linux/drivers/pinctrl/pinctrl-microchip-sgpio.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Microsemi/Microchip SoCs serial gpio driver
 *
 * Author: Lars Povlsen <lars.povlsen@microchip.com>
 *
 * Copyright (c) 2020 Microchip Technology Inc. and its subsidiaries.
 */

#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/clk.h>
#include <linux/gpio/driver.h>
#include <linux/io.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/pinctrl/pinmux.h>
#include <linux/platform_device.h>
#include <linux/property.h>

#include "core.h"
#include "pinconf.h"

#define SGPIO_BITS_PER_WORD	32
#define SGPIO_MAX_BITS		4
#define SGPIO_SRC_BITS		3 /* 3 bit wide field per pin */

enum {
	REG_INPUT_DATA,
	REG_PORT_CONFIG,
	REG_PORT_ENABLE,
	REG_SIO_CONFIG,
	REG_SIO_CLOCK,
	MAXREG
};

enum {
	SGPIO_ARCH_LUTON,
	SGPIO_ARCH_OCELOT,
	SGPIO_ARCH_SPARX5,
};

struct sgpio_properties {
	int arch;
	u8 regoff[MAXREG];
};

#define SGPIO_LUTON_AUTO_REPEAT  BIT(5)
#define SGPIO_LUTON_PORT_WIDTH   GENMASK(3, 2)
#define SGPIO_LUTON_CLK_FREQ     GENMASK(11, 0)
#define SGPIO_LUTON_BIT_SOURCE   GENMASK(11, 0)

#define SGPIO_OCELOT_AUTO_REPEAT BIT(10)
#define SGPIO_OCELOT_PORT_WIDTH  GENMASK(8, 7)
#define SGPIO_OCELOT_CLK_FREQ    GENMASK(19, 8)
#define SGPIO_OCELOT_BIT_SOURCE  GENMASK(23, 12)

#define SGPIO_SPARX5_AUTO_REPEAT BIT(6)
#define SGPIO_SPARX5_PORT_WIDTH  GENMASK(4, 3)
#define SGPIO_SPARX5_CLK_FREQ    GENMASK(19, 8)
#define SGPIO_SPARX5_BIT_SOURCE  GENMASK(23, 12)

const struct sgpio_properties properties_luton = {
	.arch   = SGPIO_ARCH_LUTON,
	.regoff = { 0x00, 0x09, 0x29, 0x2a, 0x2b },
};

const struct sgpio_properties properties_ocelot = {
	.arch   = SGPIO_ARCH_OCELOT,
	.regoff = { 0x00, 0x06, 0x26, 0x04, 0x05 },
};

const struct sgpio_properties properties_sparx5 = {
	.arch   = SGPIO_ARCH_SPARX5,
	.regoff = { 0x00, 0x06, 0x26, 0x04, 0x05 },
};

static const char * const functions[] = { "gpio" };

struct sgpio_bank {
	struct sgpio_priv *priv;
	bool is_input;
	struct gpio_chip gpio;
	struct pinctrl_desc pctl_desc;
};

struct sgpio_priv {
	struct device *dev;
	struct sgpio_bank in;
	struct sgpio_bank out;
	u32 bitcount;
	u32 ports;
	u32 clock;
	u32 __iomem *regs;
	const struct sgpio_properties *properties;
};

struct sgpio_port_addr {
	u8 port;
	u8 bit;
};

static inline void sgpio_pin_to_addr(struct sgpio_priv *priv, int pin,
				     struct sgpio_port_addr *addr)
{
	addr->port = pin / priv->bitcount;
	addr->bit = pin % priv->bitcount;
}

static inline u32 sgpio_readl(struct sgpio_priv *priv, u32 rno, u32 off)
{
	u32 __iomem *reg = &priv->regs[priv->properties->regoff[rno] + off];

	return readl(reg);
}

static inline void sgpio_writel(struct sgpio_priv *priv,
				u32 val, u32 rno, u32 off)
{
	u32 __iomem *reg = &priv->regs[priv->properties->regoff[rno] + off];

