[PATCH v3 2/4] clk: en7523: add support for dedicated PCIe PERSTOUT reset

From: Christian Marangi <ansuelsmth@gmail.com>
Date: 2026-06-27 12:15:04
Also in: linux-clk, linux-devicetree, linux-mediatek, linux-pci, lkml
Subsystem: common clk framework, the rest · Maintainers: Michael Turquette, Stephen Boyd, Linus Torvalds

Add support for resetting the PCIe lines with the PERSTOUT reset. These
special reset are controlled by the PCIC register and are specific to each
of the 3 PCIe lines.

Notice that reset logic is inverted for these bit where 0 is assert and 1
deassert. This is intenrally handled in the reset function.

PCI enable/disable are updated to drop PERSTOUT bits in favor dedicated
reset handling.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/clk/clk-en7523.c | 39 ++++++++++++++++++++++++++++-----------
 1 file changed, 28 insertions(+), 11 deletions(-)

diff --git a/drivers/clk/clk-en7523.c b/drivers/clk/clk-en7523.c
index 1ab0e2eca5d3..c9b21d9bf2f3 100644
--- a/drivers/clk/clk-en7523.c
+++ b/drivers/clk/clk-en7523.c

@@ -338,6 +338,7 @@ static const struct en_clk_desc en7581_base_clks[] = {
 static const u16 en7581_rst_ofs[] = {
 	REG_RST_CTRL2,
 	REG_RST_CTRL1,
+	REG_NP_SCU_PCIC,
 };
 
 static const u16 en751221_rst_ofs[] = {

@@ -450,6 +451,11 @@ static const u16 en7581_rst_map[] = {
 	[EN7581_CPU_TIMER_RST]		= RST_NR_PER_BANK + 28,
 	[EN7581_PCIE_HB_RST]		= RST_NR_PER_BANK + 29,
 	[EN7581_XPON_MAC_RST]		= RST_NR_PER_BANK + 31,
+
+	/* RST_PCIC */
+	[EN7581_PCIC_PERSTOUT0_RST]	= 2 * RST_NR_PER_BANK + 29,
+	[EN7581_PCIC_PERSTOUT1_RST]	= 2 * RST_NR_PER_BANK + 26,
+	[EN7581_PCIC_PERSTOUT2_RST]	= 2 * RST_NR_PER_BANK + 16,
 };
 
 static const u16 en751221_rst_map[] = {

@@ -635,9 +641,7 @@ static int en7581_pci_enable(struct clk_hw *hw)
 	void __iomem *np_base = cg->base;
 	u32 val, mask;
 
-	mask = REG_PCI_CONTROL_REFCLK_EN0 | REG_PCI_CONTROL_REFCLK_EN1 |
-	       REG_PCI_CONTROL_PERSTOUT1 | REG_PCI_CONTROL_PERSTOUT2 |
-	       REG_PCI_CONTROL_PERSTOUT;
+	mask = REG_PCI_CONTROL_REFCLK_EN0 | REG_PCI_CONTROL_REFCLK_EN1;
 	val = readl(np_base + REG_PCI_CONTROL);
 	writel(val | mask, np_base + REG_PCI_CONTROL);

@@ -650,9 +654,7 @@ static void en7581_pci_disable(struct clk_hw *hw)
 	void __iomem *np_base = cg->base;
 	u32 val, mask;
 
-	mask = REG_PCI_CONTROL_REFCLK_EN0 | REG_PCI_CONTROL_REFCLK_EN1 |
-	       REG_PCI_CONTROL_PERSTOUT1 | REG_PCI_CONTROL_PERSTOUT2 |
-	       REG_PCI_CONTROL_PERSTOUT;
+	mask = REG_PCI_CONTROL_REFCLK_EN0 | REG_PCI_CONTROL_REFCLK_EN1;
 	val = readl(np_base + REG_PCI_CONTROL);
 	writel(val & ~mask, np_base + REG_PCI_CONTROL);
 	usleep_range(1000, 2000);

@@ -754,14 +756,21 @@ static int en7523_reset_update(struct reset_controller_dev *rcdev,
 			       unsigned long id, bool assert)
 {
 	struct en_rst_data *rst_data = container_of(rcdev, struct en_rst_data, rcdev);
-	void __iomem *addr = rst_data->base + rst_data->bank_ofs[id / RST_NR_PER_BANK];
+	u32 offset = rst_data->bank_ofs[id / RST_NR_PER_BANK];
+	void __iomem *addr = rst_data->base + offset;
+	bool inverted = false;
 	u32 val;
 
+	/* For PCIC reset logic is inverted, 0:assert 1:deassert*/
+	if (offset == REG_NP_SCU_PCIC)
+		inverted = true;
+
 	val = readl(addr);
+	val &= ~BIT(id % RST_NR_PER_BANK);
 	if (assert)
-		val |= BIT(id % RST_NR_PER_BANK);
+		val |= inverted ? 0 : BIT(id % RST_NR_PER_BANK);
 	else
-		val &= ~BIT(id % RST_NR_PER_BANK);
+		val |= inverted ? BIT(id % RST_NR_PER_BANK) : 0;
 	writel(val, addr);
 
 	return 0;

@@ -783,9 +792,17 @@ static int en7523_reset_status(struct reset_controller_dev *rcdev,
 			       unsigned long id)
 {
 	struct en_rst_data *rst_data = container_of(rcdev, struct en_rst_data, rcdev);
-	void __iomem *addr = rst_data->base + rst_data->bank_ofs[id / RST_NR_PER_BANK];
+	u32 offset = rst_data->bank_ofs[id / RST_NR_PER_BANK];
+	void __iomem *addr = rst_data->base + offset;
+	bool inverted = false;
+	u32 val;
+
+	/* For PCIC reset logic is inverted, 0:assert 1:deassert*/
+	if (offset == REG_NP_SCU_PCIC)
+		inverted = true;
 
-	return !!(readl(addr) & BIT(id % RST_NR_PER_BANK));
+	val = readl(addr) & BIT(id % RST_NR_PER_BANK);
+	return inverted ? !val : !!val;
 }
 
 static int en7523_reset_xlate(struct reset_controller_dev *rcdev,

-- 
2.53.0

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