pinctrl: ralink: add a pinctrl driver for the rt2880 family

These Socs have 1-3 banks of 8-32 gpios. Rather then setting the muxing of each
pin individually, these socs have mux groups that when set will effect 1-N pins.
Pin groups have a 2, 4 or 8 different muxes.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Link: https://lore.kernel.org/r/20201208075523.7060-3-sergio.paracuellos@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 386 insertions, 0 deletions

diff --git a/drivers/pinctrl/ralink/Kconfig b/drivers/pinctrl/ralink/Kconfig
new file mode 100644
index 000000000000..8c5f6341477f
--- /dev/null
+++ b/drivers/pinctrl/ralink/Kconfig
@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "Ralink pinctrl drivers"
+        depends on RALINK
+
+config PINCTRL_RALINK
+        bool "Ralink pin control support"
+        default y if RALINK
+
+config PINCTRL_RT2880
+        bool "RT2880 pinctrl driver for RALINK/Mediatek SOCs"
+        select PINMUX
+        select GENERIC_PINCONF
+
+endmenu
diff --git a/drivers/pinctrl/ralink/Makefile b/drivers/pinctrl/ralink/Makefile
new file mode 100644
index 000000000000..242554298d07
--- /dev/null
+++ b/drivers/pinctrl/ralink/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_PINCTRL_RT2880)   += pinctrl-rt2880.o
diff --git a/drivers/pinctrl/ralink/pinctrl-rt2880.c b/drivers/pinctrl/ralink/pinctrl-rt2880.c
new file mode 100644
index 000000000000..42b1c6cecb57
--- /dev/null
+++ b/drivers/pinctrl/ralink/pinctrl-rt2880.c
@@ -0,0 +1,370 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Copyright (C) 2013 John Crispin <blogic@openwrt.org>
+ */
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinconf.h>
+#include <linux/pinctrl/pinconf-generic.h>
+#include <linux/pinctrl/pinmux.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/pinctrl/machine.h>
+
+#include <asm/mach-ralink/ralink_regs.h>
+#include <asm/mach-ralink/pinmux.h>
+#include <asm/mach-ralink/mt7620.h>
+
+#include "../core.h"
+#include "../pinctrl-utils.h"
+
+#define SYSC_REG_GPIO_MODE	0x60
+#define SYSC_REG_GPIO_MODE2	0x64
+
+struct rt2880_priv {
+	struct device *dev;
+
+	struct pinctrl_pin_desc *pads;
+	struct pinctrl_desc *desc;
+
+	struct rt2880_pmx_func **func;
+	int func_count;
+
+	struct rt2880_pmx_group *groups;
+	const char **group_names;
+	int group_count;
+
+	u8 *gpio;
+	int max_pins;
+};
+
+static int rt2880_get_group_count(struct pinctrl_dev *pctrldev)
+{
+	struct rt2880_priv *p = pinctrl_dev_get_drvdata(pctrldev);
+
+	return p->group_count;
+}
+
+static const char *rt2880_get_group_name(struct pinctrl_dev *pctrldev,
+					 unsigned int group)
+{
+	struct rt2880_priv *p = pinctrl_dev_get_drvdata(pctrldev);
+
+	return (group >= p->group_count) ? NULL : p->group_names[group];
+}
+
+static int rt2880_get_group_pins(struct pinctrl_dev *pctrldev,
+				 unsigned int group,
+				 const unsigned int **pins,
+				 unsigned int *num_pins)
+{
+	struct rt2880_priv *p = pinctrl_dev_get_drvdata(pctrldev);
+
+	if (group >= p->group_count)
+		return -EINVAL;
+
+	*pins = p->groups[group].func[0].pins;
+	*num_pins = p->groups[group].func[0].pin_count;
+
+	return 0;
+}
+
+static const struct pinctrl_ops rt2880_pctrl_ops = {
+	.get_groups_count	= rt2880_get_group_count,
+	.get_group_name		= rt2880_get_group_name,
+	.get_group_pins		= rt2880_get_group_pins,
+	.dt_node_to_map		= pinconf_generic_dt_node_to_map_all,
+	.dt_free_map		= pinconf_generic_dt_free_map,
+};
+
+static int rt2880_pmx_func_count(struct pinctrl_dev *pctrldev)
+{
+	struct rt2880_priv *p = pinctrl_dev_get_drvdata(pctrldev);
+
+	return p->func_count;
+}
+
+static const char *rt2880_pmx_func_name(struct pinctrl_dev *pctrldev,
+					unsigned int func)
+{
+	struct rt2880_priv *p = pinctrl_dev_get_drvdata(pctrldev);
+
+	return p->func[func]->name;
+}
+
+static int rt2880_pmx_group_get_groups(struct pinctrl_dev *pctrldev,
+				       unsigned int func,
+				       const char * const **groups,
