Re: [PATCH 2/3] iio: adc: stm32-adc: add analog switches supply control

From: Fabrice Gasnier
Date: Wed Jun 19 2019 - 08:44:26 EST

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In reply to: Fabrice Gasnier: "Re: [PATCH 2/3] iio: adc: stm32-adc: add analog switches supply control"
Next in thread: Jonathan Cameron: "Re: [PATCH 2/3] iio: adc: stm32-adc: add analog switches supply control"
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On 6/17/19 2:43 PM, Fabrice Gasnier wrote:
> On 6/16/19 5:07 PM, Jonathan Cameron wrote:
>> On Wed, 12 Jun 2019 09:24:35 +0200
>> Fabrice Gasnier <fabrice.gasnier@xxxxxx> wrote:
>>
>>> On stm32h7 and stm32mp1, the ADC inputs are multiplexed with analog
>>> switches which have reduced performances when their supply is below 2.7V
>>> (vdda by default):
>>> - vdd supply can be selected if above 2.7V by setting ANASWVDD syscfg bit
>>> (STM32MP1 only).
>>> - Voltage booster can be used, to get full ADC performances by setting
>>> BOOSTE/EN_BOOSTER syscfg bit (increases power consumption).
>>>
>>> Make this optional, since this is a trade-off between analog performance
>>> and power consumption.
>>>
>>> Note: STM32H7 syscfg has a set and clear register for "BOOSTE" control.
>>> STM32MP1 has separate set and clear registers pair to control EN_BOOSTER
>>> and ANASWVDD bits.
>>>
>>> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
>>
>> A few minor bits inline, but mostly seems fine to me.
>>
>> Jonathan
>>
>>> ---
>>> drivers/iio/adc/stm32-adc-core.c | 232 ++++++++++++++++++++++++++++++++++++++-
>>> 1 file changed, 230 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c
>>> index 2327ec1..9d41b16 100644
>>> --- a/drivers/iio/adc/stm32-adc-core.c
>>> +++ b/drivers/iio/adc/stm32-adc-core.c
>>> @@ -14,9 +14,11 @@
>>> #include <linux/irqchip/chained_irq.h>
>>> #include <linux/irqdesc.h>
>>> #include <linux/irqdomain.h>
>>> +#include <linux/mfd/syscon.h>
>>> #include <linux/module.h>
>>> #include <linux/of_device.h>
>>> #include <linux/pm_runtime.h>
>>> +#include <linux/regmap.h>
>>> #include <linux/regulator/consumer.h>
>>> #include <linux/slab.h>
>>>
>>> @@ -51,6 +53,20 @@
>>>
>>> #define STM32_ADC_CORE_SLEEP_DELAY_MS 2000
>>>
>>> +/* SYSCFG registers */
>>> +#define STM32H7_SYSCFG_PMCR 0x04
>>> +#define STM32MP1_SYSCFG_PMCSETR 0x04
>>> +#define STM32MP1_SYSCFG_PMCCLRR 0x44
>>> +
>>> +/* SYSCFG bit fields */
>>> +#define STM32H7_SYSCFG_BOOSTE_MASK BIT(8)
>>> +#define STM32MP1_SYSCFG_ANASWVDD_MASK BIT(9)
>>> +
>>> +/* SYSCFG capability flags */
>>> +#define HAS_VBOOSTER BIT(0)
>>> +#define HAS_ANASWVDD BIT(1)
