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SubjectRe: [PATCH v2 2/3] iio: adc: stm32-adc: add analog switches supply control
On Wed, 3 Jul 2019 12:08:15 +0200
Fabrice Gasnier <fabrice.gasnier@st.com> 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):
> - 3.3V embedded booster can be used, to get full ADC performances
> (increases power consumption).
> - vdd supply can be selected if above 2.7V by setting ANASWVDD syscfg bit,
> on STM32MP1 only.
>
> Make this optional, since this is a trade-off between analog performance
> and power consumption.
>
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Looks good to me.

Applied to the togreg branch of iio.git and pushed out as testing.

Thanks,

Jonathan

> ---
> Changes in v2:
> - Only enable vdd regulator when needed.
> - Rework vdda enabling since: "Add missing vdda-supply to STM32 ADC".
> - Booster has been added to the regulator framework. This helps also when
> there are several ADC instances like on stm32h7 (e.g. ADC12 and ADC3), to
> benefit from the use count.
> ---
> drivers/iio/adc/stm32-adc-core.c | 193 ++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 192 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c
> index 1f7ce51..4299cef 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 +53,17 @@
>
> #define STM32_ADC_CORE_SLEEP_DELAY_MS 2000
>
> +/* SYSCFG registers */
> +#define STM32MP1_SYSCFG_PMCSETR 0x04
> +#define STM32MP1_SYSCFG_PMCCLRR 0x44
> +
> +/* SYSCFG bit fields */
> +#define STM32MP1_SYSCFG_ANASWVDD_MASK BIT(9)
> +
> +/* SYSCFG capability flags */
> +#define HAS_VBOOSTER BIT(0)
> +#define HAS_ANASWVDD BIT(1)
> +
> /**
> * stm32_adc_common_regs - stm32 common registers, compatible dependent data
> * @csr: common status register offset
> @@ -74,11 +87,13 @@ struct stm32_adc_priv;
> * @regs: common registers for all instances
> * @clk_sel: clock selection routine
> * @max_clk_rate_hz: maximum analog clock rate (Hz, from datasheet)
> + * @has_syscfg: SYSCFG capability flags
> */
> struct stm32_adc_priv_cfg {
> const struct stm32_adc_common_regs *regs;
> int (*clk_sel)(struct platform_device *, struct stm32_adc_priv *);
> u32 max_clk_rate_hz;
> + unsigned int has_syscfg;
> };
>
> /**
> @@ -87,22 +102,32 @@ 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
> + * @booster: booster supply reference
> + * @vdd: vdd supply reference
> * @vdda: vdda analog supply reference
> * @vref: regulator reference
> + * @vdd_uv: vdd supply voltage (microvolts)
> + * @vdda_uv: vdda supply voltage (microvolts)
> * @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 *booster;
> + struct regulator *vdd;
> struct regulator *vdda;
> struct regulator *vref;
> + int vdd_uv;
> + int vdda_uv;
> 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)
> @@ -390,6 +415,82 @@ static void stm32_adc_irq_remove(struct platform_device *pdev,
> }
> }
>
> +static int stm32_adc_core_switches_supply_en(struct stm32_adc_priv *priv,
> + struct device *dev)
> +{
> + int ret;
> +
> + /*
> + * 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).
> + *
> + * 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 (priv->vdda_uv < 2700000) {
> + if (priv->syscfg && priv->vdd_uv > 2700000) {
> + ret = regulator_enable(priv->vdd);
> + if (ret < 0) {
> + dev_err(dev, "vdd enable failed %d\n", ret);
> + return ret;
> + }
> +
> + ret = regmap_write(priv->syscfg,
> + STM32MP1_SYSCFG_PMCSETR,
> + STM32MP1_SYSCFG_ANASWVDD_MASK);
> + if (ret < 0) {
> + regulator_disable(priv->vdd);
> + dev_err(dev, "vdd select failed, %d\n", ret);
> + return ret;
> + }
> + dev_dbg(dev, "analog switches supplied by vdd\n");
> +
> + return 0;
> + }
> +
> + if (priv->booster) {
> + /*
> + * This is optional, as this is a trade-off between
> + * analog performance and power consumption.
> + */
> + ret = regulator_enable(priv->booster);
> + if (ret < 0) {
> + dev_err(dev, "booster enable failed %d\n", ret);
> + return ret;
> + }
> + dev_dbg(dev, "analog switches supplied by booster\n");
> +
> + return 0;
> + }
> + }
> +
> + /* Fallback using vdda (default), nothing to do */
> + dev_dbg(dev, "analog switches supplied by vdda (%d uV)\n",
> + priv->vdda_uv);
> +
> + return 0;
> +}
> +