	writel(val, reg);
}

static inline void sgpio_clrsetbits(struct sgpio_priv *priv,
				    u32 rno, u32 off, u32 clear, u32 set)
{
	u32 __iomem *reg = &priv->regs[priv->properties->regoff[rno] + off];
	u32 val = readl(reg);

	val &= ~clear;
	val |= set;

	writel(val, reg);
}

static inline void sgpio_configure_bitstream(struct sgpio_priv *priv)
{
	int width = priv->bitcount - 1;
	u32 clr, set;

	switch (priv->properties->arch) {
	case SGPIO_ARCH_LUTON:
		clr = SGPIO_LUTON_PORT_WIDTH;
		set = SGPIO_LUTON_AUTO_REPEAT |
			FIELD_PREP(SGPIO_LUTON_PORT_WIDTH, width);
		break;
	case SGPIO_ARCH_OCELOT:
		clr = SGPIO_OCELOT_PORT_WIDTH;
		set = SGPIO_OCELOT_AUTO_REPEAT |
			FIELD_PREP(SGPIO_OCELOT_PORT_WIDTH, width);
		break;
	case SGPIO_ARCH_SPARX5:
		clr = SGPIO_SPARX5_PORT_WIDTH;
		set = SGPIO_SPARX5_AUTO_REPEAT |
			FIELD_PREP(SGPIO_SPARX5_PORT_WIDTH, width);
		break;
	default:
		return;
	}
	sgpio_clrsetbits(priv, REG_SIO_CONFIG, 0, clr, set);
}

static inline void sgpio_configure_clock(struct sgpio_priv *priv, u32 clkfrq)
{
	u32 clr, set;

	switch (priv->properties->arch) {
	case SGPIO_ARCH_LUTON:
		clr = SGPIO_LUTON_CLK_FREQ;
		set = FIELD_PREP(SGPIO_LUTON_CLK_FREQ, clkfrq);
		break;
	case SGPIO_ARCH_OCELOT:
		clr = SGPIO_OCELOT_CLK_FREQ;
		set = FIELD_PREP(SGPIO_OCELOT_CLK_FREQ, clkfrq);
		break;
	case SGPIO_ARCH_SPARX5:
		clr = SGPIO_SPARX5_CLK_FREQ;
		set = FIELD_PREP(SGPIO_SPARX5_CLK_FREQ, clkfrq);
		break;
	default:
		return;
	}
	sgpio_clrsetbits(priv, REG_SIO_CLOCK, 0, clr, set);
}

static void sgpio_output_set(struct sgpio_priv *priv,
			     struct sgpio_port_addr *addr,
			     int value)
{
	unsigned int bit = SGPIO_SRC_BITS * addr->bit;
	u32 clr, set;

	switch (priv->properties->arch) {
	case SGPIO_ARCH_LUTON:
		clr = FIELD_PREP(SGPIO_LUTON_BIT_SOURCE, BIT(bit));
		set = FIELD_PREP(SGPIO_LUTON_BIT_SOURCE, value << bit);
		break;
	case SGPIO_ARCH_OCELOT:
		clr = FIELD_PREP(SGPIO_OCELOT_BIT_SOURCE, BIT(bit));
		set = FIELD_PREP(SGPIO_OCELOT_BIT_SOURCE, value << bit);
		break;
	case SGPIO_ARCH_SPARX5:
		clr = FIELD_PREP(SGPIO_SPARX5_BIT_SOURCE, BIT(bit));
		set = FIELD_PREP(SGPIO_SPARX5_BIT_SOURCE, value << bit);
		break;
	default:
		return;
	}
	sgpio_clrsetbits(priv, REG_PORT_CONFIG, addr->port, clr, set);
}

static int sgpio_output_get(struct sgpio_priv *priv,
			    struct sgpio_port_addr *addr)
{
	u32 val, portval = sgpio_readl(priv, REG_PORT_CONFIG, addr->port);
	unsigned int bit = SGPIO_SRC_BITS * addr->bit;

