Input: ad714x - use DMA-safe buffers for spi_write()

spi_write() requires use of DMA-safe (cacheline aligned) buffers.
Also use the same buffers when reading data since to avoid extra
locking and potential memory allocation in spi_write_then_read().

Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

4 files changed, 131 insertions, 103 deletions

diff --git a/drivers/input/misc/ad714x-i2c.c b/drivers/input/misc/ad714x-i2c.c
index 00a6a22..6c61218 100644
--- a/drivers/input/misc/ad714x-i2c.c
+++ b/drivers/input/misc/ad714x-i2c.c
@@ -27,40 +27,46 @@ static int ad714x_i2c_resume(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(ad714x_i2c_pm, ad714x_i2c_suspend, ad714x_i2c_resume);
 
-static int ad714x_i2c_write(struct device *dev, unsigned short reg,
-				unsigned short data)
+static int ad714x_i2c_write(struct ad714x_chip *chip,
+			    unsigned short reg, unsigned short data)
 {
-	struct i2c_client *client = to_i2c_client(dev);
-	int ret = 0;
-	unsigned short tx[2] = {
-		cpu_to_be16(reg),
-		cpu_to_be16(data)
-	};
-
-	ret = i2c_master_send(client, (u8 *)tx, 4);
-	if (ret < 0)
-		dev_err(&client->dev, "I2C write error\n");
-
-	return ret;
+	struct i2c_client *client = to_i2c_client(chip->dev);
+	int error;
+
+	chip->xfer_buf[0] = cpu_to_be16(reg);
+	chip->xfer_buf[1] = cpu_to_be16(data);
+
+	error = i2c_master_send(client, (u8 *)chip->xfer_buf,
+				2 * sizeof(*chip->xfer_buf));
+	if (unlikely(error < 0)) {
+		dev_err(&client->dev, "I2C write error: %d\n", error);
+		return error;
+	}
+
+	return 0;
 }
 
-static int ad714x_i2c_read(struct device *dev, unsigned short reg,
-				unsigned short *data)
+static int ad714x_i2c_read(struct ad714x_chip *chip,
+			   unsigned short reg, unsigned short *data)
 {
-	struct i2c_client *client = to_i2c_client(dev);
-	int ret = 0;
-	unsigned short tx = cpu_to_be16(reg);
+	struct i2c_client *client = to_i2c_client(chip->dev);
+	int error;
+
+	chip->xfer_buf[0] = cpu_to_be16(reg);
 
-	ret = i2c_master_send(client, (u8 *)&tx, 2);
-	if (ret >= 0)
-		ret = i2c_master_recv(client, (u8 *)data, 2);
+	error = i2c_master_send(client, (u8 *)chip->xfer_buf,
+				sizeof(*chip->xfer_buf));
+	if (error >= 0)
+		error = i2c_master_recv(client, (u8 *)chip->xfer_buf,
+					sizeof(*chip->xfer_buf));
 
-	if (unlikely(ret < 0))
-		dev_err(&client->dev, "I2C read error\n");
-	else
-		*data = be16_to_cpu(*data);
+	if (unlikely(error < 0)) {
+		dev_err(&client->dev, "I2C read error: %d\n", error);
+		return error;
+	}
 
-	return ret;
+	*data = be16_to_cpup(chip->xfer_buf);
+	return 0;
 }
 
 static int __devinit ad714x_i2c_probe(struct i2c_client *client,
diff --git a/drivers/input/misc/ad714x-spi.c b/drivers/input/misc/ad714x-spi.c
index 0c7f948..306577d 100644
--- a/drivers/input/misc/ad714x-spi.c
+++ b/drivers/input/misc/ad714x-spi.c
@@ -30,31 +30,54 @@ static int ad714x_spi_resume(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(ad714x_spi_pm, ad714x_spi_suspend, ad714x_spi_resume);
 
