[v6,1/4] mfd: mxs-lradc: Add support for mxs-lradc MFD

Commit Message

Ksenija Stanojevic Sept. 17, 2016, 10:48 a.m. UTC

Add core files for mxs-lradc MFD driver.

Note:  this patch won't compile in iio/testing without this patch:
a8f447be8056 ("mfd: Add resource managed APIs for mfd_add_devices")

Signed-off-by: Ksenija Stanojevic <[e-mail]>
---
Changes in v6:
 - update copyright
 - add kernel-doc header for struct mxs-lradc
 - add error message
 - change EINVAL to ENODEV
 - use PLATFORM_DEVID_NONE instead -1
 - cosmetic fixes

Changes in v5:
 - use DEFINE_RES_MEM
 - don't pass ioreammaped adress to platform cells
 - move comment outside of struct mxs_lradc
 - change type of argument in mxs_lradc_reg_set, mxs_lradc_reg_clear,
   mxs_lradc_reg_wrt (struct mxs_lradc * -> void __iomem *)

Changes in v4:
 - update copyright
 - use DEFINE_RES_IRQ_NAMED
 - remove mxs_lradc_add_device function
 - use struct mfd_cell in static form
 - improve spacing
 - remove unnecessary comment
 - remove platform_get_irq
 - remove touch_ret and use ret instead
 - rename use_touchscreen to touchscreen_wire
 - use goto statements
 - remove irq[13], irq_count and irq_name from struct mxs_lradc
 - remove all defines from inside the struct definition

Changes in v3:
 - add note to commit message
 - move switch statement into if(touch_ret == 0) branch
 - add MODULE_AUTHOR

Changes in v2:
 - do not change spacing in Kconfig
 - make struct mfd_cell part of struct mxs_lradc
 - use switch instead of if in mxs_lradc_irq_mask
 - use only necessary header files in mxs_lradc.h
 - use devm_mfd_add_device
 - use separate function to register mfd device
 - change licence to GPL
 - add copyright

 drivers/mfd/Kconfig           |  17 +++
 drivers/mfd/Makefile          |   1 +
 drivers/mfd/mxs-lradc.c       | 259 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/mfd/mxs-lradc.h | 203 +++++++++++++++++++++++++++++++++
 4 files changed, 480 insertions(+)
 create mode 100644 drivers/mfd/mxs-lradc.c
 create mode 100644 include/linux/mfd/mxs-lradc.h

Comments

Lee Jones Sept. 28, 2016, 1:05 a.m. UTC | #1

On Sat, 17 Sep 2016, Ksenija Stanojevic wrote:

> Add core files for mxs-lradc MFD driver.
> 
> Note:  this patch won't compile in iio/testing without this patch:
> a8f447be8056 ("mfd: Add resource managed APIs for mfd_add_devices")
> 
> Signed-off-by: Ksenija Stanojevic <[e-mail]>
> ---
> Changes in v6:
>  - update copyright
>  - add kernel-doc header for struct mxs-lradc
>  - add error message
>  - change EINVAL to ENODEV
>  - use PLATFORM_DEVID_NONE instead -1
>  - cosmetic fixes
> 
> Changes in v5:
>  - use DEFINE_RES_MEM
>  - don't pass ioreammaped adress to platform cells
>  - move comment outside of struct mxs_lradc
>  - change type of argument in mxs_lradc_reg_set, mxs_lradc_reg_clear,
>    mxs_lradc_reg_wrt (struct mxs_lradc * -> void __iomem *)
> 
> Changes in v4:
>  - update copyright
>  - use DEFINE_RES_IRQ_NAMED
>  - remove mxs_lradc_add_device function
>  - use struct mfd_cell in static form
>  - improve spacing
>  - remove unnecessary comment
>  - remove platform_get_irq
>  - remove touch_ret and use ret instead
>  - rename use_touchscreen to touchscreen_wire
>  - use goto statements
>  - remove irq[13], irq_count and irq_name from struct mxs_lradc
>  - remove all defines from inside the struct definition
> 
> Changes in v3:
>  - add note to commit message
>  - move switch statement into if(touch_ret == 0) branch
>  - add MODULE_AUTHOR
> 
> Changes in v2:
>  - do not change spacing in Kconfig
>  - make struct mfd_cell part of struct mxs_lradc
>  - use switch instead of if in mxs_lradc_irq_mask
>  - use only necessary header files in mxs_lradc.h
>  - use devm_mfd_add_device
>  - use separate function to register mfd device
>  - change licence to GPL
>  - add copyright
> 
>  drivers/mfd/Kconfig           |  17 +++
>  drivers/mfd/Makefile          |   1 +
>  drivers/mfd/mxs-lradc.c       | 259 ++++++++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/mxs-lradc.h | 203 +++++++++++++++++++++++++++++++++
>  4 files changed, 480 insertions(+)
>  create mode 100644 drivers/mfd/mxs-lradc.c
>  create mode 100644 include/linux/mfd/mxs-lradc.h
> 
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 9ca66de..ffe14ef 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -271,6 +271,23 @@ config MFD_MC13XXX_I2C
>  	help
>  	  Select this if your MC13xxx is connected via an I2C bus.
>  
> +config MFD_MXS_LRADC
> +	tristate "Freescale i.MX23/i.MX28 LRADC"
> +	depends on ARCH_MXS || COMPILE_TEST
> +	select MFD_CORE
> +	select STMP_DEVICE
> +	help
> +	  Say yes here to build support for the Low Resolution
> +	  Analog-to-Digital Converter (LRADC) found on the i.MX23 and i.MX28
> +	  processors. This driver provides common support for accessing the
> +	  device, additional drivers must be enabled in order to use the
> +	  functionality of the device:
> +		mxs-lradc-adc for ADC readings
> +		mxs-lradc-ts  for touchscreen support
> +
> +	  This driver can also be built as a module. If so, the module will be
> +	  called mxs-lradc.
> +
>  config MFD_HI6421_PMIC
>  	tristate "HiSilicon Hi6421 PMU/Codec IC"
>  	depends on OF
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 0f230a6..ecf6399 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -198,3 +198,4 @@ intel-soc-pmic-objs		:= intel_soc_pmic_core.o intel_soc_pmic_crc.o
>  intel-soc-pmic-$(CONFIG_INTEL_PMC_IPC)	+= intel_soc_pmic_bxtwc.o
>  obj-$(CONFIG_INTEL_SOC_PMIC)	+= intel-soc-pmic.o
>  obj-$(CONFIG_MFD_MT6397)	+= mt6397-core.o
> +obj-$(CONFIG_MFD_MXS_LRADC)	+= mxs-lradc.o
> diff --git a/drivers/mfd/mxs-lradc.c b/drivers/mfd/mxs-lradc.c
> new file mode 100644
> index 0000000..05ae894
> --- /dev/null
> +++ b/drivers/mfd/mxs-lradc.c
> @@ -0,0 +1,259 @@
> +/*
> + * Freescale MXS LRADC driver

Please use the full name here.  It's helpful if people are trying to
figure out what LRADC actually means.

