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1// SPDX-License-Identifier: GPL-2.0-or-later2/* NXP PCF50633 ADC Driver3 *4 * (C) 2006-2008 by Openmoko, Inc.5 * Author: Balaji Rao <balajirrao@openmoko.org>6 * All rights reserved.7 *8 * Broken down from monstrous PCF50633 driver mainly by9 * Harald Welte, Andy Green and Werner Almesberger10 *11 * NOTE: This driver does not yet support subtractive ADC mode, which means12 * you can do only one measurement per read request.13 */14 15#include <linux/kernel.h>16#include <linux/slab.h>17#include <linux/module.h>18#include <linux/device.h>19#include <linux/platform_device.h>20#include <linux/completion.h>21 22#include <linux/mfd/pcf50633/core.h>23#include <linux/mfd/pcf50633/adc.h>24 25struct pcf50633_adc_request {26 int mux;27 int avg;28 void (*callback)(struct pcf50633 *, void *, int);29 void *callback_param;30};31 32struct pcf50633_adc_sync_request {33 int result;34 struct completion completion;35};36 37#define PCF50633_MAX_ADC_FIFO_DEPTH 838 39struct pcf50633_adc {40 struct pcf50633 *pcf;41 42 /* Private stuff */43 struct pcf50633_adc_request *queue[PCF50633_MAX_ADC_FIFO_DEPTH];44 int queue_head;45 int queue_tail;46 struct mutex queue_mutex;47};48 49static inline struct pcf50633_adc *__to_adc(struct pcf50633 *pcf)50{51 return platform_get_drvdata(pcf->adc_pdev);52}53 54static void adc_setup(struct pcf50633 *pcf, int channel, int avg)55{56 channel &= PCF50633_ADCC1_ADCMUX_MASK;57 58 /* kill ratiometric, but enable ACCSW biasing */59 pcf50633_reg_write(pcf, PCF50633_REG_ADCC2, 0x00);60 pcf50633_reg_write(pcf, PCF50633_REG_ADCC3, 0x01);61 62 /* start ADC conversion on selected channel */63 pcf50633_reg_write(pcf, PCF50633_REG_ADCC1, channel | avg |64 PCF50633_ADCC1_ADCSTART | PCF50633_ADCC1_RES_10BIT);65}66 67static void trigger_next_adc_job_if_any(struct pcf50633 *pcf)68{69 struct pcf50633_adc *adc = __to_adc(pcf);70 int head;71 72 head = adc->queue_head;73 74 if (!adc->queue[head])75 return;76 77 adc_setup(pcf, adc->queue[head]->mux, adc->queue[head]->avg);78}79 80static int81adc_enqueue_request(struct pcf50633 *pcf, struct pcf50633_adc_request *req)82{83 struct pcf50633_adc *adc = __to_adc(pcf);84 int head, tail;85 86 mutex_lock(&adc->queue_mutex);87 88 head = adc->queue_head;89 tail = adc->queue_tail;90 91 if (adc->queue[tail]) {92 mutex_unlock(&adc->queue_mutex);93 dev_err(pcf->dev, "ADC queue is full, dropping request\n");94 return -EBUSY;95 }96 97 adc->queue[tail] = req;98 if (head == tail)99 trigger_next_adc_job_if_any(pcf);100 adc->queue_tail = (tail + 1) & (PCF50633_MAX_ADC_FIFO_DEPTH - 1);101 102 mutex_unlock(&adc->queue_mutex);103 104 return 0;105}106 107static void pcf50633_adc_sync_read_callback(struct pcf50633 *pcf, void *param,108 int result)109{110 struct pcf50633_adc_sync_request *req = param;111 112 req->result = result;113 complete(&req->completion);114}115 116int pcf50633_adc_sync_read(struct pcf50633 *pcf, int mux, int avg)117{118 struct pcf50633_adc_sync_request req;119 int ret;120 121 init_completion(&req.completion);122 123 ret = pcf50633_adc_async_read(pcf, mux, avg,124 pcf50633_adc_sync_read_callback, &req);125 if (ret)126 