[PATCH 3/9] net: mdio: ipq4019: Enable GPIO reset for ipq5332 platform

[Luo Jie]

Before doing GPIO reset on the MDIO slave devices, the common clock
output to MDIO slave device should be enabled, and the related GCC
clocks also need to be configured.

Because of these extra configurations, the MDIO bus level GPIO and
PHY device level GPIO can't be leveraged. Need to add the device
tree property "phy-reset-gpio" of MDIO node to enable this special
GPIO reset.

Signed-off-by: Luo Jie <quic_luoj@xxxxxxxxxxx>
---
 drivers/net/mdio/mdio-ipq4019.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/drivers/net/mdio/mdio-ipq4019.c b/drivers/net/mdio/mdio-ipq4019.c
index a77982a1a1e1..93ae4684de31 100644
--- a/drivers/net/mdio/mdio-ipq4019.c
+++ b/drivers/net/mdio/mdio-ipq4019.c
@@ -12,6 +12,7 @@
 #include <linux/phy.h>
 #include <linux/platform_device.h>
 #include <linux/clk.h>
+#include <linux/gpio/consumer.h>
 
 #define MDIO_MODE_REG				0x40
 #define MDIO_ADDR_REG				0x44
@@ -55,6 +56,7 @@ struct ipq4019_mdio_data {
 	void __iomem *membase;
 	void __iomem *eth_ldo_rdy[ETH_LDO_RDY_CNT];
 	struct clk *clk[MDIO_CLK_CNT];
+	struct gpio_descs *reset_gpios;
 };
 
 const char *const mdio_clk_name[] = {
@@ -275,6 +277,24 @@ static int ipq_mdio_reset(struct mii_bus *bus)
 		}
 	}
 
+	/* Do the optional reset on the devices connected with MDIO bus */
+	if (priv->reset_gpios) {
+		unsigned long *values = bitmap_zalloc(priv->reset_gpios->ndescs, GFP_KERNEL);
+
+		if (!values)
+			return -ENOMEM;
+
+		bitmap_fill(values, priv->reset_gpios->ndescs);
+		gpiod_set_array_value_cansleep(priv->reset_gpios->ndescs, priv->reset_gpios->desc,
+					       priv->reset_gpios->info, values);
+
+		fsleep(IPQ_PHY_SET_DELAY_US);
+		bitmap_zero(values, priv->reset_gpios->ndescs);
+		gpiod_set_array_value_cansleep(priv->reset_gpios->ndescs, priv->reset_gpios->desc,
+					       priv->reset_gpios->info, values);
+		bitmap_free(values);
+	}
+
 	/* Configure MDIO clock source frequency if clock is specified in the device tree */
 	ret = clk_set_rate(priv->clk[MDIO_CLK_MDIO_AHB], IPQ_MDIO_CLK_RATE);
 	if (ret)
@@ -319,6 +339,19 @@ static int ipq4019_mdio_probe(struct platform_device *pdev)
 			return PTR_ERR(priv->clk[ret]);
 	}
 
+	/* This GPIO reset is for qca8084 PHY, which is only probeable by MDIO bus
+	 * after the following steps completed.
+	 *
+	 * 1. Enable LDO to provide clock for qca8084 and enable SoC GCC uniphy related clocks.
+	 * 2. Do GPIO reset on the qca8084 PHY.
+	 * 3. Configure the PHY address that is customized according to device treee.
+	 * 4. Configure the related qca8084 GCC clock & reset.
+	 */
+	priv->reset_gpios = devm_gpiod_get_array_optional(&pdev->dev, "phy-reset", GPIOD_OUT_LOW);
+	if (IS_ERR(priv->reset_gpios))
+		return dev_err_probe(&pdev->dev, PTR_ERR(priv->reset_gpios),
+				     "mii_bus %s couldn't get reset GPIO\n", bus->id);
+
 	bus->name = "ipq4019_mdio";
 	bus->read = ipq4019_mdio_read_c22;
 	bus->write = ipq4019_mdio_write_c22;
-- 
2.42.0