> + * Copyright (c) 2012 DENX Software Engineering, GmbH.
> + * Copyright (c) 2016 Ksenija Stanojevic <[e-mail]>
> + *
> + * Authors:
> + *  Marek Vasut <[e-mail]>
> + *  Ksenija Stanojevic <[e-mail]>
> + *
> + * 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.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/device.h>
> +#include <linux/mfd/core.h>
> +#include <linux/mfd/mxs-lradc.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +#define MXS_LRADC_BASE		0x80050000
> +
> +enum mx23_lradc_irqs {
> +	MX23_LRADC_TS_IRQ = 0,
> +	MX23_LRADC_CH0_IRQ,
> +	MX23_LRADC_CH1_IRQ,
> +	MX23_LRADC_CH2_IRQ,
> +	MX23_LRADC_CH3_IRQ,
> +	MX23_LRADC_CH4_IRQ,
> +	MX23_LRADC_CH5_IRQ,
> +	MX23_LRADC_CH6_IRQ,
> +	MX23_LRADC_CH7_IRQ,
> +};
> +
> +enum mx28_lradc_irqs {
> +	MX28_LRADC_TS_IRQ = 0,
> +	MX28_LRADC_TRESH0_IRQ,
> +	MX28_LRADC_TRESH1_IRQ,
> +	MX28_LRADC_CH0_IRQ,
> +	MX28_LRADC_CH1_IRQ,
> +	MX28_LRADC_CH2_IRQ,
> +	MX28_LRADC_CH3_IRQ,
> +	MX28_LRADC_CH4_IRQ,
> +	MX28_LRADC_CH5_IRQ,
> +	MX28_LRADC_CH6_IRQ,
> +	MX28_LRADC_CH7_IRQ,
> +	MX28_LRADC_BUTTON0_IRQ,
> +	MX28_LRADC_BUTTON1_IRQ,
> +};
> +
> +static struct resource mx23_adc_resources[] = {
> +	DEFINE_RES_MEM(MXS_LRADC_BASE, 0x1fff),
> +	DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH0_IRQ, "mxs-lradc-channel0"),
> +	DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH1_IRQ, "mxs-lradc-channel1"),
> +	DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH2_IRQ, "mxs-lradc-channel2"),
> +	DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH3_IRQ, "mxs-lradc-channel3"),
> +	DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH4_IRQ, "mxs-lradc-channel4"),
> +	DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH5_IRQ, "mxs-lradc-channel5"),
> +};
> +
> +static struct resource mx23_touchscreen_resources[] = {
> +	DEFINE_RES_MEM(MXS_LRADC_BASE, 0x1fff),
> +	DEFINE_RES_IRQ_NAMED(MX23_LRADC_TS_IRQ, "mxs-lradc-touchscreen"),
> +	DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH6_IRQ, "mxs-lradc-channel6"),
> +	DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH7_IRQ, "mxs-lradc-channel7"),
> +};
> +
> +static struct resource mx28_adc_resources[] = {
> +	DEFINE_RES_MEM(MXS_LRADC_BASE, 0x1fff),
> +	DEFINE_RES_IRQ_NAMED(MX28_LRADC_TRESH0_IRQ, "mxs-lradc-thresh0"),
> +	DEFINE_RES_IRQ_NAMED(MX28_LRADC_TRESH1_IRQ, "mxs-lradc-thresh1"),
> +	DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH0_IRQ, "mxs-lradc-channel0"),
> +	DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH1_IRQ, "mxs-lradc-channel1"),
> +	DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH2_IRQ, "mxs-lradc-channel2"),
> +	DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH3_IRQ, "mxs-lradc-channel3"),
> +	DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH4_IRQ, "mxs-lradc-channel4"),
> +	DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH5_IRQ, "mxs-lradc-channel5"),
> +	DEFINE_RES_IRQ_NAMED(MX28_LRADC_BUTTON0_IRQ, "mxs-lradc-button0"),
> +	DEFINE_RES_IRQ_NAMED(MX28_LRADC_BUTTON1_IRQ, "mxs-lradc-button1"),
> +};
> +
> +static struct resource mx28_touchscreen_resources[] = {
> +	DEFINE_RES_MEM(MXS_LRADC_BASE, 0x1fff),
> +	DEFINE_RES_IRQ_NAMED(MX28_LRADC_TS_IRQ, "mxs-lradc-touchscreen"),
> +	DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH6_IRQ, "mxs-lradc-channel6"),
> +	DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH7_IRQ, "mxs-lradc-channel7"),
> +};
> +
> +static struct mfd_cell mx23_cells[] = {
> +	{
> +		.name = "mxs-lradc-adc",
> +		.resources = mx23_adc_resources,
> +		.num_resources = ARRAY_SIZE(mx23_adc_resources),
> +	},
> +	{
> +		.name = "mxs-lradc-ts",
> +		.resources = mx23_touchscreen_resources,
> +		.num_resources = ARRAY_SIZE(mx23_touchscreen_resources),
> +	},
> +};
> +
> +static struct mfd_cell mx28_cells[] = {
> +	{
> +		.name = "mxs-lradc-adc",
> +		.resources = mx28_adc_resources,
> +		.num_resources = ARRAY_SIZE(mx28_adc_resources),
> +	},
> +	{
> +		.name = "mxs-lradc-ts",
> +		.resources = mx28_touchscreen_resources,
> +		.num_resources = ARRAY_SIZE(mx28_touchscreen_resources),
> +	}
> +};
> +
> +static const struct of_device_id mxs_lradc_dt_ids[] = {
> +	{ .compatible = "fsl,imx23-lradc", .data = (void *)IMX23_LRADC, },
> +	{ .compatible = "fsl,imx28-lradc", .data = (void *)IMX28_LRADC, },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, mxs_lradc_dt_ids);
> +
> +static int mxs_lradc_probe(struct platform_device *pdev)
> +{
> +	const struct of_device_id *of_id;
> +	struct device *dev = &pdev->dev;
> +	struct device_node *node = dev->of_node;
> +	struct mxs_lradc *lradc;
> +	struct mfd_cell *cells = NULL;
> +	int ret = 0;
> +	u32 ts_wires = 0;
> +
> +	lradc = devm_kzalloc(&pdev->dev, sizeof(*lradc), GFP_KERNEL);
> +	if (!lradc)
> +		return -ENOMEM;
> +
> +	of_id = of_match_device(mxs_lradc_dt_ids, &pdev->dev);
> +	lradc->soc = (enum mxs_lradc_id)of_id->data;
> +
> +	lradc->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(lradc->clk)) {
> +		dev_err(dev, "Failed to get the delay unit clock\n");
> +		return PTR_ERR(lradc->clk);
> +	}
> +
> +	ret = clk_prepare_enable(lradc->clk);
> +	if (ret) {
> +		dev_err(dev, "Failed to enable the delay unit clock\n");
> +		return ret;
> +	}
> +
> +	ret = of_property_read_u32(node, "fsl,lradc-touchscreen-wires",

Have you moved the documentation into devicetree/bindings/mfd?

> +					 &ts_wires);
> +
> +	if (!ret) {
> +		lradc->buffer_vchans = BUFFER_VCHANS_LIMITED;
> +
> +		switch (ts_wires) {
> +		case 4:
> +			lradc->touchscreen_wire = MXS_LRADC_TOUCHSCREEN_4WIRE;
> +			break;
> +		case 5:
> +			if (lradc->soc == IMX28_LRADC) {
> +				lradc->touchscreen_wire =
> +					MXS_LRADC_TOUCHSCREEN_5WIRE;
> +				break;
> +			}
> +			/* fall through to an error message for i.MX23 */
> +		default:
> +			dev_err(&pdev->dev,
> +				"Unsupported number of touchscreen wires (%d)\n"
> +				, ts_wires);
> +			ret = -EINVAL;
> +			goto err_clk;
> +		}
> +	} else {
> +		lradc->buffer_vchans = BUFFER_VCHANS_ALL;
> +	}
> +
> +	platform_set_drvdata(pdev, lradc);
> +
> +	switch (lradc->soc) {
> +	case IMX23_LRADC:
> +		cells = mx23_cells;
> +		break;
> +	case IMX28_LRADC:
> +		cells = mx28_cells;
> +		break;
> +	default:
> +		dev_err(dev, "Unsupported soc.\n");

Nit: SoC

... and drop the '.'.