+				       unsigned int * const num_groups)
+{
+	struct rt2880_priv *p = pinctrl_dev_get_drvdata(pctrldev);
+
+	if (p->func[func]->group_count == 1)
+		*groups = &p->group_names[p->func[func]->groups[0]];
+	else
+		*groups = p->group_names;
+
+	*num_groups = p->func[func]->group_count;
+
+	return 0;
+}
+
+static int rt2880_pmx_group_enable(struct pinctrl_dev *pctrldev,
+				   unsigned int func, unsigned int group)
+{
+	struct rt2880_priv *p = pinctrl_dev_get_drvdata(pctrldev);
+	u32 mode = 0;
+	u32 reg = SYSC_REG_GPIO_MODE;
+	int i;
+	int shift;
+
+	/* dont allow double use */
+	if (p->groups[group].enabled) {
+		dev_err(p->dev, "%s is already enabled\n",
+			p->groups[group].name);
+		return -EBUSY;
+	}
+
+	p->groups[group].enabled = 1;
+	p->func[func]->enabled = 1;
+
+	shift = p->groups[group].shift;
+	if (shift >= 32) {
+		shift -= 32;
+		reg = SYSC_REG_GPIO_MODE2;
+	}
+	mode = rt_sysc_r32(reg);
+	mode &= ~(p->groups[group].mask << shift);
+
+	/* mark the pins as gpio */
+	for (i = 0; i < p->groups[group].func[0].pin_count; i++)
+		p->gpio[p->groups[group].func[0].pins[i]] = 1;
+
+	/* function 0 is gpio and needs special handling */
+	if (func == 0) {
+		mode |= p->groups[group].gpio << shift;
+	} else {
+		for (i = 0; i < p->func[func]->pin_count; i++)
+			p->gpio[p->func[func]->pins[i]] = 0;
+		mode |= p->func[func]->value << shift;
+	}
+	rt_sysc_w32(mode, reg);
+
+	return 0;
+}
+
+static int rt2880_pmx_group_gpio_request_enable(struct pinctrl_dev *pctrldev,
+						struct pinctrl_gpio_range *range,
+						unsigned int pin)
+{
+	struct rt2880_priv *p = pinctrl_dev_get_drvdata(pctrldev);
+
+	if (!p->gpio[pin]) {
+		dev_err(p->dev, "pin %d is not set to gpio mux\n", pin);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct pinmux_ops rt2880_pmx_group_ops = {
+	.get_functions_count	= rt2880_pmx_func_count,
+	.get_function_name	= rt2880_pmx_func_name,
+	.get_function_groups	= rt2880_pmx_group_get_groups,
+	.set_mux		= rt2880_pmx_group_enable,
+	.gpio_request_enable	= rt2880_pmx_group_gpio_request_enable,
+};
+
+static struct pinctrl_desc rt2880_pctrl_desc = {
+	.owner		= THIS_MODULE,
+	.name		= "rt2880-pinmux",
+	.pctlops	= &rt2880_pctrl_ops,
+	.pmxops		= &rt2880_pmx_group_ops,
+};
+
+static struct rt2880_pmx_func gpio_func = {
+	.name = "gpio",
+};
+
+static int rt2880_pinmux_index(struct rt2880_priv *p)
+{
+	struct rt2880_pmx_func **f;
+	struct rt2880_pmx_group *mux = p->groups;
+	int i, j, c = 0;
+
+	/* count the mux functions */
+	while (mux->name) {
+		p->group_count++;
+		mux++;
+	}
+
+	/* allocate the group names array needed by the gpio function */
+	p->group_names = devm_kcalloc(p->dev, p->group_count,
+				      sizeof(char *), GFP_KERNEL);
+	if (!p->group_names)
+		return -1;
+
+	for (i = 0; i < p->group_count; i++) {
+		p->group_names[i] = p->groups[i].name;
+		p->func_count += p->groups[i].func_count;
+	}
+
+	/* we have a dummy function[0] for gpio */
+	p->func_count++;
+
+	/* allocate our function and group mapping index buffers */
+	f = p->func = devm_kcalloc(p->dev,
+				   p->func_count,
+				   sizeof(*p->func),
+				   GFP_KERNEL);
+	gpio_func.groups = devm_kcalloc(p->dev, p->group_count, sizeof(int),
+					GFP_KERNEL);
+	if (!f || !gpio_func.groups)
+		return -1;
+
+	/* add a backpointer to the function so it knows its group */
+	gpio_func.group_count = p->group_count;
+	for (i = 0; i < gpio_func.group_count; i++)
+		gpio_func.groups[i] = i;
+
+	f[c] = &gpio_func;
+	c++;
+
+	/* add remaining functions */
+	for (i = 0; i < p->group_count; i++) {
+		for (j = 0; j < p->groups[i].func_count; j++) {
+			f[c] = &p->groups[i].func[j];
+			f[c]->groups = devm_kzalloc(p->dev, sizeof(int),
+						    GFP_KERNEL);
+			f[c]->groups[0] = i;
+			f[c]->group_count = 1;
+			c++;
+		}
+	}
+	return 0;
+}
+
+static int rt2880_pinmux_pins(struct rt2880_priv *p)
+{
+	int i, j;
+
+	/*
+	 * loop over the functions and initialize the pins array.
