hbmc_priv *priv = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = hyperbus_unregister_device(&priv->hbdev);
+	pm_runtime_put_sync(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+
+	return ret;
+}
+
+static const struct of_device_id am654_hbmc_dt_ids[] = {
+	{
+		.compatible = "ti,am654-hbmc",
+	},
+	{ /* end of table */ }
+};
+
+MODULE_DEVICE_TABLE(of, am654_hbmc_dt_ids);
+
+static struct platform_driver am654_hbmc_platform_driver = {
+	.probe = am654_hbmc_probe,
+	.remove = am654_hbmc_remove,
+	.driver = {
+		.name = "hbmc-am654",
+		.of_match_table = am654_hbmc_dt_ids,
+	},
+};
+
+module_platform_driver(am654_hbmc_platform_driver);
+
+MODULE_DESCRIPTION("HBMC driver for AM654 SoC");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:hbmc-am654");
+MODULE_AUTHOR("Vignesh Raghavendra <vigneshr@ti.com>");