> +		ret = -ENODEV;
> +		goto err_clk;
> +	}
> +
> +	cells[0].platform_data = lradc;
> +	cells[0].pdata_size = sizeof(*lradc);

This is fragile.

Define '0' here, in case things get moved around.

Better still.  Since both cells are identical except resources, why
don't you remove one of them and dynamically set them in the switch()
above?

> +	ret = devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_NONE, &cells[0],
> +				   1, NULL, 0, NULL);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Failed to add the ADC subdevice\n");
> +		goto err_clk;
> +	}
> +
> +	if (!lradc->touchscreen_wire)
> +		return 0;

This is ugly.  Instead, fail in the touchscreen driver if you do not
have what you need.

> +	cells[1].platform_data = lradc;
> +	cells[1].pdata_size = sizeof(*lradc);
> +
> +	ret = devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_NONE, &cells[1],
> +				   1, NULL, 0, NULL);
> +	if (ret) {
> +		dev_err(&pdev->dev,
> +			"Failed to add the touchscreen subdevice\n");
> +		goto err_clk;
> +	}
> +
> +	return 0;
> +
> +err_clk:
> +	clk_disable_unprepare(lradc->clk);
> +
> +	return ret;
> +}
> +
> +static int mxs_lradc_remove(struct platform_device *pdev)
> +{
> +	struct mxs_lradc *lradc = platform_get_drvdata(pdev);
> +
> +	clk_disable_unprepare(lradc->clk);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver mxs_lradc_driver = {
> +	.driver = {
> +		.name = "mxs-lradc",
> +		.of_match_table = mxs_lradc_dt_ids,
> +	},
> +	.probe = mxs_lradc_probe,
> +	.remove = mxs_lradc_remove,
> +};
> +module_platform_driver(mxs_lradc_driver);
> +
> +MODULE_AUTHOR("Ksenija Stanojevic <[e-mail]>");
> +MODULE_DESCRIPTION("Freescale i.MX23/i.MX28 LRADC driver");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:mxs-lradc");
> diff --git a/include/linux/mfd/mxs-lradc.h b/include/linux/mfd/mxs-lradc.h
> new file mode 100644
> index 0000000..6724eb8
> --- /dev/null
> +++ b/include/linux/mfd/mxs-lradc.h
> @@ -0,0 +1,203 @@
> +/*
> + * Freescale MXS LRADC driver
> + *
> + * Copyright (c) 2012 DENX Software Engineering, GmbH.
> + * Copyright (c) 2016 Ksenija Stanojevic <[e-mail]>
> + *
> + * Author: Marek Vasut <[e-mail]>
> + *
> + * 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.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#ifndef __MFD_MXS_LRADC_H
> +#define __MFD_MXS_LRADC_H
> +
> +#include <linux/bitops.h>
> +#include <linux/io.h>
> +#include <linux/stmp_device.h>
> +
> +#define LRADC_MAX_DELAY_CHANS	4
> +#define LRADC_MAX_MAPPED_CHANS	8
> +#define LRADC_MAX_TOTAL_CHANS	16
> +
> +#define LRADC_DELAY_TIMER_HZ	2000
> +
> +#define LRADC_CTRL0				0x00
> +# define LRADC_CTRL0_MX28_TOUCH_DETECT_ENABLE	BIT(23)
> +# define LRADC_CTRL0_MX28_TOUCH_SCREEN_TYPE	BIT(22)
> +# define LRADC_CTRL0_MX28_YNNSW /* YM */	BIT(21)
> +# define LRADC_CTRL0_MX28_YPNSW /* YP */	BIT(20)
> +# define LRADC_CTRL0_MX28_YPPSW /* YP */	BIT(19)
> +# define LRADC_CTRL0_MX28_XNNSW /* XM */	BIT(18)
> +# define LRADC_CTRL0_MX28_XNPSW /* XM */	BIT(17)
> +# define LRADC_CTRL0_MX28_XPPSW /* XP */	BIT(16)
> +
> +# define LRADC_CTRL0_MX23_TOUCH_DETECT_ENABLE	BIT(20)
> +# define LRADC_CTRL0_MX23_YM			BIT(19)
> +# define LRADC_CTRL0_MX23_XM			BIT(18)
> +# define LRADC_CTRL0_MX23_YP			BIT(17)
> +# define LRADC_CTRL0_MX23_XP			BIT(16)
> +
> +# define LRADC_CTRL0_MX28_PLATE_MASK \
> +		(LRADC_CTRL0_MX28_TOUCH_DETECT_ENABLE | \
> +		LRADC_CTRL0_MX28_YNNSW | LRADC_CTRL0_MX28_YPNSW | \
> +		LRADC_CTRL0_MX28_YPPSW | LRADC_CTRL0_MX28_XNNSW | \
> +		LRADC_CTRL0_MX28_XNPSW | LRADC_CTRL0_MX28_XPPSW)
> +
> +# define LRADC_CTRL0_MX23_PLATE_MASK \
> +		(LRADC_CTRL0_MX23_TOUCH_DETECT_ENABLE | \
> +		LRADC_CTRL0_MX23_YM | LRADC_CTRL0_MX23_XM | \
> +		LRADC_CTRL0_MX23_YP | LRADC_CTRL0_MX23_XP)
> +
> +#define LRADC_CTRL1				0x10
> +#define LRADC_CTRL1_TOUCH_DETECT_IRQ_EN		BIT(24)
> +#define LRADC_CTRL1_LRADC_IRQ_EN(n)		(1 << ((n) + 16))
> +#define LRADC_CTRL1_MX28_LRADC_IRQ_EN_MASK	(0x1fff << 16)
> +#define LRADC_CTRL1_MX23_LRADC_IRQ_EN_MASK	(0x01ff << 16)
> +#define LRADC_CTRL1_LRADC_IRQ_EN_OFFSET		16
> +#define LRADC_CTRL1_TOUCH_DETECT_IRQ		BIT(8)
> +#define LRADC_CTRL1_LRADC_IRQ(n)		(1 << (n))
> +#define LRADC_CTRL1_MX28_LRADC_IRQ_MASK		0x1fff
> +#define LRADC_CTRL1_MX23_LRADC_IRQ_MASK		0x01ff
> +#define LRADC_CTRL1_LRADC_IRQ_OFFSET		0
> +
> +#define LRADC_CTRL2				0x20
> +#define LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET	24
> +#define LRADC_CTRL2_TEMPSENSE_PWD		BIT(15)
> +
> +#define LRADC_STATUS				0x40
> +#define LRADC_STATUS_TOUCH_DETECT_RAW		BIT(0)
> +
> +#define LRADC_CH(n)				(0x50 + (0x10 * (n)))
> +#define LRADC_CH_ACCUMULATE			BIT(29)
> +#define LRADC_CH_NUM_SAMPLES_MASK		(0x1f << 24)
> +#define LRADC_CH_NUM_SAMPLES_OFFSET		24
> +#define LRADC_CH_NUM_SAMPLES(x) \
> +				((x) << LRADC_CH_NUM_SAMPLES_OFFSET)
> +#define LRADC_CH_VALUE_MASK			0x3ffff
> +#define LRADC_CH_VALUE_OFFSET			0
> +
> +#define LRADC_DELAY(n)				(0xd0 + (0x10 * (n)))
> +#define LRADC_DELAY_TRIGGER_LRADCS_MASK		(0xffUL << 24)
> +#define LRADC_DELAY_TRIGGER_LRADCS_OFFSET	24
> +#define LRADC_DELAY_TRIGGER(x) \
> +				(((x) << LRADC_DELAY_TRIGGER_LRADCS_OFFSET) & \
> +				LRADC_DELAY_TRIGGER_LRADCS_MASK)
> +#define LRADC_DELAY_KICK			BIT(20)
> +#define LRADC_DELAY_TRIGGER_DELAYS_MASK		(0xf << 16)
> +#define LRADC_DELAY_TRIGGER_DELAYS_OFFSET	16
> +#define LRADC_DELAY_TRIGGER_DELAYS(x) \
> +				(((x) << LRADC_DELAY_TRIGGER_DELAYS_OFFSET) & \
> +				LRADC_DELAY_TRIGGER_DELAYS_MASK)
> +#define LRADC_DELAY_LOOP_COUNT_MASK		(0x1f << 11)
> +#define LRADC_DELAY_LOOP_COUNT_OFFSET		11
> +#define LRADC_DELAY_LOOP(x) \
> +				(((x) << LRADC_DELAY_LOOP_COUNT_OFFSET) & \
> +				LRADC_DELAY_LOOP_COUNT_MASK)
> +#define LRADC_DELAY_DELAY_MASK			0x7ff
> +#define LRADC_DELAY_DELAY_OFFSET		0
> +#define LRADC_DELAY_DELAY(x) \
> +				(((x) << LRADC_DELAY_DELAY_OFFSET) & \
> +				LRADC_DELAY_DELAY_MASK)
> +
> +#define LRADC_CTRL4				0x140
> +#define LRADC_CTRL4_LRADCSELECT_MASK(n)		(0xf << ((n) * 4))
> +#define LRADC_CTRL4_LRADCSELECT_OFFSET(n)	((n) * 4)
> +#define LRADC_CTRL4_LRADCSELECT(n, x) \
> +				(((x) << LRADC_CTRL4_LRADCSELECT_OFFSET(n)) & \
> +				LRADC_CTRL4_LRADCSELECT_MASK(n))
> +
> +#define LRADC_RESOLUTION			12
> +#define LRADC_SINGLE_SAMPLE_MASK		((1 << LRADC_RESOLUTION) - 1)
> +
> +#define BUFFER_VCHANS_LIMITED		0x3f
> +#define BUFFER_VCHANS_ALL		0xff
> +
> +	/*
> +	 * Certain LRADC channels are shared between touchscreen
> +	 * and/or touch-buttons and generic LRADC block. Therefore when using
> +	 * either of these, these channels are not available for the regular
> +	 * sampling. The shared channels are as follows:
> +	 *
> +	 * CH0 -- Touch button #0
> +	 * CH1 -- Touch button #1
> +	 * CH2 -- Touch screen XPUL
> +	 * CH3 -- Touch screen YPLL
> +	 * CH4 -- Touch screen XNUL
> +	 * CH5 -- Touch screen YNLR
> +	 * CH6 -- Touch screen WIPER (5-wire only)
> +	 *
> +	 * The bit fields below represents which parts of the LRADC block are
> +	 * switched into special mode of operation. These channels can not
> +	 * be sampled as regular LRADC channels. The driver will refuse any
> +	 * attempt to sample these channels.
> +	 */
> +#define CHAN_MASK_TOUCHBUTTON		(BIT(1) | BIT(0))
> +#define CHAN_MASK_TOUCHSCREEN_4WIRE	(0xf << 2)
> +#define CHAN_MASK_TOUCHSCREEN_5WIRE	(0x1f << 2)
> +
> +enum mxs_lradc_id {
> +	IMX23_LRADC,
> +	IMX28_LRADC,
> +};
> +
> +enum mxs_lradc_ts_wires {
> +	MXS_LRADC_TOUCHSCREEN_NONE = 0,
> +	MXS_LRADC_TOUCHSCREEN_4WIRE,
> +	MXS_LRADC_TOUCHSCREEN_5WIRE,
> +};
> +
> +/**
> + * struct mxs_lradc
> + * @soc: soc type (IMX23 or IMX28)
> + * @clk: 2 kHz clock for delay units
> + * @buffer_vchans: channels that can be used during buffered capture
> + * @touchscreen_wire: touchscreen type (4-wire or 5-wire)
> + * @use_touchbutton: button state (on or off)
> +*/
> +struct mxs_lradc {
> +	enum mxs_lradc_id	soc;
> +	struct clk		*clk;
> +	u8			buffer_vchans;
> +
> +	enum mxs_lradc_ts_wires	touchscreen_wire;
> +	bool			use_touchbutton;
> +};
> +
> +static inline void mxs_lradc_reg_set(void __iomem *base, u32 val, u32 reg)
> +{
> +	writel(val, base + reg + STMP_OFFSET_REG_SET);
> +}
> +
> +static inline void mxs_lradc_reg_clear(void __iomem *base, u32 val,
> +				       u32 reg)
> +{
> +	writel(val, base + reg + STMP_OFFSET_REG_CLR);
> +}
> +
> +static inline void mxs_lradc_reg_wrt(void __iomem *base, u32 val, u32 reg)
> +{
> +	writel(val, base + reg);
> +}
> +
> +static inline u32 mxs_lradc_irq_mask(struct mxs_lradc *lradc)
> +{
> +	switch (lradc->soc) {
> +	case IMX23_LRADC:
> +		return LRADC_CTRL1_MX23_LRADC_IRQ_MASK;
> +	case IMX28_LRADC:
> +		return LRADC_CTRL1_MX28_LRADC_IRQ_MASK;
> +	default:
> +		return 0;
> +	}
> +}
> +
> +#endif /* __MXS_LRADC_H */

