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Message-ID: <45630b06-c5cc-4512-8376-dc99fd0976bc@gmail.com>
Date: Fri, 18 Oct 2024 16:05:14 +0200
From: Javier Carrasco <javier.carrasco.cruz@...il.com>
To: Jonathan Cameron <jic23@...nel.org>, Lars-Peter Clausen
<lars@...afoo.de>, Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>
Cc: linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
devicetree@...r.kernel.org
Subject: Re: [PATCH 4/4] iio: light: veml6070: add support for integration
time
On 17/10/2024 23:39, Javier Carrasco wrote:
> The integration time of the veml6070 depends on an external resistor
> (called Rset in the datasheet) and the value configured in the IT
> field of the command register.
>
> Signed-off-by: Javier Carrasco <javier.carrasco.cruz@...il.com>
> ---
> drivers/iio/light/veml6070.c | 109 ++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 107 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/light/veml6070.c b/drivers/iio/light/veml6070.c
> index d11ae00f61f8..87dc3295a656 100644
> --- a/drivers/iio/light/veml6070.c
> +++ b/drivers/iio/light/veml6070.c
> @@ -6,7 +6,7 @@
> *
> * IIO driver for VEML6070 (7-bit I2C slave addresses 0x38 and 0x39)
> *
> - * TODO: integration time, ACK signal
> + * TODO: ACK signal
> */
>
> #include <linux/bitfield.h>
> @@ -29,15 +29,78 @@
> #define VEML6070_COMMAND_RSRVD BIT(1) /* reserved, set to 1 */
> #define VEML6070_COMMAND_SD BIT(0) /* shutdown mode when set */
>
> -#define VEML6070_IT_10 0x01 /* integration time 1x */
> +#define VEML6070_IT_05 0x00
> +#define VEML6070_IT_10 0x01
> +#define VEML6070_IT_20 0x02
> +#define VEML6070_IT_40 0x03
> +
> +#define VEML6070_MIN_RSET_KOHM 75
> +#define VEML6070_MIN_IT_US 15625 /* Rset = 75 kohm, IT = 1/2 */
>
> struct veml6070_data {
> struct i2c_client *client1;
> struct i2c_client *client2;
> u8 config;
> struct mutex lock;
> + u32 it[4][2];
> };
>
> +static void veml6070_calc_it(struct device *dev, struct veml6070_data *data)
> +{
> + u32 rset, tmp_it;
> + int i, ret;
> +
> + ret = device_property_read_u32(dev, "rset-kohms", &rset);
> + if (ret) {
> + dev_warn(dev, "no Rset specified, using default 300 kohms\n");
> + rset = 300;
> + }
> +
> + if (rset < 75) {
> + dev_warn(dev, "Rset too low, using minimum = 75 kohms\n");
> + rset = 75;
> + }
> +
> + if (rset > 1200) {
> + dev_warn(dev, "Rset too high, using maximum = 1200 kohms\n");
> + rset = 1200;
> + }
> +
> + tmp_it = VEML6070_MIN_IT_US * (rset / VEML6070_MIN_RSET_KOHM);
> + for (i = 0; i < ARRAY_SIZE(data->it); i++) {
> + data->it[i][0] = (tmp_it << i) / 1000000;
> + data->it[i][1] = (tmp_it << i) % 1000000;
> + }
> +}
> +
> +static int veml6070_get_it(struct veml6070_data *data, int *val, int *val2)
> +{
> + int it_idx = FIELD_GET(VEML6070_COMMAND_IT, data->config);
> +
> + *val = data->it[it_idx][0];
> + *val2 = data->it[it_idx][1];
> +
> + return IIO_VAL_INT_PLUS_MICRO;
> +}
> +
> +static int veml6070_set_it(struct veml6070_data *data, int val, int val2)
> +{
> + int it_idx;
> +
> + for (it_idx = 0; it_idx < ARRAY_SIZE(data->it); it_idx++) {
> + if (data->it[it_idx][0] == val && data->it[it_idx][1] == val2)
> + break;
> + }
> +
> + if (it_idx >= ARRAY_SIZE(data->it))
> + return -EINVAL;
> +
> + data->config = (data->config & ~VEML6070_COMMAND_IT) |
> + FIELD_PREP(VEML6070_COMMAND_IT, it_idx);
> +
> + return i2c_smbus_write_byte(data->client1, data->config);
> +}
> +
> static int veml6070_read(struct veml6070_data *data)
> {
> int ret;
> @@ -81,10 +144,14 @@ static const struct iio_chan_spec veml6070_channels[] = {
> .modified = 1,
> .channel2 = IIO_MOD_LIGHT_UV,
> .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
> + .info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME),
> },
> {
> .type = IIO_UVINDEX,
> .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
> + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
> + .info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME),
> }
> };
>
> @@ -127,6 +194,40 @@ static int veml6070_read_raw(struct iio_dev *indio_dev,
> else
> *val = ret;
> return IIO_VAL_INT;
> + case IIO_CHAN_INFO_INT_TIME:
> + return veml6070_get_it(data, val, val2);
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static int veml6070_read_avail(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + const int **vals, int *type, int *length,
> + long mask)
> +{
> + struct veml6070_data *data = iio_priv(indio_dev);
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_INT_TIME:
> + *vals = (int *)data->it;
> + *length = 2 * ARRAY_SIZE(data->it);
> + *type = IIO_VAL_INT_PLUS_MICRO;
> + return IIO_AVAIL_LIST;
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static int veml6070_write_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int val, int val2, long mask)
> +{
> + struct veml6070_data *data = iio_priv(indio_dev);
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_INT_TIME:
> + return veml6070_set_it(data, val, val2);
> default:
> return -EINVAL;
> }
> @@ -134,6 +235,8 @@ static int veml6070_read_raw(struct iio_dev *indio_dev,
>
I just noticed that the processed data needs to be updated to take into
account different integration times because in its current form it
provides fixed values for Rset = 270kohm, IT=1T. I will add it to v2,
which is required anyway to address changes in the dt-bindings.
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