	switch (priv->properties->arch) {
	case SGPIO_ARCH_LUTON:
		val = FIELD_GET(SGPIO_LUTON_BIT_SOURCE, portval);
		break;
	case SGPIO_ARCH_OCELOT:
		val = FIELD_GET(SGPIO_OCELOT_BIT_SOURCE, portval);
		break;
	case SGPIO_ARCH_SPARX5:
		val = FIELD_GET(SGPIO_SPARX5_BIT_SOURCE, portval);
		break;
	default:
		val = 0;
		break;
	}
	return !!(val & BIT(bit));
}

static int sgpio_input_get(struct sgpio_priv *priv,
			   struct sgpio_port_addr *addr)
{
	return !!(sgpio_readl(priv, REG_INPUT_DATA, addr->bit) & BIT(addr->port));
}

static int sgpio_pinconf_get(struct pinctrl_dev *pctldev,
			     unsigned int pin, unsigned long *config)
{
	struct sgpio_bank *bank = pinctrl_dev_get_drvdata(pctldev);
	u32 param = pinconf_to_config_param(*config);
	struct sgpio_priv *priv = bank->priv;
	struct sgpio_port_addr addr;
	int val;

	sgpio_pin_to_addr(priv, pin, &addr);

	switch (param) {
	case PIN_CONFIG_INPUT_ENABLE:
		val = bank->is_input;
		break;

	case PIN_CONFIG_OUTPUT_ENABLE:
		val = !bank->is_input;
		break;

	case PIN_CONFIG_OUTPUT:
		if (bank->is_input)
			return -EINVAL;
		val = sgpio_output_get(priv, &addr);
		break;

	default:
		return -ENOTSUPP;
	}

	*config = pinconf_to_config_packed(param, val);

	return 0;
}

static int sgpio_pinconf_set(struct pinctrl_dev *pctldev, unsigned int pin,
			     unsigned long *configs, unsigned int num_configs)
{
	struct sgpio_bank *bank = pinctrl_dev_get_drvdata(pctldev);
	struct sgpio_priv *priv = bank->priv;
	struct sgpio_port_addr addr;
	int cfg, err = 0;
	u32 param, arg;

	sgpio_pin_to_addr(priv, pin, &addr);

	for (cfg = 0; cfg < num_configs; cfg++) {
		param = pinconf_to_config_param(configs[cfg]);
		arg = pinconf_to_config_argument(configs[cfg]);

		switch (param) {
		case PIN_CONFIG_OUTPUT:
			if (bank->is_input)
				return -EINVAL;
			sgpio_output_set(priv, &addr, arg);
			break;

		default:
			err = -ENOTSUPP;
		}
	}

	return err;
}

static const struct pinconf_ops sgpio_confops = {
	.is_generic = true,
	.pin_config_get = sgpio_pinconf_get,
	.pin_config_set = sgpio_pinconf_set,
	.pin_config_config_dbg_show = pinconf_generic_dump_config,
};

static int sgpio_get_functions_count(struct pinctrl_dev *pctldev)
{
	return 1;
}

static const char *sgpio_get_function_name(struct pinctrl_dev *pctldev,
					   unsigned int function)
{
	return functions[0];
}

static int sgpio_get_function_groups(struct pinctrl_dev *pctldev,
				     unsigned int function,
				     const char *const **groups,
				     unsigned *const num_groups)
{
	*groups  = functions;
	*num_groups = ARRAY_SIZE(functions);

	return 0;
}

static int sgpio_pinmux_set_mux(struct pinctrl_dev *pctldev,
				unsigned int selector, unsigned int group)
{
	return 0;
}

static int sgpio_gpio_set_direction(struct pinctrl_dev *pctldev,
				    struct pinctrl_gpio_range *range,
				    unsigned int pin, bool input)
{
	struct sgpio_bank *bank = pinctrl_dev_get_drvdata(pctldev);

	return (input == bank->is_input) ? 0 : -EINVAL;
}

static int sgpio_gpio_request_enable(struct pinctrl_dev *pctldev,
				     struct pinctrl_gpio_range *range,
				     unsigned int offset)
{
	struct sgpio_bank *bank = pinctrl_dev_get_drvdata(pctldev);
	struct sgpio_priv *priv = bank->priv;
	struct sgpio_port_addr addr;

