ads7846: convert to input_allocate_device

Patch from David Brownell and Dmitry Torokhov: convert the ads7846 driver
to use input_allocate_device. Also fixes the bug where the SPI message was
not initialized with spi_message_init().
Signed-off-by: Imre Deak <imre.deak@nokia.com>
Signed-off-by: Juha Yrjl <juha.yrjola@nokia.com>

drivers/input/touchscreen/ads7846.c

@@ -48,10 +48,13 @@
 
 #define	TS_POLL_PERIOD	msecs_to_jiffies(10)
 
+/* this driver doesn't aim at the peak continuous sample rate */
+#define	SAMPLE_BITS	(8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
+
 struct ts_event {
 	/* For portability, we can't read 12 bit values using SPI (which
 	 * would make the controller deliver them as native byteorder u16
-	 * with msbs zeroed).  Instead, we read them as two 8-byte values,
+	 * with msbs zeroed).  Instead, we read them as two 8-bit values,
 	 * which need byteswapping then range adjustment.
 	 */
 	__be16 x;
@@ -60,7 +63,7 @@ struct ts_event {
 };
 
 struct ads7846 {
-	struct input_dev	input;
+	struct input_dev	*input;
 	char			phys[32];
 
 	struct spi_device	*spi;
@@ -68,6 +71,7 @@ struct ads7846 {
 	u16			vref_delay_usecs;
 	u16			x_plate_ohms;
 
+	u8			read_x, read_y, read_z1, read_z2;
 	struct ts_event		tc;
 
 	struct spi_transfer	xfer[8];
@@ -117,10 +121,10 @@ struct ads7846 {
 #define	READ_12BIT_DFR(x) (ADS_START | ADS_A2A1A0_d_ ## x \
 	| ADS_12_BIT | ADS_DFR)
 
-static const u8	read_y  = READ_12BIT_DFR(y)  | ADS_PD10_ADC_ON;
-static const u8	read_z1 = READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON;
-static const u8	read_z2 = READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON;
-static const u8	read_x  = READ_12BIT_DFR(x)  | ADS_PD10_PDOWN;	/* LAST */
+#define	READ_Y	(READ_12BIT_DFR(y)  | ADS_PD10_ADC_ON)
+#define	READ_Z1	(READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON)
+#define	READ_Z2	(READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON)
+#define	READ_X	(READ_12BIT_DFR(x)  | ADS_PD10_PDOWN)	/* LAST */
 
 /* single-ended samples need to first power up reference voltage;
  * we leave both ADC and VREF powered
@@ -128,8 +132,8 @@ static const u8	read_x  = READ_12BIT_DFR(x)  | ADS_PD10_PDOWN;	/* LAST */
 #define	READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
 	| ADS_12_BIT | ADS_SER)
 
-static const u8	ref_on = READ_12BIT_DFR(x) | ADS_PD10_ALL_ON;
-static const u8	ref_off = READ_12BIT_DFR(y) | ADS_PD10_PDOWN;
+#define	REF_ON	(READ_12BIT_DFR(x) | ADS_PD10_ALL_ON)
+#define	REF_OFF	(READ_12BIT_DFR(y) | ADS_PD10_PDOWN)
 
 /*--------------------------------------------------------------------------*/
 
@@ -138,7 +142,9 @@ static const u8	ref_off = READ_12BIT_DFR(y) | ADS_PD10_PDOWN;
  */
 
 struct ser_req {
+	u8			ref_on;
 	u8			command;
+	u8			ref_off;
 	u16			scratch;
 	__be16			sample;
 	struct spi_message	msg;
@@ -152,7 +158,7 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
 	struct ser_req		*req = kzalloc(sizeof *req, SLAB_KERNEL);
 	int			status;
 	int			sample;
-	int 			i;
+	int			i;
 
 	if (!req)
 		return -ENOMEM;
@@ -160,7 +166,8 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
 	INIT_LIST_HEAD(&req->msg.transfers);
 
 	/* activate reference, so it has time to settle; */
-	req->xfer[0].tx_buf = &ref_on;
+	req->ref_on = REF_ON;
+	req->xfer[0].tx_buf = &req->ref_on;
 	req->xfer[0].len = 1;
 	req->xfer[1].rx_buf = &req->scratch;
 	req->xfer[1].len = 2;
@@ -182,7 +189,8 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
 	/* REVISIT:  take a few more samples, and compare ... */
 
