1 files changed, 681 insertions, 317 deletions

diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
index a08c1736458b..e2dd7830b320 100644
--- a/drivers/staging/iio/adc/mxs-lradc.c
+++ b/drivers/staging/iio/adc/mxs-lradc.c
@@ -35,6 +35,7 @@
 #include <linux/completion.h>
 #include <linux/delay.h>
 #include <linux/input.h>
+#include <linux/clk.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/buffer.h>
@@ -129,11 +130,24 @@ enum mxs_lradc_ts {
 	MXS_LRADC_TOUCHSCREEN_5WIRE,
 };
 
+/*
+ * Touchscreen handling
+ */
+enum lradc_ts_plate {
+	LRADC_TOUCH = 0,
+	LRADC_SAMPLE_X,
+	LRADC_SAMPLE_Y,
+	LRADC_SAMPLE_PRESSURE,
+	LRADC_SAMPLE_VALID,
+};
+
 struct mxs_lradc {
 	struct device		*dev;
 	void __iomem		*base;
 	int			irq[13];
 
+	struct clk		*clk;
+
 	uint32_t		*buffer;
 	struct iio_trigger	*trig;
 
@@ -169,32 +183,63 @@ struct mxs_lradc {
 #define CHAN_MASK_TOUCHSCREEN_4WIRE	(0xf << 2)
 #define CHAN_MASK_TOUCHSCREEN_5WIRE	(0x1f << 2)
 	enum mxs_lradc_ts	use_touchscreen;
-	bool			stop_touchscreen;
 	bool			use_touchbutton;
 
 	struct input_dev	*ts_input;
-	struct work_struct	ts_work;
+
+	enum mxs_lradc_id	soc;
+	enum lradc_ts_plate	cur_plate; /* statemachine */
+	bool			ts_valid;
+	unsigned		ts_x_pos;
+	unsigned		ts_y_pos;
+	unsigned		ts_pressure;
+
+	/* handle touchscreen's physical behaviour */
+	/* samples per coordinate */
+	unsigned		over_sample_cnt;
+	/* time clocks between samples */
+	unsigned		over_sample_delay;
+	/* time in clocks to wait after the plates where switched */
+	unsigned		settling_delay;
 };
 
 #define	LRADC_CTRL0				0x00
-#define	LRADC_CTRL0_TOUCH_DETECT_ENABLE		(1 << 23)
-#define	LRADC_CTRL0_TOUCH_SCREEN_TYPE		(1 << 22)
-#define	LRADC_CTRL0_YNNSW	/* YM */	(1 << 21)
-#define	LRADC_CTRL0_YPNSW	/* YP */	(1 << 20)
-#define	LRADC_CTRL0_YPPSW	/* YP */	(1 << 19)
-#define	LRADC_CTRL0_XNNSW	/* XM */	(1 << 18)
-#define	LRADC_CTRL0_XNPSW	/* XM */	(1 << 17)
-#define	LRADC_CTRL0_XPPSW	/* XP */	(1 << 16)
-#define	LRADC_CTRL0_PLATE_MASK			(0x3f << 16)
+# define LRADC_CTRL0_MX28_TOUCH_DETECT_ENABLE	(1 << 23)
+# define LRADC_CTRL0_MX28_TOUCH_SCREEN_TYPE	(1 << 22)
+# define LRADC_CTRL0_MX28_YNNSW	/* YM */	(1 << 21)
+# define LRADC_CTRL0_MX28_YPNSW	/* YP */	(1 << 20)
+# define LRADC_CTRL0_MX28_YPPSW	/* YP */	(1 << 19)
+# define LRADC_CTRL0_MX28_XNNSW	/* XM */	(1 << 18)
+# define LRADC_CTRL0_MX28_XNPSW	/* XM */	(1 << 17)
+# define LRADC_CTRL0_MX28_XPPSW	/* XP */	(1 << 16)
+
+# define LRADC_CTRL0_MX23_TOUCH_DETECT_ENABLE	(1 << 20)
+# define LRADC_CTRL0_MX23_YM			(1 << 19)
+# define LRADC_CTRL0_MX23_XM			(1 << 18)
+# define LRADC_CTRL0_MX23_YP			(1 << 17)
+# define LRADC_CTRL0_MX23_XP			(1 << 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		(1 << 24)
 #define	LRADC_CTRL1_LRADC_IRQ_EN(n)		(1 << ((n) + 16))
-#define	LRADC_CTRL1_LRADC_IRQ_EN_MASK		(0x1fff << 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		(1 << 8)
 #define	LRADC_CTRL1_LRADC_IRQ(n)		(1 << (n))
-#define	LRADC_CTRL1_LRADC_IRQ_MASK		0x1fff
+#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
@@ -207,19 +252,33 @@ struct mxs_lradc {
 #define	LRADC_CH_ACCUMULATE			(1 << 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		(0xff << 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			(1 << 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))
@@ -228,6 +287,475 @@ struct mxs_lradc {
 #define LRADC_RESOLUTION			12
 #define LRADC_SINGLE_SAMPLE_MASK		((1 << LRADC_RESOLUTION) - 1)
 