	sgpio_pin_to_addr(priv, offset, &addr);

	if ((priv->ports & BIT(addr.port)) == 0) {
		dev_warn(priv->dev, "Request port %d.%d: Port is not enabled\n",
			 addr.port, addr.bit);
		return -EINVAL;
	}

	return 0;
}

static const struct pinmux_ops sgpio_pmx_ops = {
	.get_functions_count = sgpio_get_functions_count,
	.get_function_name = sgpio_get_function_name,
	.get_function_groups = sgpio_get_function_groups,
	.set_mux = sgpio_pinmux_set_mux,
	.gpio_set_direction = sgpio_gpio_set_direction,
	.gpio_request_enable = sgpio_gpio_request_enable,
};

static int sgpio_pctl_get_groups_count(struct pinctrl_dev *pctldev)
{
	struct sgpio_bank *bank = pinctrl_dev_get_drvdata(pctldev);

	return bank->pctl_desc.npins;
}

static const char *sgpio_pctl_get_group_name(struct pinctrl_dev *pctldev,
					     unsigned int group)
{
	struct sgpio_bank *bank = pinctrl_dev_get_drvdata(pctldev);

	return bank->pctl_desc.pins[group].name;
}

static int sgpio_pctl_get_group_pins(struct pinctrl_dev *pctldev,
				     unsigned int group,
				     const unsigned int **pins,
				     unsigned int *num_pins)
{
	struct sgpio_bank *bank = pinctrl_dev_get_drvdata(pctldev);

	*pins = &bank->pctl_desc.pins[group].number;
	*num_pins = 1;

	return 0;
}

static const struct pinctrl_ops sgpio_pctl_ops = {
	.get_groups_count = sgpio_pctl_get_groups_count,
	.get_group_name = sgpio_pctl_get_group_name,
	.get_group_pins = sgpio_pctl_get_group_pins,
	.dt_node_to_map = pinconf_generic_dt_node_to_map_pin,
	.dt_free_map = pinconf_generic_dt_free_map,
};

static int microchip_sgpio_direction_input(struct gpio_chip *gc, unsigned int gpio)
{
	struct sgpio_bank *bank = gpiochip_get_data(gc);

	/* Fixed-position function */
	return bank->is_input ? 0 : -EINVAL;
}

static int microchip_sgpio_direction_output(struct gpio_chip *gc,
				       unsigned int gpio, int value)
{
	struct sgpio_bank *bank = gpiochip_get_data(gc);
	struct sgpio_priv *priv = bank->priv;
	struct sgpio_port_addr addr;

	/* Fixed-position function */
	if (bank->is_input)
		return -EINVAL;

	sgpio_pin_to_addr(priv, gpio, &addr);

	sgpio_output_set(priv, &addr, value);

	return 0;
}

static int microchip_sgpio_get_direction(struct gpio_chip *gc, unsigned int gpio)
{
	struct sgpio_bank *bank = gpiochip_get_data(gc);

	return bank->is_input ? GPIO_LINE_DIRECTION_IN : GPIO_LINE_DIRECTION_OUT;
}

static void microchip_sgpio_set_value(struct gpio_chip *gc,
				unsigned int gpio, int value)
{
	microchip_sgpio_direction_output(gc, gpio, value);
}

static int microchip_sgpio_get_value(struct gpio_chip *gc, unsigned int gpio)
{
	struct sgpio_bank *bank = gpiochip_get_data(gc);
	struct sgpio_priv *priv = bank->priv;
	struct sgpio_port_addr addr;

	sgpio_pin_to_addr(priv, gpio, &addr);

	return bank->is_input ? sgpio_input_get(priv, &addr) : sgpio_output_get(priv, &addr);
}

static int microchip_sgpio_of_xlate(struct gpio_chip *gc,
			       const struct of_phandle_args *gpiospec,
			       u32 *flags)
{
	struct sgpio_bank *bank = gpiochip_get_data(gc);
	struct sgpio_priv *priv = bank->priv;
	int pin;

