277 lines
6.4 KiB
C
277 lines
6.4 KiB
C
/* NXP PCF50633 ADC Driver
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*
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* (C) 2006-2008 by Openmoko, Inc.
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* Author: Balaji Rao <balajirrao@openmoko.org>
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* All rights reserved.
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*
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* Broken down from monstrous PCF50633 driver mainly by
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* Harald Welte, Andy Green and Werner Almesberger
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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* NOTE: This driver does not yet support subtractive ADC mode, which means
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* you can do only one measurement per read request.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/device.h>
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#include <linux/platform_device.h>
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#include <linux/completion.h>
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#include <linux/mfd/pcf50633/core.h>
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#include <linux/mfd/pcf50633/adc.h>
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struct pcf50633_adc_request {
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int mux;
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int avg;
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int result;
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void (*callback)(struct pcf50633 *, void *, int);
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void *callback_param;
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/* Used in case of sync requests */
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struct completion completion;
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};
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#define PCF50633_MAX_ADC_FIFO_DEPTH 8
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struct pcf50633_adc {
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struct pcf50633 *pcf;
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/* Private stuff */
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struct pcf50633_adc_request *queue[PCF50633_MAX_ADC_FIFO_DEPTH];
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int queue_head;
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int queue_tail;
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struct mutex queue_mutex;
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};
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static inline struct pcf50633_adc *__to_adc(struct pcf50633 *pcf)
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{
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return platform_get_drvdata(pcf->adc_pdev);
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}
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static void adc_setup(struct pcf50633 *pcf, int channel, int avg)
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{
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channel &= PCF50633_ADCC1_ADCMUX_MASK;
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/* kill ratiometric, but enable ACCSW biasing */
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pcf50633_reg_write(pcf, PCF50633_REG_ADCC2, 0x00);
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pcf50633_reg_write(pcf, PCF50633_REG_ADCC3, 0x01);
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/* start ADC conversion on selected channel */
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pcf50633_reg_write(pcf, PCF50633_REG_ADCC1, channel | avg |
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PCF50633_ADCC1_ADCSTART | PCF50633_ADCC1_RES_10BIT);
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}
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static void trigger_next_adc_job_if_any(struct pcf50633 *pcf)
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{
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struct pcf50633_adc *adc = __to_adc(pcf);
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int head;
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head = adc->queue_head;
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if (!adc->queue[head])
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return;
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adc_setup(pcf, adc->queue[head]->mux, adc->queue[head]->avg);
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}
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static int
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adc_enqueue_request(struct pcf50633 *pcf, struct pcf50633_adc_request *req)
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{
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struct pcf50633_adc *adc = __to_adc(pcf);
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int head, tail;
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mutex_lock(&adc->queue_mutex);
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head = adc->queue_head;
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tail = adc->queue_tail;
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if (adc->queue[tail]) {
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mutex_unlock(&adc->queue_mutex);
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dev_err(pcf->dev, "ADC queue is full, dropping request\n");
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return -EBUSY;
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}
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adc->queue[tail] = req;
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if (head == tail)
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trigger_next_adc_job_if_any(pcf);
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adc->queue_tail = (tail + 1) & (PCF50633_MAX_ADC_FIFO_DEPTH - 1);
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mutex_unlock(&adc->queue_mutex);
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return 0;
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}
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static void
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pcf50633_adc_sync_read_callback(struct pcf50633 *pcf, void *param, int result)
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{
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struct pcf50633_adc_request *req = param;
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req->result = result;
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complete(&req->completion);
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}
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int pcf50633_adc_sync_read(struct pcf50633 *pcf, int mux, int avg)
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{
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struct pcf50633_adc_request *req;
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int err;
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/* req is freed when the result is ready, in interrupt handler */
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req = kzalloc(sizeof(*req), GFP_KERNEL);
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if (!req)
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return -ENOMEM;
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req->mux = mux;
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req->avg = avg;
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req->callback = pcf50633_adc_sync_read_callback;
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req->callback_param = req;
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init_completion(&req->completion);
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err = adc_enqueue_request(pcf, req);
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if (err)
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return err;
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wait_for_completion(&req->completion);
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/* FIXME by this time req might be already freed */