+static void mxs_lradc_reg_set(struct mxs_lradc *lradc, u32 val, u32 reg)
+{
+	writel(val, lradc->base + reg + STMP_OFFSET_REG_SET);
+}
+
+static void mxs_lradc_reg_clear(struct mxs_lradc *lradc, u32 val, u32 reg)
+{
+	writel(val, lradc->base + reg + STMP_OFFSET_REG_CLR);
+}
+
+static void mxs_lradc_reg_wrt(struct mxs_lradc *lradc, u32 val, u32 reg)
+{
+	writel(val, lradc->base + reg);
+}
+
+static u32 mxs_lradc_plate_mask(struct mxs_lradc *lradc)
+{
+	if (lradc->soc == IMX23_LRADC)
+		return LRADC_CTRL0_MX23_PLATE_MASK;
+	else
+		return LRADC_CTRL0_MX28_PLATE_MASK;
+}
+
+static u32 mxs_lradc_irq_en_mask(struct mxs_lradc *lradc)
+{
+	if (lradc->soc == IMX23_LRADC)
+		return LRADC_CTRL1_MX23_LRADC_IRQ_EN_MASK;
+	else
+		return LRADC_CTRL1_MX28_LRADC_IRQ_EN_MASK;
+}
+
+static u32 mxs_lradc_irq_mask(struct mxs_lradc *lradc)
+{
+	if (lradc->soc == IMX23_LRADC)
+		return LRADC_CTRL1_MX23_LRADC_IRQ_MASK;
+	else
+		return LRADC_CTRL1_MX28_LRADC_IRQ_MASK;
+}
+
+static u32 mxs_lradc_touch_detect_bit(struct mxs_lradc *lradc)
+{
+	if (lradc->soc == IMX23_LRADC)
+		return LRADC_CTRL0_MX23_TOUCH_DETECT_ENABLE;
+	else
+		return LRADC_CTRL0_MX28_TOUCH_DETECT_ENABLE;
+}
+
+static u32 mxs_lradc_drive_x_plate(struct mxs_lradc *lradc)
+{
+	if (lradc->soc == IMX23_LRADC)
+		return LRADC_CTRL0_MX23_XP | LRADC_CTRL0_MX23_XM;
+	else
+		return LRADC_CTRL0_MX28_XPPSW | LRADC_CTRL0_MX28_XNNSW;
+}
+
+static u32 mxs_lradc_drive_y_plate(struct mxs_lradc *lradc)
+{
+	if (lradc->soc == IMX23_LRADC)
+		return LRADC_CTRL0_MX23_YP | LRADC_CTRL0_MX23_YM;
+	else
+		return LRADC_CTRL0_MX28_YPPSW | LRADC_CTRL0_MX28_YNNSW;
+}
+
+static u32 mxs_lradc_drive_pressure(struct mxs_lradc *lradc)
+{
+	if (lradc->soc == IMX23_LRADC)
+		return LRADC_CTRL0_MX23_YP | LRADC_CTRL0_MX23_XM;
+	else
+		return LRADC_CTRL0_MX28_YPPSW | LRADC_CTRL0_MX28_XNNSW;
+}
+
+static bool mxs_lradc_check_touch_event(struct mxs_lradc *lradc)
+{
+	return !!(readl(lradc->base + LRADC_STATUS) &
+					LRADC_STATUS_TOUCH_DETECT_RAW);
+}
+
+static void mxs_lradc_setup_ts_channel(struct mxs_lradc *lradc, unsigned ch)
+{
+	/*
+	 * prepare for oversampling conversion
+	 *
+	 * from the datasheet:
+	 * "The ACCUMULATE bit in the appropriate channel register
+	 * HW_LRADC_CHn must be set to 1 if NUM_SAMPLES is greater then 0;
+	 * otherwise, the IRQs will not fire."
+	 */
+	mxs_lradc_reg_wrt(lradc, LRADC_CH_ACCUMULATE |
+			LRADC_CH_NUM_SAMPLES(lradc->over_sample_cnt - 1),
+			LRADC_CH(ch));
+
+	/* from the datasheet:
+	 * "Software must clear this register in preparation for a
+	 * multi-cycle accumulation.
+	 */
+	mxs_lradc_reg_clear(lradc, LRADC_CH_VALUE_MASK, LRADC_CH(ch));
+
+	/* prepare the delay/loop unit according to the oversampling count */
+	mxs_lradc_reg_wrt(lradc, LRADC_DELAY_TRIGGER(1 << ch) |
+		LRADC_DELAY_TRIGGER_DELAYS(0) |
+		LRADC_DELAY_LOOP(lradc->over_sample_cnt - 1) |
+		LRADC_DELAY_DELAY(lradc->over_sample_delay - 1),
+			LRADC_DELAY(3));
+
+	mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ(2) |
+			LRADC_CTRL1_LRADC_IRQ(3) | LRADC_CTRL1_LRADC_IRQ(4) |
+			LRADC_CTRL1_LRADC_IRQ(5), LRADC_CTRL1);
+
+	/* wake us again, when the complete conversion is done */
+	mxs_lradc_reg_set(lradc, LRADC_CTRL1_LRADC_IRQ_EN(ch), LRADC_CTRL1);
+	/*
+	 * after changing the touchscreen plates setting
+	 * the signals need some initial time to settle. Start the
+	 * SoC's delay unit and start the conversion later
+	 * and automatically.
+	 */
+	mxs_lradc_reg_wrt(lradc, LRADC_DELAY_TRIGGER(0) | /* don't trigger ADC */
+		LRADC_DELAY_TRIGGER_DELAYS(1 << 3) | /* trigger DELAY unit#3 */
+		LRADC_DELAY_KICK |
+		LRADC_DELAY_DELAY(lradc->settling_delay),
+			LRADC_DELAY(2));
+}
+
+/*
+ * Pressure detection is special:
+ * We want to do both required measurements for the pressure detection in
+ * one turn. Use the hardware features to chain both conversions and let the
+ * hardware report one interrupt if both conversions are done
+ */
+static void mxs_lradc_setup_ts_pressure(struct mxs_lradc *lradc, unsigned ch1,
+							unsigned ch2)
+{
+	u32 reg;
+
+	/*
+	 * prepare for oversampling conversion
+	 *
+	 * from the datasheet:
+	 * "The ACCUMULATE bit in the appropriate channel register
+	 * HW_LRADC_CHn must be set to 1 if NUM_SAMPLES is greater then 0;
+	 * otherwise, the IRQs will not fire."
+	 */
+	reg = LRADC_CH_ACCUMULATE |
+		LRADC_CH_NUM_SAMPLES(lradc->over_sample_cnt - 1);
+	mxs_lradc_reg_wrt(lradc, reg, LRADC_CH(ch1));
+	mxs_lradc_reg_wrt(lradc, reg, LRADC_CH(ch2));
+
+	/* from the datasheet:
+	 * "Software must clear this register in preparation for a
+	 * multi-cycle accumulation.
+	 */
+	mxs_lradc_reg_clear(lradc, LRADC_CH_VALUE_MASK, LRADC_CH(ch1));
+	mxs_lradc_reg_clear(lradc, LRADC_CH_VALUE_MASK, LRADC_CH(ch2));
+
+	/* prepare the delay/loop unit according to the oversampling count */