+	 * also work out the highest pin used.
+	 */
+	for (i = 0; i < p->func_count; i++) {
+		int pin;
+
+		if (!p->func[i]->pin_count)
+			continue;
+
+		p->func[i]->pins = devm_kcalloc(p->dev,
+						p->func[i]->pin_count,
+						sizeof(int),
+						GFP_KERNEL);
+		for (j = 0; j < p->func[i]->pin_count; j++)
+			p->func[i]->pins[j] = p->func[i]->pin_first + j;
+
+		pin = p->func[i]->pin_first + p->func[i]->pin_count;
+		if (pin > p->max_pins)
+			p->max_pins = pin;
+	}
+
+	/* the buffer that tells us which pins are gpio */
+	p->gpio = devm_kcalloc(p->dev, p->max_pins, sizeof(u8), GFP_KERNEL);
+	/* the pads needed to tell pinctrl about our pins */
+	p->pads = devm_kcalloc(p->dev, p->max_pins,
+			       sizeof(struct pinctrl_pin_desc), GFP_KERNEL);
+	if (!p->pads || !p->gpio) {
+		dev_err(p->dev, "Failed to allocate gpio data\n");
+		return -ENOMEM;
+	}
+
+	memset(p->gpio, 1, sizeof(u8) * p->max_pins);
+	for (i = 0; i < p->func_count; i++) {
+		if (!p->func[i]->pin_count)
+			continue;
+
+		for (j = 0; j < p->func[i]->pin_count; j++)
+			p->gpio[p->func[i]->pins[j]] = 0;
+	}
+
+	/* pin 0 is always a gpio */
+	p->gpio[0] = 1;
+
+	/* set the pads */
+	for (i = 0; i < p->max_pins; i++) {
+		/* strlen("ioXY") + 1 = 5 */
+		char *name = devm_kzalloc(p->dev, 5, GFP_KERNEL);
+
+		if (!name)
+			return -ENOMEM;
+		snprintf(name, 5, "io%d", i);
+		p->pads[i].number = i;
+		p->pads[i].name = name;
+	}
+	p->desc->pins = p->pads;
+	p->desc->npins = p->max_pins;
+
+	return 0;
+}
+
+static int rt2880_pinmux_probe(struct platform_device *pdev)
+{
+	struct rt2880_priv *p;
+	struct pinctrl_dev *dev;
+
+	if (!rt2880_pinmux_data)
+		return -ENOTSUPP;
+
+	/* setup the private data */
+	p = devm_kzalloc(&pdev->dev, sizeof(struct rt2880_priv), GFP_KERNEL);
+	if (!p)
+		return -ENOMEM;
+
+	p->dev = &pdev->dev;
+	p->desc = &rt2880_pctrl_desc;
+	p->groups = rt2880_pinmux_data;
+	platform_set_drvdata(pdev, p);
+
+	/* init the device */
+	if (rt2880_pinmux_index(p)) {
+		dev_err(&pdev->dev, "failed to load index\n");
+		return -EINVAL;
+	}
+	if (rt2880_pinmux_pins(p)) {
+		dev_err(&pdev->dev, "failed to load pins\n");
+		return -EINVAL;
+	}
+	dev = pinctrl_register(p->desc, &pdev->dev, p);
+	if (IS_ERR(dev))
+		return PTR_ERR(dev);
+
+	return 0;
+}
+
+static const struct of_device_id rt2880_pinmux_match[] = {
+	{ .compatible = "ralink,rt2880-pinmux" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, rt2880_pinmux_match);
+
+static struct platform_driver rt2880_pinmux_driver = {
+	.probe = rt2880_pinmux_probe,
+	.driver = {
+		.name = "rt2880-pinmux",
+		.of_match_table = rt2880_pinmux_match,
+	},
+};
+
+int __init rt2880_pinmux_init(void)
+{
+	return platform_driver_register(&rt2880_pinmux_driver);
+}
+
+core_initcall_sync(rt2880_pinmux_init);