iio: at91_adc: add low and high res support (47be16b6) · Commits · 戴 / test

Documentation/devicetree/bindings/arm/atmel-adc.txt

+11 −0

Original line number	Diff line number	Diff line
		@@ -14,9 +14,17 @@ Required properties:
		- atmel,adc-status-register: Offset of the Interrupt Status Register
		- atmel,adc-trigger-register: Offset of the Trigger Register
		- atmel,adc-vref: Reference voltage in millivolts for the conversions
		- atmel,adc-res: List of resolution in bits supported by the ADC. List size
		must be two at least.
		- atmel,adc-res-names: Contains one identifier string for each resolution
		in atmel,adc-res property. "lowres" and "highres"
		identifiers are required.

		Optional properties:
		- atmel,adc-use-external: Boolean to enable of external triggers
		- atmel,adc-use-res: String corresponding to an identifier from
		atmel,adc-res-names property. If not specified, the highest
		resolution will be used.

		Optional trigger Nodes:
		- Required properties:
		@@ -40,6 +48,9 @@ adc0: adc@fffb0000 {
		atmel,adc-trigger-register = <0x08>;
		atmel,adc-use-external;
		atmel,adc-vref = <3300>;
		atmel,adc-res = <8 10>;
		atmel,adc-res-names = "lowres", "highres";
		atmel,adc-use-res = "lowres";

		trigger@0 {
		trigger-name = "external-rising";

drivers/iio/adc/at91_adc.c

+70 −4

Original line number	Diff line number	Diff line
		@@ -57,6 +57,8 @@ struct at91_adc_state {
		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;
		};

		@@ -138,7 +140,7 @@ 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_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
		chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
		@@ -372,6 +374,59 @@ 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)
		{
		@@ -415,6 +470,10 @@ 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);
		@@ -628,6 +687,13 @@ static int at91_adc_probe(struct platform_device *pdev)
		*/
		ticks = round_up((st->startup_time * adc_clk /
		1000000) - 1, 8) / 8;

		if (st->low_res)
		at91_adc_writel(st, AT91_ADC_MR,
		AT91_ADC_LOWRES \|
		(AT91_ADC_PRESCAL_(prsc) & AT91_ADC_PRESCAL) \|
		(AT91_ADC_STARTUP_(ticks) & AT91_ADC_STARTUP));
		else
		at91_adc_writel(st, AT91_ADC_MR,
		(AT91_ADC_PRESCAL_(prsc) & AT91_ADC_PRESCAL) \|
		(AT91_ADC_STARTUP_(ticks) & AT91_ADC_STARTUP));

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