From: Michael Hennerich michael.hennerich@analog.com
commit 558a25f903b4af6361b7fbeea08a6446a0745653 upstream.
For reliable operation across the full range of supported interface rates, the AD5593R needs a STOP condition between address write, and data read (like show in the datasheet Figure 40) so in turn i2c_smbus_read_word_swapped cannot be used.
While at it, a simple helper was added to make the code simpler.
Fixes: 56ca9db862bf ("iio: dac: Add support for the AD5592R/AD5593R ADCs/DACs") Signed-off-by: Michael Hennerich michael.hennerich@analog.com Signed-off-by: Nuno Sá nuno.sa@analog.com Cc: Stable@vger.kernel.org Link: https://lore.kernel.org/r/20220913073413.140475-2-nuno.sa@analog.com Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iio/dac/ad5593r.c | 46 +++++++++++++++++++++++++++------------------- 1 file changed, 27 insertions(+), 19 deletions(-)
--- a/drivers/iio/dac/ad5593r.c +++ b/drivers/iio/dac/ad5593r.c @@ -15,6 +15,8 @@ #include <linux/of.h> #include <linux/acpi.h>
+#include <asm/unaligned.h> + #define AD5593R_MODE_CONF (0 << 4) #define AD5593R_MODE_DAC_WRITE (1 << 4) #define AD5593R_MODE_ADC_READBACK (4 << 4) @@ -22,6 +24,24 @@ #define AD5593R_MODE_GPIO_READBACK (6 << 4) #define AD5593R_MODE_REG_READBACK (7 << 4)
+static int ad5593r_read_word(struct i2c_client *i2c, u8 reg, u16 *value) +{ + int ret; + u8 buf[2]; + + ret = i2c_smbus_write_byte(i2c, reg); + if (ret < 0) + return ret; + + ret = i2c_master_recv(i2c, buf, sizeof(buf)); + if (ret < 0) + return ret; + + *value = get_unaligned_be16(buf); + + return 0; +} + static int ad5593r_write_dac(struct ad5592r_state *st, unsigned chan, u16 value) { struct i2c_client *i2c = to_i2c_client(st->dev); @@ -40,13 +60,7 @@ static int ad5593r_read_adc(struct ad559 if (val < 0) return (int) val;
- val = i2c_smbus_read_word_swapped(i2c, AD5593R_MODE_ADC_READBACK); - if (val < 0) - return (int) val; - - *value = (u16) val; - - return 0; + return ad5593r_read_word(i2c, AD5593R_MODE_ADC_READBACK, value); }
static int ad5593r_reg_write(struct ad5592r_state *st, u8 reg, u16 value) @@ -60,25 +74,19 @@ static int ad5593r_reg_write(struct ad55 static int ad5593r_reg_read(struct ad5592r_state *st, u8 reg, u16 *value) { struct i2c_client *i2c = to_i2c_client(st->dev); - s32 val; - - val = i2c_smbus_read_word_swapped(i2c, AD5593R_MODE_REG_READBACK | reg); - if (val < 0) - return (int) val;
- *value = (u16) val; - - return 0; + return ad5593r_read_word(i2c, AD5593R_MODE_REG_READBACK | reg, value); }
static int ad5593r_gpio_read(struct ad5592r_state *st, u8 *value) { struct i2c_client *i2c = to_i2c_client(st->dev); - s32 val; + u16 val; + int ret;
- val = i2c_smbus_read_word_swapped(i2c, AD5593R_MODE_GPIO_READBACK); - if (val < 0) - return (int) val; + ret = ad5593r_read_word(i2c, AD5593R_MODE_GPIO_READBACK, &val); + if (ret) + return ret;
*value = (u8) val;