-static int ad714x_spi_read(struct device *dev,
+static int ad714x_spi_read(struct ad714x_chip *chip,
 			   unsigned short reg, unsigned short *data)
 {
-	struct spi_device *spi = to_spi_device(dev);
-	unsigned short tx = cpu_to_be16(AD714x_SPI_CMD_PREFIX |
+	struct spi_device *spi = to_spi_device(chip->dev);
+	struct spi_message message;
+	struct spi_transfer xfer[2];
+	int error;
+
+	spi_message_init(&message);
+	memset(xfer, 0, sizeof(xfer));
+
+	chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX |
 					AD714x_SPI_READ | reg);
-	int ret;
+	xfer[0].tx_buf = &chip->xfer_buf[0];
+	xfer[0].len = sizeof(chip->xfer_buf[0]);
+	spi_message_add_tail(&xfer[0], &message);
 
-	ret = spi_write_then_read(spi, &tx, 2, data, 2);
+	xfer[1].rx_buf = &chip->xfer_buf[1];
+	xfer[1].len = sizeof(chip->xfer_buf[1]);
+	spi_message_add_tail(&xfer[1], &message);
 
-	*data = be16_to_cpup(data);
+	error = spi_sync(spi, &message);
+	if (unlikely(error)) {
+		dev_err(chip->dev, "SPI read error: %d\n", error);
+		return error;
+	}
 
-	return ret;
+	*data = be16_to_cpu(chip->xfer_buf[1]);
+	return 0;
 }
 
-static int ad714x_spi_write(struct device *dev,
+static int ad714x_spi_write(struct ad714x_chip *chip,
 			    unsigned short reg, unsigned short data)
 {
-	struct spi_device *spi = to_spi_device(dev);
-	unsigned short tx[2] = {
-		cpu_to_be16(AD714x_SPI_CMD_PREFIX | reg),
-		cpu_to_be16(data)
-	};
+	struct spi_device *spi = to_spi_device(chip->dev);
+	int error;
 
-	return spi_write(spi, (u8 *)tx, 4);
+	chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX | reg);
+	chip->xfer_buf[1] = cpu_to_be16(data);
+
+	error = spi_write(spi, (u8 *)chip->xfer_buf,
+			  2 * sizeof(*chip->xfer_buf));
+	if (unlikely(error)) {
+		dev_err(chip->dev, "SPI write error: %d\n", error);
+		return error;
+	}
+
+	return 0;
 }
 
 static int __devinit ad714x_spi_probe(struct spi_device *spi)
diff --git a/drivers/input/misc/ad714x.c b/drivers/input/misc/ad714x.c
index c3a62c4..2be0366c 100644
--- a/drivers/input/misc/ad714x.c
+++ b/drivers/input/misc/ad714x.c
@@ -59,7 +59,6 @@
 #define STAGE11_AMBIENT		0x27D
 
 #define PER_STAGE_REG_NUM      36
-#define STAGE_NUM              12
 #define STAGE_CFGREG_NUM       8
 #define SYS_CFGREG_NUM         8
 
@@ -124,28 +123,6 @@ struct ad714x_driver_data {
  * information to integrate all things which will be private data
  * of spi/i2c device
  */
-struct ad714x_chip {
-	unsigned short h_state;
-	unsigned short l_state;
-	unsigned short c_state;
-	unsigned short adc_reg[STAGE_NUM];
-	unsigned short amb_reg[STAGE_NUM];
-	unsigned short sensor_val[STAGE_NUM];
-
-	struct ad714x_platform_data *hw;
-	struct ad714x_driver_data *sw;
-
-	int irq;
-	struct device *dev;
-	ad714x_read_t read;
-	ad714x_write_t write;
-
-	struct mutex mutex;
-
-	unsigned product;
-	unsigned version;
-};
-
 static void ad714x_use_com_int(struct ad714x_chip *ad714x,
 				int start_stage, int end_stage)
 {
@@ -154,13 +131,13 @@ static void ad714x_use_com_int(struct ad714x_chip *ad714x,
 
 	mask = ((1 << (end_stage + 1)) - 1) - ((1 << start_stage) - 1);
 
