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iio: adc: stm32-adc: add analog switches supply control
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> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
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a85a43e045
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3a81bde545
@ -14,9 +14,11 @@
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#include <linux/irqchip/chained_irq.h>
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#include <linux/irqdesc.h>
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#include <linux/irqdomain.h>
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#include <linux/mfd/syscon.h>
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#include <linux/module.h>
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#include <linux/of_device.h>
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#include <linux/pm_runtime.h>
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#include <linux/regmap.h>
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#include <linux/regulator/consumer.h>
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#include <linux/slab.h>
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@ -51,6 +53,17 @@
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#define STM32_ADC_CORE_SLEEP_DELAY_MS 2000
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/* SYSCFG registers */
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#define STM32MP1_SYSCFG_PMCSETR 0x04
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#define STM32MP1_SYSCFG_PMCCLRR 0x44
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/* SYSCFG bit fields */
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#define STM32MP1_SYSCFG_ANASWVDD_MASK BIT(9)
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/* SYSCFG capability flags */
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#define HAS_VBOOSTER BIT(0)
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#define HAS_ANASWVDD BIT(1)
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/**
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* stm32_adc_common_regs - stm32 common registers, compatible dependent data
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* @csr: common status register offset
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@ -74,11 +87,13 @@ struct stm32_adc_priv;
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* @regs: common registers for all instances
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* @clk_sel: clock selection routine
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* @max_clk_rate_hz: maximum analog clock rate (Hz, from datasheet)
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* @has_syscfg: SYSCFG capability flags
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*/
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struct stm32_adc_priv_cfg {
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const struct stm32_adc_common_regs *regs;
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int (*clk_sel)(struct platform_device *, struct stm32_adc_priv *);
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u32 max_clk_rate_hz;
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unsigned int has_syscfg;
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};
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/**
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@ -87,22 +102,32 @@ struct stm32_adc_priv_cfg {
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* @domain: irq domain reference
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* @aclk: clock reference for the analog circuitry
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* @bclk: bus clock common for all ADCs, depends on part used
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* @booster: booster supply reference
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* @vdd: vdd supply reference
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* @vdda: vdda analog supply reference
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* @vref: regulator reference
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* @vdd_uv: vdd supply voltage (microvolts)
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* @vdda_uv: vdda supply voltage (microvolts)
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* @cfg: compatible configuration data
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* @common: common data for all ADC instances
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* @ccr_bak: backup CCR in low power mode
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* @syscfg: reference to syscon, system control registers
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*/
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struct stm32_adc_priv {
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int irq[STM32_ADC_MAX_ADCS];
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struct irq_domain *domain;
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struct clk *aclk;
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struct clk *bclk;
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struct regulator *booster;
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struct regulator *vdd;
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struct regulator *vdda;
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struct regulator *vref;
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int vdd_uv;
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int vdda_uv;
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const struct stm32_adc_priv_cfg *cfg;
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struct stm32_adc_common common;
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u32 ccr_bak;
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struct regmap *syscfg;
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};
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static struct stm32_adc_priv *to_stm32_adc_priv(struct stm32_adc_common *com)
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@ -390,6 +415,82 @@ static void stm32_adc_irq_remove(struct platform_device *pdev,
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}
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}
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static int stm32_adc_core_switches_supply_en(struct stm32_adc_priv *priv,
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struct device *dev)
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{
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int ret;
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/*
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* On STM32H7 and STM32MP1, the ADC inputs are multiplexed with analog
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* switches (via PCSEL) which have reduced performances when their
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* supply is below 2.7V (vdda by default):
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* - Voltage booster can be used, to get full ADC performances
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* (increases power consumption).
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* - Vdd can be used to supply them, if above 2.7V (STM32MP1 only).
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*
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* Recommended settings for ANASWVDD and EN_BOOSTER:
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* - vdda < 2.7V but vdd > 2.7V: ANASWVDD = 1, EN_BOOSTER = 0 (stm32mp1)
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* - vdda < 2.7V and vdd < 2.7V: ANASWVDD = 0, EN_BOOSTER = 1
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* - vdda >= 2.7V: ANASWVDD = 0, EN_BOOSTER = 0 (default)
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*/
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if (priv->vdda_uv < 2700000) {
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if (priv->syscfg && priv->vdd_uv > 2700000) {
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ret = regulator_enable(priv->vdd);
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if (ret < 0) {
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dev_err(dev, "vdd enable failed %d\n", ret);
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return ret;
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}
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ret = regmap_write(priv->syscfg,
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STM32MP1_SYSCFG_PMCSETR,
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STM32MP1_SYSCFG_ANASWVDD_MASK);
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if (ret < 0) {
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regulator_disable(priv->vdd);
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dev_err(dev, "vdd select failed, %d\n", ret);
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return ret;
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}
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dev_dbg(dev, "analog switches supplied by vdd\n");
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return 0;
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}
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if (priv->booster) {
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/*
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* This is optional, as this is a trade-off between
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* analog performance and power consumption.
