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staging:iio:ad7280a: Do not store transfer buffer on the stack

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Some I2C controllers may not be able to handle transfer buffers that are placed
on the stack.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Lars-Peter Clausen 2013-11-25 12:42:00 +00:00 committed by Jonathan Cameron
parent b39c47d193
commit 93dbad639d
1 changed files with 15 additions and 14 deletions
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29
drivers/staging/iio/adc/ad7280a.c
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@ -134,6 +134,8 @@ struct ad7280_state {
unsigned char aux_threshhigh; unsigned char aux_threshhigh;
unsigned char aux_threshlow; unsigned char aux_threshlow;
unsigned char cb_mask[AD7280A_MAX_CHAIN]; unsigned char cb_mask[AD7280A_MAX_CHAIN];
__be32 buf[2] ____cacheline_aligned;
}; };
static void ad7280_crc8_build_table(unsigned char *crc_tab) static void ad7280_crc8_build_table(unsigned char *crc_tab)
@ -189,22 +191,22 @@ static void ad7280_delay(struct ad7280_state *st)
msleep(1); msleep(1);
} }
static int __ad7280_read32(struct spi_device *spi, unsigned *val) static int __ad7280_read32(struct ad7280_state *st, unsigned *val)
{ {
__be32 rx_buf, tx_buf = cpu_to_be32(AD7280A_READ_TXVAL);
int ret; int ret;
struct spi_transfer t = { struct spi_transfer t = {
.tx_buf = &tx_buf, .tx_buf = &st->buf[0],
.rx_buf = &rx_buf, .rx_buf = &st->buf[1],
.len = 4, .len = 4,
}; };
ret = spi_sync_transfer(spi, &t, 1); st->buf[0] = cpu_to_be32(AD7280A_READ_TXVAL);
ret = spi_sync_transfer(st->spi, &t, 1);
if (ret) if (ret)
return ret; return ret;
*val = be32_to_cpu(rx_buf); *val = be32_to_cpu(st->buf[1]);
return 0; return 0;
} }
@ -214,12 +216,11 @@ static int ad7280_write(struct ad7280_state *st, unsigned devaddr,
{ {
unsigned reg = (devaddr << 27 | addr << 21 | unsigned reg = (devaddr << 27 | addr << 21 |
(val & 0xFF) << 13 | all << 12); (val & 0xFF) << 13 | all << 12);
__be32 tx_buf;
reg |= ad7280_calc_crc8(st->crc_tab, reg >> 11) << 3 | 0x2; reg |= ad7280_calc_crc8(st->crc_tab, reg >> 11) << 3 | 0x2;
tx_buf = cpu_to_be32(reg); st->buf[0] = cpu_to_be32(reg);
return spi_write(st->spi, &tx_buf, 4); return spi_write(st->spi, &st->buf[0], 4);
} }
static int ad7280_read(struct ad7280_state *st, unsigned devaddr, static int ad7280_read(struct ad7280_state *st, unsigned devaddr,
@ -249,7 +250,7 @@ static int ad7280_read(struct ad7280_state *st, unsigned devaddr,
if (ret) if (ret)
return ret; return ret;
__ad7280_read32(st->spi, &tmp); __ad7280_read32(st, &tmp);
if (ad7280_check_crc(st, tmp)) if (ad7280_check_crc(st, tmp))
return -EIO; return -EIO;
@ -287,7 +288,7 @@ static int ad7280_read_channel(struct ad7280_state *st, unsigned devaddr,
ad7280_delay(st); ad7280_delay(st);
__ad7280_read32(st->spi, &tmp); __ad7280_read32(st, &tmp);
if (ad7280_check_crc(st, tmp)) if (ad7280_check_crc(st, tmp))
return -EIO; return -EIO;
@ -320,7 +321,7 @@ static int ad7280_read_all_channels(struct ad7280_state *st, unsigned cnt,
ad7280_delay(st); ad7280_delay(st);
for (i = 0; i < cnt; i++) { for (i = 0; i < cnt; i++) {
__ad7280_read32(st->spi, &tmp); __ad7280_read32(st, &tmp);
if (ad7280_check_crc(st, tmp)) if (ad7280_check_crc(st, tmp))
return -EIO; return -EIO;
@ -363,7 +364,7 @@ static int ad7280_chain_setup(struct ad7280_state *st)
return ret; return ret;
for (n = 0; n <= AD7280A_MAX_CHAIN; n++) { for (n = 0; n <= AD7280A_MAX_CHAIN; n++) {
__ad7280_read32(st->spi, &val); __ad7280_read32(st, &val);
if (val == 0) if (val == 0)
return n - 1; return n - 1;