Re: [PATCH v4 2/3] iio: adc: vf610: implement configurable conversion modes

From: Jonathan Cameron
Date: Sat Mar 28 2015 - 08:08:09 EST

On 24/03/15 12:47, Stefan Agner wrote:
> Support configurable conversion mode through sysfs. So far, the
> mode used was low-power, which is enabled by default now. Beside
> that, the modes normal and high-speed are selectable as well.
>
> Use the new device tree property which specifies the maximum ADC
> conversion clock frequencies. Depending on the mode used, the
> available resulting conversion frequency are calculated
> dynamically.
>
One trivial bit inline, otherwise looks good to me.
I wish there was a better way of 'hinting' to drivers what power mode
is required, but in the absense of this I guess explicit control is
all we can do.
> Acked-by: Fugang Duan <B38611@xxxxxxxxxxxxx>
> Signed-off-by: Stefan Agner <stefan@xxxxxxxx>
> ---
> Documentation/ABI/testing/sysfs-bus-iio-vf610 | 7 +
> .../devicetree/bindings/iio/adc/vf610-adc.txt | 9 ++
> drivers/iio/adc/vf610_adc.c | 146 +++++++++++++++------
> 3 files changed, 120 insertions(+), 42 deletions(-)
> create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-vf610
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-vf610 b/Documentation/ABI/testing/sysfs-bus-iio-vf610
> new file mode 100644
> index 0000000..85fd0ecd5
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-iio-vf610
> @@ -0,0 +1,7 @@
> +What: /sys/bus/iio/devices/iio:deviceX/conversion_mode
> +KernelVersion: 4.1
> +Contact: linux-iio@xxxxxxxxxxxxxxx
> +Description:
> + Specifies the hardware conversion mode used. The three
> + available modes are "normal", "high-speed" and "low-power",
> + whereas the last is the default mode.
Fussy English of the day. where rather than whereas (whereas is only
used if you say something like. A is normally the case, whereas here B is the case)
I like the default that isn't 'normal' :)

> diff --git a/Documentation/devicetree/bindings/iio/adc/vf610-adc.txt b/Documentation/devicetree/bindings/iio/adc/vf610-adc.txt
> index 1a4a43d..3eb40e2 100644
> --- a/Documentation/devicetree/bindings/iio/adc/vf610-adc.txt
> +++ b/Documentation/devicetree/bindings/iio/adc/vf610-adc.txt
> @@ -11,6 +11,13 @@ Required properties:
> - clock-names: Must contain "adc", matching entry in the clocks property.
> - vref-supply: The regulator supply ADC reference voltage.
>
> +Recommended properties:
> +- fsl,adck-max-frequency: Maximum frequencies according to datasheets operating
> + requirements. Three values are required, depending on conversion mode:
> + - Frequency in normal mode (ADLPC=0, ADHSC=0)
> + - Frequency in high-speed mode (ADLPC=0, ADHSC=1)
> + - Frequency in low-power mode (ADLPC=1, ADHSC=0)
> +
> Example:
> adc0: adc@4003b000 {
> compatible = "fsl,vf610-adc";
> @@ -18,5 +25,7 @@ adc0: adc@4003b000 {
> interrupts = <0 53 0x04>;
> clocks = <&clks VF610_CLK_ADC0>;
> clock-names = "adc";
> + fsl,adck-max-frequency = <30000000>, <40000000>,
> + <20000000>;
> vref-supply = <&reg_vcc_3v3_mcu>;
> };
> diff --git a/drivers/iio/adc/vf610_adc.c b/drivers/iio/adc/vf610_adc.c
> index e63b8e7..b5f94ab8 100644