	/*
	 * Note that the SGIO pin is defined by *2* numbers, a port
	 * number between 0 and 31, and a bit index, 0 to 3.
	 */
	if (gpiospec->args[0] > SGPIO_BITS_PER_WORD ||
	    gpiospec->args[1] > priv->bitcount)
		return -EINVAL;

	pin = gpiospec->args[1] + gpiospec->args[0] * priv->bitcount;

	if (pin > gc->ngpio)
		return -EINVAL;

	if (flags)
		*flags = gpiospec->args[2];

	return pin;
}

static int microchip_sgpio_get_ports(struct sgpio_priv *priv)
{
	const char *range_property_name = "microchip,sgpio-port-ranges";
	struct device *dev = priv->dev;
	u32 range_params[64];
	int i, nranges, ret;

	/* Calculate port mask */
	nranges = device_property_count_u32(dev, range_property_name);
	if (nranges < 2 || nranges % 2 || nranges > ARRAY_SIZE(range_params)) {
		dev_err(dev, "%s port range: '%s' property\n",
			nranges == -EINVAL ? "Missing" : "Invalid",
			range_property_name);
		return -EINVAL;
	}

	ret = device_property_read_u32_array(dev, range_property_name,
					     range_params, nranges);
	if (ret) {
		dev_err(dev, "failed to parse '%s' property: %d\n",
			range_property_name, ret);
		return ret;
	}
	for (i = 0; i < nranges; i += 2) {
		int start, end;

		start = range_params[i];
		end = range_params[i + 1];
		if (start > end || end >= SGPIO_BITS_PER_WORD) {
			dev_err(dev, "Ill-formed port-range [%d:%d]\n",
				start, end);
		}
		priv->ports |= GENMASK(end, start);
	}

	return 0;
}

static int microchip_sgpio_register_bank(struct device *dev,
					 struct sgpio_priv *priv,
					 struct fwnode_handle *fwnode,
					 int bankno)
{
	struct pinctrl_pin_desc *pins;
	struct pinctrl_desc *pctl_desc;
	struct pinctrl_dev *pctldev;
	struct sgpio_bank *bank;
	struct gpio_chip *gc;
	u32 ngpios;
	int i, ret;

	/* Get overall bank struct */
	bank = (bankno == 0) ? &priv->in : &priv->out;
	bank->priv = priv;

	if (fwnode_property_read_u32(fwnode, "ngpios", &ngpios)) {
		dev_info(dev, "failed to get number of gpios for bank%d\n",
			 bankno);
		ngpios = 64;
	}

	priv->bitcount = ngpios / SGPIO_BITS_PER_WORD;
	if (priv->bitcount > SGPIO_MAX_BITS) {
		dev_err(dev, "Bit width exceeds maximum (%d)\n",
			SGPIO_MAX_BITS);
		return -EINVAL;
	}

	pctl_desc = &bank->pctl_desc;
	pctl_desc->name = devm_kasprintf(dev, GFP_KERNEL, "%s-%sput",
					 dev_name(dev),
					 bank->is_input ? "in" : "out");
	pctl_desc->pctlops = &sgpio_pctl_ops;
	pctl_desc->pmxops = &sgpio_pmx_ops;
	pctl_desc->confops = &sgpio_confops;
	pctl_desc->owner = THIS_MODULE;

	pins = devm_kzalloc(dev, sizeof(*pins)*ngpios, GFP_KERNEL);
	if (!pins)
		return -ENOMEM;

	pctl_desc->npins = ngpios;
	pctl_desc->pins = pins;

	for (i = 0; i < ngpios; i++) {
		struct sgpio_port_addr addr;

		sgpio_pin_to_addr(priv, i, &addr);

		pins[i].number = i;
		pins[i].name = devm_kasprintf(dev, GFP_KERNEL,
					      "SGPIO_%c_p%db%d",
					      bank->is_input ? 'I' : 'O',
					      addr.port, addr.bit);
		if (!pins[i].name)
			return -ENOMEM;
	}

