Re: [PATCH 3/9] regulator: mt6358: Merge VCN33_* regulators

AngeloGioacchino Del Regno
2023-06-09T08:59:05Z

Il 09/06/23 10:30, Chen-Yu Tsai ha scritto:
> The VCN33_BT and VCN33_WIFI regulators are actually the same regulator,
> having the same voltage setting and output pin. There are simply two
> enable bits that are ORed together to enable the regulator.
>
> Having two regulators representing the same output pin is misleading
> from a design matching standpoint, and also error-prone in driver
> implementations. If consumers try to set different voltages on either
> regulator, the one set later would override the one set before. There
> are ways around this, such as chaining them together and having the
> downstream one act as a switch. But given there's only one output pin,
> such a workaround doesn't match reality.
>
> Remove the VCN33_WIFI regulator. During the probe phase, have the driver
> sync the enable status of VCN33_WIFI to VCN33_BT. Also drop the suffix
> so that the regulator name matches the pin name in the datasheet.
>
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
> ---
> drivers/regulator/mt6358-regulator.c | 65 +++++++++++++++++-----
> include/linux/regulator/mt6358-regulator.h | 6 +-
> 2 files changed, 52 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/regulator/mt6358-regulator.c b/drivers/regulator/mt6358-regulator.c
> index c9e16bd092f6..faf6b0757019 100644
> --- a/drivers/regulator/mt6358-regulator.c
> +++ b/drivers/regulator/mt6358-regulator.c
> @@ -277,7 +277,7 @@ static const unsigned int vcama_voltages[] = {
> 2800000, 2900000, 3000000,
> };
>
> -static const unsigned int vcn33_bt_wifi_voltages[] = {
> +static const unsigned int vcn33_voltages[] = {
> 3300000, 3400000, 3500000,
> };
>
> @@ -321,7 +321,7 @@ static const u32 vcama_idx[] = {
> 0, 7, 9, 10, 11, 12,
> };
>
> -static const u32 vcn33_bt_wifi_idx[] = {
> +static const u32 vcn33_idx[] = {
> 1, 2, 3,
> };
>
> @@ -566,12 +566,8 @@ static struct mt6358_regulator_info mt6358_regulators[] = {
> MT6358_LDO_VCAMA1_CON0, 0, MT6358_VCAMA1_ANA_CON0, 0xf00),
> MT6358_LDO("ldo_vemc", VEMC, vmch_vemc_voltages, vmch_vemc_idx,
> MT6358_LDO_VEMC_CON0, 0, MT6358_VEMC_ANA_CON0, 0x700),
> - MT6358_LDO("ldo_vcn33_bt", VCN33_BT, vcn33_bt_wifi_voltages,
> - vcn33_bt_wifi_idx, MT6358_LDO_VCN33_CON0_0,
> - 0, MT6358_VCN33_ANA_CON0, 0x300),
> - MT6358_LDO("ldo_vcn33_wifi", VCN33_WIFI, vcn33_bt_wifi_voltages,
> - vcn33_bt_wifi_idx, MT6358_LDO_VCN33_CON0_1,
> - 0, MT6358_VCN33_ANA_CON0, 0x300),
> + MT6358_LDO("ldo_vcn33", VCN33, vcn33_voltages, vcn33_idx,
> + MT6358_LDO_VCN33_CON0_0, 0, MT6358_VCN33_ANA_CON0, 0x300),
> MT6358_LDO("ldo_vcama2", VCAMA2, vcama_voltages, vcama_idx,
> MT6358_LDO_VCAMA2_CON0, 0, MT6358_VCAMA2_ANA_CON0, 0xf00),
> MT6358_LDO("ldo_vmc", VMC, vmc_voltages, vmc_idx,
> @@ -662,12 +658,8 @@ static struct mt6358_regulator_info mt6366_regulators[] = {
> MT6358_LDO_VMCH_CON0, 0, MT6358_VMCH_ANA_CON0, 0x700),