> +static void stm32_adc_core_switches_supply_dis(struct stm32_adc_priv *priv)
> +{
> + if (priv->vdda_uv < 2700000) {
> + if (priv->syscfg && priv->vdd_uv > 2700000) {
> + regmap_write(priv->syscfg, STM32MP1_SYSCFG_PMCCLRR,
> + STM32MP1_SYSCFG_ANASWVDD_MASK);
> + regulator_disable(priv->vdd);
> + return;
> + }
> + if (priv->booster)
> + regulator_disable(priv->booster);
> + }
> +}
> +
> static int stm32_adc_core_hw_start(struct device *dev)
> {
> struct stm32_adc_common *common = dev_get_drvdata(dev);
> @@ -402,10 +503,21 @@ static int stm32_adc_core_hw_start(struct device *dev)
> return ret;
> }
>
> + ret = regulator_get_voltage(priv->vdda);
> + if (ret < 0) {
> + dev_err(dev, "vdda get voltage failed, %d\n", ret);
> + goto err_vdda_disable;
> + }
> + priv->vdda_uv = ret;
> +
> + ret = stm32_adc_core_switches_supply_en(priv, dev);
> + if (ret < 0)
> + goto err_vdda_disable;
> +
> ret = regulator_enable(priv->vref);
> if (ret < 0) {
> dev_err(dev, "vref enable failed\n");
> - goto err_vdda_disable;
> + goto err_switches_dis;
> }
>
> if (priv->bclk) {
> @@ -433,6 +545,8 @@ static int stm32_adc_core_hw_start(struct device *dev)
> clk_disable_unprepare(priv->bclk);
> err_regulator_disable:
> regulator_disable(priv->vref);
> +err_switches_dis:
> + stm32_adc_core_switches_supply_dis(priv);
> err_vdda_disable:
> regulator_disable(priv->vdda);
>
> @@ -451,9 +565,80 @@ 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(priv);
> regulator_disable(priv->vdda);
> }
>
> +static int stm32_adc_core_switches_probe(struct device *dev,
> + struct stm32_adc_priv *priv)
> +{
> + struct device_node *np = dev->of_node;
> + int ret;
> +
> + /* Analog switches supply can be controlled by syscfg (optional) */
> + priv->syscfg = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
> + if (IS_ERR(priv->syscfg)) {
> + ret = PTR_ERR(priv->syscfg);
> + if (ret != -ENODEV) {
> + if (ret != -EPROBE_DEFER)
> + dev_err(dev, "Can't probe syscfg: %d\n", ret);
> + return ret;
> + }
> + priv->syscfg = NULL;
> + }
> +
> + /* Booster can be used to supply analog switches (optional) */
> + if (priv->cfg->has_syscfg & HAS_VBOOSTER &&
> + of_property_read_bool(np, "booster-supply")) {
> + priv->booster = devm_regulator_get_optional(dev, "booster");
> + if (IS_ERR(priv->booster)) {
> + ret = PTR_ERR(priv->booster);
> + if (ret != -ENODEV) {
> + if (ret != -EPROBE_DEFER)
> + dev_err(dev, "can't get booster %d\n",
> + ret);
> + return ret;
> + }
> + priv->booster = NULL;
> + }
> + }
> +
> + /* Vdd can be used to supply analog switches (optional) */
> + if (priv->cfg->has_syscfg & HAS_ANASWVDD &&
> + of_property_read_bool(np, "vdd-supply")) {
> + priv->vdd = devm_regulator_get_optional(dev, "vdd");
> + if (IS_ERR(priv->vdd)) {
> + ret = PTR_ERR(priv->vdd);
> + if (ret != -ENODEV) {
> + if (ret != -EPROBE_DEFER)
> + dev_err(dev, "can't get vdd %d\n", ret);
> + return ret;
> + }
> + priv->vdd = NULL;
> + }
> + }
> +
> + if (priv->vdd) {
> + ret = regulator_enable(priv->vdd);
> + if (ret < 0) {
> + dev_err(dev, "vdd enable failed %d\n", ret);
> + return ret;
> + }
> +
> + ret = regulator_get_voltage(priv->vdd);
> + if (ret < 0) {
> + dev_err(dev, "vdd get voltage failed %d\n", ret);
> + regulator_disable(priv->vdd);
> + return ret;
> + }
> + priv->vdd_uv = ret;
> +
> + regulator_disable(priv->vdd);
> + }
> +
> + return 0;
> +}
> +
> static int stm32_adc_probe(struct platform_device *pdev)
> {
> struct stm32_adc_priv *priv;
> @@ -514,6 +699,10 @@ static int stm32_adc_probe(struct platform_device *pdev)
> priv->bclk = NULL;
> }
>
> + ret = stm32_adc_core_switches_probe(dev, priv);
> + if (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);
> @@ -611,12 +800,14 @@ static const struct stm32_adc_priv_cfg stm32h7_adc_priv_cfg = {
> .regs = &stm32h7_adc_common_regs,
> .clk_sel = stm32h7_adc_clk_sel,
> .max_clk_rate_hz = 36000000,
> + .has_syscfg = HAS_VBOOSTER,
> };
>
> static const struct stm32_adc_priv_cfg stm32mp1_adc_priv_cfg = {
> .regs = &stm32h7_adc_common_regs,
> .clk_sel = stm32h7_adc_clk_sel,
> .max_clk_rate_hz = 40000000,
> + .has_syscfg = HAS_VBOOSTER | HAS_ANASWVDD,
> };
>
> static const struct of_device_id stm32_adc_of_match[] = {

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