	pctldev = devm_pinctrl_register(dev, pctl_desc, bank);
	if (IS_ERR(pctldev))
		return dev_err_probe(dev, PTR_ERR(pctldev), "Failed to register pinctrl\n");

	gc			= &bank->gpio;
	gc->label		= pctl_desc->name;
	gc->parent		= dev;
	gc->of_node		= to_of_node(fwnode);
	gc->owner		= THIS_MODULE;
	gc->get_direction	= microchip_sgpio_get_direction;
	gc->direction_input	= microchip_sgpio_direction_input;
	gc->direction_output	= microchip_sgpio_direction_output;
	gc->get			= microchip_sgpio_get_value;
	gc->set			= microchip_sgpio_set_value;
	gc->request		= gpiochip_generic_request;
	gc->free		= gpiochip_generic_free;
	gc->of_xlate		= microchip_sgpio_of_xlate;
	gc->of_gpio_n_cells     = 3;
	gc->base		= -1;
	gc->ngpio		= ngpios;

	ret = devm_gpiochip_add_data(dev, gc, bank);
	if (ret)
		dev_err(dev, "Failed to register: ret %d\n", ret);

	return ret;
}

static int microchip_sgpio_probe(struct platform_device *pdev)
{
	int div_clock = 0, ret, port, i, nbanks;
	struct device *dev = &pdev->dev;
	struct fwnode_handle *fwnode;
	struct sgpio_priv *priv;
	struct clk *clk;
	u32 val;

	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	priv->dev = dev;

	clk = devm_clk_get(dev, NULL);
	if (IS_ERR(clk))
		return dev_err_probe(dev, PTR_ERR(clk), "Failed to get clock\n");

	div_clock = clk_get_rate(clk);
	if (device_property_read_u32(dev, "bus-frequency", &priv->clock))
		priv->clock = 12500000;
	if (priv->clock == 0 || priv->clock > (div_clock / 2)) {
		dev_err(dev, "Invalid frequency %d\n", priv->clock);
		return -EINVAL;
	}

	priv->regs = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(priv->regs))
		return PTR_ERR(priv->regs);
	priv->properties = device_get_match_data(dev);
	priv->in.is_input = true;

	/* Get rest of device properties */
	ret = microchip_sgpio_get_ports(priv);
	if (ret)
		return ret;

	nbanks = device_get_child_node_count(dev);
	if (nbanks != 2) {
		dev_err(dev, "Must have 2 banks (have %d)\n", nbanks);
		return -EINVAL;
	}

	i = 0;
	device_for_each_child_node(dev, fwnode) {
		ret = microchip_sgpio_register_bank(dev, priv, fwnode, i++);
		if (ret)
			return ret;
	}

	if (priv->in.gpio.ngpio != priv->out.gpio.ngpio) {
		dev_err(dev, "Banks must have same GPIO count\n");
		return -ERANGE;
	}

	sgpio_configure_bitstream(priv);

	val = max(2U, div_clock / priv->clock);
	sgpio_configure_clock(priv, val);

	for (port = 0; port < SGPIO_BITS_PER_WORD; port++)
		sgpio_writel(priv, 0, REG_PORT_CONFIG, port);
	sgpio_writel(priv, priv->ports, REG_PORT_ENABLE, 0);

	return 0;
}

static const struct of_device_id microchip_sgpio_gpio_of_match[] = {
	{
		.compatible = "microchip,sparx5-sgpio",
		.data = &properties_sparx5,
	}, {
		.compatible = "mscc,luton-sgpio",
		.data = &properties_luton,
	}, {
		.compatible = "mscc,ocelot-sgpio",
		.data = &properties_ocelot,
	}, {
		/* sentinel */
	}
};

static struct platform_driver microchip_sgpio_pinctrl_driver = {
	.driver = {
		.name = "pinctrl-microchip-sgpio",
		.of_match_table = microchip_sgpio_gpio_of_match,
		.suppress_bind_attrs = true,
	},
	.probe = microchip_sgpio_probe,
};
builtin_platform_driver(microchip_sgpio_pinctrl_driver);