1 /* NXP PCF50633 ADC Driver 2 * 3 * (C) 2006-2008 by Openmoko, Inc. 4 * Author: Balaji Rao <balajirrao@openmoko.org> 5 * All rights reserved. 6 * 7 * Broken down from monstrous PCF50633 driver mainly by 8 * Harald Welte, Andy Green and Werner Almesberger 9 * 10 * This program is free software; you can redistribute it and/or modify it 11 * under the terms of the GNU General Public License as published by the 12 * Free Software Foundation; either version 2 of the License, or (at your 13 * option) any later version. 14 * 15 * NOTE: This driver does not yet support subtractive ADC mode, which means 16 * you can do only one measurement per read request. 17 */ 18 19 #include <linux/kernel.h> 20 #include <linux/slab.h> 21 #include <linux/module.h> 22 #include <linux/device.h> 23 #include <linux/platform_device.h> 24 #include <linux/completion.h> 25 26 #include <linux/mfd/pcf50633/core.h> 27 #include <linux/mfd/pcf50633/adc.h> 28 29 struct pcf50633_adc_request { 30 int mux; 31 int avg; 32 void (*callback)(struct pcf50633 *, void *, int); 33 void *callback_param; 34 }; 35 36 struct pcf50633_adc_sync_request { 37 int result; 38 struct completion completion; 39 }; 40 41 #define PCF50633_MAX_ADC_FIFO_DEPTH 8 42 43 struct pcf50633_adc { 44 struct pcf50633 *pcf; 45 46 /* Private stuff */ 47 struct pcf50633_adc_request *queue[PCF50633_MAX_ADC_FIFO_DEPTH]; 48 int queue_head; 49 int queue_tail; 50 struct mutex queue_mutex; 51 }; 52 53 static inline struct pcf50633_adc *__to_adc(struct pcf50633 *pcf) 54 { 55 return platform_get_drvdata(pcf->adc_pdev); 56 } 57 58 static void adc_setup(struct pcf50633 *pcf, int channel, int avg) 59 { 60 channel &= PCF50633_ADCC1_ADCMUX_MASK; 61 62 /* kill ratiometric, but enable ACCSW biasing */ 63 pcf50633_reg_write(pcf, PCF50633_REG_ADCC2, 0x00); 64 pcf50633_reg_write(pcf, PCF50633_REG_ADCC3, 0x01); 65 66 /* start ADC conversion on selected channel */ 67 pcf50633_reg_write(pcf, PCF50633_REG_ADCC1, channel | avg | 68 PCF50633_ADCC1_ADCSTART | PCF50633_ADCC1_RES_10BIT); 69 } 70 71 static void trigger_next_adc_job_if_any(struct pcf50633 *pcf) 72 { 73 struct pcf50633_adc *adc = __to_adc(pcf); 74 int head; 75 76 head = adc->queue_head; 77 78 if (!adc->queue[head]) 79 return; 80 81 adc_setup(pcf, adc->queue[head]->mux, adc->queue[head]->avg); 82 } 83 84 static int 85 adc_enqueue_request(struct pcf50633 *pcf, struct pcf50633_adc_request *req) 86 { 87 struct pcf50633_adc *adc = __to_adc(pcf); 88 int head, tail; 89 90 mutex_lock(&adc->queue_mutex); 91 92 head = adc->queue_head; 93 tail = adc->queue_tail; 94 95 if (adc->queue[tail]) { 96 mutex_unlock(&adc->queue_mutex); 97 dev_err(pcf->dev, "ADC queue is full, dropping request\n"); 98 return -EBUSY; 99 } 100 101 adc->queue[tail] = req; 102 if (head == tail) 103 trigger_next_adc_job_if_any(pcf); 104 adc->queue_tail = (tail + 1) & (PCF50633_MAX_ADC_FIFO_DEPTH - 1); 105 106 mutex_unlock(&adc->queue_mutex); 107 108 return 0; 109 } 110 111 static void pcf50633_adc_sync_read_callback(struct pcf50633 *pcf, void *param, 112 int result) 113 { 114 struct pcf50633_adc_sync_request *req = param; 115 116 req->result = result; 117 complete(&req->completion); 118 } 119 120 int pcf50633_adc_sync_read(struct pcf50633 *pcf, int mux, int avg) 121 { 122 struct pcf50633_adc_sync_request req; 123 int ret; 124 125 init_completion(&req.completion); 126 