-	ad714x->read(ad714x->dev, STG_COM_INT_EN_REG, &data);
+	ad714x->read(ad714x, STG_COM_INT_EN_REG, &data);
 	data |= 1 << end_stage;
-	ad714x->write(ad714x->dev, STG_COM_INT_EN_REG, data);
+	ad714x->write(ad714x, STG_COM_INT_EN_REG, data);
 
-	ad714x->read(ad714x->dev, STG_HIGH_INT_EN_REG, &data);
+	ad714x->read(ad714x, STG_HIGH_INT_EN_REG, &data);
 	data &= ~mask;
-	ad714x->write(ad714x->dev, STG_HIGH_INT_EN_REG, data);
+	ad714x->write(ad714x, STG_HIGH_INT_EN_REG, data);
 }
 
 static void ad714x_use_thr_int(struct ad714x_chip *ad714x,
@@ -171,13 +148,13 @@ static void ad714x_use_thr_int(struct ad714x_chip *ad714x,
 
 	mask = ((1 << (end_stage + 1)) - 1) - ((1 << start_stage) - 1);
 
-	ad714x->read(ad714x->dev, STG_COM_INT_EN_REG, &data);
+	ad714x->read(ad714x, STG_COM_INT_EN_REG, &data);
 	data &= ~(1 << end_stage);
-	ad714x->write(ad714x->dev, STG_COM_INT_EN_REG, data);
+	ad714x->write(ad714x, STG_COM_INT_EN_REG, data);
 
-	ad714x->read(ad714x->dev, STG_HIGH_INT_EN_REG, &data);
+	ad714x->read(ad714x, STG_HIGH_INT_EN_REG, &data);
 	data |= mask;
-	ad714x->write(ad714x->dev, STG_HIGH_INT_EN_REG, data);
+	ad714x->write(ad714x, STG_HIGH_INT_EN_REG, data);
 }
 
 static int ad714x_cal_highest_stage(struct ad714x_chip *ad714x,
@@ -274,10 +251,8 @@ static void ad714x_slider_cal_sensor_val(struct ad714x_chip *ad714x, int idx)
 	int i;
 
 	for (i = hw->start_stage; i <= hw->end_stage; i++) {
-		ad714x->read(ad714x->dev, CDC_RESULT_S0 + i,
-			&ad714x->adc_reg[i]);
-		ad714x->read(ad714x->dev,
-				STAGE0_AMBIENT + i * PER_STAGE_REG_NUM,
+		ad714x->read(ad714x, CDC_RESULT_S0 + i, &ad714x->adc_reg[i]);
+		ad714x->read(ad714x, STAGE0_AMBIENT + i * PER_STAGE_REG_NUM,
 				&ad714x->amb_reg[i]);
 
 		ad714x->sensor_val[i] = abs(ad714x->adc_reg[i] -
@@ -445,10 +420,8 @@ static void ad714x_wheel_cal_sensor_val(struct ad714x_chip *ad714x, int idx)
 	int i;
 
 	for (i = hw->start_stage; i <= hw->end_stage; i++) {
-		ad714x->read(ad714x->dev, CDC_RESULT_S0 + i,
-			&ad714x->adc_reg[i]);
-		ad714x->read(ad714x->dev,
-				STAGE0_AMBIENT + i * PER_STAGE_REG_NUM,
+		ad714x->read(ad714x, CDC_RESULT_S0 + i, &ad714x->adc_reg[i]);
+		ad714x->read(ad714x, STAGE0_AMBIENT + i * PER_STAGE_REG_NUM,
 				&ad714x->amb_reg[i]);
 		if (ad714x->adc_reg[i] > ad714x->amb_reg[i])
 			ad714x->sensor_val[i] = ad714x->adc_reg[i] -
@@ -598,10 +571,8 @@ static void touchpad_cal_sensor_val(struct ad714x_chip *ad714x, int idx)
 	int i;
 
