diff options
Diffstat (limited to 'drivers/iio/adc/at91_adc.c')
| -rw-r--r-- | drivers/iio/adc/at91_adc.c | 98 |
1 files changed, 89 insertions, 9 deletions
diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c index 83c836ba600..e5b88d5d3b5 100644 --- a/drivers/iio/adc/at91_adc.c +++ b/drivers/iio/adc/at91_adc.c @@ -52,11 +52,15 @@ struct at91_adc_state { void __iomem *reg_base; struct at91_adc_reg_desc *registers; u8 startup_time; + u8 sample_hold_time; + bool sleep_mode; struct iio_trigger **trig; struct at91_adc_trigger *trigger_list; u32 trigger_number; bool use_external; u32 vref_mv; + u32 res; /* resolution used for convertions */ + bool low_res; /* the resolution corresponds to the lowest one */ wait_queue_head_t wq_data_avail; }; @@ -138,10 +142,10 @@ static int at91_adc_channel_init(struct iio_dev *idev) chan->channel = bit; chan->scan_index = idx; chan->scan_type.sign = 'u'; - chan->scan_type.realbits = 10; + chan->scan_type.realbits = st->res; chan->scan_type.storagebits = 16; - chan->info_mask = IIO_CHAN_INFO_SCALE_SHARED_BIT | - IIO_CHAN_INFO_RAW_SEPARATE_BIT; + chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE); + chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW); idx++; } timestamp = chan_array + idx; @@ -188,7 +192,7 @@ static u8 at91_adc_get_trigger_value_by_name(struct iio_dev *idev, static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state) { - struct iio_dev *idev = trig->private_data; + struct iio_dev *idev = iio_trigger_get_drvdata(trig); struct at91_adc_state *st = iio_priv(idev); struct iio_buffer *buffer = idev->buffer; struct at91_adc_reg_desc *reg = st->registers; @@ -254,7 +258,7 @@ static struct iio_trigger *at91_adc_allocate_trigger(struct iio_dev *idev, return NULL; trig->dev.parent = idev->dev.parent; - trig->private_data = idev; + iio_trigger_set_drvdata(trig, idev); trig->ops = &at91_adc_trigger_ops; ret = iio_trigger_register(trig); @@ -372,6 +376,59 @@ static int at91_adc_read_raw(struct iio_dev *idev, return -EINVAL; } +static int at91_adc_of_get_resolution(struct at91_adc_state *st, + struct platform_device *pdev) +{ + struct iio_dev *idev = iio_priv_to_dev(st); + struct device_node *np = pdev->dev.of_node; + int count, i, ret = 0; + char *res_name, *s; + u32 *resolutions; + + count = of_property_count_strings(np, "atmel,adc-res-names"); + if (count < 2) { + dev_err(&idev->dev, "You must specified at least two resolution names for " + "adc-res-names property in the DT\n"); + return count; + } + + resolutions = kmalloc(count * sizeof(*resolutions), GFP_KERNEL); + if (!resolutions) + return -ENOMEM; + + if (of_property_read_u32_array(np, "atmel,adc-res", resolutions, count)) { + dev_err(&idev->dev, "Missing adc-res property in the DT.\n"); + ret = -ENODEV; + goto ret; + } + + if (of_property_read_string(np, "atmel,adc-use-res", (const char **)&res_name)) + res_name = "highres"; + + for (i = 0; i < count; i++) { + if (of_property_read_string_index(np, "atmel,adc-res-names", i, (const char **)&s)) + continue; + + if (strcmp(res_name, s)) + continue; + + st->res = resolutions[i]; + if (!strcmp(res_name, "lowres")) + st->low_res = true; + else + st->low_res = false; + + dev_info(&idev->dev, "Resolution used: %u bits\n", st->res); + goto ret; + } + + dev_err(&idev->dev, "There is no resolution for %s\n", res_name); + +ret: + kfree(resolutions); + return ret; +} + static int at91_adc_probe_dt(struct at91_adc_state *st, struct platform_device *pdev) { @@ -400,6 +457,8 @@ static int at91_adc_probe_dt(struct at91_adc_state *st, } st->num_channels = prop; + st->sleep_mode = of_property_read_bool(node, "atmel,adc-sleep-mode"); + if (of_property_read_u32(node, "atmel,adc-startup-time", &prop)) { dev_err(&idev->dev, "Missing adc-startup-time property in the DT.\n"); ret = -EINVAL; @@ -407,6 +466,9 @@ static int at91_adc_probe_dt(struct at91_adc_state *st, } st->startup_time = prop; + prop = 0; + of_property_read_u32(node, "atmel,adc-sample-hold-time", &prop); + st->sample_hold_time = prop; if (of_property_read_u32(node, "atmel,adc-vref", &prop)) { dev_err(&idev->dev, "Missing adc-vref property in the DT.\n"); @@ -415,6 +477,10 @@ static int at91_adc_probe_dt(struct at91_adc_state *st, } st->vref_mv = prop; + ret = at91_adc_of_get_resolution(st, pdev); + if (ret) + goto error_ret; + st->registers = devm_kzalloc(&idev->dev, sizeof(struct at91_adc_reg_desc), GFP_KERNEL); @@ -516,11 +582,12 @@ static const struct iio_info at91_adc_info = { static int at91_adc_probe(struct platform_device *pdev) { - unsigned int prsc, mstrclk, ticks, adc_clk; + unsigned int prsc, mstrclk, ticks, adc_clk, shtim; int ret; struct iio_dev *idev; struct at91_adc_state *st; struct resource *res; + u32 reg; idev = iio_device_alloc(sizeof(struct at91_adc_state)); if (idev == NULL) { @@ -628,9 +695,22 @@ static int at91_adc_probe(struct platform_device *pdev) */ ticks = round_up((st->startup_time * adc_clk / 1000000) - 1, 8) / 8; - at91_adc_writel(st, AT91_ADC_MR, - (AT91_ADC_PRESCAL_(prsc) & AT91_ADC_PRESCAL) | - (AT91_ADC_STARTUP_(ticks) & AT91_ADC_STARTUP)); + /* + * a minimal Sample and Hold Time is necessary for the ADC to guarantee + * the best converted final value between two channels selection + * The formula thus is : Sample and Hold Time = (shtim + 1) / ADCClock + */ + shtim = round_up((st->sample_hold_time * adc_clk / + 1000000) - 1, 1); + + reg = AT91_ADC_PRESCAL_(prsc) & AT91_ADC_PRESCAL; + reg |= AT91_ADC_STARTUP_(ticks) & AT91_ADC_STARTUP; + if (st->low_res) + reg |= AT91_ADC_LOWRES; + if (st->sleep_mode) + reg |= AT91_ADC_SLEEP; + reg |= AT91_ADC_SHTIM_(shtim) & AT91_ADC_SHTIM; + at91_adc_writel(st, AT91_ADC_MR, reg); /* Setup the ADC channels available on the board */ ret = at91_adc_channel_init(idev); |