diff options
Diffstat (limited to 'drivers/iio/adc')
| -rw-r--r-- | drivers/iio/adc/ad7768-1.c | 202 |
1 files changed, 199 insertions, 3 deletions
diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c index 78449e90b2f5..0d132708c429 100644 --- a/drivers/iio/adc/ad7768-1.c +++ b/drivers/iio/adc/ad7768-1.c @@ -9,6 +9,7 @@ #include <linux/delay.h> #include <linux/device.h> #include <linux/err.h> +#include <linux/gpio/consumer.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/regulator/consumer.h> @@ -59,6 +60,18 @@ #define AD7768_REG_DIG_DIAG_STATUS 0x30 #define AD7768_REG_MCLK_COUNTER 0x31 +/* AD7768_REG_POWER_CLOCK */ +#define AD7768_PWR_MCLK_DIV_MSK GENMASK(5, 4) +#define AD7768_PWR_MCLK_DIV(x) FIELD_PREP(AD7768_PWR_MCLK_DIV_MSK, x) +#define AD7768_PWR_PWRMODE_MSK GENMASK(1, 0) +#define AD7768_PWR_PWRMODE(x) FIELD_PREP(AD7768_PWR_PWRMODE_MSK, x) + +/* AD7768_REG_DIGITAL_FILTER */ +#define AD7768_DIG_FIL_FIL_MSK GENMASK(6, 4) +#define AD7768_DIG_FIL_FIL(x) FIELD_PREP(AD7768_DIG_FIL_FIL_MSK, x) +#define AD7768_DIG_FIL_DEC_MSK GENMASK(2, 0) +#define AD7768_DIG_FIL_DEC_RATE(x) FIELD_PREP(AD7768_DIG_FIL_DEC_MSK, x) + /* AD7768_REG_CONVERSION */ #define AD7768_CONV_MODE_MSK GENMASK(2, 0) #define AD7768_CONV_MODE(x) FIELD_PREP(AD7768_CONV_MODE_MSK, x) @@ -80,11 +93,51 @@ enum ad7768_pwrmode { AD7768_FAST_MODE = 3 }; +enum ad7768_mclk_div { + AD7768_MCLK_DIV_16, + AD7768_MCLK_DIV_8, + AD7768_MCLK_DIV_4, + AD7768_MCLK_DIV_2 +}; + +enum ad7768_dec_rate { + AD7768_DEC_RATE_32 = 0, + AD7768_DEC_RATE_64 = 1, + AD7768_DEC_RATE_128 = 2, + AD7768_DEC_RATE_256 = 3, + AD7768_DEC_RATE_512 = 4, + AD7768_DEC_RATE_1024 = 5, + AD7768_DEC_RATE_8 = 9, + AD7768_DEC_RATE_16 = 10 +}; + +struct ad7768_clk_configuration { + enum ad7768_mclk_div mclk_div; + enum ad7768_dec_rate dec_rate; + unsigned int clk_div; + enum ad7768_pwrmode pwrmode; +}; + +static const struct ad7768_clk_configuration ad7768_clk_config[] = { + { AD7768_MCLK_DIV_2, AD7768_DEC_RATE_8, 16, AD7768_FAST_MODE }, + { AD7768_MCLK_DIV_2, AD7768_DEC_RATE_16, 32, AD7768_FAST_MODE }, + { AD7768_MCLK_DIV_2, AD7768_DEC_RATE_32, 64, AD7768_FAST_MODE }, + { AD7768_MCLK_DIV_2, AD7768_DEC_RATE_64, 128, AD7768_FAST_MODE }, + { AD7768_MCLK_DIV_2, AD7768_DEC_RATE_128, 256, AD7768_FAST_MODE }, + { AD7768_MCLK_DIV_4, AD7768_DEC_RATE_128, 512, AD7768_MED_MODE }, + { AD7768_MCLK_DIV_4, AD7768_DEC_RATE_256, 1024, AD7768_MED_MODE }, + { AD7768_MCLK_DIV_4, AD7768_DEC_RATE_512, 2048, AD7768_MED_MODE }, + { AD7768_MCLK_DIV_4, AD7768_DEC_RATE_1024, 4096, AD7768_MED_MODE }, + { AD7768_MCLK_DIV_8, AD7768_DEC_RATE_1024, 8192, AD7768_MED_MODE }, + { AD7768_MCLK_DIV_16, AD7768_DEC_RATE_1024, 16384, AD7768_ECO_MODE }, +}; + static const struct iio_chan_spec ad7768_channels[] = { { .type = IIO_VOLTAGE, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), .indexed = 1, .channel = 0, .scan_index = 0, @@ -102,8 +155,12 @@ struct ad7768_state { struct spi_device *spi; struct regulator *vref; struct mutex lock; + struct clk *mclk; + unsigned int mclk_freq; + unsigned int samp_freq; struct completion completion; struct iio_trigger *trig; + struct gpio_desc *gpio_sync_in; /* * DMA (thus cache coherency maintenance) requires the * transfer buffers to live in their own cache lines. @@ -210,6 +267,90 @@ err_unlock: return ret; } +static int ad7768_set_dig_fil(struct ad7768_state *st, + enum ad7768_dec_rate dec_rate) +{ + unsigned int mode; + int ret; + + if (dec_rate == AD7768_DEC_RATE_8 || dec_rate == AD7768_DEC_RATE_16) + mode = AD7768_DIG_FIL_FIL(dec_rate); + else + mode = AD7768_DIG_FIL_DEC_RATE(dec_rate); + + ret = ad7768_spi_reg_write(st, AD7768_REG_DIGITAL_FILTER, mode); + if (ret < 0) + return ret; + + /* A sync-in pulse is required every time the filter dec rate changes */ + gpiod_set_value(st->gpio_sync_in, 