[PATCH v6 15/17] reset: elbasr: Add AMD Pensando Elba SR Reset Controller

Brad Larson
2022-08-20T19:59:52Z

From: Brad Larson <blarson@amd.com>

This patch adds the reset controller functionality for the
AMD Pensando Elba System Resource Chip.

Signed-off-by: Brad Larson <blarson@amd.com>
---
drivers/reset/Kconfig | 9 +++++
drivers/reset/Makefile | 1 +
drivers/reset/reset-elbasr.c | 77 ++++++++++++++++++++++++++++++++++++
3 files changed, 87 insertions(+)
create mode 100644 drivers/reset/reset-elbasr.c

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 806773e88832..04b700c90ce4 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -66,6 +66,15 @@ config RESET_BRCMSTB_RESCAL
This enables the RESCAL reset controller for SATA, PCIe0, or PCIe1 on
BCM7216.

+config RESET_ELBASR
+ tristate "Pensando Elba System Resource reset controller"
+ depends on MFD_PENSANDO_ELBASR || COMPILE_TEST
+ help
+ This option enables support for the external reset functions
+ on the Pensando Elba System Resource Chip. Reset control
+ of peripherals is accessed over SPI to the system resource
+ chip device registers using CS0.
+
config RESET_HSDK
bool "Synopsys HSDK Reset Driver"
depends on HAS_IOMEM
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index cd5cf8e7c6a7..9e6b095ee63a 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -10,6 +10,7 @@ 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
+obj-$(CONFIG_RESET_ELBASR) += reset-elbasr.o
obj-$(CONFIG_RESET_HSDK) += reset-hsdk.o
obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
obj-$(CONFIG_RESET_INTEL_GW) += reset-intel-gw.o
diff --git a/drivers/reset/reset-elbasr.c b/drivers/reset/reset-elbasr.c
new file mode 100644
index 000000000000..ab5d49f5e6a7
--- /dev/null
+++ b/drivers/reset/reset-elbasr.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2022 Advanced Micro Devices, Inc.
+ */
+
+#include <linux/err.h>
+#include <linux/mfd/pensando-elbasr.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset-controller.h>
+
+struct elbasr_reset {
+ struct reset_controller_dev rcdev;
+ struct regmap *regmap;
+};
+
+static inline struct elbasr_reset *to_elbasr_rst(struct reset_controller_dev *rc)
+{
+ return container_of(rc, struct elbasr_reset, rcdev);
+}
+
+static int elbasr_reset_assert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct elbasr_reset *elbar = to_elbasr_rst(rcdev);
+
+ return regmap_update_bits(elbar->regmap, ELBASR_CTRL0_REG, BIT(6), BIT(6));
+}
+
+static int elbasr_reset_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct elbasr_reset *elbar = to_elbasr_rst(rcdev);
+
+ return regmap_update_bits(elbar->regmap, ELBASR_CTRL0_REG, BIT(6), 0);
+}
+
+static const struct reset_control_ops elbasr_reset_ops = {
+ .assert = elbasr_reset_assert,
+ .deassert = elbasr_reset_deassert,
+};
+
+static int elbasr_reset_probe(struct platform_device *pdev)
+{
+ struct elbasr_data *elbasr = dev_get_drvdata(pdev->dev.parent);
+ struct elbasr_reset *elbar;
+
+ elbar = devm_kzalloc(&pdev->dev, sizeof(struct elbasr_reset),
+ GFP_KERNEL);
+ if (!elbar)
+ return -ENOMEM;
+
+ elbar->rcdev.owner = THIS_MODULE;
+ elbar->rcdev.nr_resets = ELBASR_NR_RESETS;
+ elbar->rcdev.ops = &elbasr_reset_ops;
+ elbar->rcdev.of_node = pdev->dev.of_node;
+ elbar->regmap = elbasr->elbasr_regs;
+
+ platform_set_drvdata(pdev, elbar);
+
+ return devm_reset_controller_register(&pdev->dev, &elbar->rcdev);
+}
+
+static const struct of_device_id elba_reset_dt_match[] = {
+ { .compatible = "amd,pensando-elbasr-reset", },
+ { /* sentinel */ }
+};
+
+static struct platform_driver elbasr_reset_driver = {
+ .probe = elbasr_reset_probe,
+ .driver = {
+ .name = "pensando_elbasr_reset",
+ .of_match_table = elba_reset_dt_match,
+ },
+};
+builtin_platform_driver(elbasr_reset_driver);
--
2.17.1