Stefan Wahren Sept. 29, 2016, 1:38 a.m. UTC | #2

Hi Lee,

> Lee Jones <[e-mail]> hat am 28. September 2016 um 03:05
> geschrieben:
> 
> 
> On Sat, 17 Sep 2016, Ksenija Stanojevic wrote:
> 
> > +
> > +static int mxs_lradc_probe(struct platform_device *pdev)
> > +{
> > +	const struct of_device_id *of_id;
> > +	struct device *dev = &pdev->dev;
> > +	struct device_node *node = dev->of_node;
> > +	struct mxs_lradc *lradc;
> > +	struct mfd_cell *cells = NULL;
> > +	int ret = 0;
> > +	u32 ts_wires = 0;
> > +
> > +	lradc = devm_kzalloc(&pdev->dev, sizeof(*lradc), GFP_KERNEL);
> > +	if (!lradc)
> > +		return -ENOMEM;
> > +
> > +	of_id = of_match_device(mxs_lradc_dt_ids, &pdev->dev);
> > +	lradc->soc = (enum mxs_lradc_id)of_id->data;
> > +
> > +	lradc->clk = devm_clk_get(&pdev->dev, NULL);
> > +	if (IS_ERR(lradc->clk)) {
> > +		dev_err(dev, "Failed to get the delay unit clock\n");
> > +		return PTR_ERR(lradc->clk);
> > +	}
> > +
> > +	ret = clk_prepare_enable(lradc->clk);
> > +	if (ret) {
> > +		dev_err(dev, "Failed to enable the delay unit clock\n");
> > +		return ret;
> > +	}
> > +
> > +	ret = of_property_read_u32(node, "fsl,lradc-touchscreen-wires",
> 
> Have you moved the documentation into devicetree/bindings/mfd?
> 

i hope it's okay if i answer. The binding has moved to
devicetree/binding/iio/adc/ [1]

Should it move completely to mfd or split too?

I'm asking myself how we keep DT ABI in the latter case.

