net: dsa: mv88e6xxx: add support for GPIO configuration

MV88E6352 and later switches support GPIO control through the "Scratch
& Misc" global2 register. (Older switches do too, though with a slightly
different register interface. Only the 6352-style is implemented here.)

Add a new file, global2_scratch.c, for operations in the Scratch & Misc
space. Additionally, add a GPIO operations structure to present an
abstract view over GPIO manipulation.

Reverse Christmas tree and unsigned has been replaced with unsigned
int by Andrew Lunn.

Signed-off-by: Brandon Streiff <brandon.streiff@ni.com>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 240 insertions, 0 deletions

diff --git a/drivers/net/dsa/mv88e6xxx/global2_scratch.c b/drivers/net/dsa/mv88e6xxx/global2_scratch.c
new file mode 100644
index 000000000000..0ff12bff9f0e
--- /dev/null
+++ b/drivers/net/dsa/mv88e6xxx/global2_scratch.c
@@ -0,0 +1,240 @@
+/*
+ * Marvell 88E6xxx Switch Global 2 Scratch & Misc Registers support
+ *
+ * Copyright (c) 2008 Marvell Semiconductor
+ *
+ * Copyright (c) 2017 National Instruments
+ *      Brandon Streiff <brandon.streiff@ni.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include "chip.h"
+#include "global2.h"
+
+/* Offset 0x1A: Scratch and Misc. Register */
+static int mv88e6xxx_g2_scratch_read(struct mv88e6xxx_chip *chip, int reg,
+				     u8 *data)
+{
+	u16 value;
+	int err;
+
+	err = mv88e6xxx_g2_write(chip, MV88E6XXX_G2_SCRATCH_MISC_MISC,
+				 reg << 8);
+	if (err)
+		return err;
+
+	err = mv88e6xxx_g2_read(chip, MV88E6XXX_G2_SCRATCH_MISC_MISC, &value);
+	if (err)
+		return err;
+
+	*data = (value & MV88E6XXX_G2_SCRATCH_MISC_DATA_MASK);
+
+	return 0;
+}
+
+static int mv88e6xxx_g2_scratch_write(struct mv88e6xxx_chip *chip, int reg,
+				      u8 data)
+{
+	u16 value = (reg << 8) | data;
+
+	return mv88e6xxx_g2_update(chip, MV88E6XXX_G2_SCRATCH_MISC_MISC, value);
+}
+
+/**
+ * mv88e6xxx_g2_scratch_gpio_get_bit - get a bit
+ * @chip: chip private data
+ * @nr: bit index
+ * @set: is bit set?
+ */
+static int mv88e6xxx_g2_scratch_get_bit(struct mv88e6xxx_chip *chip,
+					int base_reg, unsigned int offset,
+					int *set)
+{
+	int reg = base_reg + (offset / 8);
+	u8 mask = (1 << (offset & 0x7));
+	u8 val;
+	int err;
+
+	err = mv88e6xxx_g2_scratch_read(chip, reg, &val);
+	if (err)
+		return err;
+
+	*set = !!(mask & val);
+
+	return 0;
+}
+
+/**
+ * mv88e6xxx_g2_scratch_gpio_set_bit - set (or clear) a bit
+ * @chip: chip private data
+ * @nr: bit index
+ * @set: set if true, clear if false
+ *
+ * Helper function for dealing with the direction and data registers.
+ */
+static int mv88e6xxx_g2_scratch_set_bit(struct mv88e6xxx_chip *chip,
+					int base_reg, unsigned int offset,
+					int set)
+{
+	int reg = base_reg + (offset / 8);
+	u8 mask = (1 << (offset & 0x7));
+	u8 val;
+	int err;
+
+	err = mv88e6xxx_g2_scratch_read(chip, reg, &val);
+	if (err)
+		return err;
+
+	if (set)
+		val |= mask;
+	else
+		val &= ~mask;
+
+	return mv88e6xxx_g2_scratch_write(chip, reg, val);
+}
+
+/**
+ * mv88e6352_g2_scratch_gpio_get_data - get data on gpio pin
+ * @chip: chip private data
+ * @pin: gpio index
+ *
+ * Return: 0 for low, 1 for high, negative error
+ */
+static int mv88e6352_g2_scratch_gpio_get_data(struct mv88e6xxx_chip *chip,
