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 00a6a223212a..6c6121865f0e 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 0c7f9488f5cb..306577dc0b98 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 c3a62c42cd28..2be0366c8123 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 45c54fb13f07..d12d14911fc3 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);