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Subject[PATCH v3 4/5] IIO : ADC: tiadc: Add support of TI's ADC driver
Date
This patch adds support for TI's ADC driver.
This is a multifunctional device.
Analog input lines are provided on which
voltage measurements can be carried out.
You can have upto 8 input lines.

Signed-off-by: Patil, Rachna <rachna@ti.com>
---
Changes in v2:
Addressed review comments from Matthias Kaehlcke

Changes in v3:
Addressed review comments from Jonathan Cameron.
Added comments, new line appropriately.

drivers/iio/adc/Kconfig | 7 +
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/ti_adc.c | 223 ++++++++++++++++++++++++++++++++++
drivers/mfd/ti_tscadc.c | 18 +++-
include/linux/mfd/ti_tscadc.h | 9 ++-
include/linux/platform_data/ti_adc.h | 14 ++
6 files changed, 270 insertions(+), 2 deletions(-)
create mode 100644 drivers/iio/adc/ti_adc.c
create mode 100644 include/linux/platform_data/ti_adc.h

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 8a78b4f..ad32df8 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -22,4 +22,11 @@ config AT91_ADC
help
Say yes here to build support for Atmel AT91 ADC.

+config TI_ADC
+ tristate "TI's ADC driver"
+ depends on ARCH_OMAP2PLUS
+ help
+ Say yes here to build support for Texas Instruments ADC
+ driver which is also a MFD client.
+
endmenu
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 52eec25..a930cee 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -4,3 +4,4 @@

obj-$(CONFIG_AD7266) += ad7266.o
obj-$(CONFIG_AT91_ADC) += at91_adc.o
+obj-$(CONFIG_TI_ADC) += ti_adc.o
diff --git a/drivers/iio/adc/ti_adc.c b/drivers/iio/adc/ti_adc.c
new file mode 100644
index 0000000..56f8af2
--- /dev/null
+++ b/drivers/iio/adc/ti_adc.c
@@ -0,0 +1,223 @@
+/*
+ * 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_tscadc.h>
+#include <linux/platform_data/ti_adc.h>
+
+struct adc_device {
+ struct ti_tscadc_dev *mfd_tscadc;
+ struct iio_dev *idev;
+ int channels;
+};
+
+static unsigned int adc_readl(struct adc_device *adc, unsigned int reg)
+{
+ return readl(adc->mfd_tscadc->tscadc_base + reg);
+}
+
+static void adc_writel(struct adc_device *adc, unsigned int reg,
+ unsigned int val)
+{
+ writel(val, adc->mfd_tscadc->tscadc_base + reg);
+}
+
+static void adc_step_config(struct adc_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++) {
+ adc_writel(adc_dev, REG_STEPCONFIG(i),
+ stepconfig | STEPCONFIG_INP(channels));
+ adc_writel(adc_dev, REG_STEPDELAY(i),
+ STEPCONFIG_OPENDLY);
+ channels++;
+ }
+ adc_writel(adc_dev, REG_SE, STPENB_STEPENB);
+}
+
+static int tiadc_channel_init(struct iio_dev *idev, int channels)
+{
+ struct iio_chan_spec *chan_array;
+ int i;
+
+ idev->num_channels = channels;
+ chan_array = kcalloc(idev->num_channels, sizeof(struct iio_chan_spec),
+ GFP_KERNEL);
+
+ if (chan_array == NULL)
+ return -ENOMEM;
+
+ for (i = 0; i < (idev->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;
+ }
+
+ idev->channels = chan_array;
+
+ return idev->num_channels;
+}
+
+static void tiadc_channels_remove(struct iio_dev *idev)
+{
+ kfree(idev->channels);
+}
+
+static int tiadc_read_raw(struct iio_dev *idev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct adc_device *adc_dev = iio_priv(idev);
+ 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 = adc_readl(adc_dev, REG_FIFO1CNT);
+ for (i = 0; i < fifo1count; i++) {
+ readx1 = adc_readl(adc_dev, REG_FIFO1);
+ if (i == chan->channel)
+ *val = readx1 & 0xfff;
+ }
+ adc_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 *idev;
+ int err;
+ struct adc_device *adc_dev;
+ struct ti_tscadc_dev *tscadc_dev = pdev->dev.platform_data;
+ struct mfd_tscadc_board *pdata;
+
+ pdata = (struct mfd_tscadc_board *)tscadc_dev->dev->platform_data;
+ if (!pdata || !pdata->adc_init) {
+ dev_err(tscadc_dev->dev, "Could not find platform data\n");
+ return -EINVAL;
+ }
+
+ idev = iio_device_alloc(sizeof(struct adc_device));
+ if (idev == NULL) {
+ dev_err(&pdev->dev, "failed to allocate iio device.\n");
+ err = -ENOMEM;
+ goto err_ret;
+ }
+ adc_dev = iio_priv(idev);
+
+ tscadc_dev->adc = adc_dev;
+ adc_dev->mfd_tscadc = tscadc_dev;
+ adc_dev->idev = idev;
+ adc_dev->channels = pdata->adc_init->adc_channels;
+
+ idev->dev.parent = &pdev->dev;
+ idev->name = dev_name(&pdev->dev);
+ idev->modes = INDIO_DIRECT_MODE;
+ idev->info = &tiadc_info;
+
+ adc_step_config(adc_dev);
+
+ err = tiadc_channel_init(idev, adc_dev->channels);
+ if (err < 0)
+ goto err_free_device;
+
+ err = iio_device_register(idev);
+ if (err)
+ goto err_free_channels;
+
+ dev_info(&pdev->dev, "attached adc driver\n");
+ platform_set_drvdata(pdev, idev);
+
+ return 0;
+
+err_free_channels:
+ tiadc_channels_remove(idev);
+err_free_device:
+ iio_device_free(idev);
+err_ret:
+ return err;
+}
+
+static int __devexit tiadc_remove(struct platform_device *pdev)
+{
+ struct ti_tscadc_dev *tscadc_dev = pdev->dev.platform_data;
+ struct adc_device *adc_dev = tscadc_dev->adc;
+ struct iio_dev *idev = adc_dev->idev;
+
+ iio_device_unregister(idev);
+ tiadc_channels_remove(idev);
+
+ tscadc_dev->adc = NULL;
+ iio_device_free(idev);
+
+ return 0;
+}
+
+static struct platform_driver tiadc_driver = {
+ .driver = {
+ .name = "tiadc",
+ .owner = THIS_MODULE,
+ },
+ .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");
diff --git a/drivers/mfd/ti_tscadc.c b/drivers/mfd/ti_tscadc.c
index f26e53b..9dbd6d0 100644
--- a/drivers/mfd/ti_tscadc.c
+++ b/drivers/mfd/ti_tscadc.c
@@ -23,6 +23,7 @@
#include <linux/pm_runtime.h>
#include <linux/mfd/ti_tscadc.h>
#include <linux/input/ti_tsc.h>
+#include <linux/platform_data/ti_adc.h>

