[PATCH v1] clk: microchip: mpfs: don't reset disabled peripherals

[Conor Dooley]

The current clock driver for PolarFire SoC puts the hardware behind
"periph" clocks into reset if their clock is disabled. CONFIG_PM was
recently added to the riscv defconfig and exposed issues caused by this
behaviour, where the Cadence GEM was being put into reset between its
bringup & the PHY bringup:

https://lore.kernel.org/linux-riscv/9f4b057d-1985-5fd3-65c0-f944161c7792@microchip.com/

Fix this by removing the reset enable/disable code from the driver &
rely (for now) on the bootloader bringing peripherals out of reset
during boot.

Fixes: 635e5e73370e ("clk: microchip: Add driver for Microchip PolarFire SoC")
Reviewed-by: Daire McNamara <daire.mcnamara at microchip.com>
Signed-off-by: Conor Dooley <conor.dooley at microchip.com>
---
 drivers/clk/microchip/clk-mpfs.c | 18 +++---------------
 1 file changed, 3 insertions(+), 15 deletions(-)

diff --git a/drivers/clk/microchip/clk-mpfs.c b/drivers/clk/microchip/clk-mpfs.c
index aa1561b773d6..4ddc7e7c9766 100644
--- a/drivers/clk/microchip/clk-mpfs.c
+++ b/drivers/clk/microchip/clk-mpfs.c
@@ -13,7 +13,6 @@
 /* address offset of control registers */
 #define REG_CLOCK_CONFIG_CR	0x08u
 #define REG_SUBBLK_CLOCK_CR	0x84u
-#define REG_SUBBLK_RESET_CR	0x88u
 
 struct mpfs_clock_data {
 	void __iomem *base;
@@ -177,10 +176,6 @@ 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);
@@ -200,10 +195,6 @@ static void mpfs_periph_clk_disable(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);
@@ -218,12 +209,9 @@ 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;
 }
-- 
2.35.1