203 lines
5.3 KiB
C
203 lines
5.3 KiB
C
/*
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* gpio-bd7181x.c
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* @file Access to GPOs on ROHM BD7181XMWV chip
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*
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* Copyright 2014 Embest Technology Co. Ltd. Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#define DEBUG
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/kthread.h>
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#include <linux/irq.h>
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#include <linux/gpio.h>
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#include <linux/platform_device.h>
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#include <linux/of.h>
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#include <linux/mfd/bd7181x.h>
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/** @brief bd7181x gpio chip core data */
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static struct gpio_chip bd7181xgpo_chip;
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/** @brief get gpo output value
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* @param chip pointer to core data
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* @param offset gpo number, start from 0
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* @retval 0 success
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* @retval negative error number
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*/
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static int bd7181xgpo_get(struct gpio_chip *chip, unsigned offset)
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{
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struct bd7181x *bd7181x = dev_get_drvdata(chip->parent);
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int ret = 0;
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ret = bd7181x_reg_read(bd7181x, BD7181X_REG_GPO);
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if (ret < 0)
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return ret;
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return (ret >> offset) & 1;
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}
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/** @brief set gpo direction as output
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* @param chip pointer to core data
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* @param offset gpo number, start from 0
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* @param value output value when set direction out
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* @retval 0 success
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*/
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static int bd7181xgpo_direction_out(struct gpio_chip *chip, unsigned offset,
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int value)
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{
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/* This only drives GPOs, and can't change direction */
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return 0;
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}
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/** @brief set gpo output value
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* @param chip pointer to core data
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* @param offset gpo number, start from 0
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* @param value output value, not zero as high level, 0 as low level
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* @retval 0 success
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* @retval negative error number
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*/
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static void bd7181xgpo_set(struct gpio_chip *chip, unsigned offset, int value)
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{
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struct bd7181x *bd7181x = dev_get_drvdata(chip->parent);
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int ret;
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u8 gpoctl;
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ret = bd7181x_reg_read(bd7181x, BD7181X_REG_GPO);
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if (ret < 0)
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return;
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if (value)
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gpoctl = ret | (1 << offset);
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else
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gpoctl = ret & ~(1 << offset);
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bd7181x_reg_write(bd7181x, BD7181X_REG_GPO, gpoctl);
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}
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/** @brief bd7181x gpio chip core data */
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static struct gpio_chip bd7181xgpo_chip = {
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.label = "bd7181x", ///< gpio chip name
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.owner = THIS_MODULE,
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.get = bd7181xgpo_get,
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.direction_output = bd7181xgpo_direction_out,
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.set = bd7181xgpo_set,
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.can_sleep = 1,
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};
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/*----------------------------------------------------------------------*/
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#ifdef CONFIG_OF
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/** @brief retrive gpo platform data from device tree
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* @param pdev platfrom device pointer
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* @return pointer to platform data
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* @retval NULL error
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*/
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static struct bd7181x_gpo_plat_data *of_gpio_bd7181x(
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struct platform_device *pdev)
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{
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struct bd7181x_gpo_plat_data *platform_data;
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struct device_node *np, *gpio_np;
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platform_data = devm_kzalloc(&pdev->dev, sizeof(*platform_data), GFP_KERNEL);
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if (!platform_data) {
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return NULL;
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}
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np = of_node_get(pdev->dev.parent->of_node);
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gpio_np = of_find_node_by_name(np, "gpo");
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if (!gpio_np) {
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dev_err(&pdev->dev, "gpio node not found\n");
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return NULL;
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}
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pdev->dev.of_node = gpio_np;
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if (of_property_read_u32(gpio_np, "rohm,mode", &platform_data->mode)) {
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platform_data->mode = -1;
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}
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return platform_data;
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}
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#endif
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/** @brief probe bd7181x gpo device
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* @param pdev platfrom device pointer
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* @retval 0 success
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* @retval negative error number
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*/
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static int gpo_bd7181x_probe(struct platform_device *pdev)
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{
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struct bd7181x_gpo_plat_data *pdata = pdev->dev.platform_data;
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struct device *mfd_dev = pdev->dev.parent;
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struct bd7181x *bd7181x = dev_get_drvdata(mfd_dev);
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int ret;
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#ifdef CONFIG_OF
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pdata = of_gpio_bd7181x(pdev);
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#endif
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if (pdata && pdata->gpio_base > 0)
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bd7181xgpo_chip.base = pdata->gpio_base;
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else
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bd7181xgpo_chip.base = -1;
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bd7181xgpo_chip.ngpio = 2; /* bd71815/bd71817 have 2 GPO */
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bd7181xgpo_chip.parent = &pdev->dev;
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ret = gpiochip_add(&bd7181xgpo_chip);
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if (ret < 0) {
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dev_err(&pdev->dev, "Could not register gpiochip, %d\n", ret);
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bd7181xgpo_chip.ngpio = 0;
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return ret;
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}
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if (pdata && pdata->mode != -1UL) {
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bd7181x_update_bits(bd7181x, BD7181X_REG_GPO, 0x70, pdata->mode);
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}
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return ret;
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}
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/** @brief remove bd7181x gpo device
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* @param pdev platfrom device pointer
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* @retval 0 success
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* @retval negative error number
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*/
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static int gpo_bd7181x_remove(struct platform_device *pdev)
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{
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gpiochip_remove(&bd7181xgpo_chip);
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return 0;
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}
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/* Note: this hardware lives inside an I2C-based multi-function device. */
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MODULE_ALIAS("platform:bd7181x-gpo");
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/** @brief bd7181x gpo driver core data */
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static struct platform_driver gpo_bd7181x_driver = {
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.driver = {
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.name = "bd7181x-gpo",
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.owner = THIS_MODULE,
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},
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.probe = gpo_bd7181x_probe,
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.remove = gpo_bd7181x_remove,
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};
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module_platform_driver(gpo_bd7181x_driver);
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MODULE_AUTHOR("Peter Yang <yanglsh@embest-tech.com>");
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MODULE_DESCRIPTION("GPO interface for BD71815/BD71817");
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MODULE_LICENSE("GPL");
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