Re: [PATCH v3 2/2] PCI: mediatek-gen3: Add power and reset control feature for downstream component

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Il 09/10/23 10:49, Jian Yang ha scritto:
From: "jian.yang" <jian.yang@xxxxxxxxxxxx>

Make MediaTek's controller driver capable of controlling power
supplies and reset pin of a downstream component in power-on and
power-off flow.

Some downstream components (e.g., a WIFI chip) may need an extra
reset other than PERST# and their power supplies, depending on
the requirements of platform, may need to controlled by their
parent's driver. To meet the requirements described above, I add this
feature to MediaTek's PCIe controller driver as a optional feature.

Signed-off-by: jian.yang <jian.yang@xxxxxxxxxxxx>
---
  drivers/pci/controller/pcie-mediatek-gen3.c | 93 ++++++++++++++++++++-
  1 file changed, 92 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c
index e0e27645fdf4..ad4b25c34f5d 100644
--- a/drivers/pci/controller/pcie-mediatek-gen3.c
+++ b/drivers/pci/controller/pcie-mediatek-gen3.c
@@ -8,6 +8,7 @@
#include <linux/clk.h>
  #include <linux/delay.h>
+#include <linux/gpio/consumer.h>
  #include <linux/iopoll.h>
  #include <linux/irq.h>
  #include <linux/irqchip/chained_irq.h>
@@ -20,6 +21,8 @@
  #include <linux/platform_device.h>
  #include <linux/pm_domain.h>
  #include <linux/pm_runtime.h>
+#include <linux/pm_wakeup.h>
+#include <linux/regulator/consumer.h>
  #include <linux/reset.h>
#include "../pci.h"
@@ -100,6 +103,13 @@
  #define PCIE_ATR_TLP_TYPE_MEM		PCIE_ATR_TLP_TYPE(0)
  #define PCIE_ATR_TLP_TYPE_IO		PCIE_ATR_TLP_TYPE(2)
+/* Downstream Component power supplies used by MediaTek PCIe */
+static const char *const dsc_power_supplies[] = {
+	"pcie1v8",
+	"pcie3v3",
+	"pcie12v",
+};

Please....

static const char *const dsc_power_supplies[] = {
	"vpcie1v8",
	"vpcie3v3",
	"vpcie12v",
};

+
  /**
   * struct mtk_msi_set - MSI information for each set
   * @base: IO mapped register base
@@ -122,6 +132,9 @@ struct mtk_msi_set {
   * @phy: PHY controller block
   * @clks: PCIe clocks
   * @num_clks: PCIe clocks count for this port
+ * @supplies: Downstream Component power supplies
+ * @num_supplies: Downstream Component power supplies count
+ * @dsc_reset: The GPIO pin to reset Downstream component
   * @irq: PCIe controller interrupt number
   * @saved_irq_state: IRQ enable state saved at suspend time
   * @irq_lock: lock protecting IRQ register access
@@ -141,6 +154,9 @@ struct mtk_gen3_pcie {
  	struct phy *phy;
  	struct clk_bulk_data *clks;
  	int num_clks;
+	struct regulator_bulk_data *supplies;
+	int num_supplies;
+	struct gpio_desc *dsc_reset;
int irq;
  	u32 saved_irq_state;
@@ -763,7 +779,7 @@ static int mtk_pcie_parse_port(struct mtk_gen3_pcie *pcie)
  	struct device *dev = pcie->dev;
  	struct platform_device *pdev = to_platform_device(dev);
  	struct resource *regs;
-	int ret;
+	int ret, i;

Since you anyway have to send a v4, can you please also order these by name?

int i, ret;

regs = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pcie-mac");
  	if (!regs)
@@ -809,14 +825,86 @@ static int mtk_pcie_parse_port(struct mtk_gen3_pcie *pcie)
  		return pcie->num_clks;
  	}
+ pcie->num_supplies = ARRAY_SIZE(dsc_power_supplies);
+	pcie->supplies = devm_kcalloc(dev, pcie->num_supplies,
+				      sizeof(*pcie->supplies),
+				      GFP_KERNEL);
+	if (!pcie->supplies)
+		return -ENOMEM;
+
+	for (i = 0; i < pcie->num_supplies; i++)
+		pcie->supplies[i].supply = dsc_power_supplies[i];
+
+	ret = devm_regulator_bulk_get(dev, pcie->num_supplies, pcie->supplies);
+	if (ret)
+		return ret;
+
+	pcie->dsc_reset = devm_gpiod_get_optional(dev, "dsc-reset",
+						  GPIOD_OUT_LOW);
+	if (IS_ERR(pcie->dsc_reset)) {
+		ret = PTR_ERR(pcie->dsc_reset);
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "failed to request DSC reset gpio\n");

dev_err_probe() does exactly what you're doing here, but it's shorter :-)

+
+		return ret;
+	}
+
  	return 0;
  }
+static int mtk_pcie_dsc_power_up(struct mtk_gen3_pcie *pcie)
+{
+	struct device *dev = pcie->dev;
+	int ret;
+
+	/*
+	 * Skip downstream component's power-up flow if it was kept power-on

* Skip powering up the downstream component if it was kept powered on


+	 * while system entered suspend state
+	 */
+	if (device_wakeup_path(dev))
+		return 0;
+
+	/* Assert Downstream Component reset */
+	if (pcie->dsc_reset)
+		gpiod_set_value_cansleep(pcie->dsc_reset, 1);
+
+	ret = regulator_bulk_enable(pcie->num_supplies, pcie->supplies);
+	if (ret)
+		dev_err(dev, "failed to enable DSC power supplies: %d\n", ret);
+
+	/* De-assert Downstream Component reset */
+	if (pcie->dsc_reset)
+		gpiod_set_value_cansleep(pcie->dsc_reset, 0);
+
+	return ret;
+}
+
+static void mtk_pcie_dsc_power_down(struct mtk_gen3_pcie *pcie)
+{
+	/*
+	 * Keep downstream component power-on if it need to wake up the

* Keep downstream component powered on if it is capable of waking up
* the system from suspend

+	 * system in suspend state
+	 */
+	if (device_wakeup_path(pcie->dev))
+		return;
+
+	/* Assert Downstream Component reset */
+	if (pcie->dsc_reset)
+		gpiod_set_value_cansleep(pcie->dsc_reset, 1);
+
+	regulator_bulk_disable(pcie->num_supplies, pcie->supplies);
+}
+

Regards,
Angelo





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