mips: mscc_sgpio: Add the MSCC serial GPIO device (SIO)

This add support for the the MSCC serial GPIO driver in MSCC
VCoreIII-based SOCs.

By using a serial interface, the SIO controller significantly extends
the number of available GPIOs with a minimum number of additional pins
on the device. The primary purpose of the SIO controller is to connect
control signals from SFP modules and to act as an LED controller.

This adds the base driver.

Signed-off-by: Lars Povlsen <lars.povlsen@microchip.com>

MAINTAINERS

@@ -523,6 +523,7 @@ F:	arch/mips/dts/mscc*
 F:	arch/mips/dts/ocelot*
 F:	board/mscc/
 F:	configs/mscc*
+F:	drivers/gpio/mscc_sgpio.c
 F:	include/configs/vcoreiii.h
 
 MIPS JZ4780

drivers/gpio/Kconfig

@@ -106,6 +106,17 @@ config MSCC_BITBANG_SPI_GPIO
 	  Support controlling the GPIO used for SPI bitbang by software. Can
 	  be used by the VCoreIII SoCs, but it was mainly useful for Luton.
 
+config MSCC_SGPIO
+	bool "Microsemi Serial GPIO driver"
+	depends on DM_GPIO && SOC_VCOREIII
+	help
+	  Support for the VCoreIII SoC serial GPIO device. By using a
+          serial interface, the SIO controller significantly extends
+          the number of available GPIOs with a minimum number of
+          additional pins on the device. The primary purpose of the
+          SIO controller is to connect control signals from SFP
+          modules and to act as an LED controller.
+
 config MSM_GPIO
 	bool "Qualcomm GPIO driver"
 	depends on DM_GPIO

drivers/gpio/Makefile

@@ -60,3 +60,4 @@ obj-$(CONFIG_$(SPL_)PCF8575_GPIO)	+= pcf8575_gpio.o
 obj-$(CONFIG_PM8916_GPIO)	+= pm8916_gpio.o
 obj-$(CONFIG_MT7621_GPIO)	+= mt7621_gpio.o
 obj-$(CONFIG_MSCC_BITBANG_SPI_GPIO)	+= gpio-mscc-bitbang-spi.o
+obj-$(CONFIG_MSCC_SGPIO)	+= mscc_sgpio.o