+					      unsigned int pin)
+{
+	int val = 0;
+	int err;
+
+	err = mv88e6xxx_g2_scratch_get_bit(chip,
+					   MV88E6352_G2_SCRATCH_GPIO_DATA0,
+					   pin, &val);
+	if (err)
+		return err;
+
+	return val;
+}
+
+/**
+ * mv88e6352_g2_scratch_gpio_set_data - set data on gpio pin
+ * @chip: chip private data
+ * @pin: gpio index
+ * @value: value to set
+ */
+static int mv88e6352_g2_scratch_gpio_set_data(struct mv88e6xxx_chip *chip,
+					      unsigned int pin, int value)
+{
+	u8 mask = (1 << (pin & 0x7));
+	int offset = (pin / 8);
+	int reg;
+
+	reg = MV88E6352_G2_SCRATCH_GPIO_DATA0 + offset;
+
+	if (value)
+		chip->gpio_data[offset] |= mask;
+	else
+		chip->gpio_data[offset] &= ~mask;
+
+	return mv88e6xxx_g2_scratch_write(chip, reg, chip->gpio_data[offset]);
+}
+
+/**
+ * mv88e6352_g2_scratch_gpio_get_dir - get direction of gpio pin
+ * @chip: chip private data
+ * @pin: gpio index
+ *
+ * Return: 0 for output, 1 for input (same as GPIOF_DIR_XXX).
+ */
+static int mv88e6352_g2_scratch_gpio_get_dir(struct mv88e6xxx_chip *chip,
+					     unsigned int pin)
+{
+	int val = 0;
+	int err;
+
+	err = mv88e6xxx_g2_scratch_get_bit(chip,
+					   MV88E6352_G2_SCRATCH_GPIO_DIR0,
+					   pin, &val);
+	if (err)
+		return err;
+
+	return val;
+}
+
+/**
+ * mv88e6352_g2_scratch_gpio_set_dir - set direction of gpio pin
+ * @chip: chip private data
+ * @pin: gpio index
+ */
+static int mv88e6352_g2_scratch_gpio_set_dir(struct mv88e6xxx_chip *chip,
+					     unsigned int pin, bool input)
+{
+	int value = (input ? MV88E6352_G2_SCRATCH_GPIO_DIR_IN :
+			     MV88E6352_G2_SCRATCH_GPIO_DIR_OUT);
+
+	return mv88e6xxx_g2_scratch_set_bit(chip,
+					    MV88E6352_G2_SCRATCH_GPIO_DIR0,
+					    pin, value);
+}
+
+/**
+ * mv88e6352_g2_scratch_gpio_get_pctl - get pin control setting
+ * @chip: chip private data
+ * @pin: gpio index
+ * @func: function number
+ *
+ * Note that the function numbers themselves may vary by chipset.
+ */
+static int mv88e6352_g2_scratch_gpio_get_pctl(struct mv88e6xxx_chip *chip,
+					      unsigned int pin, int *func)
+{
+	int reg = MV88E6352_G2_SCRATCH_GPIO_PCTL0 + (pin / 2);
+	int offset = (pin & 0x1) ? 4 : 0;
+	u8 mask = (0x7 << offset);
+	int err;
+	u8 val;
+
+	err = mv88e6xxx_g2_scratch_read(chip, reg, &val);
+	if (err)
+		return err;
+
+	*func = (val & mask) >> offset;
+
+	return 0;
+}
+
+/**
+ * mv88e6352_g2_scratch_gpio_set_pctl - set pin control setting
+ * @chip: chip private data
+ * @pin: gpio index
+ * @func: function number
+ */
+static int mv88e6352_g2_scratch_gpio_set_pctl(struct mv88e6xxx_chip *chip,
+					      unsigned int pin, int func)
+{
+	int reg = MV88E6352_G2_SCRATCH_GPIO_PCTL0 + (pin / 2);
+	int offset = (pin & 0x1) ? 4 : 0;
+	u8 mask = (0x7 << offset);
+	int err;
+	u8 val;
+
+	err = mv88e6xxx_g2_scratch_read(chip, reg, &val);
+	if (err)
+		return err;
+
+	val = (val & ~mask) | ((func & mask) << offset);
+
+	return mv88e6xxx_g2_scratch_write(chip, reg, val);
+}
+
+const struct mv88e6xxx_gpio_ops mv88e6352_gpio_ops = {
+	.get_data = mv88e6352_g2_scratch_gpio_get_data,
+	.set_data = mv88e6352_g2_scratch_gpio_set_data,
+	.get_dir = mv88e6352_g2_scratch_gpio_get_dir,
+	.set_dir = mv88e6352_g2_scratch_gpio_set_dir,
+	.get_pctl = mv88e6352_g2_scratch_gpio_get_pctl,
+	.set_pctl = mv88e6352_g2_scratch_gpio_set_pctl,
+};