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Subject[PATCH 3/3] PCI: apple: Add support for optional PWREN GPIO
Date
WiFi and SD card devices on M1 Macs have a separate power enable GPIO.
Add support for this to the PCIe controller. This is modeled after how
pcie-fu740 does it.

Signed-off-by: Hector Martin <marcan@marcan.st>
---
drivers/pci/controller/pcie-apple.c | 35 ++++++++++++++++++++++++++---
1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/controller/pcie-apple.c b/drivers/pci/controller/pcie-apple.c
index e3aa2d461739..5b73c03ebe94 100644
--- a/drivers/pci/controller/pcie-apple.c
+++ b/drivers/pci/controller/pcie-apple.c
@@ -518,6 +518,16 @@ static int apple_pcie_probe_port(struct device_node *np)
}

gpiod_put(gd);
+
+ gd = gpiod_get_from_of_node(np, "pwren-gpios", 0,
+ GPIOD_OUT_LOW, "PWREN");
+ if (IS_ERR(gd)) {
+ if (PTR_ERR(gd) != -ENOENT)
+ return PTR_ERR(gd);
+ } else {
+ gpiod_put(gd);
+ }
+
return 0;
}

@@ -526,7 +536,7 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie,
{
struct platform_device *platform = to_platform_device(pcie->dev);
struct apple_pcie_port *port;
- struct gpio_desc *reset;
+ struct gpio_desc *reset, *pwren = NULL;
u32 stat, idx;
int ret, i;

@@ -535,6 +545,15 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie,
if (IS_ERR(reset))
return PTR_ERR(reset);

+ pwren = devm_gpiod_get_from_of_node(pcie->dev, np, "pwren-gpios", 0,
+ GPIOD_OUT_LOW, "PWREN");
+ if (IS_ERR(pwren)) {
+ if (PTR_ERR(pwren) == -ENOENT)
+ pwren = NULL;
+ else
+ return PTR_ERR(pwren);
+ }
+
port = devm_kzalloc(pcie->dev, sizeof(*port), GFP_KERNEL);
if (!port)
return -ENOMEM;
@@ -557,12 +576,22 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie,
/* Assert PERST# before setting up the clock */
gpiod_set_value_cansleep(reset, 1);

+ /* Power on the device if required */
+ if (pwren)
+ gpiod_set_value_cansleep(pwren, 1);
+
ret = apple_pcie_setup_refclk(pcie, port);
if (ret < 0)
return ret;

- /* The minimal Tperst-clk value is 100us (PCIe CEM r5.0, 2.9.2) */
- usleep_range(100, 200);
+ /*
+ * The minimal Tperst-clk value is 100us (PCIe CEM r5.0, 2.9.2)
+ * If powering up, the minimal Tpvperl is 100ms
+ */
+ if (pwren)
+ msleep(100);
+ else
+ usleep_range(100, 200);

/* Deassert PERST# */
rmw_set(PORT_PERST_OFF, port->base + PORT_PERST);
--
2.35.1
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