[1] -
http://lxr.free-electrons.com/source/Documentation/devicetree/bindings/iio/adc/mxs-lradc.txt

> 
> -- 
> Lee Jones
> Linaro STMicroelectronics Landing Team Lead
> Linaro.org │ Open source software for ARM SoCs
> Follow Linaro: Facebook | Twitter | Blog
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Lee Jones Sept. 29, 2016, 5:15 p.m. UTC | #3

On Thu, 29 Sep 2016, Stefan Wahren wrote:
> > Lee Jones <[e-mail]> hat am 28. September 2016 um 03:05
> > geschrieben:
> > 
> > 
> > On Sat, 17 Sep 2016, Ksenija Stanojevic wrote:
> > 
> > > +
> > > +static int mxs_lradc_probe(struct platform_device *pdev)
> > > +{
> > > +	const struct of_device_id *of_id;
> > > +	struct device *dev = &pdev->dev;
> > > +	struct device_node *node = dev->of_node;
> > > +	struct mxs_lradc *lradc;
> > > +	struct mfd_cell *cells = NULL;
> > > +	int ret = 0;
> > > +	u32 ts_wires = 0;
> > > +
> > > +	lradc = devm_kzalloc(&pdev->dev, sizeof(*lradc), GFP_KERNEL);
> > > +	if (!lradc)
> > > +		return -ENOMEM;
> > > +
> > > +	of_id = of_match_device(mxs_lradc_dt_ids, &pdev->dev);
> > > +	lradc->soc = (enum mxs_lradc_id)of_id->data;
> > > +
> > > +	lradc->clk = devm_clk_get(&pdev->dev, NULL);
> > > +	if (IS_ERR(lradc->clk)) {
> > > +		dev_err(dev, "Failed to get the delay unit clock\n");
> > > +		return PTR_ERR(lradc->clk);
> > > +	}
> > > +
> > > +	ret = clk_prepare_enable(lradc->clk);
> > > +	if (ret) {
> > > +		dev_err(dev, "Failed to enable the delay unit clock\n");
> > > +		return ret;
> > > +	}
> > > +
> > > +	ret = of_property_read_u32(node, "fsl,lradc-touchscreen-wires",
> > 
> > Have you moved the documentation into devicetree/bindings/mfd?
> > 
> 
> i hope it's okay if i answer. The binding has moved to
> devicetree/binding/iio/adc/ [1]
> 
> Should it move completely to mfd or split too?
> 
> I'm asking myself how we keep DT ABI in the latter case.
> 
> [1] -
> http://lxr.free-electrons.com/source/Documentation/devicetree/bindings/iio/adc/mxs-lradc.txt

I haven't read into the documentation too to deeply, but it stands to
reason that the bindings which are now being used in MFD should be
documented in the MFD binding document, and the ones which are no longer
used in the IIO driver should be removed.

Stefan Wahren Sept. 29, 2016, 7:15 p.m. UTC | #4

Hi Lee,

[add Rob and Mark]

> Lee Jones <[e-mail]> hat am 29. September 2016 um 19:15
> geschrieben:
> 
> 
> On Thu, 29 Sep 2016, Stefan Wahren wrote:
> > > Lee Jones <[e-mail]> hat am 28. September 2016 um 03:05
> > > geschrieben:
> > > 
> > > 
> > > On Sat, 17 Sep 2016, Ksenija Stanojevic wrote:
> > > 
> > > > +
> > > > +static int mxs_lradc_probe(struct platform_device *pdev)
> > > > +{
> > > > +	const struct of_device_id *of_id;
> > > > +	struct device *dev = &pdev->dev;
> > > > +	struct device_node *node = dev->of_node;
> > > > +	struct mxs_lradc *lradc;
> > > > +	struct mfd_cell *cells = NULL;
> > > > +	int ret = 0;
> > > > +	u32 ts_wires = 0;
> > > > +
> > > > +	lradc = devm_kzalloc(&pdev->dev, sizeof(*lradc), GFP_KERNEL);
> > > > +	if (!lradc)
> > > > +		return -ENOMEM;
> > > > +
> > > > +	of_id = of_match_device(mxs_lradc_dt_ids, &pdev->dev);
> > > > +	lradc->soc = (enum mxs_lradc_id)of_id->data;
> > > > +
> > > > +	lradc->clk = devm_clk_get(&pdev->dev, NULL);
> > > > +	if (IS_ERR(lradc->clk)) {
> > > > +		dev_err(dev, "Failed to get the delay unit clock\n");
> > > > +		return PTR_ERR(lradc->clk);
> > > > +	}
> > > > +
> > > > +	ret = clk_prepare_enable(lradc->clk);
> > > > +	if (ret) {
> > > > +		dev_err(dev, "Failed to enable the delay unit clock\n");
> > > > +		return ret;
> > > > +	}
> > > > +
> > > > +	ret = of_property_read_u32(node, "fsl,lradc-touchscreen-wires",
> > > 
> > > Have you moved the documentation into devicetree/bindings/mfd?
> > > 
> > 
> > i hope it's okay if i answer. The binding has moved to
> > devicetree/binding/iio/adc/ [1]
> > 
> > Should it move completely to mfd or split too?
> > 
> > I'm asking myself how we keep DT ABI in the latter case.
> > 
> > [1] -
> > http://lxr.free-electrons.com/source/Documentation/devicetree/bindings/iio/adc/mxs-lradc.txt
> 
> I haven't read into the documentation too to deeply, but it stands to
> reason that the bindings which are now being used in MFD should be
> documented in the MFD binding document, and the ones which are no longer
> used in the IIO driver should be removed.

sure, that isn't a problem.

The more interesting question would be: do we need a new compatible string for
the mfd driver?

In that case the ADC won't probe for the combination of old devicetree blobs and
new kernel.

Regards
Stefan

> 
> -- 
> Lee Jones
> Linaro STMicroelectronics Landing Team Lead
> Linaro.org │ Open source software for ARM SoCs
> Follow Linaro: Facebook | Twitter | Blog
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Lee Jones Sept. 29, 2016, 11:14 p.m. UTC | #5

On Thu, 29 Sep 2016, Stefan Wahren wrote:

> Hi Lee,
> 
> [add Rob and Mark]
> 
> > Lee Jones <[e-mail]> hat am 29. September 2016 um 19:15
> > geschrieben:
> > 
> > 
> > On Thu, 29 Sep 2016, Stefan Wahren wrote:
> > > > Lee Jones <[e-mail]> hat am 28. September 2016 um 03:05
> > > > geschrieben:
> > > > 
> > > > 
> > > > On Sat, 17 Sep 2016, Ksenija Stanojevic wrote:
> > > > 
> > > > > +
> > > > > +static int mxs_lradc_probe(struct platform_device *pdev)
> > > > > +{
> > > > > +	const struct of_device_id *of_id;
> > > > > +	struct device *dev = &pdev->dev;
> > > > > +	struct device_node *node = dev->of_node;
> > > > > +	struct mxs_lradc *lradc;
> > > > > +	struct mfd_cell *cells = NULL;
> > > > > +	int ret = 0;
> > > > > +	u32 ts_wires = 0;
> > > > > +
> > > > > +	lradc = devm_kzalloc(&pdev->dev, sizeof(*lradc), GFP_KERNEL);
> > > > > +	if (!lradc)
> > > > > +		return -ENOMEM;
> > > > > +
> > > > > +	of_id = of_match_device(mxs_lradc_dt_ids, &pdev->dev);
> > > > > +	lradc->soc = (enum mxs_lradc_id)of_id->data;
> > > > > +
> > > > > +	lradc->clk = devm_clk_get(&pdev->dev, NULL);
> > > > > +	if (IS_ERR(lradc->clk)) {
> > > > > +		dev_err(dev, "Failed to get the delay unit clock\n");
> > > > > +		return PTR_ERR(lradc->clk);
> > > > > +	}
> > > > > +
> > > > > +	ret = clk_prepare_enable(lradc->clk);
> > > > > +	if (ret) {
> > > > > +		dev_err(dev, "Failed to enable the delay unit clock\n");
> > > > > +		return ret;
> > > > > +	}
> > > > > +
> > > > > +	ret = of_property_read_u32(node, "fsl,lradc-touchscreen-wires",
> > > > 
> > > > Have you moved the documentation into devicetree/bindings/mfd?
> > > > 
> > > 
> > > i hope it's okay if i answer. The binding has moved to
> > > devicetree/binding/iio/adc/ [1]
> > > 
> > > Should it move completely to mfd or split too?
> > > 
> > > I'm asking myself how we keep DT ABI in the latter case.
> > > 
> > > [1] -
> > > http://lxr.free-electrons.com/source/Documentation/devicetree/bindings/iio/adc/mxs-lradc.txt
> > 
> > I haven't read into the documentation too to deeply, but it stands to
> > reason that the bindings which are now being used in MFD should be
> > documented in the MFD binding document, and the ones which are no longer
> > used in the IIO driver should be removed.
> 
> sure, that isn't a problem.
> 
> The more interesting question would be: do we need a new compatible string for
> the mfd driver?