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return req->result;
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}
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EXPORT_SYMBOL_GPL(pcf50633_adc_sync_read);
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int pcf50633_adc_async_read(struct pcf50633 *pcf, int mux, int avg,
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void (*callback)(struct pcf50633 *, void *, int),
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void *callback_param)
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{
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struct pcf50633_adc_request *req;
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/* req is freed when the result is ready, in interrupt handler */
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req = kmalloc(sizeof(*req), GFP_KERNEL);
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if (!req)
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return -ENOMEM;
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req->mux = mux;
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req->avg = avg;
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req->callback = callback;
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req->callback_param = callback_param;
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return adc_enqueue_request(pcf, req);
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}
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EXPORT_SYMBOL_GPL(pcf50633_adc_async_read);
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static int adc_result(struct pcf50633 *pcf)
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{
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u8 adcs1, adcs3;
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u16 result;
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adcs1 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS1);
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adcs3 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS3);
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result = (adcs1 << 2) | (adcs3 & PCF50633_ADCS3_ADCDAT1L_MASK);
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dev_dbg(pcf->dev, "adc result = %d\n", result);
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return result;
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}
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static void pcf50633_adc_irq(int irq, void *data)
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{
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struct pcf50633_adc *adc = data;
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struct pcf50633 *pcf = adc->pcf;
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struct pcf50633_adc_request *req;
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int head, res;
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mutex_lock(&adc->queue_mutex);
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head = adc->queue_head;
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req = adc->queue[head];
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if (WARN_ON(!req)) {
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dev_err(pcf->dev, "pcf50633-adc irq: ADC queue empty!\n");
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mutex_unlock(&adc->queue_mutex);
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return;
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}
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adc->queue[head] = NULL;
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adc->queue_head = (head + 1) &
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(PCF50633_MAX_ADC_FIFO_DEPTH - 1);
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res = adc_result(pcf);
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trigger_next_adc_job_if_any(pcf);
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mutex_unlock(&adc->queue_mutex);
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req->callback(pcf, req->callback_param, res);
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kfree(req);
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}
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static int __devinit pcf50633_adc_probe(struct platform_device *pdev)
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{
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struct pcf50633_adc *adc;
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adc = kzalloc(sizeof(*adc), GFP_KERNEL);
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if (!adc)
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return -ENOMEM;
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adc->pcf = dev_to_pcf50633(pdev->dev.parent);
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platform_set_drvdata(pdev, adc);
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pcf50633_register_irq(adc->pcf, PCF50633_IRQ_ADCRDY,
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pcf50633_adc_irq, adc);
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mutex_init(&adc->queue_mutex);
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return 0;
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}
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static int __devexit pcf50633_adc_remove(struct platform_device *pdev)
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{
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struct pcf50633_adc *adc = platform_get_drvdata(pdev);
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int i, head;
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pcf50633_free_irq(adc->pcf, PCF50633_IRQ_ADCRDY);
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mutex_lock(&adc->queue_mutex);
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head = adc->queue_head;
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if (WARN_ON(adc->queue[head]))
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dev_err(adc->pcf->dev,
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"adc driver removed with request pending\n");
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for (i = 0; i < PCF50633_MAX_ADC_FIFO_DEPTH; i++)
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kfree(adc->queue[i]);
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mutex_unlock(&adc->queue_mutex);
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kfree(adc);
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return 0;
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}
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static struct platform_driver pcf50633_adc_driver = {
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.driver = {
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.name = "pcf50633-adc",
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},
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.probe = pcf50633_adc_probe,
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.remove = __devexit_p(pcf50633_adc_remove),
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};
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static int __init pcf50633_adc_init(void)
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{
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return platform_driver_register(&pcf50633_adc_driver);
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}
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module_init(pcf50633_adc_init);
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static void __exit pcf50633_adc_exit(void)
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{
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platform_driver_unregister(&pcf50633_adc_driver);
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}
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module_exit(pcf50633_adc_exit);
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MODULE_AUTHOR("Balaji Rao <balajirrao@openmoko.org>");
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MODULE_DESCRIPTION("PCF50633 adc driver");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:pcf50633-adc");
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