Re: [PATCH v2 07/16] iio: adc: sun4i-gpadc-iio: rework: support nvmem calibration data

From: Maxime Ripard
Date: Mon Jan 29 2018 - 04:41:03 EST


On Mon, Jan 29, 2018 at 12:29:10AM +0100, Philipp Rossak wrote:
> This patch reworks the driver to support nvmem calibration cells.
> The driver checks if the nvmem calibration is supported and reads out
> the nvmem.
>
> Signed-off-by: Philipp Rossak <embed3d@xxxxxxxxx>
> ---
> drivers/iio/adc/sun4i-gpadc-iio.c | 44 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 44 insertions(+)
>
> diff --git a/drivers/iio/adc/sun4i-gpadc-iio.c b/drivers/iio/adc/sun4i-gpadc-iio.c
> index ac9ad2f8232f..74eeb5cd5218 100644
> --- a/drivers/iio/adc/sun4i-gpadc-iio.c
> +++ b/drivers/iio/adc/sun4i-gpadc-iio.c
> @@ -27,6 +27,7 @@
> #include <linux/interrupt.h>
> #include <linux/io.h>
> #include <linux/module.h>
> +#include <linux/nvmem-consumer.h>
> #include <linux/of.h>
> #include <linux/of_device.h>
> #include <linux/platform_device.h>
> @@ -74,6 +75,7 @@ struct gpadc_data {
> bool has_bus_rst;
> bool has_mod_clk;
> int sensor_count;
> + bool supports_nvmem;

I think you should add some documentation along with all the fields
you're adding.

> };
>
> static const struct gpadc_data sun4i_gpadc_data = {
> @@ -87,6 +89,7 @@ static const struct gpadc_data sun4i_gpadc_data = {
> .sample_start = sun4i_gpadc_sample_start,
> .sample_end = sun4i_gpadc_sample_end,
> .sensor_count = 1,
> + .supports_nvmem = false,

That's already its value if you leave it out.

> };
>
> static const struct gpadc_data sun5i_gpadc_data = {
> @@ -100,6 +103,7 @@ static const struct gpadc_data sun5i_gpadc_data = {
> .sample_start = sun4i_gpadc_sample_start,
> .sample_end = sun4i_gpadc_sample_end,
> .sensor_count = 1,
> + .supports_nvmem = false,
> };
>
> static const struct gpadc_data sun6i_gpadc_data = {
> @@ -113,6 +117,7 @@ static const struct gpadc_data sun6i_gpadc_data = {
> .sample_start = sun4i_gpadc_sample_start,
> .sample_end = sun4i_gpadc_sample_end,
> .sensor_count = 1,
> + .supports_nvmem = false,
> };
>
> static const struct gpadc_data sun8i_a33_gpadc_data = {
> @@ -123,6 +128,7 @@ static const struct gpadc_data sun8i_a33_gpadc_data = {
> .sample_start = sun4i_gpadc_sample_start,
> .sample_end = sun4i_gpadc_sample_end,
> .sensor_count = 1,
> + .supports_nvmem = false,
> };
>
> struct sun4i_gpadc_iio {
> @@ -141,6 +147,8 @@ struct sun4i_gpadc_iio {
> struct clk *mod_clk;
> struct reset_control *reset;
> int sensor_id;
> + u32 calibration_data[2];
> + bool has_calibration_data[2];

Why do you have two different values here?

> /* prevents concurrent reads of temperature and ADC */
> struct mutex mutex;
> struct thermal_zone_device *tzd;
> @@ -561,6 +569,9 @@ static int sun4i_gpadc_probe_dt(struct platform_device *pdev,
> struct resource *mem;
> void __iomem *base;
> int ret;
> + struct nvmem_cell *cell;
> + ssize_t cell_size;
> + u64 *cell_data;
>
> info->data = of_device_get_match_data(&pdev->dev);
> if (!info->data)
> @@ -575,6 +586,39 @@ static int sun4i_gpadc_probe_dt(struct platform_device *pdev,
> if (IS_ERR(base))
> return PTR_ERR(base);
>
> + info->has_calibration_data[0] = false;
> + info->has_calibration_data[1] = false;
> +
> + if (!info->data->supports_nvmem)
> + goto no_nvmem;
> +
> + cell = nvmem_cell_get(&pdev->dev, "calibration");
> + if (IS_ERR(cell)) {
> + if (PTR_ERR(cell) == -EPROBE_DEFER)
> + return PTR_ERR(cell);
> + goto no_nvmem;

goto considered evil ? :)

> + }
> +
> + cell_data = (u64 *)nvmem_cell_read(cell, &cell_size);
> + nvmem_cell_put(cell);
> + switch (cell_size) {
> + case 8:
> + case 6:
> + info->has_calibration_data[1] = true;
> + info->calibration_data[1] = be32_to_cpu(
> + upper_32_bits(cell_data[0]));
> + case 4:
> + case 2:
> + info->has_calibration_data[0] = true;
> + info->calibration_data[0] = be32_to_cpu(
> + lower_32_bits(cell_data[0]));

Why do you need that switch?

Thanks!
Maxime

--
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

Attachment: signature.asc
Description: PGP signature