From: Matti Vaittinen Date: Mon, 11 Aug 2025 08:52:22 +0000 (+0300) Subject: iio: adc: ad7476: Support ROHM BD79105 X-Git-Tag: v6.18-rc1~74^2~7^2~131 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=6c27bf9bbfb72ccdd4821551ae8a28fe47c4e878;p=thirdparty%2Fkernel%2Fstable.git iio: adc: ad7476: Support ROHM BD79105 The ROHM BD79105 is a simple 16-bit ADC accessible via SPI*. The BD79105 has a CONVSTART pin, which must be set high to start the ADC conversion. Unlike with the ad7091 and ad7091r which also have a CONVSTART pin, the BD79105 requires that the pin must remain high also for the duration of the SPI access. (*) Couple of words about the SPI. The BD79105 has pins named as CONVSTART, SCLK, DIN and DOUT. For the curious reader, DIN is not SPI ISO. DIN is a signal which can be used as a chip-select. When DIN is pulled low, the ADC will output the completed measurement via DOUT as SCLK is clocked. According to the data-sheet, the DIN can also be used for daisy-chaining multiple ADCs. Furthermore, DOUT can be used also for a 'data-ready' -IRQ. These modes aren't supported by this driver. Support reading ADC scale and data from the BD79105 using SPI, when DIN is used as a chip-select. Signed-off-by: Matti Vaittinen Reviewed-by: Nuno Sá Reviewed-by: Andy Shevchenko Link: https://patch.msgid.link/6ee06d551256db9213ccbe72f44cfe9452717716.1754901948.git.mazziesaccount@gmail.com Signed-off-by: Jonathan Cameron --- diff --git a/drivers/iio/adc/ad7476.c b/drivers/iio/adc/ad7476.c index 6cb2cbeafbd3b..1bec6657394c3 100644 --- a/drivers/iio/adc/ad7476.c +++ b/drivers/iio/adc/ad7476.c @@ -32,8 +32,10 @@ struct ad7476_chip_info { struct iio_chan_spec channel[2]; void (*reset)(struct ad7476_state *); void (*conversion_pre_op)(struct ad7476_state *st); + void (*conversion_post_op)(struct ad7476_state *st); bool has_vref; bool has_vdrive; + bool convstart_required; }; struct ad7476_state { @@ -64,6 +66,18 @@ static void ad7091_convst(struct ad7476_state *st) udelay(1); /* Conversion time: 650 ns max */ } +static void bd79105_convst_disable(struct ad7476_state *st) +{ + gpiod_set_value_cansleep(st->convst_gpio, 0); +} + +static void bd79105_convst_enable(struct ad7476_state *st) +{ + gpiod_set_value_cansleep(st->convst_gpio, 1); + /* Worst case, 2790 ns required for conversion */ + ndelay(2790); +} + static irqreturn_t ad7476_trigger_handler(int irq, void *p) { struct iio_poll_func *pf = p; @@ -81,6 +95,8 @@ static irqreturn_t ad7476_trigger_handler(int irq, void *p) iio_push_to_buffers_with_ts(indio_dev, st->data, sizeof(st->data), iio_get_time_ns(indio_dev)); done: + if (st->chip_info->conversion_post_op) + st->chip_info->conversion_post_op(st); iio_trigger_notify_done(indio_dev->trig); return IRQ_HANDLED; @@ -103,6 +119,9 @@ static int ad7476_scan_direct(struct ad7476_state *st) if (ret) return ret; + if (st->chip_info->conversion_post_op) + st->chip_info->conversion_post_op(st); + return be16_to_cpup((__be16 *)st->data); } @@ -273,6 +292,22 @@ static const struct ad7476_chip_info ltc2314_14_chip_info = { .has_vref = true, }; +static const struct ad7476_chip_info bd79105_chip_info = { + .channel[0] = AD7091R_CHAN(16), + .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1), + /* + * The BD79105 starts ADC data conversion when the CONVSTART line is + * set HIGH. The CONVSTART must be kept HIGH until the data has been + * read from the ADC. + */ + .conversion_pre_op = bd79105_convst_enable, + .conversion_post_op = bd79105_convst_disable, + /* BD79105 won't do conversion without convstart */ + .convstart_required = true, + .has_vref = true, + .has_vdrive = true, +}; + static const struct iio_info ad7476_info = { .read_raw = &ad7476_read_raw, }; @@ -332,6 +367,9 @@ static int ad7476_probe(struct spi_device *spi) if (IS_ERR(st->convst_gpio)) return PTR_ERR(st->convst_gpio); + if (st->chip_info->convstart_required && !st->convst_gpio) + return dev_err_probe(&spi->dev, -EINVAL, "No convstart GPIO\n"); + /* * This will never happen. Unless someone changes the channel specs * in this driver. And if someone does, without changing the loop @@ -401,6 +439,7 @@ static const struct spi_device_id ad7476_id[] = { { "ads7866", (kernel_ulong_t)&ads7866_chip_info }, { "ads7867", (kernel_ulong_t)&ads7867_chip_info }, { "ads7868", (kernel_ulong_t)&ads7868_chip_info }, + { "bd79105", (kernel_ulong_t)&bd79105_chip_info }, /* * The ROHM BU79100G is identical to the TI's ADS7866 from the software * point of view. The binding document mandates the ADS7866 to be