1 files changed, 260 insertions, 0 deletions

diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
new file mode 100644
index 000000000000..02a43c87a8a3
--- /dev/null
+++ b/drivers/iio/adc/ti_am335x_adc.c
@@ -0,0 +1,260 @@
+/*
+ * TI ADC MFD driver
+ *
+ * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
+ *
+ * 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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/iio/iio.h>
+
+#include <linux/mfd/ti_am335x_tscadc.h>
+#include <linux/platform_data/ti_am335x_adc.h>
+
+struct tiadc_device {
+        struct ti_tscadc_dev *mfd_tscadc;
+        int channels;
+};
+
+static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
+{
+        return readl(adc->mfd_tscadc->tscadc_base + reg);
+}
+
+static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
+                                        unsigned int val)
+{
+        writel(val, adc->mfd_tscadc->tscadc_base + reg);
+}
+
+static void tiadc_step_config(struct tiadc_device *adc_dev)
+{
+        unsigned int stepconfig;
+        int i, channels = 0, steps;
+
+        /*
+         * There are 16 configurable steps and 8 analog input
+         * lines available which are shared between Touchscreen and ADC.
+         *
+         * Steps backwards i.e. from 16 towards 0 are used by ADC
+         * depending on number of input lines needed.
+         * Channel would represent which analog input
+         * needs to be given to ADC to digitalize data.
+         */
+
+        steps = TOTAL_STEPS - adc_dev->channels;
+        channels = TOTAL_CHANNELS - adc_dev->channels;
+
+        stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
+
+        for (i = (steps + 1); i <= TOTAL_STEPS; i++) {
+                tiadc_writel(adc_dev, REG_STEPCONFIG(i),
+                                stepconfig | STEPCONFIG_INP(channels));
+                tiadc_writel(adc_dev, REG_STEPDELAY(i),
+                                STEPCONFIG_OPENDLY);
+                channels++;
+        }
+        tiadc_writel(adc_dev, REG_SE, STPENB_STEPENB);
+}
+
+static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
+{
+        struct iio_chan_spec *chan_array;
+        int i;
+
+        indio_dev->num_channels = channels;
+        chan_array = kcalloc(indio_dev->num_channels,
+                        sizeof(struct iio_chan_spec), GFP_KERNEL);
+
+        if (chan_array == NULL)
+                return -ENOMEM;
+
+        for (i = 0; i < (indio_dev->num_channels); i++) {
+                struct iio_chan_spec *chan = chan_array + i;
+                chan->type = IIO_VOLTAGE;
+                chan->indexed = 1;
+                chan->channel = i;
+                chan->info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT;
+        }
+
+        indio_dev->channels = chan_array;
+
+        return indio_dev->num_channels;
+}
+
+static void tiadc_channels_remove(struct iio_dev *indio_dev)
+{
+        kfree(indio_dev->channels);
+}
+
+static int tiadc_read_raw(struct iio_dev *indio_dev,
+                struct iio_chan_spec const *chan,
+                int *val, int *val2, long mask)
+{
+        struct tiadc_device *adc_dev = iio_priv(indio_dev);
+        int i;
+        unsigned int fifo1count, readx1;
+
+        /*
+         * When the sub-system is first enabled,
+         * the sequencer will always start with the
+         * lowest step (1) and continue until step (16).
+         * For ex: If we have enabled 4 ADC channels and
+         * currently use only 1 out of them, the
+         * sequencer still configures all the 4 steps,
+         * leading to 3 unwanted data.
+         * Hence we need to flush out this data.
