[PATCH 11/16] net: phy: adin: PHY reset mechanisms

Alexandru Ardelean
2019-08-05T13:56:02Z

The ADIN PHYs supports 4 types of reset:
1. The standard PHY reset via BMCR_RESET bit in MII_BMCR reg
2. Reset via GPIO
3. Reset via reg GeSftRst (0xff0c) & reload previous pin configs
4. Reset via reg GeSftRst (0xff0c) & request new pin configs

Resets 2 & 4 are almost identical, with the exception that the crystal
oscillator is available during reset for 2.

Resetting via GeSftRst or via GPIO is useful when doing a warm reboot. If
doing various settings via phytool or ethtool, the sub-system registers
don't reset just via BMCR_RESET.

This change implements resetting the entire PHY subsystem during probe.
During PHY HW init (phy_hw_init() logic) the PHY core regs will be reset
again via BMCR_RESET. This will also need to happen during a PM resume.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
drivers/net/phy/adin.c | 82 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 82 insertions(+)

diff --git a/drivers/net/phy/adin.c b/drivers/net/phy/adin.c
index 3c559a3ba487..476a81ce9341 100644
--- a/drivers/net/phy/adin.c
+++ b/drivers/net/phy/adin.c
@@ -6,12 +6,14 @@
*/
#include <linux/kernel.h>
#include <linux/bitfield.h>
+#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mii.h>
#include <linux/phy.h>
#include <linux/property.h>
+#include <linux/gpio/consumer.h>

#include <dt-bindings/net/adin.h>

@@ -55,6 +57,9 @@
#define ADIN1300_CLOCK_STOP_REG 0x9400
#define ADIN1300_LPI_WAKE_ERR_CNT_REG 0xa000

+#define ADIN1300_GE_SOFT_RESET_REG 0xff0c
+#define ADIN1300_GE_SOFT_RESET BIT(0)
+
#define ADIN1300_GE_RGMII_CFG_REG 0xff23
#define ADIN1300_GE_RGMII_RX_MSK GENMASK(8, 6)
#define ADIN1300_GE_RGMII_RX_SEL(x) \
@@ -86,6 +91,14 @@ static struct clause22_mmd_map clause22_mmd_map[] = {
{ MDIO_MMD_PCS, MDIO_PCS_EEE_WK_ERR, ADIN1300_LPI_WAKE_ERR_CNT_REG },
};

+/**
+ * struct adin_priv - ADIN PHY driver private data
+ * gpiod_reset optional reset GPIO, to be used in soft_reset() cb
+ */
+struct adin_priv {
+ struct gpio_desc *gpiod_reset;
+};
+
static int adin_get_phy_internal_mode(struct phy_device *phydev)
{
struct device *dev = &phydev->mdio.dev;
@@ -429,6 +442,73 @@ static int adin_read_status(struct phy_device *phydev)
return genphy_read_status(phydev);
}

+static int adin_subsytem_soft_reset(struct phy_device *phydev)
+{
+ int reg, rc, i;
+
+ reg = phy_read_mmd(phydev, MDIO_MMD_VEND1, ADIN1300_GE_SOFT_RESET_REG);
+ if (reg < 0)
+ return reg;
+
+ reg |= ADIN1300_GE_SOFT_RESET;
+ rc = phy_write_mmd(phydev, MDIO_MMD_VEND1, ADIN1300_GE_SOFT_RESET_REG,
+ reg);
+ if (rc < 0)
+ return rc;
+
+ for (i = 0; i < 20; i++) {
+ usleep_range(500, 1000);
+ reg = phy_read_mmd(phydev, MDIO_MMD_VEND1,
+ ADIN1300_GE_SOFT_RESET_REG);
+ if (reg < 0 || (reg & ADIN1300_GE_SOFT_RESET))
+ continue;
+ return 0;
+ }
+
+ return -ETIMEDOUT;
+}
+
+static int adin_reset(struct phy_device *phydev)
+{
+ struct adin_priv *priv = phydev->priv;
+ int ret;
+
+ if (priv->gpiod_reset) {
+ /* GPIO reset requires min 10 uS low,
+ * 5 msecs max before we know that the interface is up again
+ */
+ gpiod_set_value(priv->gpiod_reset, 0);
+ usleep_range(10, 15);
+ gpiod_set_value(priv->gpiod_reset, 1);
+ mdelay(5);
+
+ return 0;
+ }
+
+ /* Reset PHY core regs & subsystem regs */
+ return adin_subsytem_soft_reset(phydev);
+}
+
+static int adin_probe(struct phy_device *phydev)
+{
+ struct device *dev = &phydev->mdio.dev;
+ struct gpio_desc *gpiod_reset;
+ struct adin_priv *priv;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ gpiod_reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+ if (IS_ERR(gpiod_reset))
+ gpiod_reset = NULL;
+
+ priv->gpiod_reset = gpiod_reset;
+ phydev->priv = priv;
+
+ return adin_reset(phydev);
+}
+
static struct phy_driver adin_driver[] = {
{
.phy_id = PHY_ID_ADIN1200,
@@ -437,6 +517,7 @@ static struct phy_driver adin_driver[] = {
.features = PHY_BASIC_FEATURES,
.flags = PHY_HAS_INTERRUPT,
.config_init = adin_config_init,
+ .probe = adin_probe,
.config_aneg = adin_config_aneg,
.read_status = adin_read_status,
.ack_interrupt = adin_phy_ack_intr,
@@ -453,6 +534,7 @@ static struct phy_driver adin_driver[] = {
.features = PHY_GBIT_FEATURES,
.flags = PHY_HAS_INTERRUPT,
.config_init = adin_config_init,
+ .probe = adin_probe,
.config_aneg = adin_config_aneg,
.read_status = adin_read_status,
.ack_interrupt = adin_phy_ack_intr,
--
2.20.1