>>> +#define HAS_CLEAR_REG BIT(2)
>>> +
>>> /**
>>> * stm32_adc_common_regs - stm32 common registers, compatible dependent data
>>> * @csr: common status register offset
>>> @@ -58,6 +74,11 @@
>>> * @eoc1: adc1 end of conversion flag in @csr
>>> * @eoc2: adc2 end of conversion flag in @csr
>>> * @eoc3: adc3 end of conversion flag in @csr
>>> + * @has_syscfg: SYSCFG capability flags
>>> + * @pmcr: SYSCFG_PMCSETR/SYSCFG_PMCR register offset
>>> + * @pmcc: SYSCFG_PMCCLRR clear register offset
>>> + * @booste_msk: SYSCFG BOOSTE / EN_BOOSTER bitmask in PMCR & PMCCLRR
>>> + * @anaswvdd_msk: SYSCFG ANASWVDD bitmask in PMCR & PMCCLRR
>>> */
>>> struct stm32_adc_common_regs {
>>> u32 csr;
>>> @@ -65,6 +86,11 @@ struct stm32_adc_common_regs {
>>> u32 eoc1_msk;
>>> u32 eoc2_msk;
>>> u32 eoc3_msk;
>>> + unsigned int has_syscfg;
>>> + u32 pmcr;
>>> + u32 pmcc;
>>> + u32 booste_msk;
>>> + u32 anaswvdd_msk;
>>> };
>>>
>>> struct stm32_adc_priv;
>>> @@ -87,20 +113,26 @@ struct stm32_adc_priv_cfg {
>>> * @domain: irq domain reference
>>> * @aclk: clock reference for the analog circuitry
>>> * @bclk: bus clock common for all ADCs, depends on part used
>>> + * @vdd: vdd supply reference
>>> + * @vdda: vdda supply reference
>>> * @vref: regulator reference
>>> * @cfg: compatible configuration data
>>> * @common: common data for all ADC instances
>>> * @ccr_bak: backup CCR in low power mode
>>> + * @syscfg: reference to syscon, system control registers
>>> */
>>> struct stm32_adc_priv {
>>> int irq[STM32_ADC_MAX_ADCS];
>>> struct irq_domain *domain;
>>> struct clk *aclk;
>>> struct clk *bclk;
>>> + struct regulator *vdd;
>>> + struct regulator *vdda;
>>> struct regulator *vref;
>>> const struct stm32_adc_priv_cfg *cfg;
>>> struct stm32_adc_common common;
>>> u32 ccr_bak;
>>> + struct regmap *syscfg;
>>> };
>>>
>>> static struct stm32_adc_priv *to_stm32_adc_priv(struct stm32_adc_common *com)
>>> @@ -284,6 +316,22 @@ static const struct stm32_adc_common_regs stm32h7_adc_common_regs = {
>>> .ccr = STM32H7_ADC_CCR,
>>> .eoc1_msk = STM32H7_EOC_MST,
>>> .eoc2_msk = STM32H7_EOC_SLV,
>>> + .has_syscfg = HAS_VBOOSTER,
>>> + .pmcr = STM32H7_SYSCFG_PMCR,
>>> + .booste_msk = STM32H7_SYSCFG_BOOSTE_MASK,
>>> +};
>>> +
>>> +/* STM32MP1 common registers definitions */
>>> +static const struct stm32_adc_common_regs stm32mp1_adc_common_regs = {
>>> + .csr = STM32H7_ADC_CSR,
>>> + .ccr = STM32H7_ADC_CCR,
>>> + .eoc1_msk = STM32H7_EOC_MST,
>>> + .eoc2_msk = STM32H7_EOC_SLV,
>>> + .has_syscfg = HAS_VBOOSTER | HAS_ANASWVDD | HAS_CLEAR_REG,
>>
>> Extra space after =
>
> Hi Jonathan,
>
> Oops, I'll fix it in v2.