+	mxs_lradc_reg_wrt(lradc, LRADC_DELAY_TRIGGER(1 << ch1) |
+		LRADC_DELAY_TRIGGER(1 << ch2) | /* start both channels */
+		LRADC_DELAY_TRIGGER_DELAYS(0) |
+		LRADC_DELAY_LOOP(lradc->over_sample_cnt - 1) |
+		LRADC_DELAY_DELAY(lradc->over_sample_delay - 1),
+					LRADC_DELAY(3));
+
+	mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ(2) |
+			LRADC_CTRL1_LRADC_IRQ(3) | LRADC_CTRL1_LRADC_IRQ(4) |
+			LRADC_CTRL1_LRADC_IRQ(5), LRADC_CTRL1);
+
+	/* wake us again, when the conversions are done */
+	mxs_lradc_reg_set(lradc, LRADC_CTRL1_LRADC_IRQ_EN(ch2), LRADC_CTRL1);
+	/*
+	 * after changing the touchscreen plates setting
+	 * the signals need some initial time to settle. Start the
+	 * SoC's delay unit and start the conversion later
+	 * and automatically.
+	 */
+	mxs_lradc_reg_wrt(lradc, LRADC_DELAY_TRIGGER(0) | /* don't trigger ADC */
+		LRADC_DELAY_TRIGGER_DELAYS(1 << 3) | /* trigger DELAY unit#3 */
+		LRADC_DELAY_KICK |
+		LRADC_DELAY_DELAY(lradc->settling_delay), LRADC_DELAY(2));
+}
+
+static unsigned mxs_lradc_read_raw_channel(struct mxs_lradc *lradc,
+							unsigned channel)
+{
+	u32 reg;
+	unsigned num_samples, val;
+
+	reg = readl(lradc->base + LRADC_CH(channel));
+	if (reg & LRADC_CH_ACCUMULATE)
+		num_samples = lradc->over_sample_cnt;
+	else
+		num_samples = 1;
+
+	val = (reg & LRADC_CH_VALUE_MASK) >> LRADC_CH_VALUE_OFFSET;
+	return val / num_samples;
+}
+
+static unsigned mxs_lradc_read_ts_pressure(struct mxs_lradc *lradc,
+						unsigned ch1, unsigned ch2)
+{
+	u32 reg, mask;
+	unsigned pressure, m1, m2;
+
+	mask = LRADC_CTRL1_LRADC_IRQ(ch1) | LRADC_CTRL1_LRADC_IRQ(ch2);
+	reg = readl(lradc->base + LRADC_CTRL1) & mask;
+
+	while (reg != mask) {
+		reg = readl(lradc->base + LRADC_CTRL1) & mask;
+		dev_dbg(lradc->dev, "One channel is still busy: %X\n", reg);
+	}
+
+	m1 = mxs_lradc_read_raw_channel(lradc, ch1);
+	m2 = mxs_lradc_read_raw_channel(lradc, ch2);
+
+	if (m2 == 0) {
+		dev_warn(lradc->dev, "Cannot calculate pressure\n");
+		return 1 << (LRADC_RESOLUTION - 1);
+	}
+
+	/* simply scale the value from 0 ... max ADC resolution */
+	pressure = m1;
+	pressure *= (1 << LRADC_RESOLUTION);
+	pressure /= m2;
+
+	dev_dbg(lradc->dev, "Pressure = %u\n", pressure);
+	return pressure;
+}
+
+#define TS_CH_XP 2
+#define TS_CH_YP 3
+#define TS_CH_XM 4
+#define TS_CH_YM 5
+
+static int mxs_lradc_read_ts_channel(struct mxs_lradc *lradc)
+{
+	u32 reg;
+	int val;
+
+	reg = readl(lradc->base + LRADC_CTRL1);
+
+	/* only channels 3 to 5 are of interest here */
+	if (reg & LRADC_CTRL1_LRADC_IRQ(TS_CH_YP)) {
+		mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ_EN(TS_CH_YP) |
+			LRADC_CTRL1_LRADC_IRQ(TS_CH_YP), LRADC_CTRL1);
+		val = mxs_lradc_read_raw_channel(lradc, TS_CH_YP);
+	} else if (reg & LRADC_CTRL1_LRADC_IRQ(TS_CH_XM)) {
+		mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ_EN(TS_CH_XM) |
+			LRADC_CTRL1_LRADC_IRQ(TS_CH_XM), LRADC_CTRL1);
+		val = mxs_lradc_read_raw_channel(lradc, TS_CH_XM);
+	} else if (reg & LRADC_CTRL1_LRADC_IRQ(TS_CH_YM)) {
+		mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ_EN(TS_CH_YM) |
+			LRADC_CTRL1_LRADC_IRQ(TS_CH_YM), LRADC_CTRL1);
+		val = mxs_lradc_read_raw_channel(lradc, TS_CH_YM);
+	} else {
+		return -EIO;
+	}
+
+	mxs_lradc_reg_wrt(lradc, 0, LRADC_DELAY(2));
+	mxs_lradc_reg_wrt(lradc, 0, LRADC_DELAY(3));
+
+	return val;
+}
+
+/*
+ * YP(open)--+-------------+
+ *           |             |--+
+ *           |             |  |
+ *    YM(-)--+-------------+  |
+ *             +--------------+
+ *             |              |
+ *         XP(weak+)        XM(open)
+ *
+ * "weak+" means 200k Ohm VDDIO
+ * (-) means GND
+ */
+static void mxs_lradc_setup_touch_detection(struct mxs_lradc *lradc)
+{
+	/*
+	 * In order to detect a touch event the 'touch detect enable' bit
+	 * enables:
+	 *  - a weak pullup to the X+ connector
+	 *  - a strong ground at the Y- connector
+	 */
+	mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
+	mxs_lradc_reg_set(lradc, mxs_lradc_touch_detect_bit(lradc),
+				LRADC_CTRL0);
+}
+
+/*
+ * YP(meas)--+-------------+
+ *           |             |--+
+ *           |             |  |
+ * YM(open)--+-------------+  |
+ *             +--------------+
+ *             |              |
+ *           XP(+)          XM(-)
+ *
+ * (+) means here 1.85 V
+ * (-) means here GND
+ */
+static void mxs_lradc_prepare_x_pos(struct mxs_lradc *lradc)
+{
+	mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
+	mxs_lradc_reg_set(lradc, mxs_lradc_drive_x_plate(lradc), LRADC_CTRL0);
+
+	lradc->cur_plate = LRADC_SAMPLE_X;
+	mxs_lradc_setup_ts_channel(lradc, TS_CH_YP);
+}
+
+/*
+ *   YP(+)--+-------------+
+ *          |             |--+
+ *          |             |  |
+ *   YM(-)--+-------------+  |
+ *            +--------------+
+ *            |              |
+ *         XP(open)        XM(meas)
