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drivers/mfd/pcf50633-adc.c
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// SPDX-License-Identifier: GPL-2.0-or-later |
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/* NXP PCF50633 ADC Driver * * (C) 2006-2008 by Openmoko, Inc. * Author: Balaji Rao <balajirrao@openmoko.org> * All rights reserved. * * Broken down from monstrous PCF50633 driver mainly by * Harald Welte, Andy Green and Werner Almesberger * |
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* NOTE: This driver does not yet support subtractive ADC mode, which means * you can do only one measurement per read request. */ #include <linux/kernel.h> |
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#include <linux/slab.h> |
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#include <linux/module.h> |
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#include <linux/device.h> #include <linux/platform_device.h> #include <linux/completion.h> #include <linux/mfd/pcf50633/core.h> #include <linux/mfd/pcf50633/adc.h> struct pcf50633_adc_request { int mux; int avg; |
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void (*callback)(struct pcf50633 *, void *, int); void *callback_param; |
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}; |
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struct pcf50633_adc_sync_request { int result; |
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struct completion completion; |
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}; #define PCF50633_MAX_ADC_FIFO_DEPTH 8 struct pcf50633_adc { struct pcf50633 *pcf; /* Private stuff */ struct pcf50633_adc_request *queue[PCF50633_MAX_ADC_FIFO_DEPTH]; int queue_head; int queue_tail; struct mutex queue_mutex; }; static inline struct pcf50633_adc *__to_adc(struct pcf50633 *pcf) { return platform_get_drvdata(pcf->adc_pdev); } static void adc_setup(struct pcf50633 *pcf, int channel, int avg) { channel &= PCF50633_ADCC1_ADCMUX_MASK; /* kill ratiometric, but enable ACCSW biasing */ pcf50633_reg_write(pcf, PCF50633_REG_ADCC2, 0x00); pcf50633_reg_write(pcf, PCF50633_REG_ADCC3, 0x01); /* start ADC conversion on selected channel */ pcf50633_reg_write(pcf, PCF50633_REG_ADCC1, channel | avg | PCF50633_ADCC1_ADCSTART | PCF50633_ADCC1_RES_10BIT); } static void trigger_next_adc_job_if_any(struct pcf50633 *pcf) { struct pcf50633_adc *adc = __to_adc(pcf); 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); } static int adc_enqueue_request(struct pcf50633 *pcf, struct pcf50633_adc_request *req) { struct pcf50633_adc *adc = __to_adc(pcf); int head, tail; mutex_lock(&adc->queue_mutex); head = adc->queue_head; tail = adc->queue_tail; if (adc->queue[tail]) { mutex_unlock(&adc->queue_mutex); |
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dev_err(pcf->dev, "ADC queue is full, dropping request "); |
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return -EBUSY; } adc->queue[tail] = req; |
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if (head == tail) trigger_next_adc_job_if_any(pcf); |
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adc->queue_tail = (tail + 1) & (PCF50633_MAX_ADC_FIFO_DEPTH - 1); mutex_unlock(&adc->queue_mutex); |
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return 0; } |
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static void pcf50633_adc_sync_read_callback(struct pcf50633 *pcf, void *param, int result) |
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{ |
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struct pcf50633_adc_sync_request *req = param; |
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req->result = result; complete(&req->completion); } int pcf50633_adc_sync_read(struct pcf50633 *pcf, int mux, int avg) { |
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struct pcf50633_adc_sync_request req; int ret; |
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init_completion(&req.completion); |
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ret = pcf50633_adc_async_read(pcf, mux, avg, pcf50633_adc_sync_read_callback, &req); if (ret) return ret; |
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wait_for_completion(&req.completion); |
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return req.result; |
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} EXPORT_SYMBOL_GPL(pcf50633_adc_sync_read); int pcf50633_adc_async_read(struct pcf50633 *pcf, int mux, int avg, void (*callback)(struct pcf50633 *, void *, int), void *callback_param) { struct pcf50633_adc_request *req; /* req is freed when the result is ready, in interrupt handler */ req = kmalloc(sizeof(*req), GFP_KERNEL); if (!req) return -ENOMEM; req->mux = mux; req->avg = avg; req->callback = callback; req->callback_param = callback_param; |
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return adc_enqueue_request(pcf, req); |
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} EXPORT_SYMBOL_GPL(pcf50633_adc_async_read); static int adc_result(struct pcf50633 *pcf) { u8 adcs1, adcs3; u16 result; adcs1 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS1); adcs3 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS3); result = (adcs1 << 2) | (adcs3 & PCF50633_ADCS3_ADCDAT1L_MASK); dev_dbg(pcf->dev, "adc result = %d ", result); return result; } static void pcf50633_adc_irq(int irq, void *data) { struct pcf50633_adc *adc = data; struct pcf50633 *pcf = adc->pcf; struct pcf50633_adc_request *req; |
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int head, res; |
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mutex_lock(&adc->queue_mutex); head = adc->queue_head; req = adc->queue[head]; if (WARN_ON(!req)) { dev_err(pcf->dev, "pcf50633-adc irq: ADC queue empty! "); mutex_unlock(&adc->queue_mutex); return; } adc->queue[head] = NULL; adc->queue_head = (head + 1) & (PCF50633_MAX_ADC_FIFO_DEPTH - 1); |
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res = adc_result(pcf); 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 pcf50633_adc_probe(struct platform_device *pdev) |
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{ |
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struct pcf50633_adc *adc; |
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adc = devm_kzalloc(&pdev->dev, sizeof(*adc), GFP_KERNEL); |
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if (!adc) 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); mutex_init(&adc->queue_mutex); return 0; } |
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static int pcf50633_adc_remove(struct platform_device *pdev) |
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{ struct pcf50633_adc *adc = platform_get_drvdata(pdev); int i, head; pcf50633_free_irq(adc->pcf, PCF50633_IRQ_ADCRDY); mutex_lock(&adc->queue_mutex); head = adc->queue_head; if (WARN_ON(adc->queue[head])) dev_err(adc->pcf->dev, "adc driver removed with request pending "); for (i = 0; i < PCF50633_MAX_ADC_FIFO_DEPTH; i++) kfree(adc->queue[i]); mutex_unlock(&adc->queue_mutex); |
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return 0; } static struct platform_driver pcf50633_adc_driver = { .driver = { .name = "pcf50633-adc", }, .probe = pcf50633_adc_probe, |
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.remove = pcf50633_adc_remove, |
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}; |
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module_platform_driver(pcf50633_adc_driver); |
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MODULE_AUTHOR("Balaji Rao <balajirrao@openmoko.org>"); MODULE_DESCRIPTION("PCF50633 adc driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:pcf50633-adc"); |