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 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 112 pcf50633_adc_sync_read_callback(struct pcf50633 *pcf, void *param, int result) 113 { 114 struct pcf50633_adc_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_request *req; 123 int err; 124 125 /* req is freed when the result is ready, in interrupt handler */ 126 req = kzalloc(sizeof(*req), GFP_KERNEL); 127 if (!req) 128 return -ENOMEM; 129 130 req->mux = mux; 131 req->avg = avg; 132 req->callback = pcf50633_adc_sync_read_callback; 133 req->callback_param = req; 134 135 init_completion(&req->completion); 136 err = adc_enqueue_request(pcf, req); 137 if (err) 138 return err; 139 140 wait_for_completion(&req->completion); 141 142 /* FIXME by this time req might be already freed */ 143 return req->result; 144 } 145 EXPORT_SYMBOL_GPL(pcf50633_adc_sync_read); 146 147 int pcf50633_adc_async_read(struct pcf50633 *pcf, int mux, int avg, 148 void (*callback)(struct pcf50633 *, void *, int), 149 void *callback_param) 150 { 151 struct pcf50633_adc_request *req; 152 153 /* req is freed when the result is ready, in interrupt handler */ 154 req = kmalloc(sizeof(*req), GFP_KERNEL); 155 if (!req) 156 return -ENOMEM; 157 158 req->mux = mux; 159 req->avg = avg; 160 req->callback = callback; 161 req->callback_param = callback_param; 162 163 return adc_enqueue_request(pcf, req); 164 } 165 EXPORT_SYMBOL_GPL(pcf50633_adc_async_read); 166 167 static int adc_result(struct pcf50633 *pcf) 168 { 169 u8 adcs1, adcs3; 170 u16 result; 171 172 adcs1 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS1); 173 adcs3 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS3); 174 result = (adcs1 << 2) | (adcs3 & PCF50633_ADCS3_ADCDAT1L_MASK); 175 176 dev_dbg(pcf->dev, "adc result = %d\n", result); 177 178 return result; 179 } 180 181 static void pcf50633_adc_irq(int irq, void *data) 182 { 183 struct pcf50633_adc *adc = data; 184 struct pcf50633 *pcf = adc->pcf; 185 struct pcf50633_adc_request *req; 186 int head, res; 187 188 mutex_lock(&adc->queue_mutex); 189 head = adc->queue_head; 190 191 req = adc->queue[head]; 192 if (WARN_ON(!req)) { 193 dev_err(pcf->dev, "pcf50633-adc irq: ADC queue empty!\n"); 194 mutex_unlock(&adc->queue_mutex); 195 return; 196 } 197 adc->queue[head] = NULL; 198 adc->queue_head = (head + 1) & 199 (PCF50633_MAX_ADC_FIFO_DEPTH - 1); 200 201 res = adc_result(pcf); 202 trigger_next_adc_job_if_any(pcf); 203 204 mutex_unlock(&adc->queue_mutex); 205 206 req->callback(pcf, req->callback_param, res); 207 kfree(req); 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