From 95e339b6e85d03438d1d9236ccaff4ecd895f3ab Mon Sep 17 00:00:00 2001 From: Fabrice Gasnier Date: Mon, 29 May 2017 11:28:20 +0200 Subject: [PATCH] iio: adc: stm32: add support for STM32H7 Add support for STM32H7 Analog to Digital Converter. It has up to 20 external channels, resolution ranges from 8 to 16bits. Either bus or asynchronous adc clock may be used. Add registers & bitfields definition. Also add new configuration options to enter/exit powerdown and perform self-calibration. Signed-off-by: Fabrice Gasnier Signed-off-by: Jonathan Cameron --- drivers/iio/adc/stm32-adc-core.c | 171 +++++++++- drivers/iio/adc/stm32-adc-core.h | 2 + drivers/iio/adc/stm32-adc.c | 532 ++++++++++++++++++++++++++++++- 3 files changed, 701 insertions(+), 4 deletions(-) diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c index c5d292ccc763..e09233b03c05 100644 --- a/drivers/iio/adc/stm32-adc-core.c +++ b/drivers/iio/adc/stm32-adc-core.c @@ -49,6 +49,23 @@ /* STM32 F4 maximum analog clock rate (from datasheet) */ #define STM32F4_ADC_MAX_CLK_RATE 36000000 +/* STM32H7 - common registers for all ADC instances */ +#define STM32H7_ADC_CSR (STM32_ADCX_COMN_OFFSET + 0x00) +#define STM32H7_ADC_CCR (STM32_ADCX_COMN_OFFSET + 0x08) + +/* STM32H7_ADC_CSR - bit fields */ +#define STM32H7_EOC_SLV BIT(18) +#define STM32H7_EOC_MST BIT(2) + +/* STM32H7_ADC_CCR - bit fields */ +#define STM32H7_PRESC_SHIFT 18 +#define STM32H7_PRESC_MASK GENMASK(21, 18) +#define STM32H7_CKMODE_SHIFT 16 +#define STM32H7_CKMODE_MASK GENMASK(17, 16) + +/* STM32 H7 maximum analog clock rate (from datasheet) */ +#define STM32H7_ADC_MAX_CLK_RATE 72000000 + /** * stm32_adc_common_regs - stm32 common registers, compatible dependent data * @csr: common status register offset @@ -80,6 +97,7 @@ struct stm32_adc_priv_cfg { * @irq: irq for ADC block * @domain: irq domain reference * @aclk: clock reference for the analog circuitry + * @bclk: bus clock common for all ADCs, depends on part used * @vref: regulator reference * @cfg: compatible configuration data * @common: common data for all ADC instances @@ -88,6 +106,7 @@ struct stm32_adc_priv { int irq; struct irq_domain *domain; struct clk *aclk; + struct clk *bclk; struct regulator *vref; const struct stm32_adc_priv_cfg *cfg; struct stm32_adc_common common; @@ -129,6 +148,7 @@ static int stm32f4_adc_clk_sel(struct platform_device *pdev, return -EINVAL; } + priv->common.rate = rate; val = readl_relaxed(priv->common.base + STM32F4_ADC_CCR); val &= ~STM32F4_ADC_ADCPRE_MASK; val |= i << STM32F4_ADC_ADCPRE_SHIFT; @@ -140,6 +160,111 @@ static int stm32f4_adc_clk_sel(struct platform_device *pdev, return 0; } +/** + * struct stm32h7_adc_ck_spec - specification for stm32h7 adc clock + * @ckmode: ADC clock mode, Async or sync with prescaler. + * @presc: prescaler bitfield for async clock mode + * @div: prescaler division ratio + */ +struct stm32h7_adc_ck_spec { + u32 ckmode; + u32 presc; + int div; +}; + +const struct stm32h7_adc_ck_spec stm32h7_adc_ckmodes_spec[] = { + /* 00: CK_ADC[1..3]: Asynchronous clock modes */ + { 0, 0, 