text: // SPDX-License-Identifier: GPL-2.0-only
  /*
   * 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>
   */
  
  /* 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,
  };
  