drivers/gpio/mscc_sgpio.c

@@ -0,0 +1,275 @@
+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/*
+ * Microsemi SoCs serial gpio driver
+ *
+ * Author: <lars.povlsen@microchip.com>
+ *
+ * Copyright (c) 2018 Microsemi Corporation
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <asm/gpio.h>
+#include <asm/io.h>
+#include <errno.h>
+#include <clk.h>
+
+#define MSCC_SGPIOS_PER_BANK	32
+#define MSCC_SGPIO_BANK_DEPTH	4
+
+enum {
+	REG_INPUT_DATA,
+	REG_PORT_CONFIG,
+	REG_PORT_ENABLE,
+	REG_SIO_CONFIG,
+	REG_SIO_CLOCK,
+	MAXREG
+};
+
+struct mscc_sgpio_bf {
+	u8 beg;
+	u8 end;
+};
+
+struct mscc_sgpio_props {
+	u8 regoff[MAXREG];
+	struct mscc_sgpio_bf auto_repeat;
+	struct mscc_sgpio_bf port_width;
+	struct mscc_sgpio_bf clk_freq;
+	struct mscc_sgpio_bf bit_source;
+};
+
+#define __M(bf)		GENMASK((bf).end, (bf).beg)
+#define __F(bf, x)	(__M(bf) & ((x) << (bf).beg))
+#define __X(bf, x)	(((x) >> (bf).beg) & GENMASK(((bf).end - (bf).beg), 0))
+
+#define MSCC_M_CFG_SIO_AUTO_REPEAT(p)		BIT(p->props->auto_repeat.beg)
+#define MSCC_F_CFG_SIO_PORT_WIDTH(p, x)		__F(p->props->port_width, x)
+#define MSCC_M_CFG_SIO_PORT_WIDTH(p)		__M(p->props->port_width)
+#define MSCC_F_CLOCK_SIO_CLK_FREQ(p, x)		__F(p->props->clk_freq, x)
+#define MSCC_M_CLOCK_SIO_CLK_FREQ(p)		__M(p->props->clk_freq)
+#define MSCC_F_PORT_CFG_BIT_SOURCE(p, x)	__F(p->props->bit_source, x)
+#define MSCC_X_PORT_CFG_BIT_SOURCE(p, x)	__X(p->props->bit_source, x)
+
+const struct mscc_sgpio_props props_luton = {
+	.regoff = { 0x00, 0x09, 0x29, 0x2a, 0x2b },
+	.auto_repeat = { 5, 5 },
+	.port_width  = { 2, 3 },
+	.clk_freq    = { 0, 11 },
+	.bit_source  = { 0, 11 },
+};
+
+const struct mscc_sgpio_props props_ocelot = {
+	.regoff = { 0x00, 0x06, 0x26, 0x04, 0x05 },
+	.auto_repeat = { 10, 10 },
+	.port_width  = {  7, 8  },
+	.clk_freq    = {  8, 19 },
+	.bit_source  = { 12, 23 },
+};
+
+struct mscc_sgpio_priv {
+	u32 bitcount;
+	u32 ports;
+	u32 clock;
+	u32 mode[MSCC_SGPIOS_PER_BANK];
+	u32 __iomem *regs;
+	const struct mscc_sgpio_props *props;
+};
+
+static inline u32 sgpio_readl(struct mscc_sgpio_priv *priv, u32 rno, u32 off)
+{
+	u32 __iomem *reg = &priv->regs[priv->props->regoff[rno] + off];
+
+	return readl(reg);
+}
+
+static inline void sgpio_writel(struct mscc_sgpio_priv *priv,
+				u32 val, u32 rno, u32 off)
+{
+	u32 __iomem *reg = &priv->regs[priv->props->regoff[rno] + off];
+
+	writel(val, reg);
+}
+
+static void sgpio_clrsetbits(struct mscc_sgpio_priv *priv,
+			     u32 rno, u32 off, u32 clear, u32 set)
+{
+	u32 __iomem *reg = &priv->regs[priv->props->regoff[rno] + off];
+
+	clrsetbits_le32(reg, clear, set);
+}
+
+static int mscc_sgpio_direction_input(struct udevice *dev, unsigned int gpio)
+{
+	struct mscc_sgpio_priv *priv = dev_get_priv(dev);
+
+	u32 port = gpio % MSCC_SGPIOS_PER_BANK;
+	u32 bit = gpio / MSCC_SGPIOS_PER_BANK;
+
+	priv->mode[port] |= BIT(bit);
+
+	return 0;
+}
+
+static int mscc_sgpio_direction_output(struct udevice *dev,
+				       unsigned int gpio, int value)
+{
+	struct mscc_sgpio_priv *priv = dev_get_priv(dev);
+	u32 port = gpio % MSCC_SGPIOS_PER_BANK;
+	u32 bit = gpio / MSCC_SGPIOS_PER_BANK;
+	u32 mask = 3 << (3 * bit);
+
+	debug("set: port %d, bit %d, mask 0x%08x, value %d\n",
+	      port, bit, mask, value);
+
+	value = (value & 3) << (3 * bit);
+	sgpio_clrsetbits(priv, REG_PORT_CONFIG, port,
+			 MSCC_F_PORT_CFG_BIT_SOURCE(priv, mask),
+			 MSCC_F_PORT_CFG_BIT_SOURCE(priv, value));
+	clrbits_le32(&priv->mode[port], BIT(bit));
+
+	return 0;
+}
+
+static int mscc_sgpio_get_function(struct udevice *dev, unsigned int gpio)
+{
+	struct mscc_sgpio_priv *priv = dev_get_priv(dev);
+	u32 port = gpio % MSCC_SGPIOS_PER_BANK;
+	u32 bit = gpio / MSCC_SGPIOS_PER_BANK;
+	u32 val = priv->mode[port] & BIT(bit);
+
+	if (val)
+		return GPIOF_INPUT;
+	else
+		return GPIOF_OUTPUT;
+}
+
+static int mscc_sgpio_set_value(struct udevice *dev,
+				unsigned int gpio, int value)
