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Subject[PATCH V2 2/7] mfd: PCF50633 adc driver
Date
This patch adds basic support for the PCF50633 ADC. The subtractive mode
is not supported yet.

Since we don't have adc subsystem, it currently lives in drivers/mfd.

Signed-off-by: Balaji Rao <balajirrao@openmoko.org>
Cc: Andy Green <andy@openmoko.com>
Cc: Samuel Ortiz <sameo@openedhand.com>
---
drivers/mfd/Kconfig | 7 +
drivers/mfd/Makefile | 1
drivers/mfd/pcf50633-adc.c | 277 ++++++++++++++++++++++++++++++++++++++
include/linux/mfd/pcf50633/adc.h | 72 ++++++++++
4 files changed, 357 insertions(+), 0 deletions(-)
create mode 100644 drivers/mfd/pcf50633-adc.c
create mode 100644 include/linux/mfd/pcf50633/adc.h

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index fb1f0f7..02e3d73 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -162,6 +162,13 @@ config MFD_PCF50633
facilities, and registers devices for the various functions
so that function-specific drivers can bind to them.

+config PCF50633_ADC
+ tristate "Support for NXP PCF50633 ADC"
+ depends on MFD_PCF50633
+ help
+ Say yes here if you want to include support for ADC in the
+ NXP PCF50633 chip.
+
endmenu

menu "Multimedia Capabilities Port drivers"
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 6a4add8..7a12b09 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -34,3 +34,4 @@ obj-$(CONFIG_UCB1400_CORE) += ucb1400_core.o
obj-$(CONFIG_PMIC_DA903X) += da903x.o

