[PATCH v2 2/2] drivers: net: phy: at803x: add phy clk setup via dts

[Michael Grzeschik <m.grzeschik@pengutronix.de>]

There are dt-bindings for the setup of the clk configuration in the phy.
This patch adds support for these bindings in the driver.

Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>

---
v1 -> v2: - returning config_init directly with clk_out_config
          - removed superflous and wrong drv_name property

 drivers/net/phy/at803x.c | 178 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 171 insertions(+), 7 deletions(-)

diff --git a/drivers/net/phy/at803x.c b/drivers/net/phy/at803x.c
index b43cb0d23e..de053a36fb 100644
--- a/drivers/net/phy/at803x.c
+++ b/drivers/net/phy/at803x.c
@@ -11,6 +11,9 @@
 #include <init.h>
 #include <linux/phy.h>
 #include <linux/string.h>
+#include <linux/bitfield.h>
+#include <linux/mdio.h>
+#include <dt-bindings/net/qca-ar803x.h>
 
 #define AT803X_INTR_ENABLE			0x12
 #define AT803X_INTR_STATUS			0x13
@@ -27,6 +30,164 @@
 #define AT803X_DEBUG_SYSTEM_MODE_CTRL		0x05
 #define AT803X_DEBUG_RGMII_TX_CLK_DLY		(1 << 8)
 
+/* AT803x supports either the XTAL input pad, an internal PLL or the
+ * DSP as clock reference for the clock output pad. The XTAL reference
+ * is only used for 25 MHz output, all other frequencies need the PLL.
+ * The DSP as a clock reference is used in synchronous ethernet
+ * applications.
+ *
+ * By default the PLL is only enabled if there is a link. Otherwise
+ * the PHY will go into low power state and disabled the PLL. You can
+ * set the PLL_ON bit (see debug register 0x1f) to keep the PLL always
+ * enabled.
+ */
+#define AT803X_MMD7_CLK25M			0x8016
+#define AT803X_CLK_OUT_MASK			GENMASK(4, 2)
+#define AT803X_CLK_OUT_25MHZ_XTAL		0
+#define AT803X_CLK_OUT_25MHZ_DSP		1
+#define AT803X_CLK_OUT_50MHZ_PLL		2
+#define AT803X_CLK_OUT_50MHZ_DSP		3
+#define AT803X_CLK_OUT_62_5MHZ_PLL		4
+#define AT803X_CLK_OUT_62_5MHZ_DSP		5
+#define AT803X_CLK_OUT_125MHZ_PLL		6
+#define AT803X_CLK_OUT_125MHZ_DSP		7
+
+/* The AR8035 has another mask which is compatible with the AR8031/AR8033 mask
+ * but doesn't support choosing between XTAL/PLL and DSP.
+ */
+#define AT8035_CLK_OUT_MASK			GENMASK(4, 3)
+
+#define AT803X_CLK_OUT_STRENGTH_MASK		GENMASK(8, 7)
+#define AT803X_CLK_OUT_STRENGTH_FULL		0
+#define AT803X_CLK_OUT_STRENGTH_HALF		1
+#define AT803X_CLK_OUT_STRENGTH_QUARTER		2
+
+#define ATH9331_PHY_ID 0x004dd041
+#define ATH8030_PHY_ID 0x004dd076
+#define ATH8031_PHY_ID 0x004dd074
+#define ATH8032_PHY_ID 0x004dd023
+#define ATH8035_PHY_ID 0x004dd072
+#define AT8030_PHY_ID_MASK			0xffffffef
+
+struct at803x_priv {
+	u16 clk_25m_reg;
+	u16 clk_25m_mask;
+};
+
+static bool at803x_match_phy_id(struct phy_device *phydev, u32 phy_id)
+{
+	struct phy_driver *drv = to_phy_driver(phydev->dev.driver);
+
+	return (phydev->phy_id & drv->phy_id_mask)
+		== (phy_id & drv->phy_id_mask);
+}
+
+static int at803x_parse_dt(struct phy_device *phydev)
+{
+	const struct device_d *dev = &phydev->dev;
+	const struct device_node *node = dev->device_node;
+	struct at803x_priv *priv = phydev->priv;
+	unsigned int sel, mask;
+	u32 freq, strength;
+	int ret;
+
+	ret = of_property_read_u32(node, "qca,clk-out-frequency", &freq);
+	if (!ret) {
+		mask = AT803X_CLK_OUT_MASK;
+		switch (freq) {
+		case 25000000:
+			sel = AT803X_CLK_OUT_25MHZ_XTAL;
+			break;
+		case 50000000:
+			sel = AT803X_CLK_OUT_50MHZ_PLL;
+			break;
+		case 62500000:
+			sel = AT803X_CLK_OUT_62_5MHZ_PLL;
+			break;
+		case 125000000:
+			sel = AT803X_CLK_OUT_125MHZ_PLL;
+			break;
+		default:
+			dev_err(dev, "invalid qca,clk-out-frequency\n");
+			return -EINVAL;
+		}
+
+		priv->clk_25m_reg |= FIELD_PREP(mask, sel);
+		priv->clk_25m_mask |= mask;
+
+		/* Fixup for the AR8030/AR8035. This chip has another mask and
+		 * doesn't support the DSP reference. Eg. the lowest bit of the
+		 * mask. The upper two bits select the same frequencies. Mask
+		 * the lowest bit here.
+		 *
+		 * Warning:
+		 *   There was no datasheet for the AR8030 available so this is
+		 *   just a guess. But the AR8035 is listed as pin compatible
+		 *   to the AR8030 so there might be a good chance it works on
+		 *   the AR8030 too.
+		 */
+		if (at803x_match_phy_id(phydev, ATH8030_PHY_ID) ||
+		    at803x_match_phy_id(phydev, ATH8035_PHY_ID)) {
+			priv->clk_25m_reg &= AT8035_CLK_OUT_MASK;
+			priv->clk_25m_mask &= AT8035_CLK_OUT_MASK;
+		}
+	}
+
+	ret = of_property_read_u32(node, "qca,clk-out-strength", &strength);
+	if (!ret) {
+		priv->clk_25m_mask |= AT803X_CLK_OUT_STRENGTH_MASK;
+		switch (strength) {
+		case AR803X_STRENGTH_FULL:
+			priv->clk_25m_reg |= AT803X_CLK_OUT_STRENGTH_FULL;
+			break;
+		case AR803X_STRENGTH_HALF:
+			priv->clk_25m_reg |= AT803X_CLK_OUT_STRENGTH_HALF;
+			break;
+		case AR803X_STRENGTH_QUARTER:
+			priv->clk_25m_reg |= AT803X_CLK_OUT_STRENGTH_QUARTER;
+			break;
+		default:
+			dev_err(dev, "invalid qca,clk-out-strength\n");
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static int at803x_probe(struct phy_device *phydev)
+{
+	struct at803x_priv *priv;
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	phydev->priv = priv;
+
+	return at803x_parse_dt(phydev);
+}
+
+static int at803x_clk_out_config(struct phy_device *phydev)
+{
+	struct at803x_priv *priv = phydev->priv;
+	int val;
+
+	if (!priv->clk_25m_mask)
+		return 0;
+
+	val = phy_read_mmd_indirect(phydev, AT803X_MMD7_CLK25M, MDIO_MMD_AN);
+	if (val < 0)
+		return val;
+
+	val &= ~priv->clk_25m_mask;
+	val |= priv->clk_25m_reg;
+
+	phy_write_mmd_indirect(phydev, AT803X_MMD7_CLK25M, MDIO_MMD_AN, val);
+
+	return 0;
+}
+
 static int at803x_config_init(struct phy_device *phydev)
 {
 	int ret;
@@ -46,33 +207,36 @@ static int at803x_config_init(struct phy_device *phydev)
 			return ret;
 	}
 
