diff options
Diffstat (limited to 'drivers/mfd/pcf50633-adc.c')
-rw-r--r-- | drivers/mfd/pcf50633-adc.c | 268 |
1 files changed, 268 insertions, 0 deletions
diff --git a/drivers/mfd/pcf50633-adc.c b/drivers/mfd/pcf50633-adc.c new file mode 100644 index 00000000..aed0d2a9 --- /dev/null +++ b/drivers/mfd/pcf50633-adc.c @@ -0,0 +1,268 @@ +/* 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 + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + * + * 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> +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/init.h> +#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; + void (*callback)(struct pcf50633 *, void *, int); + void *callback_param; +}; + +struct pcf50633_adc_sync_request { + int result; + struct completion completion; +}; + +#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; + + head = adc->queue_head; + + if (!adc->queue[head]) + return; + + 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); + dev_err(pcf->dev, "ADC queue is full, dropping request\n"); + return -EBUSY; + } + + adc->queue[tail] = req; + if (head == tail) + trigger_next_adc_job_if_any(pcf); + adc->queue_tail = (tail + 1) & (PCF50633_MAX_ADC_FIFO_DEPTH - 1); + + mutex_unlock(&adc->queue_mutex); + + return 0; +} + +static void pcf50633_adc_sync_read_callback(struct pcf50633 *pcf, void *param, + int result) +{ + struct pcf50633_adc_sync_request *req = param; + + req->result = result; + complete(&req->completion); +} + +int pcf50633_adc_sync_read(struct pcf50633 *pcf, int mux, int avg) +{ + struct pcf50633_adc_sync_request req; + int ret; + + init_completion(&req.completion); + + ret = pcf50633_adc_async_read(pcf, mux, avg, + pcf50633_adc_sync_read_callback, &req); + if (ret) + return ret; + + wait_for_completion(&req.completion); + + return req.result; +} +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; + + return adc_enqueue_request(pcf, req); +} +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\n", 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; + int head, res; + + 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!\n"); + mutex_unlock(&adc->queue_mutex); + return; + } + adc->queue[head] = NULL; + adc->queue_head = (head + 1) & + (PCF50633_MAX_ADC_FIFO_DEPTH - 1); + + res = adc_result(pcf); + trigger_next_adc_job_if_any(pcf); + + mutex_unlock(&adc->queue_mutex); + + req->callback(pcf, req->callback_param, res); + kfree(req); +} + +static int __devinit pcf50633_adc_probe(struct platform_device *pdev) +{ + struct pcf50633_adc *adc; + + adc = kzalloc(sizeof(*adc), GFP_KERNEL); + if (!adc) + return -ENOMEM; + + adc->pcf = dev_to_pcf50633(pdev->dev.parent); + platform_set_drvdata(pdev, adc); + + pcf50633_register_irq(adc->pcf, PCF50633_IRQ_ADCRDY, + pcf50633_adc_irq, adc); + + mutex_init(&adc->queue_mutex); + + return 0; +} + +static int __devexit pcf50633_adc_remove(struct platform_device *pdev) +{ + 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\n"); + + for (i = 0; i < PCF50633_MAX_ADC_FIFO_DEPTH; i++) + kfree(adc->queue[i]); + + mutex_unlock(&adc->queue_mutex); + kfree(adc); + + return 0; +} + +static struct platform_driver pcf50633_adc_driver = { + .driver = { + .name = "pcf50633-adc", + }, + .probe = pcf50633_adc_probe, + .remove = __devexit_p(pcf50633_adc_remove), +}; + +static int __init pcf50633_adc_init(void) +{ + return platform_driver_register(&pcf50633_adc_driver); +} +module_init(pcf50633_adc_init); + +static void __exit pcf50633_adc_exit(void) +{ + platform_driver_unregister(&pcf50633_adc_driver); +} +module_exit(pcf50633_adc_exit); + +MODULE_AUTHOR("Balaji Rao <balajirrao@openmoko.org>"); +MODULE_DESCRIPTION("PCF50633 adc driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:pcf50633-adc"); + |