 	for (i = hw->x_start_stage; i <= hw->x_end_stage; i++) {
-		ad714x->read(ad714x->dev, CDC_RESULT_S0 + i,
-				&ad714x->adc_reg[i]);
-		ad714x->read(ad714x->dev,
-				STAGE0_AMBIENT + i * PER_STAGE_REG_NUM,
+		ad714x->read(ad714x, CDC_RESULT_S0 + i, &ad714x->adc_reg[i]);
+		ad714x->read(ad714x, STAGE0_AMBIENT + i * PER_STAGE_REG_NUM,
 				&ad714x->amb_reg[i]);
 		if (ad714x->adc_reg[i] > ad714x->amb_reg[i])
 			ad714x->sensor_val[i] = ad714x->adc_reg[i] -
@@ -891,7 +862,7 @@ static int ad714x_hw_detect(struct ad714x_chip *ad714x)
 {
 	unsigned short data;
 
-	ad714x->read(ad714x->dev, AD714X_PARTID_REG, &data);
+	ad714x->read(ad714x, AD714X_PARTID_REG, &data);
 	switch (data & 0xFFF0) {
 	case AD7142_PARTID:
 		ad714x->product = 0x7142;
@@ -940,23 +911,22 @@ static void ad714x_hw_init(struct ad714x_chip *ad714x)
 	for (i = 0; i < STAGE_NUM; i++) {
 		reg_base = AD714X_STAGECFG_REG + i * STAGE_CFGREG_NUM;
 		for (j = 0; j < STAGE_CFGREG_NUM; j++)
-			ad714x->write(ad714x->dev, reg_base + j,
+			ad714x->write(ad714x, reg_base + j,
 					ad714x->hw->stage_cfg_reg[i][j]);
 	}
 
 	for (i = 0; i < SYS_CFGREG_NUM; i++)
-		ad714x->write(ad714x->dev, AD714X_SYSCFG_REG + i,
+		ad714x->write(ad714x, AD714X_SYSCFG_REG + i,
 			ad714x->hw->sys_cfg_reg[i]);
 	for (i = 0; i < SYS_CFGREG_NUM; i++)
-		ad714x->read(ad714x->dev, AD714X_SYSCFG_REG + i,
-			&data);
+		ad714x->read(ad714x, AD714X_SYSCFG_REG + i, &data);
 
-	ad714x->write(ad714x->dev, AD714X_STG_CAL_EN_REG, 0xFFF);
+	ad714x->write(ad714x, AD714X_STG_CAL_EN_REG, 0xFFF);
 
 	/* clear all interrupts */
-	ad714x->read(ad714x->dev, STG_LOW_INT_STA_REG, &data);
-	ad714x->read(ad714x->dev, STG_HIGH_INT_STA_REG, &data);
-	ad714x->read(ad714x->dev, STG_COM_INT_STA_REG, &data);
+	ad714x->read(ad714x, STG_LOW_INT_STA_REG, &data);
+	ad714x->read(ad714x, STG_HIGH_INT_STA_REG, &data);
+	ad714x->read(ad714x, STG_COM_INT_STA_REG, &data);
 }
 
 static irqreturn_t ad714x_interrupt_thread(int irq, void *data)
@@ -966,9 +936,9 @@ static irqreturn_t ad714x_interrupt_thread(int irq, void *data)
 
 	mutex_lock(&ad714x->mutex);
 
