reset: add BCM6345 reset controller driver

Add support for resetting blocks through the Linux reset controller
subsystem for BCM63xx SoCs.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Reviewed-by: Florian Fainelli <F.fainelli@gmail.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 07d162b179fce8c9a64836ce6641240b467476c4..dceec715e745853525d82535f7eaa6d1acc53633 100644 (file)
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -35,6 +35,13 @@ config RESET_AXS10X
        help
          This enables the reset controller driver for AXS10x.
 
+config RESET_BCM6345
+       bool "BCM6345 Reset Controller"
+       depends on BMIPS_GENERIC || COMPILE_TEST
+       default BMIPS_GENERIC
+       help
+         This enables the reset controller driver for BCM6345 SoCs.
+
 config RESET_BERLIN
        bool "Berlin Reset Driver" if COMPILE_TEST
        default ARCH_BERLIN

diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 16947610cc3bc74f4bbed2135a21d7ac9ca3fe1d..1054123fd1876fa810ebf8205d744a4da928010c 100644 (file)
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -6,6 +6,7 @@ obj-$(CONFIG_ARCH_TEGRA) += tegra/
 obj-$(CONFIG_RESET_A10SR) += reset-a10sr.o
 obj-$(CONFIG_RESET_ATH79) += reset-ath79.o
 obj-$(CONFIG_RESET_AXS10X) += reset-axs10x.o
+obj-$(CONFIG_RESET_BCM6345) += reset-bcm6345.o
 obj-$(CONFIG_RESET_BERLIN) += reset-berlin.o
 obj-$(CONFIG_RESET_BRCMSTB) += reset-brcmstb.o
 obj-$(CONFIG_RESET_BRCMSTB_RESCAL) += reset-brcmstb-rescal.o

diff --git a/drivers/reset/reset-bcm6345.c b/drivers/reset/reset-bcm6345.c
new file mode 100644 (file)
index 0000000..737e4e8
--- /dev/null
+++ b/drivers/reset/reset-bcm6345.c
@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * BCM6345 Reset Controller Driver
+ *
+ * Copyright (C) 2020 Álvaro Fernández Rojas <noltari@gmail.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+
+#define BCM6345_RESET_NUM              32
+#define BCM6345_RESET_SLEEP_MIN_US     10000
+#define BCM6345_RESET_SLEEP_MAX_US     20000
+
+struct bcm6345_reset {
+       struct reset_controller_dev rcdev;
+       void __iomem *base;
+       spinlock_t lock;
+};
+
+static inline struct bcm6345_reset *
+to_bcm6345_reset(struct reset_controller_dev *rcdev)
+{
+       return container_of(rcdev, struct bcm6345_reset, rcdev);
+}
+
+static int bcm6345_reset_update(struct reset_controller_dev *rcdev,
+                               unsigned long id, bool assert)
+{
+       struct bcm6345_reset *bcm6345_reset = to_bcm6345_reset(rcdev);
+       unsigned long flags;
+       uint32_t val;
+
+       spin_lock_irqsave(&bcm6345_reset->lock, flags);
+       val = __raw_readl(bcm6345_reset->base);
+       if (assert)
+               val &= ~BIT(id);
+       else
+               val |= BIT(id);
+       __raw_writel(val, bcm6345_reset->base);
+       spin_unlock_irqrestore(&bcm6345_reset->lock, flags);
+
+       return 0;
+}
+
+static int bcm6345_reset_assert(struct reset_controller_dev *rcdev,
+                               unsigned long id)
+{
+       return bcm6345_reset_update(rcdev, id, true);
+}
+
+static int bcm6345_reset_deassert(struct reset_controller_dev *rcdev,
+                                 unsigned long id)
+{
+       return bcm6345_reset_update(rcdev, id, false);
+}
+
+static int bcm6345_reset_reset(struct reset_controller_dev *rcdev,
+                              unsigned long id)
+{
+       bcm6345_reset_update(rcdev, id, true);
+       usleep_range(BCM6345_RESET_SLEEP_MIN_US,
+                    BCM6345_RESET_SLEEP_MAX_US);
+
+       bcm6345_reset_update(rcdev, id, false);
+       /*
+        * Ensure component is taken out reset state by sleeping also after
+        * deasserting the reset. Otherwise, the component may not be ready
+        * for operation.
+        */
+       usleep_range(BCM6345_RESET_SLEEP_MIN_US,
+                    BCM6345_RESET_SLEEP_MAX_US);
+
+       return 0;
+}
+
+static int bcm6345_reset_status(struct reset_controller_dev *rcdev,
+                               unsigned long id)
+{
+       struct bcm6345_reset *bcm6345_reset = to_bcm6345_reset(rcdev);
+
+       return !(__raw_readl(bcm6345_reset->base) & BIT(id));
+}
+
+static struct reset_control_ops bcm6345_reset_ops = {
+       .assert = bcm6345_reset_assert,
+       .deassert = bcm6345_reset_deassert,
+       .reset = bcm6345_reset_reset,
+       .status = bcm6345_reset_status,
+};
+
+static int bcm6345_reset_probe(struct platform_device *pdev)
+{
+       struct bcm6345_reset *bcm6345_reset;
+
+       bcm6345_reset = devm_kzalloc(&pdev->dev,
+                                    sizeof(*bcm6345_reset), GFP_KERNEL);
+       if (!bcm6345_reset)
+               return -ENOMEM;
+
+       platform_set_drvdata(pdev, bcm6345_reset);
+
+       bcm6345_reset->base = devm_platform_ioremap_resource(pdev, 0);
+       if (IS_ERR(bcm6345_reset->base))
+               return PTR_ERR(bcm6345_reset->base);
+
+       spin_lock_init(&bcm6345_reset->lock);
+       bcm6345_reset->rcdev.ops = &bcm6345_reset_ops;
+       bcm6345_reset->rcdev.owner = THIS_MODULE;
+       bcm6345_reset->rcdev.of_node = pdev->dev.of_node;
+       bcm6345_reset->rcdev.of_reset_n_cells = 1;
+       bcm6345_reset->rcdev.nr_resets = BCM6345_RESET_NUM;
+
+       return devm_reset_controller_register(&pdev->dev,
+                                             &bcm6345_reset->rcdev);
+}
+
+static const struct of_device_id bcm6345_reset_of_match[] = {
+       { .compatible = "brcm,bcm6345-reset" },
+       { /* sentinel */ },
+};
+
+static struct platform_driver bcm6345_reset_driver = {
+       .probe = bcm6345_reset_probe,
+       .driver = {
+               .name = "bcm6345-reset",
+               .of_match_table = bcm6345_reset_of_match,
+               .suppress_bind_attrs = true,
+       },
+};
+builtin_platform_driver(bcm6345_reset_driver);