Re: [PATCH V3 5/7] iio: adc: sc27xx: add support for PMIC sc2720 and sc2721

From: Jonathan Cameron
Date: Sun Apr 10 2022 - 12:24:10 EST

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On Thu, 7 Apr 2022 16:21:46 +0800
Cixi Geng <gengcixi@xxxxxxxxx> wrote:

> From: Cixi Geng <cixi.geng1@xxxxxxxxxx>
>
> sc2720 and sc2721 is the product of sc27xx series.
>
> Co-developed-by: Yuming Zhu <yuming.zhu1@xxxxxxxxxx>
> Signed-off-by: Yuming Zhu <yuming.zhu1@xxxxxxxxxx>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
Please state what the kernel test robot / Dan reported.
Currently this tag implies the whole patch is fixing something they
reported.

Reported-by: kernel test robot <lkp@xxxxxxxxx> #whatever it was
works for this. Note that you don't have to credit them in
a patch. That comment in the autogenerated email is really
intended for when things have already be merged and a patch fixing
the issue they have detected alone is sent.

> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Signed-off-by: Cixi Geng <cixi.geng1@xxxxxxxxxx>

I don't like having a mixture of a nice chip model specific structure and
an enum. So please encode everything in the chip model specific structure
explicitly. See below for what I mean about the handling of the vref
supply.