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*/
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ret = regulator_enable(priv->booster);
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if (ret < 0) {
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dev_err(dev, "booster enable failed %d\n", ret);
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return ret;
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}
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dev_dbg(dev, "analog switches supplied by booster\n");
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return 0;
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}
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}
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/* Fallback using vdda (default), nothing to do */
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dev_dbg(dev, "analog switches supplied by vdda (%d uV)\n",
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priv->vdda_uv);
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return 0;
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}
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static void stm32_adc_core_switches_supply_dis(struct stm32_adc_priv *priv)
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{
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if (priv->vdda_uv < 2700000) {
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if (priv->syscfg && priv->vdd_uv > 2700000) {
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regmap_write(priv->syscfg, STM32MP1_SYSCFG_PMCCLRR,
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STM32MP1_SYSCFG_ANASWVDD_MASK);
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regulator_disable(priv->vdd);
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return;
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}
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if (priv->booster)
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regulator_disable(priv->booster);
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}
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}
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static int stm32_adc_core_hw_start(struct device *dev)
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{
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struct stm32_adc_common *common = dev_get_drvdata(dev);
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@ -402,10 +503,21 @@ static int stm32_adc_core_hw_start(struct device *dev)
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return ret;
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}
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ret = regulator_get_voltage(priv->vdda);
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if (ret < 0) {
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dev_err(dev, "vdda get voltage failed, %d\n", ret);
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goto err_vdda_disable;
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}
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priv->vdda_uv = ret;
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ret = stm32_adc_core_switches_supply_en(priv, dev);
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if (ret < 0)
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goto err_vdda_disable;
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ret = regulator_enable(priv->vref);
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if (ret < 0) {
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dev_err(dev, "vref enable failed\n");
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goto err_vdda_disable;
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goto err_switches_dis;
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}
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if (priv->bclk) {
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@ -433,6 +545,8 @@ static int stm32_adc_core_hw_start(struct device *dev)
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clk_disable_unprepare(priv->bclk);
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err_regulator_disable:
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regulator_disable(priv->vref);
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err_switches_dis:
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stm32_adc_core_switches_supply_dis(priv);
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err_vdda_disable:
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regulator_disable(priv->vdda);
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@ -451,9 +565,80 @@ static void stm32_adc_core_hw_stop(struct device *dev)
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if (priv->bclk)
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clk_disable_unprepare(priv->bclk);
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regulator_disable(priv->vref);
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stm32_adc_core_switches_supply_dis(priv);
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regulator_disable(priv->vdda);
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}
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static int stm32_adc_core_switches_probe(struct device *dev,
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struct stm32_adc_priv *priv)
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{
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struct device_node *np = dev->of_node;
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int ret;
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/* Analog switches supply can be controlled by syscfg (optional) */
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priv->syscfg = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
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if (IS_ERR(priv->syscfg)) {
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ret = PTR_ERR(priv->syscfg);
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if (ret != -ENODEV) {
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if (ret != -EPROBE_DEFER)
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dev_err(dev, "Can't probe syscfg: %d\n", ret);
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return ret;
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}
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priv->syscfg = NULL;
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}
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/* Booster can be used to supply analog switches (optional) */
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if (priv->cfg->has_syscfg & HAS_VBOOSTER &&
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of_property_read_bool(np, "booster-supply")) {
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priv->booster = devm_regulator_get_optional(dev, "booster");
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if (IS_ERR(priv->booster)) {
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ret = PTR_ERR(priv->booster);
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if (ret != -ENODEV) {
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if (ret != -EPROBE_DEFER)
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dev_err(dev, "can't get booster %d\n",
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ret);
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return ret;
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}
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priv->booster = NULL;
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}
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}
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/* Vdd can be used to supply analog switches (optional) */
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if (priv->cfg->has_syscfg & HAS_ANASWVDD &&
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of_property_read_bool(np, "vdd-supply")) {
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priv->vdd = devm_regulator_get_optional(dev, "vdd");
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if (IS_ERR(priv->vdd)) {
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ret = PTR_ERR(priv->vdd);
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if (ret != -ENODEV) {
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if (ret != -EPROBE_DEFER)
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dev_err(dev, "can't get vdd %d\n", ret);
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return ret;
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}
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priv->vdd = NULL;
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}
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}
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if (priv->vdd) {
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ret = regulator_enable(priv->vdd);
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if (ret < 0) {
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dev_err(dev, "vdd enable failed %d\n", ret);
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return ret;
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}
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ret = regulator_get_voltage(priv->vdd);
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if (ret < 0) {
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dev_err(dev, "vdd get voltage failed %d\n", ret);
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regulator_disable(priv->vdd);
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return ret;
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}
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priv->vdd_uv = ret;
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regulator_disable(priv->vdd);
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}
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return 0;
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}
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static int stm32_adc_probe(struct platform_device *pdev)
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{
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struct stm32_adc_priv *priv;
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@ -514,6 +699,10 @@ static int stm32_adc_probe(struct platform_device *pdev)
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priv->bclk = NULL;
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}
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ret = stm32_adc_core_switches_probe(dev, priv);
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if (ret)
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return ret;
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pm_runtime_get_noresume(dev);
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pm_runtime_set_active(dev);
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pm_runtime_set_autosuspend_delay(dev, STM32_ADC_CORE_SLEEP_DELAY_MS);
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@ -611,12 +800,14 @@ static const struct stm32_adc_priv_cfg stm32h7_adc_priv_cfg = {
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.regs = &stm32h7_adc_common_regs,
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.clk_sel = stm32h7_adc_clk_sel,
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.max_clk_rate_hz = 36000000,
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.has_syscfg = HAS_VBOOSTER,
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};
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static const struct stm32_adc_priv_cfg stm32mp1_adc_priv_cfg = {
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.regs = &stm32h7_adc_common_regs,
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.clk_sel = stm32h7_adc_clk_sel,
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.max_clk_rate_hz = 40000000,
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.has_syscfg = HAS_VBOOSTER | HAS_ANASWVDD,
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};
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static const struct of_device_id stm32_adc_of_match[] = {
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