+ *
+ * (+) means here 1.85 V
+ * (-) means here GND
+ */
+static void mxs_lradc_prepare_y_pos(struct mxs_lradc *lradc)
+{
+	mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
+	mxs_lradc_reg_set(lradc, mxs_lradc_drive_y_plate(lradc), LRADC_CTRL0);
+
+	lradc->cur_plate = LRADC_SAMPLE_Y;
+	mxs_lradc_setup_ts_channel(lradc, TS_CH_XM);
+}
+
+/*
+ *    YP(+)--+-------------+
+ *           |             |--+
+ *           |             |  |
+ * YM(meas)--+-------------+  |
+ *             +--------------+
+ *             |              |
+ *          XP(meas)        XM(-)
+ *
+ * (+) means here 1.85 V
+ * (-) means here GND
+ */
+static void mxs_lradc_prepare_pressure(struct mxs_lradc *lradc)
+{
+	mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
+	mxs_lradc_reg_set(lradc, mxs_lradc_drive_pressure(lradc), LRADC_CTRL0);
+
+	lradc->cur_plate = LRADC_SAMPLE_PRESSURE;
+	mxs_lradc_setup_ts_pressure(lradc, TS_CH_XP, TS_CH_YM);
+}
+
+static void mxs_lradc_enable_touch_detection(struct mxs_lradc *lradc)
+{
+	mxs_lradc_setup_touch_detection(lradc);
+
+	lradc->cur_plate = LRADC_TOUCH;
+	mxs_lradc_reg_clear(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ |
+				LRADC_CTRL1_TOUCH_DETECT_IRQ_EN, LRADC_CTRL1);
+	mxs_lradc_reg_set(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ_EN, LRADC_CTRL1);
+}
+
+static void mxs_lradc_report_ts_event(struct mxs_lradc *lradc)
+{
+	input_report_abs(lradc->ts_input, ABS_X, lradc->ts_x_pos);
+	input_report_abs(lradc->ts_input, ABS_Y, lradc->ts_y_pos);
+	input_report_abs(lradc->ts_input, ABS_PRESSURE, lradc->ts_pressure);
+	input_report_key(lradc->ts_input, BTN_TOUCH, 1);
+	input_sync(lradc->ts_input);
+}
+
+static void mxs_lradc_complete_touch_event(struct mxs_lradc *lradc)
+{
+	mxs_lradc_setup_touch_detection(lradc);
+	lradc->cur_plate = LRADC_SAMPLE_VALID;
+	/*
+	 * start a dummy conversion to burn time to settle the signals
+	 * note: we are not interested in the conversion's value
+	 */
+	mxs_lradc_reg_wrt(lradc, 0, LRADC_CH(5));
+	mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ(5), LRADC_CTRL1);
+	mxs_lradc_reg_set(lradc, LRADC_CTRL1_LRADC_IRQ_EN(5), LRADC_CTRL1);
+	mxs_lradc_reg_wrt(lradc, LRADC_DELAY_TRIGGER(1 << 5) |
+		LRADC_DELAY_KICK | LRADC_DELAY_DELAY(10), /* waste 5 ms */
+			LRADC_DELAY(2));
+}
+
+/*
+ * in order to avoid false measurements, report only samples where
+ * the surface is still touched after the position measurement
+ */
+static void mxs_lradc_finish_touch_event(struct mxs_lradc *lradc, bool valid)
+{
+	/* if it is still touched, report the sample */
+	if (valid && mxs_lradc_check_touch_event(lradc)) {
+		lradc->ts_valid = true;
+		mxs_lradc_report_ts_event(lradc);
+	}
+
+	/* if it is even still touched, continue with the next measurement */
+	if (mxs_lradc_check_touch_event(lradc)) {
+		mxs_lradc_prepare_y_pos(lradc);
+		return;
+	}
+
+	if (lradc->ts_valid) {
+		/* signal the release */
+		lradc->ts_valid = false;
+		input_report_key(lradc->ts_input, BTN_TOUCH, 0);
+		input_sync(lradc->ts_input);
+	}
+
+	/* if it is released, wait for the next touch via IRQ */
+	mxs_lradc_reg_clear(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ, LRADC_CTRL1);
+	mxs_lradc_reg_set(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ_EN, LRADC_CTRL1);
+}
+
+/* touchscreen's state machine */
+static void mxs_lradc_handle_touch(struct mxs_lradc *lradc)
+{
+	int val;
+
+	switch (lradc->cur_plate) {
+	case LRADC_TOUCH:
+		/*
+		 * start with the Y-pos, because it uses nearly the same plate
+		 * settings like the touch detection
+		 */
+		if (mxs_lradc_check_touch_event(lradc)) {
+			mxs_lradc_reg_clear(lradc,
+					LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
+					LRADC_CTRL1);
+			mxs_lradc_prepare_y_pos(lradc);
+		}
+		mxs_lradc_reg_clear(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ,
+					LRADC_CTRL1);
+		return;
+
+	case LRADC_SAMPLE_Y:
+		val = mxs_lradc_read_ts_channel(lradc);
+		if (val < 0) {
+			mxs_lradc_enable_touch_detection(lradc); /* re-start */
+			return;
+		}
+		lradc->ts_y_pos = val;
+		mxs_lradc_prepare_x_pos(lradc);
+		return;
+
+	case LRADC_SAMPLE_X:
+		val = mxs_lradc_read_ts_channel(lradc);
+		if (val < 0) {
+			mxs_lradc_enable_touch_detection(lradc); /* re-start */
+			return;
+		}
+		lradc->ts_x_pos = val;
+		mxs_lradc_prepare_pressure(lradc);
+		return;
+
+	case LRADC_SAMPLE_PRESSURE:
+		lradc->ts_pressure =
+			mxs_lradc_read_ts_pressure(lradc, TS_CH_XP, TS_CH_YM);
+		mxs_lradc_complete_touch_event(lradc);
+		return;
+
+	case LRADC_SAMPLE_VALID:
+		val = mxs_lradc_read_ts_channel(lradc); /* ignore the value */
+		mxs_lradc_finish_touch_event(lradc, 1);
+		break;
+	}
+}
+
 /*
  * Raw I/O operations
  */
@@ -255,28 +783,27 @@ static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
 	if (!ret)
 		return -EBUSY;
 