1 }, + { 0, 1, 2 }, + { 0, 2, 4 }, + { 0, 3, 6 }, + { 0, 4, 8 }, + { 0, 5, 10 }, + { 0, 6, 12 }, + { 0, 7, 16 }, + { 0, 8, 32 }, + { 0, 9, 64 }, + { 0, 10, 128 }, + { 0, 11, 256 }, + /* HCLK used: Synchronous clock modes (1, 2 or 4 prescaler) */ + { 1, 0, 1 }, + { 2, 0, 2 }, + { 3, 0, 4 }, +}; + +static int stm32h7_adc_clk_sel(struct platform_device *pdev, + struct stm32_adc_priv *priv) +{ + u32 ckmode, presc, val; + unsigned long rate; + int i, div; + + /* stm32h7 bus clock is common for all ADC instances (mandatory) */ + if (!priv->bclk) { + dev_err(&pdev->dev, "No 'bus' clock found\n"); + return -ENOENT; + } + + /* + * stm32h7 can use either 'bus' or 'adc' clock for analog circuitry. + * So, choice is to have bus clock mandatory and adc clock optional. + * If optional 'adc' clock has been found, then try to use it first. + */ + if (priv->aclk) { + /* + * Asynchronous clock modes (e.g. ckmode == 0) + * From spec: PLL output musn't exceed max rate + */ + rate = clk_get_rate(priv->aclk); + + for (i = 0; i < ARRAY_SIZE(stm32h7_adc_ckmodes_spec); i++) { + ckmode = stm32h7_adc_ckmodes_spec[i].ckmode; + presc = stm32h7_adc_ckmodes_spec[i].presc; + div = stm32h7_adc_ckmodes_spec[i].div; + + if (ckmode) + continue; + + if ((rate / div) <= STM32H7_ADC_MAX_CLK_RATE) + goto out; + } + } + + /* Synchronous clock modes (e.g. ckmode is 1, 2 or 3) */ + rate = clk_get_rate(priv->bclk); + + for (i = 0; i < ARRAY_SIZE(stm32h7_adc_ckmodes_spec); i++) { + ckmode = stm32h7_adc_ckmodes_spec[i].ckmode; + presc = stm32h7_adc_ckmodes_spec[i].presc; + div = stm32h7_adc_ckmodes_spec[i].div; + + if (!ckmode) + continue; + + if ((rate / div) <= STM32H7_ADC_MAX_CLK_RATE) + goto out; + } + + dev_err(&pdev->dev, "adc clk selection failed\n"); + return -EINVAL; + +out: + /* rate used later by each ADC instance to control BOOST mode */ + priv->common.rate = rate; + + /* Set common clock mode and prescaler */ + val = readl_relaxed(priv->common.base + STM32H7_ADC_CCR); + val &= ~(STM32H7_CKMODE_MASK | STM32H7_PRESC_MASK); + val |= ckmode << STM32H7_CKMODE_SHIFT; + val |= presc << STM32H7_PRESC_SHIFT; + writel_relaxed(val, priv->common.base + STM32H7_ADC_CCR); + + dev_dbg(&pdev->dev, "Using %s clock/%d source at %ld kHz\n", + ckmode ? "bus" : "adc", div, rate / (div * 1000)); + + return 0; +} + /* STM32F4 common registers definitions */ static const struct stm32_adc_common_regs stm32f4_adc_common_regs = { .csr = STM32F4_ADC_CSR, @@ -148,6 +273,13 @@ static const struct stm32_adc_common_regs stm32f4_adc_common_regs = { .eoc3_msk = STM32F4_EOC3, }; +/* STM32H7 common registers definitions */ +static const struct stm32_adc_common_regs stm32h7_adc_common_regs = { + .csr = STM32H7_ADC_CSR, + .eoc1_msk = STM32H7_EOC_MST, + .eoc2_msk = STM32H7_EOC_SLV, +}; + /* ADC common interrupt for all instances */ static void stm32_adc_irq_handler(struct irq_desc *desc) { @@ -291,13 +423,32 @@ static int stm32_adc_probe(struct platform_device *pdev) } } + priv->bclk = devm_clk_get(&pdev->dev, "bus"); + if (IS_ERR(priv->bclk)) { + ret = PTR_ERR(priv->bclk); + if (ret == -ENOENT) { + priv->bclk = NULL; + } else { + dev_err(&pdev->dev, "Can't get 'bus' clock\n"); + goto err_aclk_disable; + } + } + + if (priv->bclk) { + ret = clk_prepare_enable(priv->bclk); + if (ret < 0) { + dev_err(&pdev->dev, "adc clk enable failed\n"); + goto err_aclk_disable; + } + } + ret = priv->cfg->clk_sel(pdev, priv); if (ret < 0) - goto err_clk_disable; + goto err_bclk_disable; ret = stm32_adc_irq_probe(pdev, priv); if (ret < 0) - goto err_clk_disable; + goto err_bclk_disable; platform_set_drvdata(pdev, &priv->common); @@ -312,7 +463,11 @@ static int stm32_adc_probe(struct platform_device *pdev) err_irq_remove: stm32_adc_irq_remove(pdev, priv); -err_clk_disable: +err_bclk_disable: + if (priv->bclk) + clk_disable_unprepare(priv->bclk); + +err_aclk_disable: if (priv->aclk) clk_disable_unprepare(priv->aclk); @@ -329,6 +484,8 @@ static int stm32_adc_remove(struct platform_device *pdev) of_platform_depopulate(&pdev->dev); stm32_adc_irq_remove(pdev, priv); + if (priv->bclk) + clk_disable_unprepare(priv->bclk); if (priv->aclk) clk_disable_unprepare(priv->aclk); regulator_disable(priv->vref); @@ -341,10 +498,18 @@ static const struct stm32_adc_priv_cfg stm32f4_adc_priv_cfg = { .clk_sel = stm32f4_adc_clk_sel, }; +static const struct stm32_adc_priv_cfg stm32h7_adc_priv_cfg = { + .regs = &stm32h7_adc_common_regs, + .clk_sel = stm32h7_adc_clk_sel, +}; + static const struct of_device_id stm32_adc_of_match[] = { { .compatible = "st,stm32f4-adc-core", .data = (void *)&stm32f4_adc_priv_cfg + }, { + .compatible = "st,stm32h7-adc-core", + .data = (void *)&stm32h7_adc_priv_cfg }, { }, }; diff --git a/drivers/iio/adc/stm32-adc-core.h b/drivers/iio/adc/stm32-adc-core.h index 2ec7abbfbcaa..250ee958a669 100644 --- a/drivers/iio/adc/stm32-adc-core.h +++ b/drivers/iio/adc/stm32-adc-core.h @@ -43,11 +43,13 @@ * struct stm32_adc_common - stm32 ADC driver common data (for all instances) * @base: control registers base cpu addr * @phys_base: control registers base physical addr + * @rate: clock rate used for analog circuitry * @vref_mv: vref voltage (mv) */ struct stm32_adc_common { void __iomem *base; phys_addr_t phys_base; + unsigned long rate; int vref_mv; }; diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c index 2ba9ca991f0a..5bfcc1f13105 100644 --- a/drivers/iio/adc/stm32-adc.c +++ b/drivers/iio/adc/stm32-adc.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include #include @@ -77,6 +78,78 @@ #define STM32F4_DMA BIT(8) #define STM32F4_ADON BIT(0) +/* STM32H7 - Registers for each ADC instance */ +#define STM32H7_ADC_ISR 0x00 +#define STM32H7_ADC_IER 0x04 +#define STM32H7_ADC_CR 0x08 +#define STM32H7_ADC_CFGR 0x0C +#define STM32H7_ADC_PCSEL 0x1C +#define STM32H7_ADC_SQR1 0x30 +#define STM32H7_ADC_SQR2 0x34 +#define STM32H7_ADC_SQR3 0x38 +#define STM32H7_ADC_SQR4 0x3C +#define STM32H7_ADC_DR 0x40 +#define STM32H7_ADC_CALFACT 0xC4 +#define STM32H7_ADC_CALFACT2 0xC8 + +/* STM32H7_ADC_ISR - bit fields */ +#define STM32H7_EOC BIT(2) +#define STM32H7_ADRDY BIT(0) + +/* STM32H7_ADC_IER - bit fields */ +#define