No, I don't think that is necessary.

> In that case the ADC won't probe for the combination of old devicetree blobs and
> new kernel.

Patch

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 9ca66de..ffe14ef 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -271,6 +271,23 @@  config MFD_MC13XXX_I2C
 	help
 	  Select this if your MC13xxx is connected via an I2C bus.
 
+config MFD_MXS_LRADC
+	tristate "Freescale i.MX23/i.MX28 LRADC"
+	depends on ARCH_MXS || COMPILE_TEST
+	select MFD_CORE
+	select STMP_DEVICE
+	help
+	  Say yes here to build support for the Low Resolution
+	  Analog-to-Digital Converter (LRADC) found on the i.MX23 and i.MX28
+	  processors. This driver provides common support for accessing the
+	  device, additional drivers must be enabled in order to use the
+	  functionality of the device:
+		mxs-lradc-adc for ADC readings
+		mxs-lradc-ts  for touchscreen support
+
+	  This driver can also be built as a module. If so, the module will be
+	  called mxs-lradc.
+
 config MFD_HI6421_PMIC
 	tristate "HiSilicon Hi6421 PMU/Codec IC"
 	depends on OF
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 0f230a6..ecf6399 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -198,3 +198,4 @@  intel-soc-pmic-objs		:= intel_soc_pmic_core.o intel_soc_pmic_crc.o
 intel-soc-pmic-$(CONFIG_INTEL_PMC_IPC)	+= intel_soc_pmic_bxtwc.o
 obj-$(CONFIG_INTEL_SOC_PMIC)	+= intel-soc-pmic.o
 obj-$(CONFIG_MFD_MT6397)	+= mt6397-core.o
+obj-$(CONFIG_MFD_MXS_LRADC)	+= mxs-lradc.o
diff --git a/drivers/mfd/mxs-lradc.c b/drivers/mfd/mxs-lradc.c
new file mode 100644
index 0000000..05ae894
--- /dev/null
+++ b/drivers/mfd/mxs-lradc.c
@@ -0,0 +1,259 @@ 
+/*
+ * Freescale MXS LRADC driver
+ *
+ * Copyright (c) 2012 DENX Software Engineering, GmbH.
+ * Copyright (c) 2016 Ksenija Stanojevic <[e-mail]>
+ *
+ * Authors:
+ *  Marek Vasut <[e-mail]>
+ *  Ksenija Stanojevic <[e-mail]>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/mxs-lradc.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#define MXS_LRADC_BASE		0x80050000
+
+enum mx23_lradc_irqs {
+	MX23_LRADC_TS_IRQ = 0,
+	MX23_LRADC_CH0_IRQ,
+	MX23_LRADC_CH1_IRQ,
+	MX23_LRADC_CH2_IRQ,
+	MX23_LRADC_CH3_IRQ,
+	MX23_LRADC_CH4_IRQ,
+	MX23_LRADC_CH5_IRQ,
+	MX23_LRADC_CH6_IRQ,
+	MX23_LRADC_CH7_IRQ,
+};
+
+enum mx28_lradc_irqs {
+	MX28_LRADC_TS_IRQ = 0,
+	MX28_LRADC_TRESH0_IRQ,
+	MX28_LRADC_TRESH1_IRQ,
+	MX28_LRADC_CH0_IRQ,
+	MX28_LRADC_CH1_IRQ,
+	MX28_LRADC_CH2_IRQ,
+	MX28_LRADC_CH3_IRQ,
+	MX28_LRADC_CH4_IRQ,
+	MX28_LRADC_CH5_IRQ,
+	MX28_LRADC_CH6_IRQ,
+	MX28_LRADC_CH7_IRQ,
+	MX28_LRADC_BUTTON0_IRQ,
+	MX28_LRADC_BUTTON1_IRQ,
+};
+
+static struct resource mx23_adc_resources[] = {
+	DEFINE_RES_MEM(MXS_LRADC_BASE, 0x1fff),
+	DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH0_IRQ, "mxs-lradc-channel0"),
+	DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH1_IRQ, "mxs-lradc-channel1"),
+	DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH2_IRQ, "mxs-lradc-channel2"),
+	DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH3_IRQ, "mxs-lradc-channel3"),
+	DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH4_IRQ, "mxs-lradc-channel4"),
+	DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH5_IRQ, "mxs-lradc-channel5"),
+};
+
+static struct resource mx23_touchscreen_resources[] = {
+	DEFINE_RES_MEM(MXS_LRADC_BASE, 0x1fff),
+	DEFINE_RES_IRQ_NAMED(MX23_LRADC_TS_IRQ, "mxs-lradc-touchscreen"),
+	DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH6_IRQ, "mxs-lradc-channel6"),
+	DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH7_IRQ, "mxs-lradc-channel7"),
+};
+
+static struct resource mx28_adc_resources[] = {
+	DEFINE_RES_MEM(MXS_LRADC_BASE, 0x1fff),
+	DEFINE_RES_IRQ_NAMED(MX28_LRADC_TRESH0_IRQ, "mxs-lradc-thresh0"),
+	DEFINE_RES_IRQ_NAMED(MX28_LRADC_TRESH1_IRQ, "mxs-lradc-thresh1"),
+	DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH0_IRQ, "mxs-lradc-channel0"),
+	DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH1_IRQ, "mxs-lradc-channel1"),
+	DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH2_IRQ, "mxs-lradc-channel2"),
+	DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH3_IRQ, "mxs-lradc-channel3"),
+	DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH4_IRQ, "mxs-lradc-channel4"),
+	DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH5_IRQ, "mxs-lradc-channel5"),
+	DEFINE_RES_IRQ_NAMED(MX28_LRADC_BUTTON0_IRQ, "mxs-lradc-button0"),
+	DEFINE_RES_IRQ_NAMED(MX28_LRADC_BUTTON1_IRQ, "mxs-lradc-button1"),
+};
+
+static struct resource mx28_touchscreen_resources[] = {
+	DEFINE_RES_MEM(MXS_LRADC_BASE, 0x1fff),
+	DEFINE_RES_IRQ_NAMED(MX28_LRADC_TS_IRQ, "mxs-lradc-touchscreen"),
+	DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH6_IRQ, "mxs-lradc-channel6"),
+	DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH7_IRQ, "mxs-lradc-channel7"),
+};
+
+static struct mfd_cell mx23_cells[] = {
+	{
+		.name = "mxs-lradc-adc",
+		.resources = mx23_adc_resources,
+		.num_resources = ARRAY_SIZE(mx23_adc_resources),
+	},
+	{
+		.name = "mxs-lradc-ts",
+		.resources = mx23_touchscreen_resources,