-	INIT_COMPLETION(lradc->completion);
+	reinit_completion(&lradc->completion);
 
 	/*
 	 * No buffered operation in progress, map the channel and trigger it.
 	 * Virtual channel 0 is always used here as the others are always not
 	 * used if doing raw sampling.
 	 */
-	writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
-		lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
-	writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
+	if (lradc->soc == IMX28_LRADC)
+		mxs_lradc_reg_clear(lradc, LRADC_CTRL1_MX28_LRADC_IRQ_EN_MASK,
+			LRADC_CTRL1);
+	mxs_lradc_reg_clear(lradc, 0xff, LRADC_CTRL0);
 
 	/* Clean the slot's previous content, then set new one. */
-	writel(LRADC_CTRL4_LRADCSELECT_MASK(0),
-		lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
-	writel(chan->channel, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
+	mxs_lradc_reg_clear(lradc, LRADC_CTRL4_LRADCSELECT_MASK(0), LRADC_CTRL4);
+	mxs_lradc_reg_set(lradc, chan->channel, LRADC_CTRL4);
 
-	writel(0, lradc->base + LRADC_CH(0));
+	mxs_lradc_reg_wrt(lradc, 0, LRADC_CH(0));
 
 	/* Enable the IRQ and start sampling the channel. */
-	writel(LRADC_CTRL1_LRADC_IRQ_EN(0),
-		lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
-	writel(1 << 0, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
+	mxs_lradc_reg_set(lradc, LRADC_CTRL1_LRADC_IRQ_EN(0), LRADC_CTRL1);
+	mxs_lradc_reg_set(lradc, 1 << 0, LRADC_CTRL0);
 
 	/* Wait for completion on the channel, 1 second max. */
 	ret = wait_for_completion_killable_timeout(&lradc->completion, HZ);
@@ -290,8 +817,7 @@ static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
 	ret = IIO_VAL_INT;
 
 err:
-	writel(LRADC_CTRL1_LRADC_IRQ_EN(0),
-		lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
+	mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ_EN(0), LRADC_CTRL1);
 
 	mutex_unlock(&lradc->lock);
 
@@ -303,220 +829,33 @@ static const struct iio_info mxs_lradc_iio_info = {
 	.read_raw		= mxs_lradc_read_raw,
 };
 
-/*
- * Touchscreen handling
- */
-enum lradc_ts_plate {
-	LRADC_SAMPLE_X,
-	LRADC_SAMPLE_Y,
-	LRADC_SAMPLE_PRESSURE,
-};
-
-static int mxs_lradc_ts_touched(struct mxs_lradc *lradc)
-{
-	uint32_t reg;
-
-	/* Enable touch detection. */
-	writel(LRADC_CTRL0_PLATE_MASK,
-		lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
-	writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
-		lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
-
-	msleep(LRADC_TS_SAMPLE_DELAY_MS);
-
-	reg = readl(lradc->base + LRADC_STATUS);
-
-	return reg & LRADC_STATUS_TOUCH_DETECT_RAW;
-}
-
-static int32_t mxs_lradc_ts_sample(struct mxs_lradc *lradc,
-				enum lradc_ts_plate plate, int change)
-{
-	unsigned long delay, jiff;
-	uint32_t reg, ctrl0 = 0, chan = 0;
-	/* The touchscreen always uses CTRL4 slot #7. */
-	const uint8_t slot = 7;
-	uint32_t val;
-
-	/*
-	 * There are three correct configurations of the controller sampling
-	 * the touchscreen, each of these configuration provides different
-	 * information from the touchscreen.
-	 *
-	 * The following table describes the sampling configurations:
-	 * +-------------+-------+-------+-------+
-	 * | Wire \ Axis |   X   |   Y   |   Z   |
-	 * +---------------------+-------+-------+
-	 * |   X+ (CH2)  |   HI  |   TS  |   TS  |
-	 * +-------------+-------+-------+-------+
-	 * |   X- (CH4)  |   LO  |   SH  |   HI  |
-	 * +-------------+-------+-------+-------+
-	 * |   Y+ (CH3)  |   SH  |   HI  |   HI  |
-	 * +-------------+-------+-------+-------+
-	 * |   Y- (CH5)  |   TS  |   LO  |   SH  |
-	 * +-------------+-------+-------+-------+
-	 *
-	 * HI ... strong '1'  ; LO ... strong '0'
-	 * SH ... sample here ; TS ... tri-state
-	 *
-	 * There are a few other ways of obtaining the Z coordinate
-	 * (aka. pressure), but the one in the table seems to be the
-	 * most reliable one.
-	 */
-	switch (plate) {
-	case LRADC_SAMPLE_X:
-		ctrl0 = LRADC_CTRL0_XPPSW | LRADC_CTRL0_XNNSW;
-		chan = 3;
-		break;
-	case LRADC_SAMPLE_Y:
-		ctrl0 = LRADC_CTRL0_YPPSW | LRADC_CTRL0_YNNSW;
-		chan = 4;
-		break;
-	case LRADC_SAMPLE_PRESSURE:
-		ctrl0 = LRADC_CTRL0_YPPSW | LRADC_CTRL0_XNNSW;
-		chan = 5;
-		break;
-	}
-
-	if (change) {
-		writel(LRADC_CTRL0_PLATE_MASK,
-			lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
-		writel(ctrl0, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
-
-		writel(LRADC_CTRL4_LRADCSELECT_MASK(slot),
-			lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
-		writel(chan << LRADC_CTRL4_LRADCSELECT_OFFSET(slot),
-			lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
-	}
-
-	writel(0xffffffff, lradc->base + LRADC_CH(slot) + STMP_OFFSET_REG_CLR);
-	writel(1 << slot, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
-
-	delay = jiffies + msecs_to_jiffies(LRADC_TS_SAMPLE_DELAY_MS);
-	do {
-		jiff = jiffies;
-		reg = readl_relaxed(lradc->base + LRADC_CTRL1);
-		if (reg & LRADC_CTRL1_LRADC_IRQ(slot))
-			break;
-	} while (time_before(jiff, delay));
-
-	writel(LRADC_CTRL1_LRADC_IRQ(slot),
-		lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
-
-	if (time_after_eq(jiff, delay))
-		return -ETIMEDOUT;
-
-	val = readl(lradc->base + LRADC_CH(slot));
-	val &= LRADC_CH_VALUE_MASK;
-
-	return val;
-}
-
-static int32_t mxs_lradc_ts_sample_filter(struct mxs_lradc *lradc,
-				enum lradc_ts_plate plate)
-{
-	int32_t val, tot = 0;
-	int i;
-
-	val = mxs_lradc_ts_sample(lradc, plate, 1);
-
-	/* Delay a bit so the touchscreen is stable. */
-	mdelay(2);
-
-	for (i = 0; i < LRADC_TS_SAMPLE_AMOUNT; i++) {
-		val = mxs_lradc_ts_sample(lradc, plate, 0);
-		tot += val;
-	}
-
-	return tot / LRADC_TS_SAMPLE_AMOUNT;
-}
-
-static void mxs_lradc_ts_work(struct work_struct *ts_work)
-{
-	struct mxs_lradc *lradc = container_of(ts_work,
-				struct mxs_lradc, ts_work);
-	int val_x, val_y, val_p;
-	bool valid = false;
-
-	while (mxs_lradc_ts_touched(lradc)) {
-		/* Disable touch detector so we can sample the touchscreen. */
-		writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
-			lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
-
-		if (likely(valid)) {
-			input_report_abs(lradc->ts_input, ABS_X, val_x);
-			input_report_abs(lradc->ts_input, ABS_Y, val_y);
-			input_report_abs(lradc->ts_input, ABS_PRESSURE, val_p);
-			input_report_key(lradc->ts_input, BTN_TOUCH, 1);
-			input_sync(lradc->ts_input);
-		}
-
-		valid = false;
-
-		val_x = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_X);
-		if (val_x < 0)
-			continue;
-		val_y = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_Y);
-		if (val_y < 0)
-			continue;
-		val_p = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_PRESSURE);
-		if (val_p < 0)
-			continue;
-
-		valid = true;
-	}
-
-	input_report_abs(lradc->ts_input, ABS_PRESSURE, 0);
-	input_report_key(lradc->ts_input, BTN_TOUCH, 0);
-	input_sync(lradc->ts_input);
-
-	/* Do not restart the TS IRQ if the driver is shutting down. */
-	if (lradc->stop_touchscreen)
-		return;
-
-	/* Restart the touchscreen interrupts. */
-	writel(LRADC_CTRL1_TOUCH_DETECT_IRQ,
-		lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
-	writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
-		lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
-}
-
 static int mxs_lradc_ts_open(struct input_dev *dev)
 {
 	struct mxs_lradc *lradc = input_get_drvdata(dev);
 
