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80a04ea953
Add a common upper-half character driver for digital potentiometers with a generic set of ioctl commands (wiper set/get, terminal control, device properties) that can be shared by chip-specific lower halves. Signed-off-by: raiden00pl <raiden00@railab.me> Assisted-by: Claude Code
422 lines
11 KiB
C
422 lines
11 KiB
C
/****************************************************************************
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* drivers/analog/pot.c
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/types.h>
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#include <stdint.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <assert.h>
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#include <errno.h>
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#include <nuttx/debug.h>
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#include <nuttx/arch.h>
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#include <nuttx/fs/fs.h>
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#include <nuttx/analog/pot.h>
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#include <nuttx/irq.h>
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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static int pot_open(FAR struct file *filep);
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static int pot_close(FAR struct file *filep);
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static int pot_ioctl(FAR struct file *filep, int cmd, unsigned long arg);
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static const struct file_operations g_pot_fops =
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{
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pot_open, /* open */
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pot_close, /* close */
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NULL, /* read */
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NULL, /* write */
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NULL, /* seek */
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pot_ioctl, /* ioctl */
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: pot_open
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*
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* Description:
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* This function is called whenever the potentiometer device is opened.
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*
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****************************************************************************/
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static int pot_open(FAR struct file *filep)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct pot_dev_s *dev = inode->i_private;
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uint8_t tmp;
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int ret;
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/* If the port is the middle of closing, wait until the close is
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* finished.
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*/
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ret = nxmutex_lock(&dev->pd_closelock);
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if (ret >= 0)
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{
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/* Increment the count of references to the device. If this is the
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* first time that the driver has been opened for this device, then
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* initialize the device.
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*/
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tmp = dev->pd_ocount + 1;
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if (tmp == 0)
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{
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/* More than 255 opens; uint8_t overflows to zero */
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ret = -EMFILE;
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}
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else
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{
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/* Check if this is the first time that the driver has been
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* opened.
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*/
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if (tmp == 1)
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{
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/* Yes.. perform one time hardware initialization. */
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ret = dev->pd_ops->po_setup(dev);
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if (ret == OK)
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{
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/* Save the new open count on success */
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dev->pd_ocount = tmp;
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}
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}
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}
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nxmutex_unlock(&dev->pd_closelock);
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}
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return ret;
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}
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/****************************************************************************
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* Name: pot_close
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*
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* Description:
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* This routine is called when the potentiometer device is closed.
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*
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****************************************************************************/
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static int pot_close(FAR struct file *filep)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct pot_dev_s *dev = inode->i_private;
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int ret;
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ret = nxmutex_lock(&dev->pd_closelock);
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if (ret >= 0)
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{
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/* Decrement the references to the driver. If the reference count
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* will decrement to 0, then uninitialize the driver.
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*/
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if (dev->pd_ocount > 1)
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{
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dev->pd_ocount--;
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}
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else
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{
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/* There are no more references to the port */
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dev->pd_ocount = 0;
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/* Disable the potentiometer device */
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dev->pd_ops->po_shutdown(dev);
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}
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nxmutex_unlock(&dev->pd_closelock);
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}
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return ret;
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}
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/****************************************************************************
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* Name: pot_ioctl
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****************************************************************************/
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static int pot_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct pot_dev_s *dev = inode->i_private;
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int ret = OK;
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ret = nxmutex_lock(&dev->pd_lock);
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if (ret < 0)
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{
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return ret;
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}
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switch (cmd)
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{
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/* Get the device properties */
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case POTIOC_GET_INFO:
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{
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FAR struct pot_info_s *info =
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(FAR struct pot_info_s *)((uintptr_t)arg);
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DEBUGASSERT(info != NULL);
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info->nwipers = dev->pd_nwipers;
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info->max = dev->pd_max;
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info->rab = dev->pd_rab;
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info->caps = 0;
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if (dev->pd_ops->po_getwiper)
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{
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info->caps |= POT_CAP_READBACK;
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}
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if (dev->pd_ops->po_move)
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{
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info->caps |= POT_CAP_MOVE;
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}
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if (dev->pd_ops->po_enable)
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{
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info->caps |= POT_CAP_ENABLE;
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}
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if (dev->pd_ops->po_store || dev->pd_ops->po_recall)
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{
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info->caps |= POT_CAP_NV;
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}
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break;
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}
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/* Set a wiper value */
