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@xxxxxx> --- 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@xxxxxx>"); +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 -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
