On Wed, 3 Jul 2019 12:08:15 +0200 Fabrice Gasnier <[email protected]> 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 <[email protected]> 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[] = {