+		.num_resources = ARRAY_SIZE(mx23_touchscreen_resources),
+	},
+};
+
+static struct mfd_cell mx28_cells[] = {
+	{
+		.name = "mxs-lradc-adc",
+		.resources = mx28_adc_resources,
+		.num_resources = ARRAY_SIZE(mx28_adc_resources),
+	},
+	{
+		.name = "mxs-lradc-ts",
+		.resources = mx28_touchscreen_resources,
+		.num_resources = ARRAY_SIZE(mx28_touchscreen_resources),
+	}
+};
+
+static const struct of_device_id mxs_lradc_dt_ids[] = {
+	{ .compatible = "fsl,imx23-lradc", .data = (void *)IMX23_LRADC, },
+	{ .compatible = "fsl,imx28-lradc", .data = (void *)IMX28_LRADC, },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mxs_lradc_dt_ids);
+
+static int mxs_lradc_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *of_id;
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	struct mxs_lradc *lradc;
+	struct mfd_cell *cells = NULL;
+	int ret = 0;
+	u32 ts_wires = 0;
+
+	lradc = devm_kzalloc(&pdev->dev, sizeof(*lradc), GFP_KERNEL);
+	if (!lradc)
+		return -ENOMEM;
+
+	of_id = of_match_device(mxs_lradc_dt_ids, &pdev->dev);
+	lradc->soc = (enum mxs_lradc_id)of_id->data;
+
+	lradc->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(lradc->clk)) {
+		dev_err(dev, "Failed to get the delay unit clock\n");
+		return PTR_ERR(lradc->clk);
+	}
+
+	ret = clk_prepare_enable(lradc->clk);
+	if (ret) {
+		dev_err(dev, "Failed to enable the delay unit clock\n");
+		return ret;
+	}
+
+	ret = of_property_read_u32(node, "fsl,lradc-touchscreen-wires",
+					 &ts_wires);
+
+	if (!ret) {
+		lradc->buffer_vchans = BUFFER_VCHANS_LIMITED;
+
+		switch (ts_wires) {
+		case 4:
+			lradc->touchscreen_wire = MXS_LRADC_TOUCHSCREEN_4WIRE;
+			break;
+		case 5:
+			if (lradc->soc == IMX28_LRADC) {
+				lradc->touchscreen_wire =
+					MXS_LRADC_TOUCHSCREEN_5WIRE;
+				break;
+			}
+			/* fall through to an error message for i.MX23 */
+		default:
+			dev_err(&pdev->dev,
+				"Unsupported number of touchscreen wires (%d)\n"
+				, ts_wires);
+			ret = -EINVAL;
+			goto err_clk;
+		}
+	} else {
+		lradc->buffer_vchans = BUFFER_VCHANS_ALL;
+	}
+
+	platform_set_drvdata(pdev, lradc);
+
+	switch (lradc->soc) {
+	case IMX23_LRADC:
+		cells = mx23_cells;
+		break;
+	case IMX28_LRADC:
+		cells = mx28_cells;
+		break;
+	default:
+		dev_err(dev, "Unsupported soc.\n");
+		ret = -ENODEV;
+		goto err_clk;
+	}
+
+	cells[0].platform_data = lradc;
+	cells[0].pdata_size = sizeof(*lradc);
+
+	ret = devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_NONE, &cells[0],
+				   1, NULL, 0, NULL);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to add the ADC subdevice\n");
+		goto err_clk;
+	}
+
+	if (!lradc->touchscreen_wire)
+		return 0;
+
+	cells[1].platform_data = lradc;
+	cells[1].pdata_size = sizeof(*lradc);
+
+	ret = devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_NONE, &cells[1],
+				   1, NULL, 0, NULL);
+	if (ret) {
+		dev_err(&pdev->dev,
+			"Failed to add the touchscreen subdevice\n");
+		goto err_clk;
+	}
+
+	return 0;
+
+err_clk:
+	clk_disable_unprepare(lradc->clk);
+
+	return ret;
+}
+
+static int mxs_lradc_remove(struct platform_device *pdev)
+{
+	struct mxs_lradc *lradc = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(lradc->clk);
+
+	return 0;
+}
+
+static struct platform_driver mxs_lradc_driver = {
+	.driver = {
+		.name = "mxs-lradc",
+		.of_match_table = mxs_lradc_dt_ids,
+	},
+	.probe = mxs_lradc_probe,
+	.remove = mxs_lradc_remove,
+};
+module_platform_driver(mxs_lradc_driver);
+
+MODULE_AUTHOR("Ksenija Stanojevic <[e-mail]>");
+MODULE_DESCRIPTION("Freescale i.MX23/i.MX28 LRADC driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:mxs-lradc");
diff --git a/include/linux/mfd/mxs-lradc.h b/include/linux/mfd/mxs-lradc.h
new file mode 100644
index 0000000..6724eb8
--- /dev/null
+++ b/include/linux/mfd/mxs-lradc.h
@@ -0,0 +1,203 @@ 
+/*
+ * Freescale MXS LRADC driver
+ *
+ * Copyright (c) 2012 DENX Software Engineering, GmbH.
+ * Copyright (c) 2016 Ksenija Stanojevic <[e-mail]>
+ *
+ * Author: Marek Vasut <[e-mail]>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __MFD_MXS_LRADC_H
+#define __MFD_MXS_LRADC_H
+
+#include <linux/bitops.h>
+#include <linux/io.h>
+#include <linux/stmp_device.h>
+
+#define LRADC_MAX_DELAY_CHANS	4
+#define LRADC_MAX_MAPPED_CHANS	8
+#define LRADC_MAX_TOTAL_CHANS	16
+
+#define LRADC_DELAY_TIMER_HZ	2000
+
+#define LRADC_CTRL0				0x00
+# define LRADC_CTRL0_MX28_TOUCH_DETECT_ENABLE	BIT(23)
+# define LRADC_CTRL0_MX28_TOUCH_SCREEN_TYPE	BIT(22)
+# define LRADC_CTRL0_MX28_YNNSW /* YM */	BIT(21)
+# define LRADC_CTRL0_MX28_YPNSW /* YP */	BIT(20)
+# define LRADC_CTRL0_MX28_YPPSW /* YP */	BIT(19)
+# define LRADC_CTRL0_MX28_XNNSW /* XM */	BIT(18)
+# define LRADC_CTRL0_MX28_XNPSW /* XM */	BIT(17)
+# define LRADC_CTRL0_MX28_XPPSW /* XP */	BIT(16)
+
+# define LRADC_CTRL0_MX23_TOUCH_DETECT_ENABLE	BIT(20)
+# define LRADC_CTRL0_MX23_YM			BIT(19)
+# define LRADC_CTRL0_MX23_XM			BIT(18)
+# define LRADC_CTRL0_MX23_YP			BIT(17)
+# define LRADC_CTRL0_MX23_XP			BIT(16)
+
+# define LRADC_CTRL0_MX28_PLATE_MASK \
