On Sat, 25 Mar 2017, Martin Blumenstingl wrote:
nitpicking below
> Meson GX SoCs however use some magic bits to prevent simultaneous (=
> conflicting, because only consumer should use the FIFO buffer with the
> ADC results) usage by the Linux kernel and the bootloader (the BL30
> bootloader uses the SAR ADC to read the CPU temperature).
> This patch changes guards all BL30 functionality so it is skipped on
> SoCs which don't have it. Since the hardware itself doesn't know whether
> BL30 is available the internal meson_sar_adc_data is extended so this
> information can be provided per of_device_id.data inside the driver.
>
> Additionally the clocks "adc_clk" and "adc_sel" are not provided by the
> clock-controller itself. "adc_sel" is not available at all. "adc_clk"
> is provided by the SAR ADC IP block itself on Meson8b (and earlier).
> This is already supported by the meson_saradc driver.
>
> Finally a new of_device_id for the Meson8b SoC is added so it can be
> wired up in the corresponding DT.
>
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
> ---
> drivers/iio/adc/meson_saradc.c | 70 +++++++++++++++++++++++++++---------------
> 1 file changed, 46 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
> index dd4190b50df6..f78fe66e0ec8 100644
> --- a/drivers/iio/adc/meson_saradc.c
> +++ b/drivers/iio/adc/meson_saradc.c
> @@ -220,6 +220,7 @@ enum meson_sar_adc_chan7_mux_sel {
> };
>
> struct meson_sar_adc_data {
> + char has_bl30_integration;
bool?
> unsigned int resolution;
> const char *name;
> };
> @@ -437,19 +438,24 @@ static int meson_sar_adc_lock(struct iio_dev *indio_dev)
>
> mutex_lock(&indio_dev->mlock);
>
> - /* prevent BL30 from using the SAR ADC while we are using it */
> - regmap_update_bits(priv->regmap, MESON_SAR_ADC_DELAY,
> - MESON_SAR_ADC_DELAY_KERNEL_BUSY,
> - MESON_SAR_ADC_DELAY_KERNEL_BUSY);
> -
> - /* wait until BL30 releases it's lock (so we can use the SAR ADC) */
> - do {
> - udelay(1);
> - regmap_read(priv->regmap, MESON_SAR_ADC_DELAY, &val);
> - } while (val & MESON_SAR_ADC_DELAY_BL30_BUSY && timeout--);
> -
> - if (timeout < 0)
> - return -ETIMEDOUT;
> + if (priv->data->has_bl30_integration) {
> + /* prevent BL30 from using the SAR ADC while we are using it */
> + regmap_update_bits(priv->regmap, MESON_SAR_ADC_DELAY,
> + MESON_SAR_ADC_DELAY_KERNEL_BUSY,
> + MESON_SAR_ADC_DELAY_KERNEL_BUSY);
> +
> + /*
> + * wait until BL30 releases it's lock (so we can use the SAR
its
> + * ADC)
> + */
> + do {
> + udelay(1);
> + regmap_read(priv->regmap, MESON_SAR_ADC_DELAY, &val);
> + } while (val & MESON_SAR_ADC_DELAY_BL30_BUSY && timeout--);
> +
> + if (timeout < 0)
> + return -ETIMEDOUT;
> + }
>
> return 0;
> }
> @@ -458,9 +464,10 @@ static void meson_sar_adc_unlock(struct iio_dev *indio_dev)
> {
> struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
>
> - /* allow BL30 to use the SAR ADC again */
> - regmap_update_bits(priv->regmap, MESON_SAR_ADC_DELAY,
> - MESON_SAR_ADC_DELAY_KERNEL_BUSY, 0);
> + if (priv->data->has_bl30_integration)
> + /* allow BL30 to use the SAR ADC again */
> + regmap_update_bits(priv->regmap, MESON_SAR_ADC_DELAY,
> + MESON_SAR_ADC_DELAY_KERNEL_BUSY, 0);
>
> mutex_unlock(&indio_dev->mlock);
> }
> @@ -614,14 +621,16 @@ static int meson_sar_adc_init(struct iio_dev *indio_dev)
> */
> meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_CH7_INPUT);
>
> - /*
> - * leave sampling delay and the input clocks as configured by BL30 to
> - * make sure BL30 gets the values it expects when reading the
> - * temperature sensor.
> - */
> - regmap_read(priv->regmap, MESON_SAR_ADC_REG3, ®val);
> - if (regval & MESON_SAR_ADC_REG3_BL30_INITIALIZED)
> - return 0;
> + if (priv->data->has_bl30_integration) {
> + /*
> + * leave sampling delay and the input clocks as configured by
> + * BL30 to make sure BL30 gets the values it expects when
> + * reading the temperature sensor.
> + */
> + regmap_read(priv->regmap, MESON_SAR_ADC_REG3, ®val);
> + if (regval & MESON_SAR_ADC_REG3_BL30_INITIALIZED)
> + return 0;
> + }
>
> meson_sar_adc_stop_sample_engine(indio_dev);
>
> @@ -834,23 +843,36 @@ static const struct iio_info meson_sar_adc_iio_info = {
> .driver_module = THIS_MODULE,
> };
>
> +struct meson_sar_adc_data meson_sar_adc_meson8b_data = {
> + .has_bl30_integration = 0,
= false
> + .resolution = 10,
> + .name = "meson-meson8b-saradc",
> +};
> +
> struct meson_sar_adc_data meson_sar_adc_gxbb_data = {
> + .has_bl30_integration = 1,
= true
> .resolution = 10,
> .name = "meson-gxbb-saradc",
> };
>
> struct meson_sar_adc_data meson_sar_adc_gxl_data = {
> + .has_bl30_integration = 1,
> .resolution = 12,
> .name = "meson-gxl-saradc",
> };
>
> struct meson_sar_adc_data meson_sar_adc_gxm_data = {
> + .has_bl30_integration = 1,
> .resolution = 12,
> .name = "meson-gxm-saradc",
> };
>
> static const struct of_device_id meson_sar_adc_of_match[] = {
> {
> + .compatible = "amlogic,meson8b-saradc",
> + .data = &meson_sar_adc_meson8b_data,
> + },
> + {
> .compatible = "amlogic,meson-gxbb-saradc",
> .data = &meson_sar_adc_gxbb_data,
> }, {
>
--
Peter Meerwald-Stadler
Mobile: +43 664 24 44 418
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