-	/* The touchscreen is starting. */
-	lradc->stop_touchscreen = false;
-
 	/* Enable the touch-detect circuitry. */
-	writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
-		lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
-
-	/* Enable the touch-detect IRQ. */
-	writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
-		lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
+	mxs_lradc_enable_touch_detection(lradc);
 
 	return 0;
 }
 
-static void mxs_lradc_ts_close(struct input_dev *dev)
+static void mxs_lradc_disable_ts(struct mxs_lradc *lradc)
 {
-	struct mxs_lradc *lradc = input_get_drvdata(dev);
+	/* stop all interrupts from firing */
+	mxs_lradc_reg_clear(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ_EN |
+		LRADC_CTRL1_LRADC_IRQ_EN(2) | LRADC_CTRL1_LRADC_IRQ_EN(3) |
+		LRADC_CTRL1_LRADC_IRQ_EN(4) | LRADC_CTRL1_LRADC_IRQ_EN(5),
+		LRADC_CTRL1);
 
-	/* Indicate the touchscreen is stopping. */
-	lradc->stop_touchscreen = true;
-	mb();
-
-	/* Wait until touchscreen thread finishes any possible remnants. */
-	cancel_work_sync(&lradc->ts_work);
+	/* Power-down touchscreen touch-detect circuitry. */
+	mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
+}
 
-	/* Disable touchscreen touch-detect IRQ. */
-	writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
-		lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
+static void mxs_lradc_ts_close(struct input_dev *dev)
+{
+	struct mxs_lradc *lradc = input_get_drvdata(dev);
 
-	/* Power-down touchscreen touch-detect circuitry. */
-	writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
-		lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
+	mxs_lradc_disable_ts(lradc);
 }
 
 static int mxs_lradc_ts_register(struct mxs_lradc *lradc)
@@ -529,10 +868,8 @@ static int mxs_lradc_ts_register(struct mxs_lradc *lradc)
 		return 0;
 
 	input = input_allocate_device();
-	if (!input) {
-		dev_err(dev, "Failed to allocate TS device!\n");
+	if (!input)
 		return -ENOMEM;
-	}
 
 	input->name = DRIVER_NAME;
 	input->id.bustype = BUS_HOST;
@@ -562,8 +899,7 @@ static void mxs_lradc_ts_unregister(struct mxs_lradc *lradc)
 	if (!lradc->use_touchscreen)
 		return;
 
-	cancel_work_sync(&lradc->ts_work);
-
+	mxs_lradc_disable_ts(lradc);
 	input_unregister_device(lradc->ts_input);
 }
 
@@ -576,31 +912,24 @@ static irqreturn_t mxs_lradc_handle_irq(int irq, void *data)
 	struct mxs_lradc *lradc = iio_priv(iio);
 	unsigned long reg = readl(lradc->base + LRADC_CTRL1);
 	const uint32_t ts_irq_mask =
-		LRADC_CTRL1_TOUCH_DETECT_IRQ_EN |
-		LRADC_CTRL1_TOUCH_DETECT_IRQ;
+		LRADC_CTRL1_TOUCH_DETECT_IRQ |
+		LRADC_CTRL1_LRADC_IRQ(2) |
+		LRADC_CTRL1_LRADC_IRQ(3) |
+		LRADC_CTRL1_LRADC_IRQ(4) |
+		LRADC_CTRL1_LRADC_IRQ(5);
 
-	if (!(reg & LRADC_CTRL1_LRADC_IRQ_MASK))
+	if (!(reg & mxs_lradc_irq_mask(lradc)))
 		return IRQ_NONE;
 
-	/*
-	 * Touchscreen IRQ handling code has priority and therefore
-	 * is placed here. In case touchscreen IRQ arrives, disable
-	 * it ASAP
-	 */
-	if (reg & LRADC_CTRL1_TOUCH_DETECT_IRQ) {
-		writel(ts_irq_mask,
-			lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
-		if (!lradc->stop_touchscreen)
-			schedule_work(&lradc->ts_work);
-	}
+	if (lradc->use_touchscreen && (reg & ts_irq_mask))
+		mxs_lradc_handle_touch(lradc);
 
 	if (iio_buffer_enabled(iio))
 		iio_trigger_poll(iio->trig, iio_get_time_ns());
 	else if (reg & LRADC_CTRL1_LRADC_IRQ(0))
 		complete(&lradc->completion);
 
