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/module.h> 21 #include <linux/init.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 int result; 33 void (*callback)(struct pcf50633 *, void *, int); 34 void *callback_param; 35 36 /* Used in case of sync requests */ 37 struct completion completion; 38 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 mutex_lock(&adc->queue_mutex); 77 78 head = adc->queue_head; 79 80 if (!adc->queue[head]) { 81 mutex_unlock(&adc->queue_mutex); 82 return; 83 } 84 mutex_unlock(&adc->queue_mutex); 85 86 adc_setup(pcf, adc->queue[head]->mux, adc->queue[head]->avg); 87 } 88 89 static int 90 adc_enqueue_request(struct pcf50633 *pcf, struct pcf50633_adc_request *req) 91 { 92 struct pcf50633_adc *adc = __to_adc(pcf); 93 int head, tail; 94 95 mutex_lock(&adc->queue_mutex); 96 97 head = adc->queue_head; 98 tail = adc->queue_tail; 99 100 if (adc->queue[tail]) { 101 mutex_unlock(&adc->queue_mutex); 102 return -EBUSY; 103 } 104 105 adc->queue[tail] = req; 106 adc->queue_tail = (tail + 1) & (PCF50633_MAX_ADC_FIFO_DEPTH - 1); 107 108 mutex_unlock(&adc->queue_mutex); 109 110 trigger_next_adc_job_if_any(pcf); 111 112 return 0; 113 } 114 115 static void 116 pcf50633_adc_sync_read_callback(struct pcf50633 *pcf, void *param, int result) 117 { 118 struct pcf50633_adc_request *req = param; 119 120 req->result = result; 121 complete(&req->completion); 122 } 123 124 int pcf50633_adc_sync_read(struct pcf50633 *pcf, int mux, int avg) 125 { 126 struct pcf50633_adc_request *req; 127 128 /* req is freed when the result is ready, in interrupt handler */ 129 req = kzalloc(sizeof(*req), GFP_KERNEL); 130 if (!req) 131 return -ENOMEM; 132 133 req->mux = mux; 134 req->avg = avg; 135 req->callback = pcf50633_adc_sync_read_callback; 136 req->callback_param = req; 137 138 init_completion(&req->completion); 139 adc_enqueue_request(pcf, req); 140 wait_for_completion(&req->completion); 141 142 return req->result; 143 } 144 EXPORT_SYMBOL_GPL(pcf50633_adc_sync_read); 145 146 int pcf50633_adc_async_read(struct pcf50633 *pcf, int mux, int avg, 147 void (*callback)(struct pcf50633 *, void *, int), 148 void *callback_param) 149 { 150 struct pcf50633_adc_request *req; 151 152 /* req is freed when the result is ready, in interrupt handler */ 153 req = kmalloc(sizeof(*req), GFP_KERNEL); 154 if (!req) 155 return -ENOMEM; 156 157 req->mux = mux; 158 req->avg = avg; 159 req->callback = callback; 160 req->callback_param = callback_param; 161 162 adc_enqueue_request(pcf, req); 163 164 return 0; 165 } 166 EXPORT_SYMBOL_GPL(pcf50633_adc_async_read); 167 168 static int adc_result(struct pcf50633 *pcf) 169 { 170 u8 adcs1, adcs3; 171 u16 result; 172 173 adcs1 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS1); 174 adcs3 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS3); 175 result = (adcs1 << 2) | (adcs3 & PCF50633_ADCS3_ADCDAT1L_MASK); 176 177 dev_dbg(pcf->dev, "adc result = %d\n", result); 178 179 return result; 180 } 181 182 static void pcf50633_adc_irq(int irq, void *data) 183 { 184 struct pcf50633_adc *adc = data; 185 struct pcf50633 *pcf = adc->pcf; 186 struct pcf50633_adc_request *req; 187 int head; 188 189 mutex_lock(&adc->queue_mutex); 190 head = adc->queue_head; 191 192 req = adc->queue[head]; 193 if (WARN_ON(!req)) { 194 dev_err(pcf->dev, "pcf50633-adc irq: ADC queue empty!\n"); 195 mutex_unlock(&adc->queue_mutex); 196 return; 197 } 198 adc->queue[head] = NULL; 199 adc->queue_head = (head + 1) & 200 (PCF50633_MAX_ADC_FIFO_DEPTH - 1); 201 202 mutex_unlock(&adc->queue_mutex); 203 204 req->callback(pcf, req->callback_param, adc_result(pcf)); 205 kfree(req); 206 207 trigger_next_adc_job_if_any(pcf); 208 } 209 210 static int __devinit pcf50633_adc_probe(struct platform_device *pdev) 211 { 212 struct pcf50633_subdev_pdata *pdata = pdev->dev.platform_data; 213 struct pcf50633_adc *adc; 214 215 adc = kzalloc(sizeof(*adc), GFP_KERNEL); 216 if (!adc) 217 return -ENOMEM; 218 219 adc->pcf = pdata->pcf; 220 platform_set_drvdata(pdev, adc); 221 222 pcf50633_register_irq(pdata->pcf, PCF50633_IRQ_ADCRDY, 223 pcf50633_adc_irq, adc); 224 225 mutex_init(&adc->queue_mutex); 226 227 return 0; 228 } 229 230 static int __devexit pcf50633_adc_remove(struct platform_device *pdev) 231 { 232 struct pcf50633_adc *adc = platform_get_drvdata(pdev); 233 int i, head; 234 235 pcf50633_free_irq(adc->pcf, PCF50633_IRQ_ADCRDY); 236 237 mutex_lock(&adc->queue_mutex); 238 head = adc->queue_head; 239 240 if (WARN_ON(adc->queue[head])) 241 dev_err(adc->pcf->dev, 242 "adc driver removed with request pending\n"); 243 244 for (i = 0; i < PCF50633_MAX_ADC_FIFO_DEPTH; i++) 245 kfree(adc->queue[i]); 246 247 mutex_unlock(&adc->queue_mutex); 248 kfree(adc); 249 250 return 0; 251 } 252 253 static struct platform_driver pcf50633_adc_driver = { 254 .driver = { 255 .name = "pcf50633-adc", 256 }, 257 .probe = pcf50633_adc_probe, 258 .remove = __devexit_p(pcf50633_adc_remove), 259 }; 260 261 static int __init pcf50633_adc_init(void) 262 { 263 return platform_driver_register(&pcf50633_adc_driver); 264 } 265 module_init(pcf50633_adc_init); 266 267 static void __exit pcf50633_adc_exit(void) 268 { 269 platform_driver_unregister(&pcf50633_adc_driver); 270 } 271 module_exit(pcf50633_adc_exit); 272 273 MODULE_AUTHOR("Balaji Rao <balajirrao@openmoko.org>"); 274 MODULE_DESCRIPTION("PCF50633 adc driver"); 275 MODULE_LICENSE("GPL"); 276 MODULE_ALIAS("platform:pcf50633-adc"); 277 278