Re: [PATCH v2 net-next] net: dsa: mv88e6xxx: scratch registers and external MDIO pins

[David Miller]

From: Andrew Lunn 
Date: Thu, 22 Feb 2018 01:51:49 +0100

> MV88E6352 and later switches support GPIO control through the "Scratch
> & Misc" global2 register. Two of the pins controlled this way on the
> mv88e6390 family are the external MDIO pins. They can either by used
> as part of the MII interface for port 0, GPIOs, or MDIO. Add a
> function to configure them for MDIO, if possible, and call it when
> registering the external MDIO bus.
> 
> Suggested-by: Russell King 
> Signed-off-by: Andrew Lunn 
> ---
> v2: Make stub function static inline, as reported by 0-day.

Applied, thanks Andrew.

[PATCH v2 net-next] net: dsa: mv88e6xxx: scratch registers and external MDIO pins

[Andrew Lunn]

MV88E6352 and later switches support GPIO control through the "Scratch
& Misc" global2 register. Two of the pins controlled this way on the
mv88e6390 family are the external MDIO pins. They can either by used
as part of the MII interface for port 0, GPIOs, or MDIO. Add a
function to configure them for MDIO, if possible, and call it when
registering the external MDIO bus.

Suggested-by: Russell King 
Signed-off-by: Andrew Lunn 
---
v2: Make stub function static inline, as reported by 0-day.

 drivers/net/dsa/mv88e6xxx/chip.c|  9 +
 drivers/net/dsa/mv88e6xxx/global2.h | 14 
 drivers/net/dsa/mv88e6xxx/global2_scratch.c | 51 +
 3 files changed, 74 insertions(+)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 39c7ad7e490f..e1b5c5c66fce 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -2165,6 +2165,15 @@ static int mv88e6xxx_mdio_register(struct mv88e6xxx_chip 
*chip,
struct mii_bus *bus;
int err;
 
+   if (external) {
+   mutex_lock(>reg_lock);
+   err = mv88e6xxx_g2_scratch_gpio_set_smi(chip, true);
+   mutex_unlock(>reg_lock);
+
+   if (err)
+   return err;
+   }
+
bus = devm_mdiobus_alloc_size(chip->dev, sizeof(*mdio_bus));
if (!bus)
return -ENOMEM;
diff --git a/drivers/net/dsa/mv88e6xxx/global2.h 
b/drivers/net/dsa/mv88e6xxx/global2.h
index 25f92b3d7157..d85c91036c0f 100644
--- a/drivers/net/dsa/mv88e6xxx/global2.h
+++ b/drivers/net/dsa/mv88e6xxx/global2.h
@@ -266,6 +266,11 @@
 #define MV88E6352_G2_SCRATCH_GPIO_PCTL50x6D
 #define MV88E6352_G2_SCRATCH_GPIO_PCTL60x6E
 #define MV88E6352_G2_SCRATCH_GPIO_PCTL70x6F
+#define MV88E6352_G2_SCRATCH_CONFIG_DATA0  0x70
+#define MV88E6352_G2_SCRATCH_CONFIG_DATA1  0x71
+#define MV88E6352_G2_SCRATCH_CONFIG_DATA1_NO_CPU   BIT(2)
+#define MV88E6352_G2_SCRATCH_CONFIG_DATA2  0x72
+#define MV88E6352_G2_SCRATCH_CONFIG_DATA2_P0_MODE_MASK 0x3
 
 #define MV88E6352_G2_SCRATCH_GPIO_PCTL_GPIO0
 #define MV88E6352_G2_SCRATCH_GPIO_PCTL_TRIG1
@@ -325,6 +330,9 @@ extern const struct mv88e6xxx_avb_ops mv88e6390_avb_ops;
 
 extern const struct mv88e6xxx_gpio_ops mv88e6352_gpio_ops;
 
+int mv88e6xxx_g2_scratch_gpio_set_smi(struct mv88e6xxx_chip *chip,
+ bool external);
+
 #else /* !CONFIG_NET_DSA_MV88E6XXX_GLOBAL2 */
 
 static inline int mv88e6xxx_g2_require(struct mv88e6xxx_chip *chip)
@@ -465,6 +473,12 @@ static const struct mv88e6xxx_avb_ops mv88e6390_avb_ops = 
{};
 
 static const struct mv88e6xxx_gpio_ops mv88e6352_gpio_ops = {};
 
+static inline int mv88e6xxx_g2_scratch_gpio_set_smi(struct mv88e6xxx_chip 
*chip,
+   bool external)
+{
+   return -EOPNOTSUPP;
+}
+
 #endif /* CONFIG_NET_DSA_MV88E6XXX_GLOBAL2 */
 
 #endif /* _MV88E6XXX_GLOBAL2_H */
diff --git a/drivers/net/dsa/mv88e6xxx/global2_scratch.c 
b/drivers/net/dsa/mv88e6xxx/global2_scratch.c
index 0ff12bff9f0e..3f92b8892dc7 100644
--- a/drivers/net/dsa/mv88e6xxx/global2_scratch.c
+++ b/drivers/net/dsa/mv88e6xxx/global2_scratch.c
@@ -238,3 +238,54 @@ const struct mv88e6xxx_gpio_ops mv88e6352_gpio_ops = {
.get_pctl = mv88e6352_g2_scratch_gpio_get_pctl,
.set_pctl = mv88e6352_g2_scratch_gpio_set_pctl,
 };
+
+/**
+ * mv88e6xxx_g2_gpio_set_smi - set gpio muxing for external smi
+ * @chip: chip private data
+ * @external: set mux for external smi, or free for gpio usage
+ *
+ * Some mv88e6xxx models have GPIO pins that may be configured as
+ * an external SMI interface, or they may be made free for other
+ * GPIO uses.
+ */
+int mv88e6xxx_g2_scratch_gpio_set_smi(struct mv88e6xxx_chip *chip,
+ bool external)
+{
+   int misc_cfg = MV88E6352_G2_SCRATCH_MISC_CFG;
+   int config_data1 = MV88E6352_G2_SCRATCH_CONFIG_DATA1;
+   int config_data2 = MV88E6352_G2_SCRATCH_CONFIG_DATA2;
+   bool no_cpu;
+   u8 p0_mode;
+   int err;
+   u8 val;
+
+   err = mv88e6xxx_g2_scratch_read(chip, config_data2, );
+   if (err)
+   return err;
+
+   p0_mode = val & MV88E6352_G2_SCRATCH_CONFIG_DATA2_P0_MODE_MASK;
+
+   if (p0_mode == 0x01 || p0_mode == 0x02)
+   return -EBUSY;
+
+   err = mv88e6xxx_g2_scratch_read(chip, config_data1, );
+   if (err)
+   return err;
+
+   no_cpu = !!(val & MV88E6352_G2_SCRATCH_CONFIG_DATA1_NO_CPU);
+
+   err = mv88e6xxx_g2_scratch_read(chip, misc_cfg, );
+   if (err)
+   return err;
+
+   /* NO_CPU being 0 inverts the meaning of the bit */
+   if (!no_cpu)
+   external = !external;
+
+   if (external)
+   val |= MV88E6352_G2_SCRATCH_MISC_CFG_NORMALSMI;
+   else
+