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authorLars-Peter Clausen <lars@metafoo.de>2012-11-20 17:36:00 +0400
committerJonathan Cameron <jic23@kernel.org>2012-11-21 01:26:37 +0400
commit484a0bf091c93c379e6524a17bb037c33c898e01 (patch)
treeb84cf4f38c21825bcfdcba02a23f5216680c69fb
parent9caed0d9d6db12cb6d81ba68d5bc98432d6b4711 (diff)
downloadlinux-484a0bf091c93c379e6524a17bb037c33c898e01.tar.xz
iio:imu:adis: Add paging support
Some of the newer generation devices from the ADIS16XXX series have more registers than what can be supported with the current register addressing scheme. These devices implement register paging to support a larger register range. Each page is 128 registers large and the currently active page can be selected via register 0x00 in each page. This patch implements transparent paging inside the common adis library. The register read/write interface stays the same and when a register is accessed the library automatically switches to the correct page if it is not already selected. The page number is encoded in the upper bits of the register number, e.g. register 0x5 of page 1 is 0x85. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
-rw-r--r--drivers/iio/imu/adis.c70
-rw-r--r--drivers/iio/imu/adis_buffer.c15
-rw-r--r--include/linux/iio/imu/adis.h10
3 files changed, 77 insertions, 18 deletions
diff --git a/drivers/iio/imu/adis.c b/drivers/iio/imu/adis.c
index 280a49584adf..c4ea04ffa60e 100644
--- a/drivers/iio/imu/adis.c
+++ b/drivers/iio/imu/adis.c
@@ -30,6 +30,7 @@
int adis_write_reg(struct adis *adis, unsigned int reg,
unsigned int value, unsigned int size)
{
+ unsigned int page = reg / ADIS_PAGE_SIZE;
int ret, i;
struct spi_message msg;
struct spi_transfer xfers[] = {
@@ -56,39 +57,53 @@ int adis_write_reg(struct adis *adis, unsigned int reg,
.bits_per_word = 8,
.len = 2,
.delay_usecs = adis->data->write_delay,
+ }, {
+ .tx_buf = adis->tx + 8,
+ .bits_per_word = 8,
+ .len = 2,
+ .delay_usecs = adis->data->write_delay,
},
};
mutex_lock(&adis->txrx_lock);
spi_message_init(&msg);
+
+ if (adis->current_page != page) {
+ adis->tx[0] = ADIS_WRITE_REG(ADIS_REG_PAGE_ID);
+ adis->tx[1] = page;
+ spi_message_add_tail(&xfers[0], &msg);
+ }
+
switch (size) {
case 4:
- adis->tx[6] = ADIS_WRITE_REG(reg + 3);
- adis->tx[7] = (value >> 24) & 0xff;
- adis->tx[4] = ADIS_WRITE_REG(reg + 2);
- adis->tx[5] = (value >> 16) & 0xff;
+ adis->tx[8] = ADIS_WRITE_REG(reg + 3);
+ adis->tx[9] = (value >> 24) & 0xff;
+ adis->tx[6] = ADIS_WRITE_REG(reg + 2);
+ adis->tx[7] = (value >> 16) & 0xff;
case 2:
- adis->tx[2] = ADIS_WRITE_REG(reg + 1);
- adis->tx[3] = (value >> 8) & 0xff;
+ adis->tx[4] = ADIS_WRITE_REG(reg + 1);
+ adis->tx[5] = (value >> 8) & 0xff;
case 1:
- adis->tx[0] = ADIS_WRITE_REG(reg);
- adis->tx[1] = value & 0xff;
+ adis->tx[2] = ADIS_WRITE_REG(reg);
+ adis->tx[3] = value & 0xff;
break;
default:
ret = -EINVAL;
goto out_unlock;
}
- xfers[size - 1].cs_change = 0;
+ xfers[size].cs_change = 0;
- for (i = 0; i < size; i++)
+ for (i = 1; i <= size; i++)
spi_message_add_tail(&xfers[i], &msg);
ret = spi_sync(adis->spi, &msg);
if (ret) {
dev_err(&adis->spi->dev, "Failed to write register 0x%02X: %d\n",
reg, ret);
+ } else {
+ adis->current_page = page;
}
out_unlock:
@@ -107,6 +122,7 @@ EXPORT_SYMBOL_GPL(adis_write_reg);
int adis_read_reg(struct adis *adis, unsigned int reg,
unsigned int *val, unsigned int size)
{
+ unsigned int page = reg / ADIS_PAGE_SIZE;
struct spi_message msg;
int ret;
struct spi_transfer xfers[] = {