-	writel(reg & LRADC_CTRL1_LRADC_IRQ_MASK,
-		lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
+	mxs_lradc_reg_clear(lradc, reg & mxs_lradc_irq_mask(lradc), LRADC_CTRL1);
 
 	return IRQ_HANDLED;
 }
@@ -619,19 +948,13 @@ static irqreturn_t mxs_lradc_trigger_handler(int irq, void *p)
 
 	for_each_set_bit(i, iio->active_scan_mask, LRADC_MAX_TOTAL_CHANS) {
 		lradc->buffer[j] = readl(lradc->base + LRADC_CH(j));
-		writel(chan_value, lradc->base + LRADC_CH(j));
+		mxs_lradc_reg_wrt(lradc, chan_value, LRADC_CH(j));
 		lradc->buffer[j] &= LRADC_CH_VALUE_MASK;
 		lradc->buffer[j] /= LRADC_DELAY_TIMER_LOOP;
 		j++;
 	}
 
-	if (iio->scan_timestamp) {
-		s64 *timestamp = (s64 *)((u8 *)lradc->buffer +
-					ALIGN(j, sizeof(s64)));
-		*timestamp = pf->timestamp;
-	}
-
-	iio_push_to_buffers(iio, (u8 *)lradc->buffer);
+	iio_push_to_buffers_with_timestamp(iio, lradc->buffer, pf->timestamp);
 
 	iio_trigger_notify_done(iio->trig);
 
@@ -644,7 +967,7 @@ static int mxs_lradc_configure_trigger(struct iio_trigger *trig, bool state)
 	struct mxs_lradc *lradc = iio_priv(iio);
 	const uint32_t st = state ? STMP_OFFSET_REG_SET : STMP_OFFSET_REG_CLR;
 
-	writel(LRADC_DELAY_KICK, lradc->base + LRADC_DELAY(0) + st);
+	mxs_lradc_reg_wrt(lradc, LRADC_DELAY_KICK, LRADC_DELAY(0) + st);
 
 	return 0;
 }
@@ -716,38 +1039,30 @@ static int mxs_lradc_buffer_preenable(struct iio_dev *iio)
 		goto err_mem;
 	}
 
-	ret = iio_sw_buffer_preenable(iio);
-	if (ret < 0)
-		goto err_buf;
-
-	writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
-		lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
-	writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
+	if (lradc->soc == IMX28_LRADC)
+		mxs_lradc_reg_clear(lradc, LRADC_CTRL1_MX28_LRADC_IRQ_EN_MASK,
+							LRADC_CTRL1);
+	mxs_lradc_reg_clear(lradc, 0xff, LRADC_CTRL0);
 
 	for_each_set_bit(chan, iio->active_scan_mask, LRADC_MAX_TOTAL_CHANS) {
 		ctrl4_set |= chan << LRADC_CTRL4_LRADCSELECT_OFFSET(ofs);
 		ctrl4_clr |= LRADC_CTRL4_LRADCSELECT_MASK(ofs);
 		ctrl1_irq |= LRADC_CTRL1_LRADC_IRQ_EN(ofs);
-		writel(chan_value, lradc->base + LRADC_CH(ofs));
+		mxs_lradc_reg_wrt(lradc, chan_value, LRADC_CH(ofs));
 		bitmap_set(&enable, ofs, 1);
 		ofs++;
 	}
 
-	writel(LRADC_DELAY_TRIGGER_LRADCS_MASK | LRADC_DELAY_KICK,
-		lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_CLR);
-
-	writel(ctrl4_clr, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
-	writel(ctrl4_set, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
-
-	writel(ctrl1_irq, lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
-
-	writel(enable << LRADC_DELAY_TRIGGER_LRADCS_OFFSET,
-		lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_SET);
+	mxs_lradc_reg_clear(lradc, LRADC_DELAY_TRIGGER_LRADCS_MASK |
+					LRADC_DELAY_KICK, LRADC_DELAY(0));
+	mxs_lradc_reg_clear(lradc, ctrl4_clr, LRADC_CTRL4);
+	mxs_lradc_reg_set(lradc, ctrl4_set, LRADC_CTRL4);
+	mxs_lradc_reg_set(lradc, ctrl1_irq, LRADC_CTRL1);
+	mxs_lradc_reg_set(lradc, enable << LRADC_DELAY_TRIGGER_LRADCS_OFFSET,
+					LRADC_DELAY(0));
 
 	return 0;
 
-err_buf:
-	kfree(lradc->buffer);
 err_mem:
 	mutex_unlock(&lradc->lock);
 	return ret;
@@ -757,12 +1072,13 @@ static int mxs_lradc_buffer_postdisable(struct iio_dev *iio)
 {
 	struct mxs_lradc *lradc = iio_priv(iio);
 
-	writel(LRADC_DELAY_TRIGGER_LRADCS_MASK | LRADC_DELAY_KICK,
-		lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_CLR);
+	mxs_lradc_reg_clear(lradc, LRADC_DELAY_TRIGGER_LRADCS_MASK |
+					LRADC_DELAY_KICK, LRADC_DELAY(0));
 
-	writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
-	writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
-		lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
+	mxs_lradc_reg_clear(lradc, 0xff, LRADC_CTRL0);
+	if (lradc->soc == IMX28_LRADC)
+		mxs_lradc_reg_clear(lradc, LRADC_CTRL1_MX28_LRADC_IRQ_EN_MASK,
+					LRADC_CTRL1);
 
 	kfree(lradc->buffer);
 	mutex_unlock(&lradc->lock);
@@ -857,24 +1173,25 @@ static int mxs_lradc_hw_init(struct mxs_lradc *lradc)
 		return ret;
 
 	/* Configure DELAY CHANNEL 0 for generic ADC sampling. */
-	writel(adc_cfg, lradc->base + LRADC_DELAY(0));
+	mxs_lradc_reg_wrt(lradc, adc_cfg, LRADC_DELAY(0));
 
 	/* Disable remaining DELAY CHANNELs */
-	writel(0, lradc->base + LRADC_DELAY(1));
-	writel(0, lradc->base + LRADC_DELAY(2));
-	writel(0, lradc->base + LRADC_DELAY(3));
+	mxs_lradc_reg_wrt(lradc, 0, LRADC_DELAY(1));
+	mxs_lradc_reg_wrt(lradc, 0, LRADC_DELAY(2));
+	mxs_lradc_reg_wrt(lradc, 0, LRADC_DELAY(3));
 
 	/* Configure the touchscreen type */
-	writel(LRADC_CTRL0_TOUCH_SCREEN_TYPE,
-		lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
+	if (lradc->soc == IMX28_LRADC) {
+		mxs_lradc_reg_clear(lradc, LRADC_CTRL0_MX28_TOUCH_SCREEN_TYPE,
+							LRADC_CTRL0);
 