>
>>
>>
>>> + .pmcr = STM32MP1_SYSCFG_PMCSETR,
>>> + .pmcc = STM32MP1_SYSCFG_PMCCLRR,
>>> + .booste_msk = STM32H7_SYSCFG_BOOSTE_MASK,
>>> + .anaswvdd_msk = STM32MP1_SYSCFG_ANASWVDD_MASK,
>>> };
>>>
>>> /* ADC common interrupt for all instances */
>>> @@ -388,16 +436,145 @@ static void stm32_adc_irq_remove(struct platform_device *pdev,
>>> }
>>> }
>>>
>>> +static int stm32_adc_core_switches_supply_en(struct device *dev)
>>> +{
>>> + struct stm32_adc_common *common = dev_get_drvdata(dev);
>>> + struct stm32_adc_priv *priv = to_stm32_adc_priv(common);
>>> + const struct stm32_adc_common_regs *regs = priv->cfg->regs;
>>> + int ret, vdda, vdd = 0;
>>> + u32 mask, clrmask, setmask = 0;
>>> +
>>> + /*
>>> + * On STM32H7 and STM32MP1, the ADC inputs are multiplexed with analog
>>> + * switches (via PCSEL) which have reduced performances when their
>>> + * supply is below 2.7V (vdda by default):
>>> + * - Voltage booster can be used, to get full ADC performances
>>> + * (increases power consumption).
>>> + * - Vdd can be used to supply them, if above 2.7V (STM32MP1 only).
>>> + *
>>> + * This is optional, as this is a trade-off between analog performance
>>> + * and power consumption.
>>> + */
>>> + if (!regs->has_syscfg || !priv->vdda || !priv->syscfg) {
>>> + dev_dbg(dev, "Not configuring analog switches\n");
>>> + return 0;
>>> + }
>>> +
>>> + ret = regulator_enable(priv->vdda);
>>> + if (ret < 0) {
>>> + dev_err(dev, "vdda enable failed %d\n", ret);
>>> + return ret;
>>> + }
>>> +
>>> + ret = regulator_get_voltage(priv->vdda);
>>> + if (ret < 0) {
>>> + dev_err(dev, "vdda get voltage failed %d\n", ret);
>>> + goto vdda_dis;
>>> + }
>>> + vdda = ret;
>>> +
>> We only need to do the following block if vdaa is too low. Should probably
>> not turn on vdd if there is not chance we are going to use it?
>
> You're right, then I probably need to move the regulator_get_voltage()
> call at probe time, to avoid enabling it for nothing at runtime. (e.g.
> to figure out it's not going to be used).
> In fact, vdd is used also for other things on the platform (I/Os, other
> supplies...), and is marked "always-on" in the device tree. But I
> understand your point.
>
> I'll rework this and send a v2.

Hi Jonathan,

When reworking this part, I figured out the vdda should be described as
required supply for the STM32 ADC. So I pushed out a fix series to
address this "Add missing vdda-supply to STM32 ADC". I'll resume v2 of
this series that has some dependencies on the fix series .

Thanks
Best Regards,
Fabrice

>
> Thanks,
> Fabrice
>
>>
>>> + if (priv->vdd && regs->has_syscfg & HAS_ANASWVDD) {
>>> + ret = regulator_enable(priv->vdd);
>>> + if (ret < 0) {
>>> + dev_err(dev, "vdd enable failed %d\n", ret);
>>> + goto vdda_dis;
>>> + }
>>> +
>>> + ret = regulator_get_voltage(priv->vdd);
>>> + if (ret < 0) {
>>> + dev_err(dev, "vdd get voltage failed %d\n", ret);
>>> + goto vdd_dis;
>>> + }
>>> + vdd = ret;
>>> + }