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case POTIOC_SET_WIPER:
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{
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FAR struct pot_wiper_s *wiper =
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(FAR struct pot_wiper_s *)((uintptr_t)arg);
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DEBUGASSERT(wiper != NULL);
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if (wiper->wiper >= dev->pd_nwipers || wiper->val > dev->pd_max)
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{
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ret = -EINVAL;
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}
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else if (dev->pd_ops->po_setwiper == NULL)
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{
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ret = -ENOTSUP;
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}
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else
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{
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ret = dev->pd_ops->po_setwiper(dev, wiper->wiper, wiper->val);
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}
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break;
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}
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/* Get a wiper value */
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case POTIOC_GET_WIPER:
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{
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FAR struct pot_wiper_s *wiper =
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(FAR struct pot_wiper_s *)((uintptr_t)arg);
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DEBUGASSERT(wiper != NULL);
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if (wiper->wiper >= dev->pd_nwipers)
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{
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ret = -EINVAL;
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}
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else if (dev->pd_ops->po_getwiper == NULL)
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{
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ret = -ENOTSUP;
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}
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else
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{
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ret = dev->pd_ops->po_getwiper(dev, wiper->wiper, &wiper->val);
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}
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break;
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}
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/* Move a wiper by a number of steps */
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case POTIOC_MOVE_WIPER:
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{
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FAR struct pot_move_s *move =
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(FAR struct pot_move_s *)((uintptr_t)arg);
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DEBUGASSERT(move != NULL);
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if (move->wiper >= dev->pd_nwipers)
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{
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ret = -EINVAL;
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}
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else if (dev->pd_ops->po_move == NULL)
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{
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ret = -ENOTSUP;
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}
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else
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{
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ret = dev->pd_ops->po_move(dev, move->wiper, move->steps);
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}
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break;
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}
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/* Enable or force a wiper into shutdown */
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case POTIOC_SET_ENABLE:
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{
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FAR struct pot_enable_s *enable =
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(FAR struct pot_enable_s *)((uintptr_t)arg);
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DEBUGASSERT(enable != NULL);
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if (enable->wiper >= dev->pd_nwipers)
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{
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ret = -EINVAL;
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}
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else if (dev->pd_ops->po_enable == NULL)
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{
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ret = -ENOTSUP;
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}
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else
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{
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ret = dev->pd_ops->po_enable(dev, enable->wiper,
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enable->enable);
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}
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break;
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}
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/* Store a wiper value to a non-volatile slot */
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case POTIOC_STORE_WIPER:
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{
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FAR struct pot_nv_s *nv = (FAR struct pot_nv_s *)((uintptr_t)arg);
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DEBUGASSERT(nv != NULL);
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if (nv->wiper >= dev->pd_nwipers)
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{
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ret = -EINVAL;
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}
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else if (dev->pd_ops->po_store == NULL)
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{
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ret = -ENOTSUP;
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}
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else
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{
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ret = dev->pd_ops->po_store(dev, nv->wiper, nv->slot);
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}
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break;
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}
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/* Recall a wiper value from a non-volatile slot */
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case POTIOC_RECALL_WIPER:
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{
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FAR struct pot_nv_s *nv = (FAR struct pot_nv_s *)((uintptr_t)arg);
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DEBUGASSERT(nv != NULL);
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if (nv->wiper >= dev->pd_nwipers)
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{
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ret = -EINVAL;
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}
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else if (dev->pd_ops->po_recall == NULL)
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{
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ret = -ENOTSUP;
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}
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else
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{
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ret = dev->pd_ops->po_recall(dev, nv->wiper, nv->slot);
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}
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break;
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}
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/* Forward any unrecognized commands to the lower half */
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default:
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{
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if (dev->pd_ops->po_ioctl)
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{
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ret = dev->pd_ops->po_ioctl(dev, cmd, arg);
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}
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else
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{
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ret = -ENOTTY;
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}
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break;
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}
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}
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nxmutex_unlock(&dev->pd_lock);
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return ret;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: pot_register
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****************************************************************************/
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int pot_register(FAR const char *path, FAR struct pot_dev_s *dev)
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{
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int ret;
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DEBUGASSERT(dev != NULL && dev->pd_ops != NULL);
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/* Initialize the potentiometer device structure */
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dev->pd_ocount = 0;
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/* Initialize mutexes */
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nxmutex_init(&dev->pd_closelock);
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nxmutex_init(&dev->pd_lock);
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/* Register the potentiometer character driver */
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ret = register_driver(path, &g_pot_fops, 0666, dev);
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if (ret < 0)
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{
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nxmutex_destroy(&dev->pd_closelock);
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nxmutex_destroy(&dev->pd_lock);
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}
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return ret;
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}
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