diff options
Diffstat (limited to 'drivers/iio/adc/meson_saradc.c')
| -rw-r--r-- | drivers/iio/adc/meson_saradc.c | 165 |
1 files changed, 141 insertions, 24 deletions
diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c index 89def6034f40..dd4190b50df6 100644 --- a/drivers/iio/adc/meson_saradc.c +++ b/drivers/iio/adc/meson_saradc.c @@ -18,7 +18,9 @@ #include <linux/io.h> #include <linux/iio/iio.h> #include <linux/module.h> +#include <linux/interrupt.h> #include <linux/of.h> +#include <linux/of_irq.h> #include <linux/of_device.h> #include <linux/platform_device.h> #include <linux/regmap.h> @@ -163,6 +165,9 @@ #define MESON_SAR_ADC_REG13_12BIT_CALIBRATION_MASK GENMASK(13, 8) #define MESON_SAR_ADC_MAX_FIFO_SIZE 32 +#define MESON_SAR_ADC_TIMEOUT 100 /* ms */ +/* for use with IIO_VAL_INT_PLUS_MICRO */ +#define MILLION 1000000 #define MESON_SAR_ADC_CHAN(_chan) { \ .type = IIO_VOLTAGE, \ @@ -170,7 +175,9 @@ .channel = _chan, \ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ BIT(IIO_CHAN_INFO_AVERAGE_RAW), \ - .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \ + BIT(IIO_CHAN_INFO_CALIBBIAS) | \ + BIT(IIO_CHAN_INFO_CALIBSCALE), \ .datasheet_name = "SAR_ADC_CH"#_chan, \ } @@ -229,6 +236,9 @@ struct meson_sar_adc_priv { struct clk_gate clk_gate; struct clk *adc_div_clk; struct clk_divider clk_div; + struct completion done; + int calibbias; + int calibscale; }; static const struct regmap_config meson_sar_adc_regmap_config = { @@ -248,6 +258,17 @@ static unsigned int meson_sar_adc_get_fifo_count(struct iio_dev *indio_dev) return FIELD_GET(MESON_SAR_ADC_REG0_FIFO_COUNT_MASK, regval); } +static int meson_sar_adc_calib_val(struct iio_dev *indio_dev, int val) +{ + struct meson_sar_adc_priv *priv = iio_priv(indio_dev); + int tmp; + + /* use val_calib = scale * val_raw + offset calibration function */ + tmp = div_s64((s64)val * priv->calibscale, MILLION) + priv->calibbias; + + return clamp(tmp, 0, (1 << priv->data->resolution) - 1); +} + static int meson_sar_adc_wait_busy_clear(struct iio_dev *indio_dev) { struct meson_sar_adc_priv *priv = iio_priv(indio_dev); @@ -274,33 +295,31 @@ static int meson_sar_adc_read_raw_sample(struct iio_dev *indio_dev, int *val) { struct meson_sar_adc_priv *priv = iio_priv(indio_dev); - int ret, regval, fifo_chan, fifo_val, sum = 0, count = 0; + int regval, fifo_chan, fifo_val, count; - ret = meson_sar_adc_wait_busy_clear(indio_dev); - if (ret) - return ret; - - while (meson_sar_adc_get_fifo_count(indio_dev) > 0 && - count < MESON_SAR_ADC_MAX_FIFO_SIZE) { - regmap_read(priv->regmap, MESON_SAR_ADC_FIFO_RD, ®val); - - fifo_chan = FIELD_GET(MESON_SAR_ADC_FIFO_RD_CHAN_ID_MASK, - regval); - if (fifo_chan != chan->channel) - continue; - - fifo_val = FIELD_GET(MESON_SAR_ADC_FIFO_RD_SAMPLE_VALUE_MASK, - regval); - fifo_val &= (BIT(priv->data->resolution) - 1); + if(!wait_for_completion_timeout(&priv->done, + msecs_to_jiffies(MESON_SAR_ADC_TIMEOUT))) + return -ETIMEDOUT; - sum += fifo_val; - count++; + count = meson_sar_adc_get_fifo_count(indio_dev); + if (count != 1) { + dev_err(&indio_dev->dev, + "ADC FIFO has %d element(s) instead of one\n", count); + return -EINVAL; } - if (!count) - return -ENOENT; + regmap_read(priv->regmap, MESON_SAR_ADC_FIFO_RD, ®val); + fifo_chan = FIELD_GET(MESON_SAR_ADC_FIFO_RD_CHAN_ID_MASK, regval); + if (fifo_chan != chan->channel) { + dev_err(&indio_dev->dev, + "ADC FIFO entry belongs to channel %d instead of %d\n", + fifo_chan, chan->channel); + return -EINVAL; + } - *val = sum / count; + fifo_val = FIELD_GET(MESON_SAR_ADC_FIFO_RD_SAMPLE_VALUE_MASK, regval); + fifo_val &= GENMASK(priv->data->resolution - 1, 0); + *val = meson_sar_adc_calib_val(indio_dev, fifo_val); return 0; } @@ -378,6 +397,12 @@ static void meson_sar_adc_start_sample_engine(struct iio_dev *indio_dev) { struct meson_sar_adc_priv *priv = iio_priv(indio_dev); + reinit_completion(&priv->done); + + regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0, + MESON_SAR_ADC_REG0_FIFO_IRQ_EN, + MESON_SAR_ADC_REG0_FIFO_IRQ_EN); + regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0, MESON_SAR_ADC_REG0_SAMPLE_ENGINE_ENABLE, MESON_SAR_ADC_REG0_SAMPLE_ENGINE_ENABLE); @@ -392,6 +417,9 @@ static void meson_sar_adc_stop_sample_engine(struct iio_dev *indio_dev) struct meson_sar_adc_priv *priv = iio_priv(indio_dev); regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0, + MESON_SAR_ADC_REG0_FIFO_IRQ_EN, 0); + + regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0, MESON_SAR_ADC_REG0_SAMPLING_STOP, MESON_SAR_ADC_REG0_SAMPLING_STOP); @@ -516,6 +544,15 @@ static int meson_sar_adc_iio_info_read_raw(struct iio_dev *indio_dev, *val2 = priv->data->resolution; return IIO_VAL_FRACTIONAL_LOG2; + case IIO_CHAN_INFO_CALIBBIAS: + *val = priv->calibbias; + return IIO_VAL_INT; + + case IIO_CHAN_INFO_CALIBSCALE: + *val = priv->calibscale / MILLION; + *val2 = priv->calibscale % MILLION; + return IIO_VAL_INT_PLUS_MICRO; + default: return -EINVAL; } @@ -643,6 +680,7 @@ static int meson_sar_adc_hw_enable(struct iio_dev *indio_dev) { struct meson_sar_adc_priv *priv = iio_priv(indio_dev); int ret; + u32 regval; ret = meson_sar_adc_lock(indio_dev); if (ret) @@ -667,6 +705,9 @@ static int meson_sar_adc_hw_enable(struct iio_dev *indio_dev) goto err_sana_clk; } + regval = FIELD_PREP(MESON_SAR_ADC_REG0_FIFO_CNT_IRQ_MASK, 1); + regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0, + MESON_SAR_ADC_REG0_FIFO_CNT_IRQ_MASK, regval); regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG11, MESON_SAR_ADC_REG11_BANDGAP_EN, MESON_SAR_ADC_REG11_BANDGAP_EN); @@ -728,6 +769,66 @@ static int meson_sar_adc_hw_disable(struct iio_dev *indio_dev) return 0; } +static irqreturn_t meson_sar_adc_irq(int irq, void *data) +{ + struct iio_dev *indio_dev = data; + struct meson_sar_adc_priv *priv = iio_priv(indio_dev); + unsigned int cnt, threshold; + u32 regval; + + regmap_read(priv->regmap, MESON_SAR_ADC_REG0, ®val); + cnt = FIELD_GET(MESON_SAR_ADC_REG0_FIFO_COUNT_MASK, regval); + threshold = FIELD_GET(MESON_SAR_ADC_REG0_FIFO_CNT_IRQ_MASK, regval); + + if (cnt < threshold) + return IRQ_NONE; + + complete(&priv->done); + + return IRQ_HANDLED; +} + +static int meson_sar_adc_calib(struct iio_dev *indio_dev) +{ + struct meson_sar_adc_priv *priv = iio_priv(indio_dev); + int ret, nominal0, nominal1, value0, value1; + + /* use points 25% and 75% for calibration */ + nominal0 = (1 << priv->data->resolution) / 4; + nominal1 = (1 << priv->data->resolution) * 3 / 4; + + meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_DIV4); + usleep_range(10, 20); + ret = meson_sar_adc_get_sample(indio_dev, + &meson_sar_adc_iio_channels[7], + MEAN_AVERAGING, EIGHT_SAMPLES, &value0); + if (ret < 0) + goto out; + + meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_MUL3_DIV4); + usleep_range(10, 20); + ret = meson_sar_adc_get_sample(indio_dev, + &meson_sar_adc_iio_channels[7], + MEAN_AVERAGING, EIGHT_SAMPLES, &value1); + if (ret < 0) + goto out; + + if (value1 <= value0) { + ret = -EINVAL; + goto out; + } + + priv->calibscale = div_s64((nominal1 - nominal0) * (s64)MILLION, + value1 - value0); + priv->calibbias = nominal0 - div_s64((s64)value0 * priv->calibscale, + MILLION); + ret = 0; +out: + meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_CH7_INPUT); + + return ret; +} + static const struct iio_info meson_sar_adc_iio_info = { .read_raw = meson_sar_adc_iio_info_read_raw, .driver_module = THIS_MODULE, @@ -770,7 +871,7 @@ static int meson_sar_adc_probe(struct platform_device *pdev) struct resource *res; void __iomem *base; const struct of_device_id *match; - int ret; + int irq, ret; indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*priv)); if (!indio_dev) { @@ -779,6 +880,7 @@ static int meson_sar_adc_probe(struct platform_device *pdev) } priv = iio_priv(indio_dev); + init_completion(&priv->done); match = of_match_device(meson_sar_adc_of_match, &pdev->dev); priv->data = match->data; @@ -797,6 +899,15 @@ static int meson_sar_adc_probe(struct platform_device *pdev) if (IS_ERR(base)) return PTR_ERR(base); + irq = irq_of_parse_and_map(pdev->dev.of_node, 0); + if (!irq) + return -EINVAL; + + ret = devm_request_irq(&pdev->dev, irq, meson_sar_adc_irq, IRQF_SHARED, + dev_name(&pdev->dev), indio_dev); + if (ret) + return ret; + priv->regmap = devm_regmap_init_mmio(&pdev->dev, base, &meson_sar_adc_regmap_config); if (IS_ERR(priv->regmap)) @@ -857,6 +968,8 @@ static int meson_sar_adc_probe(struct platform_device *pdev) return PTR_ERR(priv->vref); } + priv->calibscale = MILLION; + ret = meson_sar_adc_init(indio_dev); if (ret) goto err; @@ -865,6 +978,10 @@ static int meson_sar_adc_probe(struct platform_device *pdev) if (ret) goto err; + ret = meson_sar_adc_calib(indio_dev); + if (ret) + dev_warn(&pdev->dev, "calibration failed\n"); + platform_set_drvdata(pdev, indio_dev); ret = iio_device_register(indio_dev); |