 	/* turn off reference */
-	req->xfer[4].tx_buf = &ref_off;
+	req->ref_off = REF_OFF;
+	req->xfer[4].tx_buf = &req->ref_off;
 	req->xfer[4].len = 1;
 	req->xfer[5].rx_buf = &req->scratch;
 	req->xfer[5].len = 2;
@@ -236,11 +244,12 @@ SHOW(vbatt)
 
 static void ads7846_rx(void *ads)
 {
-	struct ads7846	*ts = ads;
-	unsigned	Rt;
-	unsigned	sync = 0;
-	u16		x, y, z1, z2;
-	unsigned long	flags;
+	struct ads7846		*ts = ads;
+	struct input_dev	*input_dev = ts->input;
+	unsigned		Rt;
+	unsigned		sync = 0;
+	u16			x, y, z1, z2;
+	unsigned long		flags;
 
 	/* adjust:  12 bit samples (left aligned), built from
 	 * two 8 bit values writen msb-first.
@@ -276,21 +285,21 @@ static void ads7846_rx(void *ads)
 	 * won't notice that, even if nPENIRQ never fires ...
 	 */
 	if (!ts->pendown && Rt != 0) {
-		input_report_key(&ts->input, BTN_TOUCH, 1);
+		input_report_key(input_dev, BTN_TOUCH, 1);
 		sync = 1;
 	} else if (ts->pendown && Rt == 0) {
-		input_report_key(&ts->input, BTN_TOUCH, 0);
+		input_report_key(input_dev, BTN_TOUCH, 0);
 		sync = 1;
 	}
 
 	if (Rt) {
-		input_report_abs(&ts->input, ABS_X, x);
-		input_report_abs(&ts->input, ABS_Y, y);
-		input_report_abs(&ts->input, ABS_PRESSURE, Rt);
+		input_report_abs(input_dev, ABS_X, x);
+		input_report_abs(input_dev, ABS_Y, y);
+		input_report_abs(input_dev, ABS_PRESSURE, Rt);
 		sync = 1;
 	}
 	if (sync)
-		input_sync(&ts->input);
+		input_sync(input_dev);
 
 #ifdef	VERBOSE
 	if (Rt || ts->pendown)
@@ -396,9 +405,10 @@ static int ads7846_resume(struct spi_device *spi)
 static int __devinit ads7846_probe(struct spi_device *spi)
 {
 	struct ads7846			*ts;
+	struct input_dev		*input_dev;
 	struct ads7846_platform_data	*pdata = spi->dev.platform_data;
 	struct spi_transfer		*x;
-	int				i;
+	int				err;
 
 	if (!spi->irq) {
 		dev_dbg(&spi->dev, "no IRQ?\n");
@@ -411,9 +421,9 @@ static int __devinit ads7846_probe(struct spi_device *spi)
 	}
 
 	/* don't exceed max specified sample rate */
-	if (spi->max_speed_hz > (125000 * 16)) {
+	if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
 		dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
-				(spi->max_speed_hz/16)/1000);
+				(spi->max_speed_hz/SAMPLE_BITS)/1000);
 		return -EINVAL;
 	}
 
@@ -423,13 +433,18 @@ static int __devinit ads7846_probe(struct spi_device *spi)
 	 * to discard the four garbage LSBs.
 	 */
 
-	if (!(ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL)))
-		return -ENOMEM;
+	ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
+	input_dev = input_allocate_device();
+	if (!ts || !input_dev) {
+		err = -ENOMEM;
+		goto err_free_mem;
+	}
 
 	dev_set_drvdata(&spi->dev, ts);
+	spi->dev.power.power_state = PMSG_ON;
 
 	ts->spi = spi;
-	spi->dev.power.power_state = PMSG_ON;
+	ts->input = input_dev;
 
 	init_timer(&ts->timer);
 	ts->timer.data = (unsigned long) ts;
@@ -439,70 +454,80 @@ static int __devinit ads7846_probe(struct spi_device *spi)
 	ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
 	ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
 
-	init_input_dev(&ts->input);
+	snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
 
-	ts->input.dev = &spi->dev;
-	ts->input.name = "ADS784x Touchscreen";
-	snprintf(ts->phys, sizeof ts->phys, "%s/input0", spi->dev.bus_id);
-	ts->input.phys = ts->phys;
+	input_dev->name = "ADS784x Touchscreen";
+	input_dev->phys = ts->phys;
+	input_dev->cdev.dev = &spi->dev;
 
