src/kernel/linux/v4.19/drivers/pinctrl/meson/pinctrl-meson8-pmx.c

/*
 * First generation of pinmux driver for Amlogic Meson SoCs
 *
 * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
 * Copyright (C) 2017 Jerome Brunet  <jbrunet@baylibre.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

/* For this first generation of pinctrl driver every pinmux group can be
 * enabled by a specific bit in the first register range. When all groups for
 * a given pin are disabled the pin acts as a GPIO.
 */
#include <linux/device.h>
#include <linux/regmap.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/pinctrl/pinmux.h>

#include "pinctrl-meson.h"
#include "pinctrl-meson8-pmx.h"

/**
 * meson8_pmx_disable_other_groups() - disable other groups using a given pin
 *
 * @pc:		meson pin controller device
 * @pin:	number of the pin
 * @sel_group:	index of the selected group, or -1 if none
 *
 * The function disables all pinmux groups using a pin except the
 * selected one. If @sel_group is -1 all groups are disabled, leaving
 * the pin in GPIO mode.
 */
static void meson8_pmx_disable_other_groups(struct meson_pinctrl *pc,
					    unsigned int pin, int sel_group)
{
	struct meson_pmx_group *group;
	struct meson8_pmx_data *pmx_data;
	int i, j;

	for (i = 0; i < pc->data->num_groups; i++) {
		group = &pc->data->groups[i];
		pmx_data = (struct meson8_pmx_data *)group->data;
		if (pmx_data->is_gpio || i == sel_group)
			continue;

		for (j = 0; j < group->num_pins; j++) {
			if (group->pins[j] == pin) {
				/* We have found a group using the pin */
				regmap_update_bits(pc->reg_mux,
						   pmx_data->reg * 4,
						   BIT(pmx_data->bit), 0);
			}
		}
	}
}

static int meson8_pmx_set_mux(struct pinctrl_dev *pcdev, unsigned func_num,
			      unsigned group_num)
{
	struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);
	struct meson_pmx_func *func = &pc->data->funcs[func_num];
	struct meson_pmx_group *group = &pc->data->groups[group_num];
	struct meson8_pmx_data *pmx_data =
		(struct meson8_pmx_data *)group->data;
	int i, ret = 0;

	dev_dbg(pc->dev, "enable function %s, group %s\n", func->name,
		group->name);

	/*
	 * Disable groups using the same pin.
	 * The selected group is not disabled to avoid glitches.
	 */
	for (i = 0; i < group->num_pins; i++)
		meson8_pmx_disable_other_groups(pc, group->pins[i], group_num);

	/* Function 0 (GPIO) doesn't need any additional setting */
	if (func_num)
		ret = regmap_update_bits(pc->reg_mux, pmx_data->reg * 4,
					 BIT(pmx_data->bit),
					 BIT(pmx_data->bit));

	return ret;
}

static int meson8_pmx_request_gpio(struct pinctrl_dev *pcdev,
				   struct pinctrl_gpio_range *range,
				   unsigned offset)
{
	struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);

	meson8_pmx_disable_other_groups(pc, offset, -1);

	return 0;
}

const struct pinmux_ops meson8_pmx_ops = {
	.set_mux = meson8_pmx_set_mux,
	.get_functions_count = meson_pmx_get_funcs_count,
	.get_function_name = meson_pmx_get_func_name,
	.get_function_groups = meson_pmx_get_groups,
	.gpio_request_enable = meson8_pmx_request_gpio,
};