mfd: PCF50633 adc driver
Balaji Rao [Fri, 9 Jan 2009 00:49:26 +0000 (01:49 +0100)]
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>
Acked-by: Jonathan Cameron <jonathan.cameron@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@openedhand.com>

drivers/mfd/Kconfig
drivers/mfd/Makefile
drivers/mfd/pcf50633-adc.c [new file with mode: 0644]
include/linux/mfd/pcf50633/adc.h [new file with mode: 0644]

index 3ac32e4..2fa3504 100644 (file)
@@ -226,6 +226,13 @@ 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"
index 23d4d10..138f9c4 100644 (file)
@@ -38,4 +38,5 @@ obj-$(CONFIG_UCB1400_CORE)    += ucb1400_core.o
 
 obj-$(CONFIG_PMIC_DA903X)      += da903x.o
 
-obj-$(CONFIG_MFD_PCF50633)     += pcf50633-core.o
\ No newline at end of file
+obj-$(CONFIG_MFD_PCF50633)     += pcf50633-core.o
+obj-$(CONFIG_PCF50633_ADC)     += pcf50633-adc.o
\ No newline at end of file
diff --git a/drivers/mfd/pcf50633-adc.c b/drivers/mfd/pcf50633-adc.c
new file mode 100644 (file)
index 0000000..c2d05be
--- /dev/null
@@ -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_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_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 (file)
index 0000000..56669b4
--- /dev/null
@@ -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 */