Re: [PATCH 2/9] iio: adc: at91_adc: rework resolution selection

From: Jonathan Cameron
Date: Sat Nov 14 2020 - 11:59:36 EST

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In reply to: Alexandre Belloni: "[PATCH 2/9] iio: adc: at91_adc: rework resolution selection"
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On Fri, 13 Nov 2020 22:26:43 +0100
Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx> wrote:

> Move the possible resolution values back to the driver. This removes the
> atmel,adc-res and atmel,adc-res-names properties, leaving only
> atmel,adc-use-res. As atmel,adc-res-names had to contain "lowres" and
> "highres", those where already the only allowed values for
> atmel,adc-use-res.
>
> Also introduce a new compatible string for the sama5d3 as this is the only
> one with a different resolution. Also it doesn't event have the LOWRES

even?

> bit.
>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>

Looks good otherwise.

> ---
> .../devicetree/bindings/iio/adc/at91_adc.txt | 13 +--
> drivers/iio/adc/at91_adc.c | 97 ++++++++-----------
> 2 files changed, 44 insertions(+), 66 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/iio/adc/at91_adc.txt b/Documentation/devicetree/bindings/iio/adc/at91_adc.txt
> index f65b04fb7962..da393ac5c05f 100644
> --- a/Documentation/devicetree/bindings/iio/adc/at91_adc.txt
> +++ b/Documentation/devicetree/bindings/iio/adc/at91_adc.txt
> @@ -2,7 +2,7 @@
>
> Required properties:
> - compatible: Should be "atmel,<chip>-adc"
> - <chip> can be "at91sam9260", "at91sam9g45" or "at91sam9x5"
> + <chip> can be "at91sam9260", "at91sam9g45", "at91sam9x5" or "sama5d3"
> - reg: Should contain ADC registers location and length
> - interrupts: Should contain the IRQ line for the ADC
> - clock-names: tuple listing input clock names.
> @@ -13,17 +13,12 @@ Required properties:
> - atmel,adc-startup-time: Startup Time of the ADC in microseconds as
> defined in the datasheet
> - atmel,adc-vref: Reference voltage in millivolts for the conversions
> - - atmel,adc-res: List of resolutions 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-triggers: Boolean to enable the 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.
> + - atmel,adc-use-res: String selecting the resolution, can be "lowres" or
> + "highres". If not specified, the highest resolution will
> + be used.
> - atmel,adc-sleep-mode: Boolean to enable sleep mode when no conversion
> - atmel,adc-sample-hold-time: Sample and Hold Time in microseconds
> - atmel,adc-ts-wires: Number of touchscreen wires. Should be 4 or 5. If this
> diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
> index 62bd35af8b13..0d67c812ef3d 100644
> --- a/drivers/iio/adc/at91_adc.c
> +++ b/drivers/iio/adc/at91_adc.c
> @@ -204,6 +204,9 @@ struct at91_adc_caps {
> u32 (*calc_startup_ticks)(u32 startup_time, u32 adc_clk_khz);
>
> u8 num_channels;
> +
> + u8 low_res_bits;
> + u8 high_res_bits;
> struct at91_adc_reg_desc registers;
> };
>
> @@ -229,7 +232,6 @@ struct at91_adc_state {
> 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;
> struct at91_adc_caps *caps;
>
> @@ -754,58 +756,6 @@ static int at91_adc_read_raw(struct iio_dev *idev,
> return -EINVAL;
> }
>
> -static int at91_adc_of_get_resolution(struct iio_dev *idev,
> - struct platform_device *pdev)
> -{
> - struct at91_adc_state *st = iio_priv(idev);
> - 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_array(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 u32 calc_startup_ticks_9260(u32 startup_time, u32 adc_clk_khz)
> {
> @@ -891,6 +841,7 @@ static int at91_adc_probe_dt(struct iio_dev *idev,
> struct device_node *trig_node;
> int i = 0, ret;
> u32 prop;
> + char *s;
>
> st->caps = (struct at91_adc_caps *)
> of_match_device(at91_adc_dt_ids, &pdev->dev)->data;