+{
+	return mscc_sgpio_direction_output(dev, gpio, value);
+}
+
+static int mscc_sgpio_get_value(struct udevice *dev, unsigned int gpio)
+{
+	struct mscc_sgpio_priv *priv = dev_get_priv(dev);
+	u32 port = gpio % MSCC_SGPIOS_PER_BANK;
+	u32 bit = gpio / MSCC_SGPIOS_PER_BANK;
+	int ret;
+
+	if (mscc_sgpio_get_function(dev, gpio) == GPIOF_INPUT) {
+		ret = !!(sgpio_readl(priv, REG_INPUT_DATA, bit) & BIT(port));
+	} else {
+		u32 portval = sgpio_readl(priv, REG_PORT_CONFIG, port);
+
+		ret = MSCC_X_PORT_CFG_BIT_SOURCE(priv, portval);
+		ret = !!(ret & (3 << (3 * bit)));
+	}
+
+	debug("get: gpio %d, port %d, bit %d, value %d\n",
+	      gpio, port, bit, ret);
+	return ret;
+}
+
+static int mscc_sgpio_get_count(struct udevice *dev)
+{
+	struct ofnode_phandle_args args;
+	int count = 0, i = 0, ret;
+
+	ret = dev_read_phandle_with_args(dev, "gpio-ranges", NULL, 3, i, &args);
+	while (ret != -ENOENT) {
+		count += args.args[2];
+		ret = dev_read_phandle_with_args(dev, "gpio-ranges", NULL, 3,
+						 ++i, &args);
+	}
+	return count;
+}
+
+static int mscc_sgpio_probe(struct udevice *dev)
+{
+	struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
+	struct mscc_sgpio_priv *priv = dev_get_priv(dev);
+	int err, div_clock = 0, port;
+	u32 val;
+	struct clk clk;
+
+	err = clk_get_by_index(dev, 0, &clk);
+	if (!err) {
+		err = clk_get_rate(&clk);
+		if (IS_ERR_VALUE(err)) {
+			dev_err(dev, "Invalid clk rate\n");
+			return -EINVAL;
+		}
+		div_clock = err;
+	} else {
+		dev_err(dev, "Failed to get clock\n");
+		return err;
+	}
+
+	priv->props = (const struct mscc_sgpio_props *)dev_get_driver_data(dev);
+	priv->ports = dev_read_u32_default(dev, "mscc,sgpio-ports", 0xFFFFFFFF);
+	priv->clock = dev_read_u32_default(dev, "mscc,sgpio-frequency",
+					   12500000);
+	if (priv->clock <= 0 || priv->clock > div_clock) {
+		dev_err(dev, "Invalid frequency %d\n", priv->clock);
+		return -EINVAL;
+	}
+
+	uc_priv->gpio_count = mscc_sgpio_get_count(dev);
+	uc_priv->gpio_count = dev_read_u32_default(dev, "ngpios",
+						   uc_priv->gpio_count);
+	if (uc_priv->gpio_count < 1 || uc_priv->gpio_count >
+	    (4 * MSCC_SGPIOS_PER_BANK)) {
+		dev_err(dev, "Invalid gpio count %d\n", uc_priv->gpio_count);
+		return -EINVAL;
+	}
+	priv->bitcount = DIV_ROUND_UP(uc_priv->gpio_count,
+				      MSCC_SGPIOS_PER_BANK);
+	debug("probe: gpios = %d, bit-count = %d\n",
+	      uc_priv->gpio_count, priv->bitcount);
+
+	priv->regs = (u32 __iomem *)dev_read_addr(dev);
+	uc_priv->bank_name = "sgpio";
+
+	sgpio_clrsetbits(priv, REG_SIO_CONFIG, 0,
+			 MSCC_M_CFG_SIO_PORT_WIDTH(priv),
+			 MSCC_F_CFG_SIO_PORT_WIDTH(priv, priv->bitcount - 1) |
+			 MSCC_M_CFG_SIO_AUTO_REPEAT(priv));
+	val = div_clock / priv->clock;
+	debug("probe: div-clock = %d KHz, freq = %d KHz, div = %d\n",
+	      div_clock / 1000, priv->clock / 1000, val);
+	sgpio_clrsetbits(priv, REG_SIO_CLOCK, 0,
+			 MSCC_M_CLOCK_SIO_CLK_FREQ(priv),
+			 MSCC_F_CLOCK_SIO_CLK_FREQ(priv, val));
+
+	for (port = 0; port < 32; port++)
+		sgpio_writel(priv, 0, REG_PORT_CONFIG, port);
+	sgpio_writel(priv, priv->ports, REG_PORT_ENABLE, 0);
+
+	debug("probe: sgpio regs = %p\n", priv->regs);
+
+	return 0;
+}
+
+static const struct dm_gpio_ops mscc_sgpio_ops = {
+	.direction_input	= mscc_sgpio_direction_input,
+	.direction_output	= mscc_sgpio_direction_output,
+	.get_function		= mscc_sgpio_get_function,
+	.get_value		= mscc_sgpio_get_value,
+	.set_value		= mscc_sgpio_set_value,
+};
+
+static const struct udevice_id mscc_sgpio_ids[] = {
+	{ .compatible = "mscc,luton-sgpio", .data = (ulong)&props_luton },
+	{ .compatible = "mscc,ocelot-sgpio", .data = (ulong)&props_ocelot },
+	{ }
+};
+
+U_BOOT_DRIVER(gpio_mscc_sgpio) = {
+	.name			= "mscc-sgpio",
+	.id			= UCLASS_GPIO,
+	.of_match		= mscc_sgpio_ids,
+	.ops			= &mscc_sgpio_ops,
+	.probe			= mscc_sgpio_probe,
+	.priv_auto_alloc_size	= sizeof(struct mscc_sgpio_priv),
+};