-	if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_5WIRE) {
-		writel(LRADC_CTRL0_TOUCH_SCREEN_TYPE,
-			lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
+	if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_5WIRE)
+		mxs_lradc_reg_set(lradc, LRADC_CTRL0_MX28_TOUCH_SCREEN_TYPE,
+				LRADC_CTRL0);
 	}
 
 	/* Start internal temperature sensing. */
-	writel(0, lradc->base + LRADC_CTRL2);
+	mxs_lradc_reg_wrt(lradc, 0, LRADC_CTRL2);
 
 	return 0;
 }
@@ -883,11 +1200,10 @@ static void mxs_lradc_hw_stop(struct mxs_lradc *lradc)
 {
 	int i;
 
-	writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
-		lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
+	mxs_lradc_reg_clear(lradc, mxs_lradc_irq_en_mask(lradc), LRADC_CTRL1);
 
 	for (i = 0; i < LRADC_MAX_DELAY_CHANS; i++)
-		writel(0, lradc->base + LRADC_DELAY(i));
+		mxs_lradc_reg_wrt(lradc, 0, LRADC_DELAY(i));
 }
 
 static const struct of_device_id mxs_lradc_dt_ids[] = {
@@ -897,6 +1213,52 @@ static const struct of_device_id mxs_lradc_dt_ids[] = {
 };
 MODULE_DEVICE_TABLE(of, mxs_lradc_dt_ids);
 
+static int mxs_lradc_probe_touchscreen(struct mxs_lradc *lradc,
+						struct device_node *lradc_node)
+{
+	int ret;
+	u32 ts_wires = 0, adapt;
+
+	ret = of_property_read_u32(lradc_node, "fsl,lradc-touchscreen-wires",
+				&ts_wires);
+	if (ret)
+		return -ENODEV; /* touchscreen feature disabled */
+
+	switch (ts_wires) {
+	case 4:
+		lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_4WIRE;
+		break;
+	case 5:
+		if (lradc->soc == IMX28_LRADC) {
+			lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_5WIRE;
+			break;
+		}
+		/* fall through an error message for i.MX23 */
+	default:
+		dev_err(lradc->dev,
+			"Unsupported number of touchscreen wires (%d)\n",
+			ts_wires);
+		return -EINVAL;
+	}
+
+	lradc->over_sample_cnt = 4;
+	ret = of_property_read_u32(lradc_node, "fsl,ave-ctrl", &adapt);
+	if (ret == 0)
+		lradc->over_sample_cnt = adapt;
+
+	lradc->over_sample_delay = 2;
+	ret = of_property_read_u32(lradc_node, "fsl,ave-delay", &adapt);
+	if (ret == 0)
+		lradc->over_sample_delay = adapt;
+
+	lradc->settling_delay = 10;
+	ret = of_property_read_u32(lradc_node, "fsl,settling", &adapt);
+	if (ret == 0)
+		lradc->settling_delay = adapt;
+
+	return 0;
+}
+
 static int mxs_lradc_probe(struct platform_device *pdev)
 {
 	const struct of_device_id *of_id =
@@ -908,8 +1270,7 @@ static int mxs_lradc_probe(struct platform_device *pdev)
 	struct mxs_lradc *lradc;
 	struct iio_dev *iio;
 	struct resource *iores;
-	uint32_t ts_wires = 0;
-	int ret = 0;
+	int ret = 0, touch_ret;
 	int i;
 
 	/* Allocate the IIO device. */
@@ -920,6 +1281,7 @@ static int mxs_lradc_probe(struct platform_device *pdev)
 	}
 
 	lradc = iio_priv(iio);
+	lradc->soc = (enum mxs_lradc_id)of_id->data;
 
 	/* Grab the memory area */
 	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -928,20 +1290,18 @@ static int mxs_lradc_probe(struct platform_device *pdev)
 	if (IS_ERR(lradc->base))
 		return PTR_ERR(lradc->base);
 
-	INIT_WORK(&lradc->ts_work, mxs_lradc_ts_work);
+	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 != 0) {
+		dev_err(dev, "Failed to enable the delay unit clock\n");
+		return ret;
+	}
 
-	/* Check if touchscreen is enabled in DT. */
-	ret = of_property_read_u32(node, "fsl,lradc-touchscreen-wires",
-				&ts_wires);
-	if (ret)
-		dev_info(dev, "Touchscreen not enabled.\n");
-	else if (ts_wires == 4)
-		lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_4WIRE;
-	else if (ts_wires == 5)
-		lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_5WIRE;
-	else
-		dev_warn(dev, "Unsupported number of touchscreen wires (%d)\n",
-				ts_wires);
+	touch_ret = mxs_lradc_probe_touchscreen(lradc, node);
 
 	/* Grab all IRQ sources */
 	for (i = 0; i < of_cfg->irq_count; i++) {
@@ -985,9 +1345,11 @@ static int mxs_lradc_probe(struct platform_device *pdev)
 		goto err_dev;
 
 	/* Register the touchscreen input device. */
-	ret = mxs_lradc_ts_register(lradc);
-	if (ret)
-		goto err_dev;
+	if (touch_ret == 0) {
+		ret = mxs_lradc_ts_register(lradc);
+		if (ret)
+			goto err_ts_register;
+	}
 
 	/* Register IIO device. */
 	ret = iio_device_register(iio);
@@ -1000,6 +1362,8 @@ static int mxs_lradc_probe(struct platform_device *pdev)
 
 err_ts:
 	mxs_lradc_ts_unregister(lradc);
+err_ts_register:
+	mxs_lradc_hw_stop(lradc);
 err_dev:
 	mxs_lradc_trigger_remove(iio);
 err_trig:
@@ -1012,14 +1376,13 @@ static int mxs_lradc_remove(struct platform_device *pdev)
 	struct iio_dev *iio = platform_get_drvdata(pdev);
 	struct mxs_lradc *lradc = iio_priv(iio);
 
+	iio_device_unregister(iio);
 	mxs_lradc_ts_unregister(lradc);
-
 	mxs_lradc_hw_stop(lradc);
-
-	iio_device_unregister(iio);
-	iio_triggered_buffer_cleanup(iio);
 	mxs_lradc_trigger_remove(iio);
+	iio_triggered_buffer_cleanup(iio);
 
+	clk_disable_unprepare(lradc->clk);
 	return 0;
 }
 
@@ -1038,3 +1401,4 @@ module_platform_driver(mxs_lradc_driver);
 MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
 MODULE_DESCRIPTION("Freescale i.MX28 LRADC driver");
 MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRIVER_NAME);