reset: Add Altera Arria10 SR Reset Controller

This patch adds the reset controller functionality for
Peripheral PHYs to the Arria10 System Resource Chip.

Signed-off-by: Thor Thayer <thor.thayer@linux.intel.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

4 files changed, 147 insertions, 0 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 27558d547f12..0f37c5a5e1c9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -653,6 +653,7 @@ M:	Thor Thayer <thor.thayer@linux.intel.com>
 S:      Maintained
 F:      drivers/gpio/gpio-altera-a10sr.c
 F:      drivers/mfd/altera-a10sr.c
+F:      drivers/reset/reset-a10sr.c
 F:      include/linux/mfd/altera-a10sr.h
 F:      include/dt-bindings/reset/altr,rst-mgr-a10sr.h
 
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index c9e74592742b..d21c07ccc94e 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -14,6 +14,13 @@ menuconfig RESET_CONTROLLER
 
 if RESET_CONTROLLER
 
+config RESET_A10SR
+        tristate "Altera Arria10 System Resource Reset"
+        depends on MFD_ALTERA_A10SR
+        help
+          This option enables support for the external reset functions for
+          peripheral PHYs on the Altera Arria10 System Resource Chip.
+
 config RESET_ATH79
         bool "AR71xx Reset Driver" if COMPILE_TEST
         default ATH79
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index c7ac1d6908ee..02a74db94339 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -2,6 +2,7 @@ obj-y += core.o
 obj-y += hisilicon/
 obj-$(CONFIG_ARCH_STI) += sti/
 obj-$(CONFIG_ARCH_TEGRA) += tegra/
+obj-$(CONFIG_RESET_A10SR) += reset-a10sr.o
 obj-$(CONFIG_RESET_ATH79) += reset-ath79.o
 obj-$(CONFIG_RESET_BERLIN) += reset-berlin.o
 obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
diff --git a/drivers/reset/reset-a10sr.c b/drivers/reset/reset-a10sr.c
new file mode 100644
index 000000000000..37496bd27fa2
--- /dev/null
+++ b/drivers/reset/reset-a10sr.c
@@ -0,0 +1,138 @@
+/*
+ *  Copyright Intel Corporation (C) 2017. All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Reset driver for Altera Arria10 MAX5 System Resource Chip
+ *
+ * Adapted from reset-socfpga.c
+ */
+
+#include <linux/err.h>
+#include <linux/mfd/altera-a10sr.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+
+#include <dt-bindings/reset/altr,rst-mgr-a10sr.h>
+
+struct a10sr_reset {
+        struct reset_controller_dev     rcdev;
+        struct regmap *regmap;
+};
+
+static inline struct a10sr_reset *to_a10sr_rst(struct reset_controller_dev *rc)
+{
+        return container_of(rc, struct a10sr_reset, rcdev);
+}
+
+static inline int a10sr_reset_shift(unsigned long id)
+{
+        switch (id) {
+        case A10SR_RESET_ENET_HPS:
+                return 1;
+        case A10SR_RESET_PCIE:
+        case A10SR_RESET_FILE:
+        case A10SR_RESET_BQSPI:
+        case A10SR_RESET_USB:
+                return id + 11;
+        default:
+                return -EINVAL;
+        }
+}
+
+static int a10sr_reset_update(struct reset_controller_dev *rcdev,
+                              unsigned long id, bool assert)
+{
+        struct a10sr_reset *a10r = to_a10sr_rst(rcdev);
+        int offset = a10sr_reset_shift(id);
+        u8 mask = ALTR_A10SR_REG_BIT_MASK(offset);
+        int index = ALTR_A10SR_HPS_RST_REG + ALTR_A10SR_REG_OFFSET(offset);
+
+        return regmap_update_bits(a10r->regmap, index, mask, assert ? 0 : mask);
+}
+
+static int a10sr_reset_assert(struct reset_controller_dev *rcdev,
+                              unsigned long id)
+{
+        return a10sr_reset_update(rcdev, id, true);
+}
+
+static int a10sr_reset_deassert(struct reset_controller_dev *rcdev,
+                                unsigned long id)
+{
+        return a10sr_reset_update(rcdev, id, false);
+}
+
+static int a10sr_reset_status(struct reset_controller_dev *rcdev,
+                              unsigned long id)
+{
+        int ret;
+        struct a10sr_reset *a10r = to_a10sr_rst(rcdev);
+        int offset = a10sr_reset_shift(id);
+        u8 mask = ALTR_A10SR_REG_BIT_MASK(offset);
+        int index = ALTR_A10SR_HPS_RST_REG + ALTR_A10SR_REG_OFFSET(offset);
+        unsigned int value;
+
+        ret = regmap_read(a10r->regmap, index, &value);
+        if (ret < 0)
+                return ret;
+
+        return !!(value & mask);
+}
+
+static const struct reset_control_ops a10sr_reset_ops = {
+        .assert         = a10sr_reset_assert,
+        .deassert       = a10sr_reset_deassert,
+        .status         = a10sr_reset_status,
+};
+
+static int a10sr_reset_probe(struct platform_device *pdev)
+{
+        struct altr_a10sr *a10sr = dev_get_drvdata(pdev->dev.parent);
+        struct a10sr_reset *a10r;
+
+        a10r = devm_kzalloc(&pdev->dev, sizeof(struct a10sr_reset),
+                            GFP_KERNEL);
+        if (!a10r)
+                return -ENOMEM;
+
+        a10r->rcdev.owner = THIS_MODULE;
+        a10r->rcdev.nr_resets = A10SR_RESET_NUM;
+        a10r->rcdev.ops = &a10sr_reset_ops;
+        a10r->rcdev.of_node = pdev->dev.of_node;
+        a10r->regmap = a10sr->regmap;
+
+        platform_set_drvdata(pdev, a10r);
+
+        return devm_reset_controller_register(&pdev->dev, &a10r->rcdev);
+}
+
+static const struct of_device_id a10sr_reset_of_match[] = {
+        { .compatible = "altr,a10sr-reset" },
+        { },
+};
+MODULE_DEVICE_TABLE(of, a10sr_reset_of_match);
+
+static struct platform_driver a10sr_reset_driver = {
+        .probe  = a10sr_reset_probe,
+        .driver = {
+                .name           = "altr_a10sr_reset",
+        },
+};
+module_platform_driver(a10sr_reset_driver);
+
+MODULE_AUTHOR("Thor Thayer <thor.thayer@linux.intel.com>");
+MODULE_DESCRIPTION("Altera Arria10 System Resource Reset Controller Driver");
+MODULE_LICENSE("GPL v2");