return ret;127 128 wait_for_completion(&req.completion);129 130 return req.result;131}132EXPORT_SYMBOL_GPL(pcf50633_adc_sync_read);133 134int pcf50633_adc_async_read(struct pcf50633 *pcf, int mux, int avg,135 void (*callback)(struct pcf50633 *, void *, int),136 void *callback_param)137{138 struct pcf50633_adc_request *req;139 int ret;140 141 /* req is freed when the result is ready, in interrupt handler */142 req = kmalloc(sizeof(*req), GFP_KERNEL);143 if (!req)144 return -ENOMEM;145 146 req->mux = mux;147 req->avg = avg;148 req->callback = callback;149 req->callback_param = callback_param;150 151 ret = adc_enqueue_request(pcf, req);152 if (ret)153 kfree(req);154 155 return ret;156}157EXPORT_SYMBOL_GPL(pcf50633_adc_async_read);158 159static int adc_result(struct pcf50633 *pcf)160{161 u8 adcs1, adcs3;162 u16 result;163 164 adcs1 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS1);165 adcs3 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS3);166 result = (adcs1 << 2) | (adcs3 & PCF50633_ADCS3_ADCDAT1L_MASK);167 168 dev_dbg(pcf->dev, "adc result = %d\n", result);169 170 return result;171}172 173static void pcf50633_adc_irq(int irq, void *data)174{175 struct pcf50633_adc *adc = data;176 struct pcf50633 *pcf = adc->pcf;177 struct pcf50633_adc_request *req;178 int head, res;179 180 mutex_lock(&adc->queue_mutex);181 head = adc->queue_head;182 183 req = adc->queue[head];184 if (WARN_ON(!req)) {185 dev_err(pcf->dev, "pcf50633-adc irq: ADC queue empty!\n");186 mutex_unlock(&adc->queue_mutex);187 return;188 }189 adc->queue[head] = NULL;190 adc->queue_head = (head + 1) &191 (PCF50633_MAX_ADC_FIFO_DEPTH - 1);192 193 res = adc_result(pcf);194 trigger_next_adc_job_if_any(pcf);195 196 mutex_unlock(&adc->queue_mutex);197 198 req->callback(pcf, req->callback_param, res);199 kfree(req);200}201 202static int pcf50633_adc_probe(struct platform_device *pdev)203{204 struct pcf50633_adc *adc;205 206 adc = devm_kzalloc(&pdev->dev, sizeof(*adc), GFP_KERNEL);207 if (!adc)208 return -ENOMEM;209 210 adc->pcf = dev_to_pcf50633(pdev->dev.parent);211 platform_set_drvdata(pdev, adc);212 213 pcf50633_register_irq(adc->pcf, PCF50633_IRQ_ADCRDY,214 pcf50633_adc_irq, adc);215 216 mutex_init(&adc->queue_mutex);217 218 return 0;219}220 221static void pcf50633_adc_remove(struct platform_device *pdev)222{223 struct pcf50633_adc *adc = platform_get_drvdata(pdev);224 int i, head;225 226 pcf50633_free_irq(adc->pcf, PCF50633_IRQ_ADCRDY);227 228 mutex_lock(&adc->queue_mutex);229 head = adc->queue_head;230 231 if (WARN_ON(adc->queue[head]))232 dev_err(adc->pcf->dev,233 "adc driver removed with request pending\n");234 235 for (i = 0; i < PCF50633_MAX_ADC_FIFO_DEPTH; i++)236 kfree(adc->queue[i]);237 238 mutex_unlock(&adc->queue_mutex);239}240 241static struct platform_driver pcf50633_adc_driver = {242 .driver = {243 .name = "pcf50633-adc",244 },245 .probe = pcf50633_adc_probe,246 .remove_new = pcf50633_adc_remove,247};248 249module_platform_driver(pcf50633_adc_driver);250 251MODULE_AUTHOR("Balaji Rao <balajirrao@openmoko.org>");252MODULE_DESCRIPTION("PCF50633 adc driver");253MODULE_LICENSE("GPL");254MODULE_ALIAS("platform:pcf50633-adc");255 256