+		(LRADC_CTRL0_MX28_TOUCH_DETECT_ENABLE | \
+		LRADC_CTRL0_MX28_YNNSW | LRADC_CTRL0_MX28_YPNSW | \
+		LRADC_CTRL0_MX28_YPPSW | LRADC_CTRL0_MX28_XNNSW | \
+		LRADC_CTRL0_MX28_XNPSW | LRADC_CTRL0_MX28_XPPSW)
+
+# define LRADC_CTRL0_MX23_PLATE_MASK \
+		(LRADC_CTRL0_MX23_TOUCH_DETECT_ENABLE | \
+		LRADC_CTRL0_MX23_YM | LRADC_CTRL0_MX23_XM | \
+		LRADC_CTRL0_MX23_YP | LRADC_CTRL0_MX23_XP)
+
+#define LRADC_CTRL1				0x10
+#define LRADC_CTRL1_TOUCH_DETECT_IRQ_EN		BIT(24)
+#define LRADC_CTRL1_LRADC_IRQ_EN(n)		(1 << ((n) + 16))
+#define LRADC_CTRL1_MX28_LRADC_IRQ_EN_MASK	(0x1fff << 16)
+#define LRADC_CTRL1_MX23_LRADC_IRQ_EN_MASK	(0x01ff << 16)
+#define LRADC_CTRL1_LRADC_IRQ_EN_OFFSET		16
+#define LRADC_CTRL1_TOUCH_DETECT_IRQ		BIT(8)
+#define LRADC_CTRL1_LRADC_IRQ(n)		(1 << (n))
+#define LRADC_CTRL1_MX28_LRADC_IRQ_MASK		0x1fff
+#define LRADC_CTRL1_MX23_LRADC_IRQ_MASK		0x01ff
+#define LRADC_CTRL1_LRADC_IRQ_OFFSET		0
+
+#define LRADC_CTRL2				0x20
+#define LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET	24
+#define LRADC_CTRL2_TEMPSENSE_PWD		BIT(15)
+
+#define LRADC_STATUS				0x40
+#define LRADC_STATUS_TOUCH_DETECT_RAW		BIT(0)
+
+#define LRADC_CH(n)				(0x50 + (0x10 * (n)))
+#define LRADC_CH_ACCUMULATE			BIT(29)
+#define LRADC_CH_NUM_SAMPLES_MASK		(0x1f << 24)
+#define LRADC_CH_NUM_SAMPLES_OFFSET		24
+#define LRADC_CH_NUM_SAMPLES(x) \
+				((x) << LRADC_CH_NUM_SAMPLES_OFFSET)
+#define LRADC_CH_VALUE_MASK			0x3ffff
+#define LRADC_CH_VALUE_OFFSET			0
+
+#define LRADC_DELAY(n)				(0xd0 + (0x10 * (n)))
+#define LRADC_DELAY_TRIGGER_LRADCS_MASK		(0xffUL << 24)
+#define LRADC_DELAY_TRIGGER_LRADCS_OFFSET	24
+#define LRADC_DELAY_TRIGGER(x) \
+				(((x) << LRADC_DELAY_TRIGGER_LRADCS_OFFSET) & \
+				LRADC_DELAY_TRIGGER_LRADCS_MASK)
+#define LRADC_DELAY_KICK			BIT(20)
+#define LRADC_DELAY_TRIGGER_DELAYS_MASK		(0xf << 16)
+#define LRADC_DELAY_TRIGGER_DELAYS_OFFSET	16
+#define LRADC_DELAY_TRIGGER_DELAYS(x) \
+				(((x) << LRADC_DELAY_TRIGGER_DELAYS_OFFSET) & \
+				LRADC_DELAY_TRIGGER_DELAYS_MASK)
+#define LRADC_DELAY_LOOP_COUNT_MASK		(0x1f << 11)
+#define LRADC_DELAY_LOOP_COUNT_OFFSET		11
+#define LRADC_DELAY_LOOP(x) \
+				(((x) << LRADC_DELAY_LOOP_COUNT_OFFSET) & \
+				LRADC_DELAY_LOOP_COUNT_MASK)
+#define LRADC_DELAY_DELAY_MASK			0x7ff
+#define LRADC_DELAY_DELAY_OFFSET		0
+#define LRADC_DELAY_DELAY(x) \
+				(((x) << LRADC_DELAY_DELAY_OFFSET) & \
+				LRADC_DELAY_DELAY_MASK)
+
+#define LRADC_CTRL4				0x140
+#define LRADC_CTRL4_LRADCSELECT_MASK(n)		(0xf << ((n) * 4))
+#define LRADC_CTRL4_LRADCSELECT_OFFSET(n)	((n) * 4)
+#define LRADC_CTRL4_LRADCSELECT(n, x) \
+				(((x) << LRADC_CTRL4_LRADCSELECT_OFFSET(n)) & \
+				LRADC_CTRL4_LRADCSELECT_MASK(n))
+
+#define LRADC_RESOLUTION			12
+#define LRADC_SINGLE_SAMPLE_MASK		((1 << LRADC_RESOLUTION) - 1)
+
+#define BUFFER_VCHANS_LIMITED		0x3f
+#define BUFFER_VCHANS_ALL		0xff
+
+	/*
+	 * Certain LRADC channels are shared between touchscreen
+	 * and/or touch-buttons and generic LRADC block. Therefore when using
+	 * either of these, these channels are not available for the regular
+	 * sampling. The shared channels are as follows:
+	 *
+	 * CH0 -- Touch button #0
+	 * CH1 -- Touch button #1
+	 * CH2 -- Touch screen XPUL
+	 * CH3 -- Touch screen YPLL
+	 * CH4 -- Touch screen XNUL
+	 * CH5 -- Touch screen YNLR
+	 * CH6 -- Touch screen WIPER (5-wire only)
+	 *
+	 * The bit fields below represents which parts of the LRADC block are
+	 * switched into special mode of operation. These channels can not
+	 * be sampled as regular LRADC channels. The driver will refuse any
+	 * attempt to sample these channels.
+	 */
+#define CHAN_MASK_TOUCHBUTTON		(BIT(1) | BIT(0))
+#define CHAN_MASK_TOUCHSCREEN_4WIRE	(0xf << 2)
+#define CHAN_MASK_TOUCHSCREEN_5WIRE	(0x1f << 2)
+
+enum mxs_lradc_id {
+	IMX23_LRADC,
+	IMX28_LRADC,
+};
+
+enum mxs_lradc_ts_wires {
+	MXS_LRADC_TOUCHSCREEN_NONE = 0,
+	MXS_LRADC_TOUCHSCREEN_4WIRE,
+	MXS_LRADC_TOUCHSCREEN_5WIRE,
+};
+
+/**
+ * struct mxs_lradc
+ * @soc: soc type (IMX23 or IMX28)
+ * @clk: 2 kHz clock for delay units
+ * @buffer_vchans: channels that can be used during buffered capture
+ * @touchscreen_wire: touchscreen type (4-wire or 5-wire)
+ * @use_touchbutton: button state (on or off)
+*/
+struct mxs_lradc {
+	enum mxs_lradc_id	soc;
+	struct clk		*clk;
+	u8			buffer_vchans;
+
+	enum mxs_lradc_ts_wires	touchscreen_wire;
+	bool			use_touchbutton;
+};
+
+static inline void mxs_lradc_reg_set(void __iomem *base, u32 val, u32 reg)
+{
+	writel(val, base + reg + STMP_OFFSET_REG_SET);
+}
+
+static inline void mxs_lradc_reg_clear(void __iomem *base, u32 val,
+				       u32 reg)
+{
+	writel(val, base + reg + STMP_OFFSET_REG_CLR);
+}
+
+static inline void mxs_lradc_reg_wrt(void __iomem *base, u32 val, u32 reg)
+{
+	writel(val, base + reg);
+}
+
+static inline u32 mxs_lradc_irq_mask(struct mxs_lradc *lradc)
+{
+	switch (lradc->soc) {
+	case IMX23_LRADC:
+		return LRADC_CTRL1_MX23_LRADC_IRQ_MASK;
+	case IMX28_LRADC:
+		return LRADC_CTRL1_MX28_LRADC_IRQ_MASK;
+	default:
+		return 0;
+	}
+}
+
+#endif /* __MXS_LRADC_H */