Jonathan

> ---
> drivers/iio/adc/sc27xx_adc.c | 211 ++++++++++++++++++++++++++++++++++-
> 1 file changed, 209 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/adc/sc27xx_adc.c b/drivers/iio/adc/sc27xx_adc.c
> index 60c0a6aa3f45..eb9e789dd8ee 100644
> --- a/drivers/iio/adc/sc27xx_adc.c
> +++ b/drivers/iio/adc/sc27xx_adc.c
> @@ -9,11 +9,13 @@
> #include <linux/of_device.h>
> #include <linux/platform_device.h>
> #include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
> #include <linux/slab.h>
>
> /* PMIC global registers definition */
> #define SC2731_MODULE_EN 0xc08
> #define SC27XX_MODULE_ADC_EN BIT(5)
> +#define SC2721_ARM_CLK_EN 0xc0c
> #define SC2731_ARM_CLK_EN 0xc10
> #define SC27XX_CLK_ADC_EN BIT(5)
> #define SC27XX_CLK_ADC_CLK_EN BIT(6)
> @@ -37,7 +39,9 @@
> /* Bits and mask definition for SC27XX_ADC_CH_CFG register */
> #define SC27XX_ADC_CHN_ID_MASK GENMASK(4, 0)
> #define SC27XX_ADC_SCALE_MASK GENMASK(10, 9)
> +#define SC2721_ADC_SCALE_MASK BIT(5)
> #define SC27XX_ADC_SCALE_SHIFT 9
> +#define SC2721_ADC_SCALE_SHIFT 5
>
> /* Bits definitions for SC27XX_ADC_INT_EN registers */
> #define SC27XX_ADC_IRQ_EN BIT(0)
> @@ -67,8 +71,20 @@
> #define SC27XX_RATIO_NUMERATOR_OFFSET 16
> #define SC27XX_RATIO_DENOMINATOR_MASK GENMASK(15, 0)
>
> +/* ADC specific channel reference voltage 3.5V */
> +#define SC27XX_ADC_REFVOL_VDD35 3500000
> +
> +/* ADC default channel reference voltage is 2.8V */
> +#define SC27XX_ADC_REFVOL_VDD28 2800000
> +
> +enum sc27xx_pmic_type {
> + SC27XX_ADC,
> + SC2721_ADC,
> +};
> +
> struct sc27xx_adc_data {
> struct device *dev;
> + struct regulator *volref;
> struct regmap *regmap;
> /*
> * One hardware spinlock to synchronize between the multiple
> @@ -87,6 +103,7 @@ struct sc27xx_adc_data {
> * in the device data structure.
> */
> struct sc27xx_adc_variant_data {
> + enum sc27xx_pmic_type pmic_type;
> u32 module_en;
> u32 clk_en;
> u32 scale_shift;
> @@ -131,6 +148,16 @@ static const struct sc27xx_adc_linear_graph sc2731_small_scale_graph_calib = {
> 100, 84,
> };
>
> +static const struct sc27xx_adc_linear_graph big_scale_graph_calib = {
> + 4200, 856,
> + 3600, 733,
> +};
> +
> +static const struct sc27xx_adc_linear_graph small_scale_graph_calib = {
> + 1000, 833,
> + 100, 80,
> +};
> +
> static int sc27xx_adc_get_calib_data(u32 calib_data, int calib_adc)
> {
> return ((calib_data & 0xff) + calib_adc - 128) * 4;
> @@ -192,6 +219,94 @@ static int sc27xx_adc_scale_calibration(struct sc27xx_adc_data *data,
> return 0;
> }
>
> +static int sc2720_adc_get_ratio(int channel, int scale)
> +{
> + switch (channel) {
> + case 14:
> + switch (scale) {
> + case 0:
> + return SC27XX_VOLT_RATIO(68, 900);
> + case 1:
> + return SC27XX_VOLT_RATIO(68, 1760);
> + case 2:
> + return SC27XX_VOLT_RATIO(68, 2327);
> + case 3:
> + return SC27XX_VOLT_RATIO(68, 3654);
> + default:
> + return SC27XX_VOLT_RATIO(1, 1);
> + }
> + case 16:
> + switch (scale) {
> + case 0:
> + return SC27XX_VOLT_RATIO(48, 100);
> + case 1:
> + return SC27XX_VOLT_RATIO(480, 1955);
> + case 2:
> + return SC27XX_VOLT_RATIO(480, 2586);
> + case 3:
> + return SC27XX_VOLT_RATIO(48, 406);
> + default:
> + return SC27XX_VOLT_RATIO(1, 1);
> + }
> + case 21:
> + case 22:
> + case 23:
> + switch (scale) {
> + case 0:
> + return SC27XX_VOLT_RATIO(3, 8);
> + case 1:
> + return SC27XX_VOLT_RATIO(375, 1955);
> + case 2:
> + return SC27XX_VOLT_RATIO(375, 2586);
> + case 3:
> + return SC27XX_VOLT_RATIO(300, 3248);
> + default:
> + return SC27XX_VOLT_RATIO(1, 1);
> + }
> + default:
> + switch (scale) {
> + case 0:
> + return SC27XX_VOLT_RATIO(1, 1);
> + case 1:
> + return SC27XX_VOLT_RATIO(1000, 1955);
> + case 2:
> + return SC27XX_VOLT_RATIO(1000, 2586);
> + case 3:
> + return SC27XX_VOLT_RATIO(100, 406);
> + default:
> + return SC27XX_VOLT_RATIO(1, 1);
> + }
> + }
> + return SC27XX_VOLT_RATIO(1, 1);
> +}
> +
> +static int sc2721_adc_get_ratio(int channel, int scale)
> +{
> + switch (channel) {
> + case 1:
> + case 2:
> + case 3:
> + case 4:
> + return scale ? SC27XX_VOLT_RATIO(400, 1025) :
> + SC27XX_VOLT_RATIO(1, 1);
> + case 5:
> + return SC27XX_VOLT_RATIO(7, 29);
> + case 7:
> + case 9:
> + return scale ? SC27XX_VOLT_RATIO(100, 125) :
> + SC27XX_VOLT_RATIO(1, 1);
> + case 14:
> + return SC27XX_VOLT_RATIO(68, 900);
> + case 16:
> + return SC27XX_VOLT_RATIO(48, 100);
> + case 19:
> + return SC27XX_VOLT_RATIO(1, 3);
> + default:
> + return SC27XX_VOLT_RATIO(1, 1);
> + }
> + return SC27XX_VOLT_RATIO(1, 1);
> +}
> +
> static int sc2731_adc_get_ratio(int channel, int scale)
> {
> switch (channel) {
> @@ -220,6 +335,34 @@ static int sc2731_adc_get_ratio(int channel, int scale)
> /*
> * According to the datasheet set specific value on some channel.
> */
> +static void sc2720_adc_scale_init(struct sc27xx_adc_data *data)
> +{
> + int i;
> +
> + for (i = 0; i < SC27XX_ADC_CHANNEL_MAX; i++) {
> + switch (i) {
> + case 5:
> + data->channel_scale[i] = 3;
> + break;
> + case 7:
> + case 9:
> + data->channel_scale[i] = 2;
> + break;
> + case 13:
> + data->channel_scale[i] = 1;
> + break;
> + case 19:
> + case 30:
> + case 31:
> + data->channel_scale[i] = 3;
> + break;
> + default:
> + data->channel_scale[i] = 0;
> + break;
> + }
> + }
> +}
> +
> static void sc2731_adc_scale_init(struct sc27xx_adc_data *data)
> {
> int i;
> @@ -237,7 +380,7 @@ static void sc2731_adc_scale_init(struct sc27xx_adc_data *data)
> static int sc27xx_adc_read(struct sc27xx_adc_data *data, int channel,
> int scale, int *val)
> {
> - int ret;
> + int ret, ret_volref;
> u32 tmp, value, status;
>
> ret = hwspin_lock_timeout_raw(data->hwlock, SC27XX_ADC_HWLOCK_TIMEOUT);
> @@ -246,10 +389,25 @@ static int sc27xx_adc_read(struct sc27xx_adc_data *data, int channel,
> return ret;
> }
>
> + /*
> + * According to the sc2721 chip data sheet, the reference voltage of
> + * specific channel 30 and channel 31 in ADC module needs to be set from
> + * the default 2.8v to 3.5v.
> + */
> + if ((data->var_data->pmic_type == SC2721_ADC) && (channel == 30 || channel == 31)) {
As below. I'd prefer
if (data->var_data->vref && (channel...