>>> +
>>> + /*
>>> + * Recommended settings for ANASWVDD and EN_BOOSTER:
>>> + * - vdda < 2.7V but vdd > 2.7V: ANASWVDD = 1, EN_BOOSTER = 0 (stm32mp1)
>>> + * - vdda < 2.7V and vdd < 2.7V: ANASWVDD = 0, EN_BOOSTER = 1
>>> + * - vdda >= 2.7V: ANASWVDD = 0, EN_BOOSTER = 0 (default)
>>> + */
>>> + if (vdda < 2700000) {
>>> + if (vdd > 2700000) {
>>> + dev_dbg(dev, "analog switches supplied by vdd\n");
>>> + setmask = regs->anaswvdd_msk;
>>> + clrmask = regs->booste_msk;
>>> + } else {
>>> + dev_dbg(dev, "Enabling voltage booster\n");
>>> + setmask = regs->booste_msk;
>>> + clrmask = regs->anaswvdd_msk;
>>> + }
>>> + } else {
>>> + dev_dbg(dev, "analog switches supplied by vdda\n");
>>> + clrmask = regs->booste_msk | regs->anaswvdd_msk;
>>> + }
>>> +
>>> + mask = regs->booste_msk | regs->anaswvdd_msk;
>>> + if (regs->has_syscfg & HAS_CLEAR_REG) {
>>> + ret = regmap_write(priv->syscfg, regs->pmcc, clrmask);
>>> + if (ret) {
>>> + dev_err(dev, "syscfg clear failed, %d\n", ret);
>>> + goto vdd_dis;
>>> + }
>>> + mask = setmask;
>>> + }
>>> +
>>> + ret = regmap_update_bits(priv->syscfg, regs->pmcr, mask, setmask);
>>> + if (ret) {
>>> + dev_err(dev, "syscfg update failed, %d\n", ret);
>>> + goto vdd_dis;
>>> + }
>>> +
>>> + /* Booster voltage can take up to 50 us to stabilize */
>>> + if (setmask & regs->booste_msk)
>>> + usleep_range(50, 100);
>>> +
>>> + return ret;
>>> +
>>> +vdd_dis:
>>> + if (priv->vdd && (regs->has_syscfg & HAS_ANASWVDD))
>>> + regulator_disable(priv->vdd);
>>> +vdda_dis:
>>> + regulator_disable(priv->vdda);
>>> +
>>> + return ret;
>>> +}
>>> +
>>> +static void stm32_adc_core_switches_supply_dis(struct device *dev)
>>> +{
>>> + struct stm32_adc_common *common = dev_get_drvdata(dev);
>>> + struct stm32_adc_priv *priv = to_stm32_adc_priv(common);
>>> + const struct stm32_adc_common_regs *regs = priv->cfg->regs;
>>> + u32 mask = regs->booste_msk | regs->anaswvdd_msk;
>>> +
>>> + if (!regs->has_syscfg || !priv->vdda || !priv->syscfg)
>>> + return;
>>> +
>>> + if (regs->has_syscfg & HAS_CLEAR_REG)
>>> + regmap_write(priv->syscfg, regs->pmcc, mask);
>>> + else
>>> + regmap_update_bits(priv->syscfg, regs->pmcr, mask, 0);
>>> +
>>> + if (priv->vdd && (regs->has_syscfg & HAS_ANASWVDD))
>>> + regulator_disable(priv->vdd);
>>> +
>>> + regulator_disable(priv->vdda);
>>> +}
>>> +
>>> static int stm32_adc_core_hw_start(struct device *dev)
>>> {
>>> struct stm32_adc_common *common = dev_get_drvdata(dev);
>>> struct stm32_adc_priv *priv = to_stm32_adc_priv(common);
>>> int ret;
>>>
>>> + ret = stm32_adc_core_switches_supply_en(dev);
>>> + if (ret < 0)
>>> + return ret;
>>> +
>>> ret = regulator_enable(priv->vref);
>>> if (ret < 0) {
>>> dev_err(dev, "vref enable failed\n");
>>> - return ret;
>>> + goto err_switches_disable;
>>> }
>>>
>>> if (priv->bclk) {
>>> @@ -425,6 +602,8 @@ static int stm32_adc_core_hw_start(struct device *dev)
>>> clk_disable_unprepare(priv->bclk);
>>> err_regulator_disable:
>>> regulator_disable(priv->vref);
>>> +err_switches_disable:
>>> + stm32_adc_core_switches_supply_dis(dev);
>>>
>>> return ret;
>>> }
>>> @@ -441,6 +620,24 @@ static void stm32_adc_core_hw_stop(struct device *dev)
>>> if (priv->bclk)
>>> clk_disable_unprepare(priv->bclk);
>>> regulator_disable(priv->vref);
>>> + stm32_adc_core_switches_supply_dis(dev);
>>> +}
>>> +
>>> +static int stm32_adc_core_syscfg_probe(struct device_node *np,
>>> + struct stm32_adc_priv *priv)
>>> +{
>>> + if (!priv->cfg->regs->has_syscfg)
>>> + return 0;
>>> +
>>> + priv->syscfg = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
>>> + if (IS_ERR(priv->syscfg)) {
>>> + /* Optional */
>>> + if (PTR_ERR(priv->syscfg) != -ENODEV)
>>> + return PTR_ERR(priv->syscfg);
>>> + priv->syscfg = NULL;
>>> + }
>>> +
>>> + return 0;
>>> }
>>>
>>> static int stm32_adc_probe(struct platform_device *pdev)
>>> @@ -475,6 +672,30 @@ static int stm32_adc_probe(struct platform_device *pdev)
>>> return ret;
>>> }
>>>
>>> + priv->vdda = devm_regulator_get_optional(&pdev->dev, "vdda");
>>> + if (IS_ERR(priv->vdda)) {
>>> + ret = PTR_ERR(priv->vdda);
>>> + if (ret != -ENODEV) {
>>> + if (ret != -EPROBE_DEFER)
>>> + dev_err(&pdev->dev, "vdda get failed, %d\n",
>>> + ret);
>>> + return ret;
>>> + }
>>> + priv->vdda = NULL;
>>> + }
>>> +
>>> + priv->vdd = devm_regulator_get_optional(&pdev->dev, "vdd");
>>> + if (IS_ERR(priv->vdd)) {
>>> + ret = PTR_ERR(priv->vdd);
>>> + if (ret != -ENODEV) {
>>> + if (ret != -EPROBE_DEFER)
>>> + dev_err(&pdev->dev, "vdd get failed, %d\n",
>>> + ret);
>>> + return ret;
>>> + }
>>> + priv->vdd = NULL;
>>> + }
>>> +
>>> priv->aclk = devm_clk_get(&pdev->dev, "adc");
>>> if (IS_ERR(priv->aclk)) {
>>> ret = PTR_ERR(priv->aclk);
>>> @@ -495,6 +716,13 @@ static int stm32_adc_probe(struct platform_device *pdev)
>>> priv->bclk = NULL;
>>> }
>>>
>>> + ret = stm32_adc_core_syscfg_probe(np, priv);
>>> + if (ret) {
>>> + if (ret != -EPROBE_DEFER)
>>> + dev_err(&pdev->dev, "Can't probe syscfg: %d\n", ret);
>>> + return ret;
>>> + }
>>> +
>>> pm_runtime_get_noresume(dev);
>>> pm_runtime_set_active(dev);
>>> pm_runtime_set_autosuspend_delay(dev, STM32_ADC_CORE_SLEEP_DELAY_MS);
>>> @@ -595,7 +823,7 @@ static const struct stm32_adc_priv_cfg stm32h7_adc_priv_cfg = {
>>> };
>>>
>>> static const struct stm32_adc_priv_cfg stm32mp1_adc_priv_cfg = {
>>> - .regs = &stm32h7_adc_common_regs,
>>> + .regs = &stm32mp1_adc_common_regs,
>>> .clk_sel = stm32h7_adc_clk_sel,
>>> .max_clk_rate_hz = 40000000,
>>> };
>>

Next message: Will Deacon: "Re: [PATCH RFC 11/14] arm64: Move the ASID allocator code in a separate file"
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In reply to: Fabrice Gasnier: "Re: [PATCH 2/3] iio: adc: stm32-adc: add analog switches supply control"
Next in thread: Jonathan Cameron: "Re: [PATCH 2/3] iio: adc: stm32-adc: add analog switches supply control"
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