obj-$(CONFIG_MFD_PCF50633) += pcf50633-core.o
+obj-$(CONFIG_PCF50633_ADC) += pcf50633-adc.o
diff --git a/drivers/mfd/pcf50633-adc.c b/drivers/mfd/pcf50633-adc.c
new file mode 100644
index 0000000..f5f1fb0
--- /dev/null
+++ b/drivers/mfd/pcf50633-adc.c
@@ -0,0 +1,277 @@
+/* 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/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;
+ int result;
+ void (*callback)(struct pcf50633 *, void *, int);
+ void *callback_param;
+
+ /* Used in case of sync requests */
+ 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_read_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;
+
+ mutex_lock(&adc->queue_mutex);
+
+ head = adc->queue_head;
+
+ if (!adc->queue[head]) {
+ mutex_unlock(&adc->queue_mutex);
+ return;
+ }
+ mutex_unlock(&adc->queue_mutex);
+
+ adc_read_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);
+ return -EBUSY;
+ }
+
+ adc->queue[tail] = req;
+ adc->queue_tail = (tail + 1) & (PCF50633_MAX_ADC_FIFO_DEPTH - 1);
+
+ mutex_unlock(&adc->queue_mutex);
+
+ trigger_next_adc_job_if_any(pcf);
+
+ return 0;
+}
+
+static void
+pcf50633_adc_sync_read_callback(struct pcf50633 *pcf, void *param, int result)
+{
+ struct pcf50633_adc_request *req = param;
+
+ req->result = result;
+ complete(&req->completion);
+}
+
+int pcf50633_adc_sync_read(struct pcf50633 *pcf, int mux, int avg)
+{
+ struct pcf50633_adc_request *req;
+
+ /* req is freed when the result is ready, in interrupt handler */
+ req = kzalloc(sizeof(*req), GFP_KERNEL);
+ if (!req)
+ return -ENOMEM;
+
+ req->mux = mux;
+ req->avg = avg;
+ req->callback = pcf50633_adc_sync_read_callback;
+ req->callback_param = req;
+
+ init_completion(&req->completion);
+ adc_enqueue_request(pcf, req);
+ 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;
+
+ adc_enqueue_request(pcf, req);
+
+ return 0;
+}
+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;
+
+ 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);
+
+ mutex_unlock(&adc->queue_mutex);
+
+ req->callback(pcf, req->callback_param, adc_result(pcf));
+ kfree(req);
+
+ trigger_next_adc_job_if_any(pcf);
+}
+
+static int __devinit pcf50633_adc_probe(struct platform_device *pdev)
+{
+ struct pcf50633_subdev_pdata *pdata = pdev->dev.platform_data;
+ struct pcf50633_adc *adc;
+
+ adc = kzalloc(sizeof(*adc), GFP_KERNEL);
+ if (!adc)
+ return -ENOMEM;
+
+ adc->pcf = pdata->pcf;
+ platform_set_drvdata(pdev, adc);
+
+ pcf50633_register_irq(pdata->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");
+
diff --git a/include/linux/mfd/pcf50633/adc.h b/include/linux/mfd/pcf50633/adc.h
new file mode 100644
index 0000000..56669b4
--- /dev/null
+++ b/include/linux/mfd/pcf50633/adc.h
@@ -0,0 +1,72 @@
+/*
+ * adc.h -- Driver for NXP PCF50633 ADC
+ *
+ * (C) 2006-2008 by Openmoko, Inc.
+ * All rights reserved.
+ *
+ * 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.
+ */
+
+#ifndef __LINUX_MFD_PCF50633_ADC_H
+#define __LINUX_MFD_PCF50633_ADC_H
+
+#include <linux/mfd/pcf50633/core.h>
+#include <linux/platform_device.h>
+
+/* ADC Registers */
+#define PCF50633_REG_ADCC3 0x52
+#define PCF50633_REG_ADCC2 0x53
+#define PCF50633_REG_ADCC1 0x54
+#define PCF50633_REG_ADCS1 0x55
+#define PCF50633_REG_ADCS2 0x56
+#define PCF50633_REG_ADCS3 0x57
+
+#define PCF50633_ADCC1_ADCSTART 0x01
+#define PCF50633_ADCC1_RES_10BIT 0x02
+#define PCF50633_ADCC1_AVERAGE_NO 0x00
+#define PCF50633_ADCC1_AVERAGE_4 0x04
+#define PCF50633_ADCC1_AVERAGE_8 0x08
+#define PCF50633_ADCC1_AVERAGE_16 0x0c
+#define PCF50633_ADCC1_MUX_BATSNS_RES 0x00
+#define PCF50633_ADCC1_MUX_BATSNS_SUBTR 0x10
+#define PCF50633_ADCC1_MUX_ADCIN2_RES 0x20
+#define PCF50633_ADCC1_MUX_ADCIN2_SUBTR 0x30
+#define PCF50633_ADCC1_MUX_BATTEMP 0x60
+#define PCF50633_ADCC1_MUX_ADCIN1 0x70
+#define PCF50633_ADCC1_AVERAGE_MASK 0x0c
+#define PCF50633_ADCC1_ADCMUX_MASK 0xf0
+
+#define PCF50633_ADCC2_RATIO_NONE 0x00
+#define PCF50633_ADCC2_RATIO_BATTEMP 0x01
+#define PCF50633_ADCC2_RATIO_ADCIN1 0x02
+#define PCF50633_ADCC2_RATIO_BOTH 0x03
+#define PCF50633_ADCC2_RATIOSETTL_100US 0x04
+
+#define PCF50633_ADCC3_ACCSW_EN 0x01
+#define PCF50633_ADCC3_NTCSW_EN 0x04
+#define PCF50633_ADCC3_RES_DIV_TWO 0x10
+#define PCF50633_ADCC3_RES_DIV_THREE 0x00
+
+#define PCF50633_ADCS3_REF_NTCSW 0x00
+#define PCF50633_ADCS3_REF_ACCSW 0x10
+#define PCF50633_ADCS3_REF_2V0 0x20
+#define PCF50633_ADCS3_REF_VISA 0x30
+#define PCF50633_ADCS3_REF_2V0_2 0x70
+#define PCF50633_ADCS3_ADCRDY 0x80
+
+#define PCF50633_ADCS3_ADCDAT1L_MASK 0x03
+#define PCF50633_ADCS3_ADCDAT2L_MASK 0x0c
+#define PCF50633_ADCS3_ADCDAT2L_SHIFT 2
+#define PCF50633_ASCS3_REF_MASK 0x70
+
+extern int
+pcf50633_adc_async_read(struct pcf50633 *pcf, int mux, int avg,
+ void (*callback)(struct pcf50633 *, void *, int),
+ void *callback_param);
+extern int
+pcf50633_adc_sync_read(struct pcf50633 *pcf, int mux, int avg);
+
+#endif /* __LINUX_PCF50633_ADC_H */


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