[PATCH v1 03/14] clk: microchip: mpfs: add reset controller

Conor Dooley
2022-06-30T08:08:21Z

Add a reset controller to PolarFire SoC's clock driver. This reset
controller is registered as an aux device and read/write functions
exported to the drivers namespace so that the reset controller can
access the peripheral device reset register.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
drivers/clk/microchip/Kconfig | 1 +
drivers/clk/microchip/clk-mpfs.c | 116 ++++++++++++++++++++++++++++---
include/soc/microchip/mpfs.h | 8 +++
3 files changed, 114 insertions(+), 11 deletions(-)

diff --git a/drivers/clk/microchip/Kconfig b/drivers/clk/microchip/Kconfig
index a5a99873c4f5..b46e864b3bd8 100644
--- a/drivers/clk/microchip/Kconfig
+++ b/drivers/clk/microchip/Kconfig
@@ -6,5 +6,6 @@ config COMMON_CLK_PIC32
config MCHP_CLK_MPFS
bool "Clk driver for PolarFire SoC"
depends on (RISCV && SOC_MICROCHIP_POLARFIRE) || COMPILE_TEST
+ select AUXILIARY_BUS
help
Supports Clock Configuration for PolarFire SoC
diff --git a/drivers/clk/microchip/clk-mpfs.c b/drivers/clk/microchip/clk-mpfs.c
index 070c3b896559..a93f78619dc3 100644
--- a/drivers/clk/microchip/clk-mpfs.c
+++ b/drivers/clk/microchip/clk-mpfs.c
@@ -3,12 +3,14 @@
* Daire McNamara,<daire.mcnamara@microchip.com>
* Copyright (C) 2020 Microchip Technology Inc. All rights reserved.
*/
+#include <linux/auxiliary_bus.h>
#include <linux/clk-provider.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <dt-bindings/clock/microchip,mpfs-clock.h>
+#include <soc/microchip/mpfs.h>

/* address offset of control registers */
#define REG_MSSPLL_REF_CR 0x08u
@@ -28,6 +30,7 @@
#define MSSPLL_FIXED_DIV 4u

struct mpfs_clock_data {
+ struct device *dev;
void __iomem *base;
void __iomem *msspll_base;
struct clk_hw_onecell_data hw_data;
@@ -302,10 +305,6 @@ static int mpfs_periph_clk_enable(struct clk_hw *hw)

spin_lock_irqsave(&mpfs_clk_lock, flags);

- reg = readl_relaxed(base_addr + REG_SUBBLK_RESET_CR);
- val = reg & ~(1u << periph->shift);
- writel_relaxed(val, base_addr + REG_SUBBLK_RESET_CR);
-
reg = readl_relaxed(base_addr + REG_SUBBLK_CLOCK_CR);
val = reg | (1u << periph->shift);
writel_relaxed(val, base_addr + REG_SUBBLK_CLOCK_CR);
@@ -339,12 +338,9 @@ static int mpfs_periph_clk_is_enabled(struct clk_hw *hw)
void __iomem *base_addr = periph_hw->sys_base;
u32 reg;

- reg = readl_relaxed(base_addr + REG_SUBBLK_RESET_CR);
- if ((reg & (1u << periph->shift)) == 0u) {
- reg = readl_relaxed(base_addr + REG_SUBBLK_CLOCK_CR);
- if (reg & (1u << periph->shift))
- return 1;
- }
+ reg = readl_relaxed(base_addr + REG_SUBBLK_CLOCK_CR);
+ if (reg & (1u << periph->shift))
+ return 1;

return 0;
}
@@ -438,6 +434,98 @@ static int mpfs_clk_register_periphs(struct device *dev, struct mpfs_periph_hw_c
return 0;
}