@@ -115,9 +131,15 @@ int adis_read_reg(struct adis *adis, unsigned int reg,
.bits_per_word = 8,
.len = 2,
.cs_change = 1,
- .delay_usecs = adis->data->read_delay,
+ .delay_usecs = adis->data->write_delay,
}, {
.tx_buf = adis->tx + 2,
+ .bits_per_word = 8,
+ .len = 2,
+ .cs_change = 1,
+ .delay_usecs = adis->data->read_delay,
+ }, {
+ .tx_buf = adis->tx + 4,
.rx_buf = adis->rx,
.bits_per_word = 8,
.len = 2,
@@ -134,16 +156,22 @@ int adis_read_reg(struct adis *adis, unsigned int reg,
mutex_lock(&adis->txrx_lock);
spi_message_init(&msg);
+ if (adis->current_page != page) {
+ adis->tx[0] = ADIS_WRITE_REG(ADIS_REG_PAGE_ID);
+ adis->tx[1] = page;
+ spi_message_add_tail(&xfers[0], &msg);
+ }
+
switch (size) {
case 4:
- adis->tx[0] = ADIS_READ_REG(reg + 2);
- adis->tx[1] = 0;
- spi_message_add_tail(&xfers[0], &msg);
- case 2:
- adis->tx[2] = ADIS_READ_REG(reg);
+ adis->tx[2] = ADIS_READ_REG(reg + 2);
adis->tx[3] = 0;
spi_message_add_tail(&xfers[1], &msg);
+ case 2:
+ adis->tx[4] = ADIS_READ_REG(reg);
+ adis->tx[5] = 0;
spi_message_add_tail(&xfers[2], &msg);
+ spi_message_add_tail(&xfers[3], &msg);
break;
default:
ret = -EINVAL;
@@ -155,6 +183,8 @@ int adis_read_reg(struct adis *adis, unsigned int reg,
dev_err(&adis->spi->dev, "Failed to read register 0x%02X: %d\n",
reg, ret);
goto out_unlock;
+ } else {
+ adis->current_page = page;
}
switch (size) {
@@ -390,6 +420,14 @@ int adis_init(struct adis *adis, struct iio_dev *indio_dev,
adis->data = data;
iio_device_set_drvdata(indio_dev, adis);
+ if (data->has_paging) {
+ /* Need to set the page before first read/write */
+ adis->current_page = -1;
+ } else {
+ /* Page will always be 0 */
+ adis->current_page = 0;
+ }
+
return adis_enable_irq(adis, false);
}
EXPORT_SYMBOL_GPL(adis_init);
diff --git a/drivers/iio/imu/adis_buffer.c b/drivers/iio/imu/adis_buffer.c
index 785713349e9f..99d8e0b0dd34 100644
--- a/drivers/iio/imu/adis_buffer.c
+++ b/drivers/iio/imu/adis_buffer.c
@@ -83,10 +83,25 @@ static irqreturn_t adis_trigger_handler(int irq, void *p)
if (!adis->buffer)
return -ENOMEM;
+ if (adis->data->has_paging) {
+ mutex_lock(&adis->txrx_lock);
+ if (adis->current_page != 0) {
+ adis->tx[0] = ADIS_WRITE_REG(ADIS_REG_PAGE_ID);
+ adis->tx[1] = 0;
+ spi_write(adis->spi, adis->tx, 2);
+ }
+ }
+
ret = spi_sync(adis->spi, &adis->msg);
if (ret)
dev_err(&adis->spi->dev, "Failed to read data: %d", ret);
+
+ if (adis->data->has_paging) {
+ adis->current_page = 0;
+ mutex_unlock(&adis->txrx_lock);
+ }
+
/* Guaranteed to be aligned with 8 byte boundary */
if (indio_dev->scan_timestamp) {
void *b = adis->buffer + indio_dev->scan_bytes - sizeof(s64);
diff --git a/include/linux/iio/imu/adis.h b/include/linux/iio/imu/adis.h
index 6402a08c0e65..e82cd0827e91 100644
--- a/include/linux/iio/imu/adis.h
+++ b/include/linux/iio/imu/adis.h
@@ -14,8 +14,11 @@
#include <linux/interrupt.h>
#include <linux/iio/types.h>
-#define ADIS_WRITE_REG(reg) (0x80 | (reg))
-#define ADIS_READ_REG(reg) (reg)
+#define ADIS_WRITE_REG(reg) ((0x80 | (reg)))
+#define ADIS_READ_REG(reg) ((reg) & 0x7f)
+
+#define ADIS_PAGE_SIZE 0x80
+#define ADIS_REG_PAGE_ID 0x00
/**
* struct adis_data - ADIS chip variant specific data
@@ -40,6 +43,8 @@ struct adis_data {
const char * const *status_error_msgs;
unsigned int status_error_mask;
+
+ bool has_paging;
};
struct adis {
@@ -51,6 +56,7 @@ struct adis {
struct mutex txrx_lock;
struct spi_message msg;
struct spi_transfer *xfer;
+ unsigned int current_page;
void *buffer;
uint8_t tx[10] ____cacheline_aligned;