-	ts->input.evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
-	ts->input.keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
-	input_set_abs_params(&ts->input, ABS_X,
+	input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
+	input_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
+	input_set_abs_params(input_dev, ABS_X,
 			pdata->x_min ? : 0,
 			pdata->x_max ? : MAX_12BIT,
 			0, 0);
-	input_set_abs_params(&ts->input, ABS_Y,
+	input_set_abs_params(input_dev, ABS_Y,
 			pdata->y_min ? : 0,
 			pdata->y_max ? : MAX_12BIT,
 			0, 0);
-	input_set_abs_params(&ts->input, ABS_PRESSURE,
+	input_set_abs_params(input_dev, ABS_PRESSURE,
 			pdata->pressure_min, pdata->pressure_max, 0, 0);
 
-	input_register_device(&ts->input);
-
 	/* set up the transfers to read touchscreen state; this assumes we
 	 * use formula #2 for pressure, not #3.
 	 */
+	INIT_LIST_HEAD(&ts->msg.transfers);
 	x = ts->xfer;
 
 	/* y- still on; turn on only y+ (and ADC) */
-	x->tx_buf = &read_y;
+	ts->read_y = READ_Y;
+	x->tx_buf = &ts->read_y;
 	x->len = 1;
+	spi_message_add_tail(x, &ts->msg);
+
 	x++;
 	x->rx_buf = &ts->tc.y;
 	x->len = 2;
-	x++;
+	spi_message_add_tail(x, &ts->msg);
 
 	/* turn y+ off, x- on; we'll use formula #2 */
 	if (ts->model == 7846) {
-		x->tx_buf = &read_z1;
+		x++;
+		ts->read_z1 = READ_Z1;
+		x->tx_buf = &ts->read_z1;
 		x->len = 1;
+		spi_message_add_tail(x, &ts->msg);
+
 		x++;
 		x->rx_buf = &ts->tc.z1;
 		x->len = 2;
-		x++;
+		spi_message_add_tail(x, &ts->msg);
 
-		x->tx_buf = &read_z2;
+		x++;
+		ts->read_z2 = READ_Z2;
+		x->tx_buf = &ts->read_z2;
 		x->len = 1;
+		spi_message_add_tail(x, &ts->msg);
+
 		x++;
 		x->rx_buf = &ts->tc.z2;
 		x->len = 2;
-		x++;
+		spi_message_add_tail(x, &ts->msg);
 	}
 
 	/* turn y- off, x+ on, then leave in lowpower */
-	x->tx_buf = &read_x;
+	x++;
+	ts->read_x = READ_X;
+	x->tx_buf = &ts->read_x;
 	x->len = 1;
+	spi_message_add_tail(x, &ts->msg);
+
 	x++;
 	x->rx_buf = &ts->tc.x;
 	x->len = 2;
-	x++;
-
-	CS_CHANGE(x[-1]);
+	CS_CHANGE(*x);
+	spi_message_add_tail(x, &ts->msg);
 
-	for (i = 0; i < x - ts->xfer; i++)
-		spi_message_add_tail(&ts->xfer[i], &ts->msg);
 	ts->msg.complete = ads7846_rx;
 	ts->msg.context = ts;
 
@@ -510,9 +535,8 @@ static int __devinit ads7846_probe(struct spi_device *spi)
 			SA_SAMPLE_RANDOM | SA_TRIGGER_FALLING,
 			spi->dev.bus_id, ts)) {
 		dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
-		input_unregister_device(&ts->input);
-		kfree(ts);
-		return -EBUSY;
+		err = -EBUSY;
+		goto err_free_mem;
 	}
 
 	dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
@@ -534,7 +558,18 @@ static int __devinit ads7846_probe(struct spi_device *spi)
 		device_create_file(&spi->dev, &dev_attr_vbatt);
 	device_create_file(&spi->dev, &dev_attr_vaux);
 
+	err = input_register_device(input_dev);
+	if (err)
+		goto err_free_irq;
+
 	return 0;
+
+ err_free_irq:
+	free_irq(spi->irq, ts);
+ err_free_mem:
+	input_free_device(input_dev);
+	kfree(ts);
+	return err;
 }
 
 static int __devexit ads7846_remove(struct spi_device *spi)
@@ -554,7 +589,7 @@ static int __devexit ads7846_remove(struct spi_device *spi)
 		device_remove_file(&spi->dev, &dev_attr_vbatt);
 	device_remove_file(&spi->dev, &dev_attr_vaux);
 
-	input_unregister_device(&ts->input);
+	input_unregister_device(ts->input);
 	kfree(ts);
 
 	dev_dbg(&spi->dev, "unregistered touchscreen\n");