-	return 0;
+	return at803x_clk_out_config(phydev);
 }
 
 static struct phy_driver at803x_driver[] = {
 {
 	/* ATHEROS 8035 */
-	.phy_id		= 0x004dd072,
-	.phy_id_mask	= 0xffffffef,
+	.phy_id		= ATH8035_PHY_ID,
+	.phy_id_mask	= AT8030_PHY_ID_MASK,
 	.drv.name	= "Atheros 8035 ethernet",
+	.probe		= at803x_probe,
 	.config_init	= at803x_config_init,
 	.features	= PHY_GBIT_FEATURES,
 	.config_aneg	= &genphy_config_aneg,
 	.read_status	= &genphy_read_status,
 }, {
 	/* ATHEROS 8030 */
-	.phy_id		= 0x004dd076,
-	.phy_id_mask	= 0xffffffef,
+	.phy_id		= ATH8030_PHY_ID,
+	.phy_id_mask	= AT8030_PHY_ID_MASK,
 	.drv.name	= "Atheros 8030 ethernet",
 	.config_init	= at803x_config_init,
+	.probe		= at803x_probe,
 	.features	= PHY_GBIT_FEATURES,
 	.config_aneg	= &genphy_config_aneg,
 	.read_status	= &genphy_read_status,
 }, {
 	/* ATHEROS 8031 */
-	.phy_id		= 0x004dd074,
-	.phy_id_mask	= 0xffffffef,
+	.phy_id		= ATH8031_PHY_ID,
+	.phy_id_mask	= AT8030_PHY_ID_MASK,
 	.drv.name	= "Atheros 8031 ethernet",
+	.probe		= at803x_probe,
 	.config_init	= at803x_config_init,
 	.features	= PHY_GBIT_FEATURES,
 	.config_aneg	= &genphy_config_aneg,
-- 
2.27.0


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