> --- a/drivers/iio/adc/vf610_adc.c
> +++ b/drivers/iio/adc/vf610_adc.c
> @@ -118,15 +118,21 @@ enum average_sel {
> VF610_ADC_SAMPLE_32,
> };
>
> +enum conversion_mode_sel {
> + VF610_ADC_CONV_NORMAL,
> + VF610_ADC_CONV_HIGH_SPEED,
> + VF610_ADC_CONV_LOW_POWER,
> +};
> +
> struct vf610_adc_feature {
> enum clk_sel clk_sel;
> enum vol_ref vol_ref;
> + enum conversion_mode_sel conv_mode;
>
> int clk_div;
> int sample_rate;
> int res_mode;
>
> - bool lpm;
> bool calibration;
> bool ovwren;
> };
> @@ -139,6 +145,8 @@ struct vf610_adc {
> u32 vref_uv;
> u32 value;
> struct regulator *vref;
> +
> + u32 max_adck_rate[3];
> struct vf610_adc_feature adc_feature;
>
> u32 sample_freq_avail[5];
> @@ -148,46 +156,22 @@ struct vf610_adc {
>
> static const u32 vf610_hw_avgs[] = { 1, 4, 8, 16, 32 };
>
> -#define VF610_ADC_CHAN(_idx, _chan_type) { \
> - .type = (_chan_type), \
> - .indexed = 1, \
> - .channel = (_idx), \
> - .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> - .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
> - BIT(IIO_CHAN_INFO_SAMP_FREQ), \
> -}
> -
> -#define VF610_ADC_TEMPERATURE_CHAN(_idx, _chan_type) { \
> - .type = (_chan_type), \
> - .channel = (_idx), \
> - .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
> -}
> -
> -static const struct iio_chan_spec vf610_adc_iio_channels[] = {
> - VF610_ADC_CHAN(0, IIO_VOLTAGE),
> - VF610_ADC_CHAN(1, IIO_VOLTAGE),
> - VF610_ADC_CHAN(2, IIO_VOLTAGE),
> - VF610_ADC_CHAN(3, IIO_VOLTAGE),
> - VF610_ADC_CHAN(4, IIO_VOLTAGE),
> - VF610_ADC_CHAN(5, IIO_VOLTAGE),
> - VF610_ADC_CHAN(6, IIO_VOLTAGE),
> - VF610_ADC_CHAN(7, IIO_VOLTAGE),
> - VF610_ADC_CHAN(8, IIO_VOLTAGE),
> - VF610_ADC_CHAN(9, IIO_VOLTAGE),
> - VF610_ADC_CHAN(10, IIO_VOLTAGE),
> - VF610_ADC_CHAN(11, IIO_VOLTAGE),
> - VF610_ADC_CHAN(12, IIO_VOLTAGE),
> - VF610_ADC_CHAN(13, IIO_VOLTAGE),
> - VF610_ADC_CHAN(14, IIO_VOLTAGE),
> - VF610_ADC_CHAN(15, IIO_VOLTAGE),
> - VF610_ADC_TEMPERATURE_CHAN(26, IIO_TEMP),
> - /* sentinel */
> -};
> -
> static inline void vf610_adc_calculate_rates(struct vf610_adc *info)
> {
> + struct vf610_adc_feature *adc_feature = &info->adc_feature;
> unsigned long adck_rate, ipg_rate = clk_get_rate(info->clk);
> - int i;
> + int divisor, i;
> +
> + adck_rate = info->max_adck_rate[adc_feature->conv_mode];
> +
> + if (adck_rate) {
> + /* calculate clk divider which is within specification */
> + divisor = ipg_rate / adck_rate;
> + adc_feature->clk_div = 1 << fls(divisor + 1);
> + } else {
> + /* fall-back value using a safe divisor */
> + adc_feature->clk_div = 8;
> + }
>
> /*
> * Calculate ADC sample frequencies
> @@ -219,10 +203,8 @@ static inline void vf610_adc_cfg_init(struct vf610_adc *info)
>
> adc_feature->res_mode = 12;
> adc_feature->sample_rate = 1;
> - adc_feature->lpm = true;
>
> - /* Use a save ADCK which is below 20MHz on all devices */
> - adc_feature->clk_div = 8;
> + adc_feature->conv_mode = VF610_ADC_CONV_LOW_POWER;
>
> vf610_adc_calculate_rates(info);
> }
> @@ -307,10 +289,12 @@ static void vf610_adc_cfg_set(struct vf610_adc *info)
> cfg_data = readl(info->regs + VF610_REG_ADC_CFG);
>
