Re: [PATCH 1/5] iio: adc: ti-ads112c14: support external clock

[Jonathan Cameron]

On Fri, 07 Aug 2026 19:19:46 -0500
"David Lechner (TI)" <dlechner@xxxxxxxxxxxx> wrote:

> Add support for external an external clock source to the TI ADS112C14
> ADC driver. The unused fclk_hZ field is added in preparation for filter

Hz

Other than that LGTM.

> support.
> 
> Signed-off-by: David Lechner (TI) <dlechner@xxxxxxxxxxxx>
> ---
>  drivers/iio/adc/ti-ads112c14.c | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/drivers/iio/adc/ti-ads112c14.c b/drivers/iio/adc/ti-ads112c14.c
> index fa6eeaf81738..5f03e6985efa 100644
> --- a/drivers/iio/adc/ti-ads112c14.c
> +++ b/drivers/iio/adc/ti-ads112c14.c
> @@ -11,6 +11,7 @@
>  #include <linux/bitfield.h>
>  #include <linux/bitmap.h>
>  #include <linux/cleanup.h>
> +#include <linux/clk.h>
>  #include <linux/completion.h>
>  #include <linux/crc8.h>
>  #include <linux/delay.h>
> @@ -178,6 +179,8 @@ static const u32 ads112c14_pga_gains_x10[] = {
>  	200, 320, 500, 640, 1000, 1280, 2000, 2560,	/* 8 - 15 */
>  };
>  
> +#define ADS112C14_INTERNAL_CLK_Hz 4096000
> +
>  #define ADS112C14_I2C_CRC8_POLYNOMIAL 0x07
>  DECLARE_CRC8_TABLE(ads112c14_crc8_table);
>  
> @@ -268,6 +271,7 @@ struct ads112c14_data {
>  	struct iio_trigger *drdy_trig;
>  	/* Synchronizes access to register value fields. */
>  	struct mutex lock;
> +	long fclk_Hz;
>  	int drdy_irq;
>  	struct completion drdy_completion;
>  	bool i2c_crc_enabled;
> @@ -1516,6 +1520,7 @@ static int ads112c14_probe(struct i2c_client *client)
>  	const struct ads112c14_chip_info *info;
>  	struct iio_dev *indio_dev;
>  	struct ads112c14_data *data;
> +	struct clk *clk;
>  	bool need_avdd_ref, need_ext_ref;
>  	u32 refp_uV = 0;
>  	u32 refn_uV = 0;
> @@ -1608,6 +1613,12 @@ static int ads112c14_probe(struct i2c_client *client)
>  		return dev_err_probe(dev, -EINVAL,
>  				     "external reference measurements require either refp-supply or ti,refp-refn-resistor-ohms property\n");
>  
> +	clk = devm_clk_get_optional_enabled(dev, NULL);
> +	if (IS_ERR(clk))
> +		return dev_err_probe(dev, PTR_ERR(clk), "failed to get clk\n");
> +
> +	data->fclk_Hz = clk ? clk_get_rate(clk) : ADS112C14_INTERNAL_CLK_Hz;
> +
>  	/* It takes some time for the internal reference to stabilize. */
>  	fsleep(10 * USEC_PER_MSEC);
>  
> @@ -1678,6 +1689,10 @@ static int ads112c14_probe(struct i2c_client *client)
>  			return dev_err_probe(dev, data->drdy_irq,
>  					     "failed to get drdy interrupt\n");
>  
> +		if (clk)
> +			return dev_err_probe(dev, -EINVAL,
> +					     "cannot use both DRDY and CLK - they share the same pin\n");
> +
>  		/*
>  		 * REVISIT: would probably need to implement a pin controller in
>  		 * order to support open drain option here.
> @@ -1717,6 +1732,20 @@ static int ads112c14_probe(struct i2c_client *client)
>  			return ret;
>  	}
>  
> +	if (clk) {
> +		ret = regmap_update_bits(data->regmap, ADS112C14_REG_GPIO_CFG,
> +					 ADS112C14_GPIO_CFG_GPIO3_CFG,
> +					 FIELD_PREP(ADS112C14_GPIO_CFG_GPIO3_CFG,
> +						    ADS112C14_GPIO_CFG_GPIO_CFG_INPUT));
> +		if (ret)
> +			return ret;
> +
> +		ret = regmap_set_bits(data->regmap, ADS112C14_REG_DEVICE_CFG,
> +				      ADS112C14_DEVICE_CFG_CLK_SEL);
> +		if (ret)
> +			return ret;
> +	}
> +
>  	ads112c14_populate_tables(data);
>  
>  	indio_dev->name = info->name;
>