> @@ -924,9 +875,13 @@ static int at91_adc_probe_dt(struct iio_dev *idev,
> }
> st->vref_mv = prop;
>
> - ret = at91_adc_of_get_resolution(idev, pdev);
> - if (ret)
> - goto error_ret;
> + st->res = st->caps->high_res_bits;
> + if (st->caps->low_res_bits &&
> + !of_property_read_string(node, "atmel,adc-use-res", (const char **)&s)
> + && !strcmp(s, "lowres"))
> + st->res = st->caps->low_res_bits;
> +
> + dev_info(&idev->dev, "Resolution used: %u bits\n", st->res);
>
> st->registers = &st->caps->registers;
> st->num_channels = st->caps->num_channels;
> @@ -1248,7 +1203,7 @@ static int at91_adc_probe(struct platform_device *pdev)
>
> reg = AT91_ADC_PRESCAL_(prsc) & st->registers->mr_prescal_mask;
> reg |= AT91_ADC_STARTUP_(ticks) & st->registers->mr_startup_mask;
> - if (st->low_res)
> + if (st->res == st->caps->low_res_bits)
> reg |= AT91_ADC_LOWRES;
> if (st->sleep_mode)
> reg |= AT91_ADC_SLEEP;
> @@ -1363,6 +1318,8 @@ static SIMPLE_DEV_PM_OPS(at91_adc_pm_ops, at91_adc_suspend, at91_adc_resume);
> static struct at91_adc_caps at91sam9260_caps = {
> .calc_startup_ticks = calc_startup_ticks_9260,
> .num_channels = 4,
> + .low_res_bits = 8,
> + .high_res_bits = 10,
> .registers = {
> .channel_base = AT91_ADC_CHR(0),
> .drdy_mask = AT91_ADC_DRDY,
> @@ -1377,6 +1334,8 @@ static struct at91_adc_caps at91sam9rl_caps = {
> .has_ts = true,
> .calc_startup_ticks = calc_startup_ticks_9260, /* same as 9260 */
> .num_channels = 6,
> + .low_res_bits = 8,
> + .high_res_bits = 10,
> .registers = {
> .channel_base = AT91_ADC_CHR(0),
> .drdy_mask = AT91_ADC_DRDY,
> @@ -1391,6 +1350,8 @@ static struct at91_adc_caps at91sam9g45_caps = {
> .has_ts = true,
> .calc_startup_ticks = calc_startup_ticks_9260, /* same as 9260 */
> .num_channels = 8,
> + .low_res_bits = 8,
> + .high_res_bits = 10,
> .registers = {
> .channel_base = AT91_ADC_CHR(0),
> .drdy_mask = AT91_ADC_DRDY,
> @@ -1408,6 +1369,8 @@ static struct at91_adc_caps at91sam9x5_caps = {
> .ts_pen_detect_sensitivity = 2,
> .calc_startup_ticks = calc_startup_ticks_9x5,
> .num_channels = 12,
> + .low_res_bits = 8,
> + .high_res_bits = 10,
> .registers = {
> .channel_base = AT91_ADC_CDR0_9X5,
> .drdy_mask = AT91_ADC_SR_DRDY_9X5,
> @@ -1419,11 +1382,31 @@ static struct at91_adc_caps at91sam9x5_caps = {
> },
> };
>
> +static struct at91_adc_caps sama5d3_caps = {
> + .has_ts = true,
> + .has_tsmr = true,
> + .ts_filter_average = 3,
> + .ts_pen_detect_sensitivity = 2,
> + .calc_startup_ticks = calc_startup_ticks_9x5,
> + .num_channels = 12,
> + .low_res_bits = 0,
> + .high_res_bits = 12,
> + .registers = {
> + .channel_base = AT91_ADC_CDR0_9X5,
> + .drdy_mask = AT91_ADC_SR_DRDY_9X5,
> + .status_register = AT91_ADC_SR_9X5,
> + .trigger_register = AT91_ADC_TRGR_9X5,
> + .mr_prescal_mask = AT91_ADC_PRESCAL_9G45,
> + .mr_startup_mask = AT91_ADC_STARTUP_9X5,
> + },
> +};
> +
> static const struct of_device_id at91_adc_dt_ids[] = {
> { .compatible = "atmel,at91sam9260-adc", .data = &at91sam9260_caps },
> { .compatible = "atmel,at91sam9rl-adc", .data = &at91sam9rl_caps },
> { .compatible = "atmel,at91sam9g45-adc", .data = &at91sam9g45_caps },
> { .compatible = "atmel,at91sam9x5-adc", .data = &at91sam9x5_caps },
> + { .compatible = "atmel,sama5d3-adc", .data = &sama5d3_caps },
> {},
> };
> MODULE_DEVICE_TABLE(of, at91_adc_dt_ids);

Next message: Jonathan Cameron: "Re: [PATCH 4/9] iio: adc: at91_adc: rework trigger definition"
Previous message: Jonathan Cameron: "Re: [PATCH 3/9] dt-bindings:iio:adc:atmel,sama9260-adc: conversion to yaml from at91_adc.txt"
In reply to: Alexandre Belloni: "[PATCH 2/9] iio: adc: at91_adc: rework resolution selection"
Next in thread: Jonathan Cameron: "Re: [PATCH 0/9] iio: adc: at91_adc: cleanup DT bindings"
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