> cfg_data &= ~VF610_ADC_ADLPC_EN;
> - if (adc_feature->lpm)
> + if (adc_feature->conv_mode == VF610_ADC_CONV_LOW_POWER)
> cfg_data |= VF610_ADC_ADLPC_EN;
>
> cfg_data &= ~VF610_ADC_ADHSC_EN;
> + if (adc_feature->conv_mode == VF610_ADC_CONV_HIGH_SPEED)
> + cfg_data |= VF610_ADC_ADHSC_EN;
>
> writel(cfg_data, info->regs + VF610_REG_ADC_CFG);
> }
> @@ -412,6 +396,81 @@ static void vf610_adc_hw_init(struct vf610_adc *info)
> vf610_adc_cfg_set(info);
> }
>
> +static int vf610_set_conversion_mode(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *chan,
> + unsigned int mode)
> +{
> + struct vf610_adc *info = iio_priv(indio_dev);
> +
> + mutex_lock(&indio_dev->mlock);
> + info->adc_feature.conv_mode = mode;
> + vf610_adc_calculate_rates(info);
> + vf610_adc_hw_init(info);
> + mutex_unlock(&indio_dev->mlock);
> +
> + return 0;
> +}
> +
> +static int vf610_get_conversion_mode(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *chan)
> +{
> + struct vf610_adc *info = iio_priv(indio_dev);
> +
> + return info->adc_feature.conv_mode;
> +}
> +
> +static const char * const vf610_conv_modes[] = { "normal", "high-speed",
> + "low-power" };
> +
> +static const struct iio_enum vf610_conversion_mode = {
> + .items = vf610_conv_modes,
> + .num_items = ARRAY_SIZE(vf610_conv_modes),
> + .get = vf610_get_conversion_mode,
> + .set = vf610_set_conversion_mode,
> +};
> +
> +static const struct iio_chan_spec_ext_info vf610_ext_info[] = {
> + IIO_ENUM("conversion_mode", IIO_SHARED_BY_DIR, &vf610_conversion_mode),
> + {},
> +};
> +
> +#define VF610_ADC_CHAN(_idx, _chan_type) { \
> + .type = (_chan_type), \
> + .indexed = 1, \
> + .channel = (_idx), \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
> + BIT(IIO_CHAN_INFO_SAMP_FREQ), \
> + .ext_info = vf610_ext_info, \
> +}
> +
> +#define VF610_ADC_TEMPERATURE_CHAN(_idx, _chan_type) { \
> + .type = (_chan_type), \
> + .channel = (_idx), \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
> +}
> +
> +static const struct iio_chan_spec vf610_adc_iio_channels[] = {
> + VF610_ADC_CHAN(0, IIO_VOLTAGE),
> + VF610_ADC_CHAN(1, IIO_VOLTAGE),
> + VF610_ADC_CHAN(2, IIO_VOLTAGE),
> + VF610_ADC_CHAN(3, IIO_VOLTAGE),
> + VF610_ADC_CHAN(4, IIO_VOLTAGE),
> + VF610_ADC_CHAN(5, IIO_VOLTAGE),
> + VF610_ADC_CHAN(6, IIO_VOLTAGE),
> + VF610_ADC_CHAN(7, IIO_VOLTAGE),
> + VF610_ADC_CHAN(8, IIO_VOLTAGE),
> + VF610_ADC_CHAN(9, IIO_VOLTAGE),
> + VF610_ADC_CHAN(10, IIO_VOLTAGE),
> + VF610_ADC_CHAN(11, IIO_VOLTAGE),
> + VF610_ADC_CHAN(12, IIO_VOLTAGE),
> + VF610_ADC_CHAN(13, IIO_VOLTAGE),
> + VF610_ADC_CHAN(14, IIO_VOLTAGE),
> + VF610_ADC_CHAN(15, IIO_VOLTAGE),
> + VF610_ADC_TEMPERATURE_CHAN(26, IIO_TEMP),
> + /* sentinel */
> +};
> +
> static int vf610_adc_read_data(struct vf610_adc *info)
> {
> int result;
> @@ -654,6 +713,9 @@ static int vf610_adc_probe(struct platform_device *pdev)
>
> info->vref_uv = regulator_get_voltage(info->vref);
>
> + of_property_read_u32_array(pdev->dev.of_node, "fsl,adck-max-frequency",
> + info->max_adck_rate, 3);
> +
> platform_set_drvdata(pdev, indio_dev);
>
> init_completion(&info->completion);
>

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