+         */
+
+        fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
+        for (i = 0; i < fifo1count; i++) {
+                readx1 = tiadc_readl(adc_dev, REG_FIFO1);
+                if (i == chan->channel)
+                        *val = readx1 & 0xfff;
+        }
+        tiadc_writel(adc_dev, REG_SE, STPENB_STEPENB);
+
+        return IIO_VAL_INT;
+}
+
+static const struct iio_info tiadc_info = {
+        .read_raw = &tiadc_read_raw,
+};
+
+static int __devinit tiadc_probe(struct platform_device *pdev)
+{
+        struct iio_dev          *indio_dev;
+        struct tiadc_device     *adc_dev;
+        struct ti_tscadc_dev    *tscadc_dev = pdev->dev.platform_data;
+        struct mfd_tscadc_board *pdata;
+        int                     err;
+
+        pdata = tscadc_dev->dev->platform_data;
+        if (!pdata || !pdata->adc_init) {
+                dev_err(&pdev->dev, "Could not find platform data\n");
+                return -EINVAL;
+        }
+
+        indio_dev = iio_device_alloc(sizeof(struct tiadc_device));
+        if (indio_dev == NULL) {
+                dev_err(&pdev->dev, "failed to allocate iio device\n");
+                err = -ENOMEM;
+                goto err_ret;
+        }
+        adc_dev = iio_priv(indio_dev);
+
+        adc_dev->mfd_tscadc = tscadc_dev;
+        adc_dev->channels = pdata->adc_init->adc_channels;
+
+        indio_dev->dev.parent = &pdev->dev;
+        indio_dev->name = dev_name(&pdev->dev);
+        indio_dev->modes = INDIO_DIRECT_MODE;
+        indio_dev->info = &tiadc_info;
+
+        tiadc_step_config(adc_dev);
+
+        err = tiadc_channel_init(indio_dev, adc_dev->channels);
+        if (err < 0)
+                goto err_free_device;
+
+        err = iio_device_register(indio_dev);
+        if (err)
+                goto err_free_channels;
+
+        platform_set_drvdata(pdev, indio_dev);
+
+        return 0;
+
+err_free_channels:
+        tiadc_channels_remove(indio_dev);
+err_free_device:
+        iio_device_free(indio_dev);
+err_ret:
+        return err;
+}
+
+static int __devexit tiadc_remove(struct platform_device *pdev)
+{
+        struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+
+        iio_device_unregister(indio_dev);
+        tiadc_channels_remove(indio_dev);
+
+        iio_device_free(indio_dev);
+
+        return 0;
+}
+
+#ifdef CONFIG_PM
+static int tiadc_suspend(struct device *dev)
+{
+        struct iio_dev *indio_dev = dev_get_drvdata(dev);
+        struct tiadc_device *adc_dev = iio_priv(indio_dev);
+        struct ti_tscadc_dev *tscadc_dev = dev->platform_data;
+        unsigned int idle;
+
+        if (!device_may_wakeup(tscadc_dev->dev)) {
+                idle = tiadc_readl(adc_dev, REG_CTRL);
+                idle &= ~(CNTRLREG_TSCSSENB);
+                tiadc_writel(adc_dev, REG_CTRL, (idle |
+                                CNTRLREG_POWERDOWN));
+        }
+
+        return 0;
+}
+
+static int tiadc_resume(struct device *dev)
+{
+        struct iio_dev *indio_dev = dev_get_drvdata(dev);
+        struct tiadc_device *adc_dev = iio_priv(indio_dev);
+        unsigned int restore;
+
+        /* Make sure ADC is powered up */
+        restore = tiadc_readl(adc_dev, REG_CTRL);
+        restore &= ~(CNTRLREG_POWERDOWN);
+        tiadc_writel(adc_dev, REG_CTRL, restore);
+
+        tiadc_step_config(adc_dev);
+
+        return 0;
+}
+
+static const struct dev_pm_ops tiadc_pm_ops = {
+        .suspend = tiadc_suspend,
+        .resume = tiadc_resume,
+};
+#define TIADC_PM_OPS (&tiadc_pm_ops)
+#else
+#define TIADC_PM_OPS NULL
+#endif
+
+static struct platform_driver tiadc_driver = {
+        .driver = {
+                .name   = "tiadc",
+                .owner  = THIS_MODULE,
+                .pm     = TIADC_PM_OPS,
+        },
+        .probe  = tiadc_probe,
+        .remove = __devexit_p(tiadc_remove),
+};
+
+module_platform_driver(tiadc_driver);
+
+MODULE_DESCRIPTION("TI ADC controller driver");
+MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
+MODULE_LICENSE("GPL");