> + ret = regulator_set_voltage(data->volref,
> + SC27XX_ADC_REFVOL_VDD35,
> + SC27XX_ADC_REFVOL_VDD35);
> + if (ret) {
> + dev_err(data->dev, "failed to set the volref 3.5v\n");
> + goto unlock_adc;
> + }
> + }
> +
> ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL,
> SC27XX_ADC_EN, SC27XX_ADC_EN);
> if (ret)
> - goto unlock_adc;
> + goto regulator_restore;
>
> ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_INT_CLR,
> SC27XX_ADC_IRQ_CLR, SC27XX_ADC_IRQ_CLR);
> @@ -300,6 +458,17 @@ static int sc27xx_adc_read(struct sc27xx_adc_data *data, int channel,
> regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL,
> SC27XX_ADC_EN, 0);
>
> +regulator_restore:
> + if ((data->var_data->pmic_type == SC2721_ADC) && (channel == 30 || channel == 31)) {
> + ret_volref = regulator_set_voltage(data->volref,
> + SC27XX_ADC_REFVOL_VDD28,
> + SC27XX_ADC_REFVOL_VDD28);
> + if (ret_volref) {
> + dev_err(data->dev, "failed to set the volref 2.8v,ret_volref = 0x%x\n",
> + ret_volref);
> + ret = ret || ret_volref;
> + }
> + }
> unlock_adc:
> hwspin_unlock_raw(data->hwlock);
>
> @@ -540,6 +709,7 @@ static void sc27xx_adc_disable(void *_data)
> }
>
> static const struct sc27xx_adc_variant_data sc2731_data = {
> + .pmic_type = SC27XX_ADC,
> .module_en = SC2731_MODULE_EN,
> .clk_en = SC2731_ARM_CLK_EN,
> .scale_shift = SC27XX_ADC_SCALE_SHIFT,
> @@ -550,6 +720,30 @@ static const struct sc27xx_adc_variant_data sc2731_data = {
> .get_ratio = sc2731_adc_get_ratio,
> };
>
> +static const struct sc27xx_adc_variant_data sc2721_data = {
> + .pmic_type = SC2721_ADC,
> + .module_en = SC2731_MODULE_EN,
> + .clk_en = SC2721_ARM_CLK_EN,
> + .scale_shift = SC2721_ADC_SCALE_SHIFT,
> + .scale_mask = SC2721_ADC_SCALE_MASK,
> + .bscale_cal = &sc2731_big_scale_graph_calib,
> + .sscale_cal = &sc2731_small_scale_graph_calib,
> + .init_scale = sc2731_adc_scale_init,
> + .get_ratio = sc2721_adc_get_ratio,
> +};
> +
> +static const struct sc27xx_adc_variant_data sc2720_data = {
> + .pmic_type = SC27XX_ADC,
> + .module_en = SC2731_MODULE_EN,
> + .clk_en = SC2721_ARM_CLK_EN,
> + .scale_shift = SC27XX_ADC_SCALE_SHIFT,
> + .scale_mask = SC27XX_ADC_SCALE_MASK,
> + .bscale_cal = &big_scale_graph_calib,
> + .sscale_cal = &small_scale_graph_calib,
> + .init_scale = sc2720_adc_scale_init,
> + .get_ratio = sc2720_adc_get_ratio,
> +};
> +
> static int sc27xx_adc_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> @@ -600,6 +794,17 @@ static int sc27xx_adc_probe(struct platform_device *pdev)
> }
>
> sc27xx_data->dev = dev;
> + if (pdata->pmic_type == SC2721_ADC) {

I'd prefer it if this was encoded explicitly in the pdata.
Perhaps add a bool pdata.vref that is set only for
the SC2721. That builds in flexibility for future variants that need
this feature. Then you don't need to carry a pmic_type around, just
use the vref flag for that.

You may need to make that more complex long term to cope with
devices that need vref to be tweaked for different sets of channels, but
that can be solved when the need comes up.

> + sc27xx_data->volref = devm_regulator_get(dev, "vref");
> + if (IS_ERR(sc27xx_data->volref)) {
> + ret = PTR_ERR(sc27xx_data->volref);
> + if (ret == -ENODEV)
> + dev_err(dev, "failed to supply the regulator\n");

Why is it useful to have a double error print in this path? Next message will print that
it was an ENODEV anyway.

> + dev_err(dev, "failed to get ADC volref, the err volref: %d\n", ret);
This could be a deferred probe situation so you should use
dev_err_probe()

> + return ret;
> + }
> + }
> +
> sc27xx_data->var_data = pdata;
> sc27xx_data->var_data->init_scale(sc27xx_data);
>
> @@ -629,6 +834,8 @@ static int sc27xx_adc_probe(struct platform_device *pdev)
>
> static const struct of_device_id sc27xx_adc_of_match[] = {
> { .compatible = "sprd,sc2731-adc", .data = &sc2731_data},
> + { .compatible = "sprd,sc2721-adc", .data = &sc2721_data},
> + { .compatible = "sprd,sc2720-adc", .data = &sc2720_data},
> { }
> };
> MODULE_DEVICE_TABLE(of, sc27xx_adc_of_match);

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