static unsigned int tscadc_readl(struct ti_tscadc_dev *tsadc, unsigned int reg)
{
@@ -55,14 +56,23 @@ static int __devinit ti_tscadc_probe(struct platform_device *pdev)
int irq;
int err, ctrl;
int clk_value, clock_rate;
- int tsc_wires;
+ int tsc_wires, adc_channels = 0, total_channels;

if (!pdata) {
dev_err(&pdev->dev, "Could not find platform data\n");
return -EINVAL;
}

+ if (pdata->adc_init)
+ adc_channels = pdata->adc_init->adc_channels;
+
tsc_wires = pdata->tsc_init->wires;
+ total_channels = tsc_wires + adc_channels;
+
+ if (total_channels > 8) {
+ dev_err(&pdev->dev, "Number of i/p channels more than 8\n");
+ return -EINVAL;
+ }

res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
@@ -149,6 +159,12 @@ static int __devinit ti_tscadc_probe(struct platform_device *pdev)
cell->platform_data = tscadc;
cell->pdata_size = sizeof(*tscadc);

+ /* ADC Cell */
+ cell = &tscadc->cells[ADC_CELL];
+ cell->name = "tiadc";
+ cell->platform_data = tscadc;
+ cell->pdata_size = sizeof(*tscadc);
+
err = mfd_add_devices(&pdev->dev, pdev->id, tscadc->cells,
TSCADC_CELLS, NULL, 0);
if (err < 0)
diff --git a/include/linux/mfd/ti_tscadc.h b/include/linux/mfd/ti_tscadc.h
index d28a35c..67b7d5e 100644
--- a/include/linux/mfd/ti_tscadc.h
+++ b/include/linux/mfd/ti_tscadc.h
@@ -117,15 +117,19 @@

#define ADC_CLK 3000000
#define MAX_CLK_DIV 7
+#define TOTAL_STEPS 16
+#define TOTAL_CHANNELS 8

-#define TSCADC_CELLS 1
+#define TSCADC_CELLS 2

enum tscadc_cells {
TSC_CELL,
+ ADC_CELL,
};

struct mfd_tscadc_board {
struct tsc_data *tsc_init;
+ struct adc_data *adc_init;
};

struct ti_tscadc_dev {
@@ -136,6 +140,9 @@ struct ti_tscadc_dev {

/* tsc device */
struct tscadc *tsc;
+
+ /* adc device */
+ struct adc_device *adc;
};

#endif
diff --git a/include/linux/platform_data/ti_adc.h b/include/linux/platform_data/ti_adc.h
new file mode 100644
index 0000000..5a89f1d
--- /dev/null
+++ b/include/linux/platform_data/ti_adc.h
@@ -0,0 +1,14 @@
+#ifndef __LINUX_TI_ADC_H
+#define __LINUX_TI_ADC_H
+
+/**
+ * struct adc_data ADC Input information
+ * @adc_channels: Number of analog inputs
+ * available for ADC.
+ */
+
+struct adc_data {
+ int adc_channels;
+};
+
+#endif
--
1.7.0.4


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