> MT6366_LDO("ldo_vemc", VEMC, vmch_vemc_voltages, vmch_vemc_idx,
> MT6358_LDO_VEMC_CON0, 0, MT6358_VEMC_ANA_CON0, 0x700),
> - MT6366_LDO("ldo_vcn33_bt", VCN33_BT, vcn33_bt_wifi_voltages,
> - vcn33_bt_wifi_idx, MT6358_LDO_VCN33_CON0_0,
> - 0, MT6358_VCN33_ANA_CON0, 0x300),
> - MT6366_LDO("ldo_vcn33_wifi", VCN33_WIFI, vcn33_bt_wifi_voltages,
> - vcn33_bt_wifi_idx, MT6358_LDO_VCN33_CON0_1,
> - 0, MT6358_VCN33_ANA_CON0, 0x300),
> + MT6366_LDO("ldo_vcn33", VCN33, vcn33_voltages, vcn33_idx,
> + MT6358_LDO_VCN33_CON0_0, 0, MT6358_VCN33_ANA_CON0, 0x300),
> MT6366_LDO("ldo_vmc", VMC, vmc_voltages, vmc_idx,
> MT6358_LDO_VMC_CON0, 0, MT6358_VMC_ANA_CON0, 0xf00),
> MT6366_LDO("ldo_vsim2", VSIM2, vsim_voltages, vsim_idx,
> @@ -690,13 +682,56 @@ static struct mt6358_regulator_info mt6366_regulators[] = {
> MT6358_LDO_VSRAM_CON1, 0x7f),
> };
>
> +static int mt6358_sync_vcn33_setting(struct device *dev)
> +{
> + struct mt6397_chip *mt6397 = dev_get_drvdata(dev->parent);
> + unsigned int val;
> + int ret;
> +
> + /*
> + * VCN33_WIFI and VCN33_BT are two separate enable bits for the same
> + * regulator. They share the same voltage setting and output pin.
> + * Instead of having two potentially conflicting regulators, just have
> + * one VCN33 regulator. Sync the two enable bits and only use one in
> + * the regulator device.
> + */
> + ret = regmap_read(mt6397->regmap, MT6358_LDO_VCN33_CON0_1, &val);
> + if (ret) {
> + dev_err(dev, "Failed to read VCN33_WIFI setting\n");
> + return ret;
> + }
> +
> + if (!(val & BIT(0)))
> + return 0;
> +
> + /* Sync VCN33_WIFI enable status to VCN33_BT */
> + ret = regmap_update_bits(mt6397->regmap, MT6358_LDO_VCN33_CON0_0, BIT(0), BIT(0));
> + if (ret) {
> + dev_err(dev, "Failed to sync VCN33_WIFI setting to VCN33_BT\n");
> + return ret;
> + }
> +
> + /* Disable VCN33_WIFI */
> + ret = regmap_update_bits(mt6397->regmap, MT6358_LDO_VCN33_CON0_1, BIT(0), 0);
> + if (ret) {
> + dev_err(dev, "Failed to disable VCN33_BT\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> static int mt6358_regulator_probe(struct platform_device *pdev)
> {
> struct mt6397_chip *mt6397 = dev_get_drvdata(pdev->dev.parent);
> struct regulator_config config = {};
> struct regulator_dev *rdev;
> struct mt6358_regulator_info *mt6358_info;
> - int i, max_regulator;
> + int i, max_regulator, ret;
> +
> + ret = mt6358_sync_vcn33_setting(&pdev->dev);
> + if (ret)
> + return ret;

I'd put this after the chip_id check, and I would also add a safety check for
that...

switch (mt6397->chip_id) {
case MT6366_CHIP_ID:
max_regulator = MT6366_MAX_REGULATOR;
mt6358_info = mt6366_regulators;
break;
case MT6358_CHIP_ID:
max_regulator = MT6358_MAX_REGULATOR;
mt6358_info = mt6358_regulators;
break;
default:
return -EINVAL;
}

ret = mt6358_sync_vcn33_setting(....)

...but I agree with your point here about this being a strange design and
also with your way of fixing the driver.

Regards,
Angelo