reset: img: Add Pistachio reset controller driver

Add reset controller driver for Pistachio SoC

Signed-off-by: Damien Horsley <Damien.Horsley@imgtec.com>
Signed-off-by: James Hartley <james.hartley@imgtec.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

1 files changed, 154 insertions, 0 deletions

diff --git a/drivers/reset/reset-pistachio.c b/drivers/reset/reset-pistachio.c
new file mode 100644
index 000000000000..b31cdb0570fc
--- /dev/null
+++ b/drivers/reset/reset-pistachio.c
@@ -0,0 +1,154 @@
+/*
+ * Pistachio SoC Reset Controller driver
+ *
+ * Copyright (C) 2015 Imagination Technologies Ltd.
+ *
+ * Author: Damien Horsley <Damien.Horsley@imgtec.com>
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset-controller.h>
+#include <linux/slab.h>
+#include <linux/mfd/syscon.h>
+
+#include <dt-bindings/reset/pistachio-resets.h>
+
+#define PISTACHIO_SOFT_RESET            0
+
+struct pistachio_reset_data {
+        struct reset_controller_dev     rcdev;
+        struct regmap                   *periph_regs;
+};
+
+static inline int pistachio_reset_shift(unsigned long id)
+{
+        switch (id) {
+        case PISTACHIO_RESET_I2C0:
+        case PISTACHIO_RESET_I2C1:
+        case PISTACHIO_RESET_I2C2:
+        case PISTACHIO_RESET_I2C3:
+        case PISTACHIO_RESET_I2S_IN:
+        case PISTACHIO_RESET_PRL_OUT:
+        case PISTACHIO_RESET_SPDIF_OUT:
+        case PISTACHIO_RESET_SPI:
+        case PISTACHIO_RESET_PWM_PDM:
+        case PISTACHIO_RESET_UART0:
+        case PISTACHIO_RESET_UART1:
+        case PISTACHIO_RESET_QSPI:
+        case PISTACHIO_RESET_MDC:
+        case PISTACHIO_RESET_SDHOST:
+        case PISTACHIO_RESET_ETHERNET:
+        case PISTACHIO_RESET_IR:
+        case PISTACHIO_RESET_HASH:
+        case PISTACHIO_RESET_TIMER:
+                return id;
+        case PISTACHIO_RESET_I2S_OUT:
+        case PISTACHIO_RESET_SPDIF_IN:
+        case PISTACHIO_RESET_EVT:
+                return id + 6;
+        case PISTACHIO_RESET_USB_H:
+        case PISTACHIO_RESET_USB_PR:
+        case PISTACHIO_RESET_USB_PHY_PR:
+        case PISTACHIO_RESET_USB_PHY_PON:
+                return id + 7;
+        default:
+                return -EINVAL;
+        }
+}
+
+static int pistachio_reset_assert(struct reset_controller_dev *rcdev,
+                                  unsigned long id)
+{
+        struct pistachio_reset_data *rd;
+        u32 mask;
+        int shift;
+
+        rd = container_of(rcdev, struct pistachio_reset_data, rcdev);
+        shift = pistachio_reset_shift(id);
+        if (shift < 0)
+                return shift;
+        mask = BIT(shift);
+
+        return regmap_update_bits(rd->periph_regs, PISTACHIO_SOFT_RESET,
+                                  mask, mask);
+}
+
+static int pistachio_reset_deassert(struct reset_controller_dev *rcdev,
+                                    unsigned long id)
+{
+        struct pistachio_reset_data *rd;
+        u32 mask;
+        int shift;
+
+        rd = container_of(rcdev, struct pistachio_reset_data, rcdev);
+        shift = pistachio_reset_shift(id);
+        if (shift < 0)
+                return shift;
+        mask = BIT(shift);
+
+        return regmap_update_bits(rd->periph_regs, PISTACHIO_SOFT_RESET,
+                                  mask, 0);
+}
+
+static struct reset_control_ops pistachio_reset_ops = {
+        .assert         = pistachio_reset_assert,
+        .deassert       = pistachio_reset_deassert,
+};
+
+static int pistachio_reset_probe(struct platform_device *pdev)
+{
+        struct pistachio_reset_data *rd;
+        struct device *dev = &pdev->dev;
+        struct device_node *np = pdev->dev.of_node;
+
+        rd = devm_kzalloc(dev, sizeof(*rd), GFP_KERNEL);
+        if (!rd)
+                return -ENOMEM;
+
+        rd->periph_regs = syscon_node_to_regmap(np->parent);
+        if (IS_ERR(rd->periph_regs))
+                return PTR_ERR(rd->periph_regs);
+
+        rd->rcdev.owner = THIS_MODULE;
+        rd->rcdev.nr_resets = PISTACHIO_RESET_MAX + 1;
+        rd->rcdev.ops = &pistachio_reset_ops;
+        rd->rcdev.of_node = np;
+
+        return reset_controller_register(&rd->rcdev);
+}
+
+static int pistachio_reset_remove(struct platform_device *pdev)
+{
+        struct pistachio_reset_data *data = platform_get_drvdata(pdev);
+
+        reset_controller_unregister(&data->rcdev);
+
+        return 0;
+}
+
+static const struct of_device_id pistachio_reset_dt_ids[] = {
+         { .compatible = "img,pistachio-reset", },
+         { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, pistachio_reset_dt_ids);
+
+static struct platform_driver pistachio_reset_driver = {
+        .probe  = pistachio_reset_probe,
+        .remove = pistachio_reset_remove,
+        .driver = {
+                .name           = "pistachio-reset",
+                .of_match_table = pistachio_reset_dt_ids,
+        },
+};
+module_platform_driver(pistachio_reset_driver);
+
+MODULE_AUTHOR("Damien Horsley <Damien.Horsley@imgtec.com>");
+MODULE_DESCRIPTION("Pistacho Reset Controller Driver");
+MODULE_LICENSE("GPL v2");