[PATCH 14/18] PCI: aardvark: Add clock support

Marek Behún
2022-02-20T19:34:30Z

From: Miquel Raynal <miquel.raynal@bootlin.com>

The IP relies on a gated clock. When we will add S2RAM support, this
clock will need to be resumed before any PCIe registers are
accessed. Add support for this clock.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
---
drivers/pci/controller/pci-aardvark.c | 32 +++++++++++++++++++++++++++
1 file changed, 32 insertions(+)

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index 41127a26c5bc..3b51f47abd72 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -8,6 +8,7 @@
* Author: Hezi Shahmoon <hezi.shahmoon@marvell.com>
*/

+#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/interrupt.h>
@@ -297,6 +298,7 @@ struct advk_pcie {
struct timer_list link_irq_timer;
struct pci_bridge_emul bridge;
struct gpio_desc *reset_gpio;
+ struct clk *clk;
struct phy *phy;
};

@@ -1813,6 +1815,29 @@ static int advk_pcie_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
return of_irq_parse_and_map_pci(dev, slot, pin);
}

+static int advk_pcie_setup_clk(struct advk_pcie *pcie)
+{
+ struct device *dev = &pcie->pdev->dev;
+ int ret;
+
+ pcie->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(pcie->clk) && (PTR_ERR(pcie->clk) == -EPROBE_DEFER))
+ return PTR_ERR(pcie->clk);
+
+ /* Old bindings miss the clock handle */
+ if (IS_ERR(pcie->clk)) {
+ dev_warn(dev, "Clock unavailable (%ld)\n", PTR_ERR(pcie->clk));
+ pcie->clk = NULL;
+ return 0;
+ }
+
+ ret = clk_prepare_enable(pcie->clk);
+ if (ret)
+ dev_err(dev, "Clock initialization failed (%d)\n", ret);
+
+ return ret;
+}
+
static void advk_pcie_disable_phy(struct advk_pcie *pcie)
{
phy_power_off(pcie->phy);
@@ -1998,6 +2023,10 @@ static int advk_pcie_probe(struct platform_device *pdev)
slot_power_limit / 1000,
(slot_power_limit / 100) % 10);

+ ret = advk_pcie_setup_clk(pcie);
+ if (ret)
+ return ret;
+
ret = advk_pcie_setup_phy(pcie);
if (ret)
return ret;
@@ -2126,6 +2155,9 @@ static int advk_pcie_remove(struct platform_device *pdev)
/* Disable phy */
advk_pcie_disable_phy(pcie);

+ /* Disable clock */
+ clk_disable_unprepare(pcie->clk);
+
return 0;
}

--
2.34.1