+/*
+ * Peripheral clock resets
+ */
+
+#if IS_ENABLED(CONFIG_RESET_CONTROLLER)
+
+u32 mpfs_reset_read(struct device *dev)
+{
+ struct mpfs_clock_data *clock_data = dev_get_drvdata(dev->parent);
+
+ return readl_relaxed(clock_data->base + REG_SUBBLK_RESET_CR);
+}
+EXPORT_SYMBOL_NS_GPL(mpfs_reset_read, MCHP_CLK_MPFS);
+
+void mpfs_reset_write(struct device *dev, u32 val)
+{
+ struct mpfs_clock_data *clock_data = dev_get_drvdata(dev->parent);
+
+ writel_relaxed(val, clock_data->base + REG_SUBBLK_RESET_CR);
+}
+EXPORT_SYMBOL_NS_GPL(mpfs_reset_write, MCHP_CLK_MPFS);
+
+static void mpfs_reset_unregister_adev(void *_adev)
+{
+ struct auxiliary_device *adev = _adev;
+
+ auxiliary_device_delete(adev);
+}
+
+static void mpfs_reset_adev_release(struct device *dev)
+{
+ struct auxiliary_device *adev = to_auxiliary_dev(dev);
+
+ auxiliary_device_uninit(adev);
+
+ kfree(adev);
+}
+
+static struct auxiliary_device *mpfs_reset_adev_alloc(struct mpfs_clock_data *clk_data)
+{
+ struct auxiliary_device *adev;
+ int ret;
+
+ adev = kzalloc(sizeof(*adev), GFP_KERNEL);
+ if (!adev)
+ return ERR_PTR(-ENOMEM);
+
+ adev->name = "reset-mpfs";
+ adev->dev.parent = clk_data->dev;
+ adev->dev.release = mpfs_reset_adev_release;
+ adev->id = 666u;
+
+ ret = auxiliary_device_init(adev);
+ if (ret) {
+ kfree(adev);
+ return ERR_PTR(ret);
+ }
+
+ return adev;
+}
+
+static int mpfs_reset_controller_register(struct mpfs_clock_data *clk_data)
+{
+ struct auxiliary_device *adev;
+ int ret;
+
+ adev = mpfs_reset_adev_alloc(clk_data);
+ if (IS_ERR(adev))
+ return PTR_ERR(adev);
+
+ ret = auxiliary_device_add(adev);
+ if (ret) {
+ auxiliary_device_uninit(adev);
+ return ret;
+ }
+
+ ret = devm_add_action_or_reset(clk_data->dev, mpfs_reset_unregister_adev, adev);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+#else /* !CONFIG_RESET_CONTROLLER */
+
+static int mpfs_reset_controller_register(struct mpfs_clock_data *clk_data)
+{
+ return 0;
+}
+
+#endif /* !CONFIG_RESET_CONTROLLER */
+
static int mpfs_clk_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
@@ -462,6 +550,8 @@ static int mpfs_clk_probe(struct platform_device *pdev)
return PTR_ERR(clk_data->msspll_base);

clk_data->hw_data.num = num_clks;
+ clk_data->dev = dev;
+ dev_set_drvdata(dev, clk_data);

ret = mpfs_clk_register_mssplls(dev, mpfs_msspll_clks, ARRAY_SIZE(mpfs_msspll_clks),
clk_data);
@@ -481,6 +571,10 @@ static int mpfs_clk_probe(struct platform_device *pdev)
if (ret)
return ret;

+ ret = mpfs_reset_controller_register(clk_data);
+ if (ret)
+ return ret;
+
return ret;
}

@@ -488,7 +582,7 @@ static const struct of_device_id mpfs_clk_of_match_table[] = {
{ .compatible = "microchip,mpfs-clkcfg", },
{}
};
-MODULE_DEVICE_TABLE(of, mpfs_clk_match_table);
+MODULE_DEVICE_TABLE(of, mpfs_clk_of_match_table);

static struct platform_driver mpfs_clk_driver = {
.probe = mpfs_clk_probe,
diff --git a/include/soc/microchip/mpfs.h b/include/soc/microchip/mpfs.h
index 6466515262bd..f916dcde457f 100644
--- a/include/soc/microchip/mpfs.h
+++ b/include/soc/microchip/mpfs.h
@@ -40,4 +40,12 @@ struct mpfs_sys_controller *mpfs_sys_controller_get(struct device *dev);

#endif /* if IS_ENABLED(CONFIG_POLARFIRE_SOC_SYS_CTRL) */

+#if IS_ENABLED(CONFIG_MCHP_CLK_MPFS)
+
+u32 mpfs_reset_read(struct device *dev);
+
+void mpfs_reset_write(struct device *dev, u32 val);
+
+#endif /* if IS_ENABLED(CONFIG_MCHP_CLK_MPFS) */
+
#endif /* __SOC_MPFS_H__ */
--
2.36.1