-	ad714x->read(ad714x->dev, STG_LOW_INT_STA_REG, &ad714x->l_state);
-	ad714x->read(ad714x->dev, STG_HIGH_INT_STA_REG, &ad714x->h_state);
-	ad714x->read(ad714x->dev, STG_COM_INT_STA_REG, &ad714x->c_state);
+	ad714x->read(ad714x, STG_LOW_INT_STA_REG, &ad714x->l_state);
+	ad714x->read(ad714x, STG_HIGH_INT_STA_REG, &ad714x->h_state);
+	ad714x->read(ad714x, STG_COM_INT_STA_REG, &ad714x->c_state);
 
 	for (i = 0; i < ad714x->hw->button_num; i++)
 		ad714x_button_state_machine(ad714x, i);
@@ -1245,7 +1215,7 @@ int ad714x_disable(struct ad714x_chip *ad714x)
 	mutex_lock(&ad714x->mutex);
 
 	data = ad714x->hw->sys_cfg_reg[AD714X_PWR_CTRL] | 0x3;
-	ad714x->write(ad714x->dev, AD714X_PWR_CTRL, data);
+	ad714x->write(ad714x, AD714X_PWR_CTRL, data);
 
 	mutex_unlock(&ad714x->mutex);
 
@@ -1263,16 +1233,16 @@ int ad714x_enable(struct ad714x_chip *ad714x)
 
 	/* resume to non-shutdown mode */
 
-	ad714x->write(ad714x->dev, AD714X_PWR_CTRL,
+	ad714x->write(ad714x, AD714X_PWR_CTRL,
 			ad714x->hw->sys_cfg_reg[AD714X_PWR_CTRL]);
 
 	/* make sure the interrupt output line is not low level after resume,
 	 * otherwise we will get no chance to enter falling-edge irq again
 	 */
 
-	ad714x->read(ad714x->dev, STG_LOW_INT_STA_REG, &data);
-	ad714x->read(ad714x->dev, STG_HIGH_INT_STA_REG, &data);
-	ad714x->read(ad714x->dev, STG_COM_INT_STA_REG, &data);
+	ad714x->read(ad714x, STG_LOW_INT_STA_REG, &data);
+	ad714x->read(ad714x, STG_HIGH_INT_STA_REG, &data);
+	ad714x->read(ad714x, STG_COM_INT_STA_REG, &data);
 
 	mutex_unlock(&ad714x->mutex);
 
diff --git a/drivers/input/misc/ad714x.h b/drivers/input/misc/ad714x.h
index 45c54fb..d12d149 100644
--- a/drivers/input/misc/ad714x.h
+++ b/drivers/input/misc/ad714x.h
@@ -11,11 +11,40 @@
 
 #include <linux/types.h>
 
+#define STAGE_NUM              12
+
 struct device;
+struct ad714x_platform_data;
+struct ad714x_driver_data;
 struct ad714x_chip;
 
-typedef int (*ad714x_read_t)(struct device *, unsigned short, unsigned short *);
-typedef int (*ad714x_write_t)(struct device *, unsigned short, unsigned short);
+typedef int (*ad714x_read_t)(struct ad714x_chip *, unsigned short, unsigned short *);
+typedef int (*ad714x_write_t)(struct ad714x_chip *, unsigned short, unsigned short);
+
+struct ad714x_chip {
+	unsigned short h_state;
+	unsigned short l_state;
+	unsigned short c_state;
+	unsigned short adc_reg[STAGE_NUM];
+	unsigned short amb_reg[STAGE_NUM];
+	unsigned short sensor_val[STAGE_NUM];
+
+	struct ad714x_platform_data *hw;
+	struct ad714x_driver_data *sw;
+
+	int irq;
+	struct device *dev;
+	ad714x_read_t read;
+	ad714x_write_t write;
+
+	struct mutex mutex;
+
+	unsigned product;
+	unsigned version;
+
+	__be16 xfer_buf[16] ____cacheline_aligned;
+
+};
 
 int ad714x_disable(struct ad714x_chip *ad714x);
 int ad714x_enable(struct ad714x_chip *ad714x);