1); + gpiod_set_value(st->gpio_sync_in, 0); + + return 0; +} + +static int ad7768_set_freq(struct ad7768_state *st, + unsigned int freq) +{ + unsigned int diff_new, diff_old, pwr_mode, i, idx; + int res, ret; + + diff_old = U32_MAX; + idx = 0; + + res = DIV_ROUND_CLOSEST(st->mclk_freq, freq); + + /* Find the closest match for the desired sampling frequency */ + for (i = 0; i < ARRAY_SIZE(ad7768_clk_config); i++) { + diff_new = abs(res - ad7768_clk_config[i].clk_div); + if (diff_new < diff_old) { + diff_old = diff_new; + idx = i; + } + } + + /* + * Set both the mclk_div and pwrmode with a single write to the + * POWER_CLOCK register + */ + pwr_mode = AD7768_PWR_MCLK_DIV(ad7768_clk_config[idx].mclk_div) | + AD7768_PWR_PWRMODE(ad7768_clk_config[idx].pwrmode); + ret = ad7768_spi_reg_write(st, AD7768_REG_POWER_CLOCK, pwr_mode); + if (ret < 0) + return ret; + + ret = ad7768_set_dig_fil(st, ad7768_clk_config[idx].dec_rate); + if (ret < 0) + return ret; + + st->samp_freq = DIV_ROUND_CLOSEST(st->mclk_freq, + ad7768_clk_config[idx].clk_div); + + return 0; +} + +static ssize_t ad7768_sampling_freq_avail(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct ad7768_state *st = iio_priv(indio_dev); + unsigned int freq; + int i, len = 0; + + for (i = 0; i < ARRAY_SIZE(ad7768_clk_config); i++) { + freq = DIV_ROUND_CLOSEST(st->mclk_freq, + ad7768_clk_config[i].clk_div); + len += scnprintf(buf + len, PAGE_SIZE - len, "%d ", freq); + } + + buf[len - 1] = '\n'; + + return len; +} + +static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(ad7768_sampling_freq_avail); + static int ad7768_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long info) @@ -242,13 +383,43 @@ static int ad7768_read_raw(struct iio_dev *indio_dev, *val2 = chan->scan_type.realbits; return IIO_VAL_FRACTIONAL_LOG2; + + case IIO_CHAN_INFO_SAMP_FREQ: + *val = st->samp_freq; + + return IIO_VAL_INT; } return -EINVAL; } +static int ad7768_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long info) +{ + struct ad7768_state *st = iio_priv(indio_dev); + + switch (info) { + case IIO_CHAN_INFO_SAMP_FREQ: + return ad7768_set_freq(st, val); + default: + return -EINVAL; + } +} + +static struct attribute *ad7768_attributes[] = { + &iio_dev_attr_sampling_frequency_available.dev_attr.attr, + NULL +}; + +static const struct attribute_group ad7768_group = { + .attrs = ad7768_attributes, +}; + static const struct iio_info ad7768_info = { + .attrs = &ad7768_group, .read_raw = &ad7768_read_raw, + .write_raw = &ad7768_write_raw, .debugfs_reg_access = &ad7768_reg_access, }; @@ -270,9 +441,13 @@ static int ad7768_setup(struct ad7768_state *st) if (ret) return ret; - /* Set power mode to fast */ - return ad7768_spi_reg_write(st, AD7768_REG_POWER_CLOCK, - AD7768_FAST_MODE); + st->gpio_sync_in = devm_gpiod_get(&st->spi->dev, "adi,sync-in", + GPIOD_OUT_LOW); + if (IS_ERR(st->gpio_sync_in)) + return PTR_ERR(st->gpio_sync_in); + + /* Set the default sampling frequency to 32000 kSPS */ + return ad7768_set_freq(st, 32000); } static irqreturn_t ad7768_trigger_handler(int irq, void *p) @@ -356,6 +531,13 @@ static void ad7768_regulator_disable(void *data) regulator_disable(st->vref); } +static void ad7768_clk_disable(void *data) +{ + struct ad7768_state *st = data; + + clk_disable_unprepare(st->mclk); +} + static int ad7768_probe(struct spi_device *spi) { struct ad7768_state *st; @@ -383,6 +565,20 @@ static int ad7768_probe(struct spi_device *spi) if (ret) return ret; + st->mclk = devm_clk_get(&spi->dev, "mclk"); + if (IS_ERR(st->mclk)) + return PTR_ERR(st->mclk); + + ret = clk_prepare_enable(st->mclk); + if (ret < 0) + return ret; + + ret = devm_add_action_or_reset(&spi->dev, ad7768_clk_disable, st); + if (ret) + return ret; + + st->mclk_freq = clk_get_rate(st->mclk); + spi_set_drvdata(spi, indio_dev); mutex_init(&st->lock); |