[PATCH v6 06/17] iio: adc: ad7768: Validate master clock rate
From: Janani Sunil <janani.sunil@analog.com>
Date: 2026-09-04 14:16:08
Also in:
linux-devicetree, linux-gpio, linux-iio, lkml
Subsystem:
analog devices inc iio drivers, iio subsystem and drivers, the rest · Maintainers:
Nuno Sá, Michael Hennerich, Jonathan Cameron, Linus Torvalds
Reject master clock rates outside the limits specified by the device. External CMOS and LVDS clocks support 1.15 MHz to 34 MHz, while a crystal requires 8 MHz to 34 MHz. Signed-off-by: Janani Sunil <janani.sunil@analog.com> --- drivers/iio/adc/ad7768.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)
diff --git a/drivers/iio/adc/ad7768.c b/drivers/iio/adc/ad7768.c
index c80056a9edd8..707f3ae70a95 100644
--- a/drivers/iio/adc/ad7768.c
+++ b/drivers/iio/adc/ad7768.c@@ -95,6 +95,9 @@ #define AD7768_SPI_REG_MASK GENMASK(14, 8) #define AD7768_SPI_DATA_MASK GENMASK(7, 0) +#define AD7768_MIN_MCLK_FREQ_HZ (1150 * HZ_PER_KHZ) +#define AD7768_MIN_XTAL_FREQ_HZ (8 * HZ_PER_MHZ) +#define AD7768_MAX_MCLK_FREQ_HZ (34 * HZ_PER_MHZ) #define AD7768_MAX_CHANNEL 8 enum ad7768_clock_source {
@@ -777,6 +780,23 @@ static int ad7768_get_enable_vref(struct device *dev, unsigned int index) return refp_uV - refn_uV; } +static int ad7768_validate_mclk_rate(struct device *dev, + const struct ad7768_state *st) +{ + unsigned long min_rate = AD7768_MIN_MCLK_FREQ_HZ; + unsigned long rate = clk_get_rate(st->mclk); + + if (st->clock_source == AD7768_CLOCK_SOURCE_XTAL) + min_rate = AD7768_MIN_XTAL_FREQ_HZ; + + if (rate < min_rate || rate > AD7768_MAX_MCLK_FREQ_HZ) + return dev_err_probe(dev, -EINVAL, + "MCLK rate %lu Hz outside %lu-%lu Hz\n", + rate, min_rate, AD7768_MAX_MCLK_FREQ_HZ); + + return 0; +} + static int ad7768_probe(struct spi_device *spi) { unsigned int spi_readback, rev_id;
@@ -852,6 +872,10 @@ static int ad7768_probe(struct spi_device *spi) return dev_err_probe(dev, PTR_ERR(st->mclk), "Failed to get master clock\n"); + ret = ad7768_validate_mclk_rate(dev, st); + if (ret) + return ret; + st->regmap = devm_regmap_init(dev, &ad7768_regmap_bus, spi, st->chip_info->regmap_config); if (IS_ERR(st->regmap))
--
2.43.0