127 ret = pcf50633_adc_async_read(pcf, mux, avg, 128 pcf50633_adc_sync_read_callback, &req); 129 if (ret) 130 return ret; 131 132 wait_for_completion(&req.completion); 133 134 return req.result; 135 } 136 EXPORT_SYMBOL_GPL(pcf50633_adc_sync_read); 137 138 int pcf50633_adc_async_read(struct pcf50633 *pcf, int mux, int avg, 139 void (*callback)(struct pcf50633 *, void *, int), 140 void *callback_param) 141 { 142 struct pcf50633_adc_request *req; 143 144 /* req is freed when the result is ready, in interrupt handler */ 145 req = kmalloc(sizeof(*req), GFP_KERNEL); 146 if (!req) 147 return -ENOMEM; 148 149 req->mux = mux; 150 req->avg = avg; 151 req->callback = callback; 152 req->callback_param = callback_param; 153 154 return adc_enqueue_request(pcf, req); 155 } 156 EXPORT_SYMBOL_GPL(pcf50633_adc_async_read); 157 158 static int adc_result(struct pcf50633 *pcf) 159 { 160 u8 adcs1, adcs3; 161 u16 result; 162 163 adcs1 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS1); 164 adcs3 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS3); 165 result = (adcs1 << 2) | (adcs3 & PCF50633_ADCS3_ADCDAT1L_MASK); 166 167 dev_dbg(pcf->dev, "adc result = %d\n", result); 168 169 return result; 170 } 171 172 static void pcf50633_adc_irq(int irq, void *data) 173 { 174 struct pcf50633_adc *adc = data; 175 struct pcf50633 *pcf = adc->pcf; 176 struct pcf50633_adc_request *req; 177 int head, res; 178 179 mutex_lock(&adc->queue_mutex); 180 head = adc->queue_head; 181 182 req = adc->queue[head]; 183 if (WARN_ON(!req)) { 184 dev_err(pcf->dev, "pcf50633-adc irq: ADC queue empty!\n"); 185 mutex_unlock(&adc->queue_mutex); 186 return; 187 } 188 adc->queue[head] = NULL; 189 adc->queue_head = (head + 1) & 190 (PCF50633_MAX_ADC_FIFO_DEPTH - 1); 191 192 res = adc_result(pcf); 193 trigger_next_adc_job_if_any(pcf); 194 195 mutex_unlock(&adc->queue_mutex); 196 197 req->callback(pcf, req->callback_param, res); 198 kfree(req); 199 } 200 201 static int pcf50633_adc_probe(struct platform_device *pdev) 202 { 203 struct pcf50633_adc *adc; 204 205 adc = devm_kzalloc(&pdev->dev, sizeof(*adc), GFP_KERNEL); 206 if (!adc) 207 return -ENOMEM; 208 209 adc->pcf = dev_to_pcf50633(pdev->dev.parent); 210 platform_set_drvdata(pdev, adc); 211 212 pcf50633_register_irq(adc->pcf, PCF50633_IRQ_ADCRDY, 213 pcf50633_adc_irq, adc); 214 215 mutex_init(&adc->queue_mutex); 216 217 return 0; 218 } 219 220 static int pcf50633_adc_remove(struct platform_device *pdev) 221 { 222 struct pcf50633_adc *adc = platform_get_drvdata(pdev); 223 int i, head; 224 225 pcf50633_free_irq(adc->pcf, PCF50633_IRQ_ADCRDY); 226 227 mutex_lock(&adc->queue_mutex); 228 head = adc->queue_head; 229 230 if (WARN_ON(adc->queue[head])) 231 dev_err(adc->pcf->dev, 232 "adc driver removed with request pending\n"); 233 234 for (i = 0; i < PCF50633_MAX_ADC_FIFO_DEPTH; i++) 235 kfree(adc->queue[i]); 236 237 mutex_unlock(&adc->queue_mutex); 238 239 return 0; 240 } 241 242 static struct platform_driver pcf50633_adc_driver = { 243 .driver = { 244 .name = "pcf50633-adc", 245 }, 246 .probe = pcf50633_adc_probe, 247 .remove = pcf50633_adc_remove, 248 }; 249 250 module_platform_driver(pcf50633_adc_driver); 251 252 MODULE_AUTHOR("Balaji Rao <balajirrao@openmoko.org>"); 253 MODULE_DESCRIPTION("PCF50633 adc driver"); 254 MODULE_LICENSE("GPL"); 255 MODULE_ALIAS("platform:pcf50633-adc"); 256 257