STM32H7_EOCIE STM32H7_EOC + +/* STM32H7_ADC_CR - bit fields */ +#define STM32H7_ADCAL BIT(31) +#define STM32H7_ADCALDIF BIT(30) +#define STM32H7_DEEPPWD BIT(29) +#define STM32H7_ADVREGEN BIT(28) +#define STM32H7_LINCALRDYW6 BIT(27) +#define STM32H7_LINCALRDYW5 BIT(26) +#define STM32H7_LINCALRDYW4 BIT(25) +#define STM32H7_LINCALRDYW3 BIT(24) +#define STM32H7_LINCALRDYW2 BIT(23) +#define STM32H7_LINCALRDYW1 BIT(22) +#define STM32H7_ADCALLIN BIT(16) +#define STM32H7_BOOST BIT(8) +#define STM32H7_ADSTP BIT(4) +#define STM32H7_ADSTART BIT(2) +#define STM32H7_ADDIS BIT(1) +#define STM32H7_ADEN BIT(0) + +/* STM32H7_ADC_CFGR bit fields */ +#define STM32H7_EXTEN_SHIFT 10 +#define STM32H7_EXTEN_MASK GENMASK(11, 10) +#define STM32H7_EXTSEL_SHIFT 5 +#define STM32H7_EXTSEL_MASK GENMASK(9, 5) +#define STM32H7_RES_SHIFT 2 +#define STM32H7_RES_MASK GENMASK(4, 2) +#define STM32H7_DMNGT_SHIFT 0 +#define STM32H7_DMNGT_MASK GENMASK(1, 0) + +enum stm32h7_adc_dmngt { + STM32H7_DMNGT_DR_ONLY, /* Regular data in DR only */ + STM32H7_DMNGT_DMA_ONESHOT, /* DMA one shot mode */ + STM32H7_DMNGT_DFSDM, /* DFSDM mode */ + STM32H7_DMNGT_DMA_CIRC, /* DMA circular mode */ +}; + +/* STM32H7_ADC_CALFACT - bit fields */ +#define STM32H7_CALFACT_D_SHIFT 16 +#define STM32H7_CALFACT_D_MASK GENMASK(26, 16) +#define STM32H7_CALFACT_S_SHIFT 0 +#define STM32H7_CALFACT_S_MASK GENMASK(10, 0) + +/* STM32H7_ADC_CALFACT2 - bit fields */ +#define STM32H7_LINCALFACT_SHIFT 0 +#define STM32H7_LINCALFACT_MASK GENMASK(29, 0) + +/* Number of linear calibration shadow registers / LINCALRDYW control bits */ +#define STM32H7_LINCALFACT_NUM 6 + +/* BOOST bit must be set on STM32H7 when ADC clock is above 20MHz */ +#define STM32H7_BOOST_CLKRATE 20000000UL + #define STM32_ADC_MAX_SQ 16 /* SQ1..SQ16 */ #define STM32_ADC_TIMEOUT_US 100000 #define STM32_ADC_TIMEOUT (msecs_to_jiffies(STM32_ADC_TIMEOUT_US / 1000)) @@ -121,6 +194,18 @@ struct stm32_adc_trig_info { enum stm32_adc_extsel extsel; }; +/** + * struct stm32_adc_calib - optional adc calibration data + * @calfact_s: Calibration offset for single ended channels + * @calfact_d: Calibration offset in differential + * @lincalfact: Linearity calibration factor + */ +struct stm32_adc_calib { + u32 calfact_s; + u32 calfact_d; + u32 lincalfact[STM32H7_LINCALFACT_NUM]; +}; + /** * stm32_adc_regs - stm32 ADC misc registers & bitfield desc * @reg: register offset @@ -161,16 +246,22 @@ struct stm32_adc; * @adc_info: per instance input channels definitions * @trigs: external trigger sources * @clk_required: clock is required + * @selfcalib: optional routine for self-calibration + * @prepare: optional prepare routine (power-up, enable) * @start_conv: routine to start conversions * @stop_conv: routine to stop conversions + * @unprepare: optional unprepare routine (disable, power-down) */ struct stm32_adc_cfg { const struct stm32_adc_regspec *regs; const struct stm32_adc_info *adc_info; struct stm32_adc_trig_info *trigs; bool clk_required; + int (*selfcalib)(struct stm32_adc *); + int (*prepare)(struct stm32_adc *); void (*start_conv)(struct stm32_adc *, bool dma); void (*stop_conv)(struct stm32_adc *); + void (*unprepare)(struct stm32_adc *); }; /** @@ -191,6 +282,8 @@ struct stm32_adc_cfg { * @rx_buf: dma rx buffer cpu address * @rx_dma_buf: dma rx buffer bus address * @rx_buf_sz: dma rx buffer size + * @pcsel bitmask to preselect channels on some devices + * @cal: optional calibration data on some devices */ struct stm32_adc { struct stm32_adc_common *common; @@ -209,6 +302,8 @@ struct stm32_adc { u8 *rx_buf; dma_addr_t rx_dma_buf; unsigned int rx_buf_sz; + u32 pcsel; + struct stm32_adc_calib cal; }; /** @@ -240,6 +335,7 @@ struct stm32_adc_info { /* * Input definitions common for all instances: * stm32f4 can have up to 16 channels + * stm32h7 can have up to 20 channels */ static const struct stm32_adc_chan_spec stm32_adc_channels[] = { { IIO_VOLTAGE, 0, "in0" }, @@ -258,6 +354,10 @@ static const struct stm32_adc_chan_spec stm32_adc_channels[] = { { IIO_VOLTAGE, 13, "in13" }, { IIO_VOLTAGE, 14, "in14" }, { IIO_VOLTAGE, 15, "in15" }, + { IIO_VOLTAGE, 16, "in16" }, + { IIO_VOLTAGE, 17, "in17" }, + { IIO_VOLTAGE, 18, "in18" }, + { IIO_VOLTAGE, 19, "in19" }, }; static const unsigned int stm32f4_adc_resolutions[] = { @@ -272,6 +372,18 @@ static const struct stm32_adc_info stm32f4_adc_info = { .num_res = ARRAY_SIZE(stm32f4_adc_resolutions), }; +static const unsigned int stm32h7_adc_resolutions[] = { + /* sorted values so the index matches RES[2:0] in STM32H7_ADC_CFGR */ + 16, 14, 12, 10, 8, +}; + +static const struct stm32_adc_info stm32h7_adc_info = { + .channels = stm32_adc_channels, + .max_channels = 20, + .resolutions = stm32h7_adc_resolutions, + .num_res = ARRAY_SIZE(stm32h7_adc_resolutions), +}; + /** * stm32f4_sq - describe regular sequence registers * - L: sequence len (register & bit field) @@ -330,6 +442,58 @@ static const struct stm32_adc_regspec stm32f4_adc_regspec = { .res = { STM32F4_ADC_CR1, STM32F4_RES_MASK, STM32F4_RES_SHIFT }, }; +static const struct stm32_adc_regs stm32h7_sq[STM32_ADC_MAX_SQ + 1] = { + /* L: len bit field description to be kept as first element */ + { STM32H7_ADC_SQR1, GENMASK(3, 0), 0 }, + /* SQ1..SQ16 registers & bit fields (reg, mask, shift) */ + { STM32H7_ADC_SQR1, GENMASK(10, 6), 6 }, + { STM32H7_ADC_SQR1, GENMASK(16, 12), 12 }, + { STM32H7_ADC_SQR1, GENMASK(22, 18), 18 }, + { STM32H7_ADC_SQR1, GENMASK(28, 24), 24 }, + { STM32H7_ADC_SQR2, GENMASK(4, 0), 0 }, + { STM32H7_ADC_SQR2, GENMASK(10, 6), 6 }, + { STM32H7_ADC_SQR2, GENMASK(16, 12), 12 }, + { STM32H7_ADC_SQR2, GENMASK(22, 18), 18 }, + { STM32H7_ADC_SQR2, GENMASK(28, 24), 24 }, + { STM32H7_ADC_SQR3, GENMASK(4, 0), 0 }, + { STM32H7_ADC_SQR3, GENMASK(10, 6), 6 }, + { STM32H7_ADC_SQR3, GENMASK(16, 12), 12 }, + { STM32H7_ADC_SQR3, GENMASK(22, 18), 18 }, + { STM32H7_ADC_SQR3, GENMASK(28, 24), 24 }, + { STM32H7_ADC_SQR4, GENMASK(4, 0), 0 }, + { STM32H7_ADC_SQR4, GENMASK(10, 6), 6 }, +}; + +/* STM32H7 external trigger sources for all instances */ +static struct stm32_adc_trig_info stm32h7_adc_trigs[] = { + { TIM1_CH1, STM32_EXT0 }, + { TIM1_CH2, STM32_EXT1 }, + { TIM1_CH3, STM32_EXT2 }, + { TIM2_CH2, STM32_EXT3 }, + { TIM3_TRGO, STM32_EXT4 }, + { TIM4_CH4, STM32_EXT5 }, + { TIM8_TRGO, STM32_EXT7 }, + { TIM8_TRGO2, STM32_EXT8 }, + { TIM1_TRGO, STM32_EXT9 }, + { TIM1_TRGO2, STM32_EXT10 }, + { TIM2_TRGO, STM32_EXT11 }, + { TIM4_TRGO, STM32_EXT12 }, + { TIM6_TRGO, STM32_EXT13 }, + { TIM3_CH4, STM32_EXT15 }, + {}, +}; + +static const struct stm32_adc_regspec stm32h7_adc_regspec = { + .dr = STM32H7_ADC_DR, + .ier_eoc = { STM32H7_ADC_IER, STM32H7_EOCIE }, + .isr_eoc = { STM32H7_ADC_ISR, STM32H7_EOC }, + .sqr = stm32h7_sq, + .exten = { STM32H7_ADC_CFGR, STM32H7_EXTEN_MASK, STM32H7_EXTEN_SHIFT }, + .extsel = { STM32H7_ADC_CFGR, STM32H7_EXTSEL_MASK, + STM32H7_EXTSEL_SHIFT }, + .res = { STM32H7_ADC_CFGR, STM32H7_RES_MASK, STM32H7_RES_SHIFT }, +}; + /** * STM32 ADC registers access routines * @adc: stm32 adc instance @@ -343,6 +507,12 @@ static u32 stm32_adc_readl(struct stm32_adc *adc, u32 reg) return readl_relaxed(adc->common->base + adc->offset + reg); } +#define stm32_adc_readl_addr(addr) stm32_adc_readl(adc, addr) + +#define stm32_adc_readl_poll_timeout(reg, val, cond, sleep_us, timeout_us) \ + readx_poll_timeout(stm32_adc_readl_addr, reg, val, \ + cond, sleep_us, timeout_us) + static u16 stm32_adc_readw(struct stm32_adc *adc, u32 reg) { return readw_relaxed(adc->common->base + adc->offset + reg); @@ -439,6 +609,324 @@ static void stm32f4_adc_stop_conv(struct stm32_adc *adc) STM32F4_ADON | STM32F4_DMA | STM32F4_DDS); } +static void stm32h7_adc_start_conv(struct stm32_adc *adc, bool dma) +{ + enum stm32h7_adc_dmngt dmngt; + unsigned long flags; + u32 val; + + if (dma) + dmngt = STM32H7_DMNGT_DMA_CIRC; + else + dmngt = STM32H7_DMNGT_DR_ONLY; + + spin_lock_irqsave(&adc->lock, flags); + val = stm32_adc_readl(adc, STM32H7_ADC_CFGR); + val = (val & ~STM32H7_DMNGT_MASK) | (dmngt << STM32H7_DMNGT_SHIFT); + stm32_adc_writel(adc, STM32H7_ADC_CFGR, val); + spin_unlock_irqrestore(&adc->lock, flags); + + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADSTART); +} + +static void stm32h7_adc_stop_conv(struct stm32_adc *adc) +{ + struct iio_dev *indio_dev = iio_priv_to_dev(adc); + int ret; + u32 val; + + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADSTP); + + ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val, + !(val & (STM32H7_ADSTART)), + 100, STM32_ADC_TIMEOUT_US); + if (ret) + dev_warn(&indio_dev->dev, "stop failed\n"); + + stm32_adc_clr_bits(adc, STM32H7_ADC_CFGR, STM32H7_DMNGT_MASK); +} + +static void stm32h7_adc_exit_pwr_down(struct stm32_adc *adc) +{ + /* Exit deep power down, then enable ADC voltage regulator */ + stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_DEEPPWD); + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADVREGEN); + + if (adc->common->rate > STM32H7_BOOST_CLKRATE) + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_BOOST); + + /* Wait for startup time */ + usleep_range(10, 20); +} + +static void stm32h7_adc_enter_pwr_down(struct stm32_adc *adc) +{ + stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_BOOST); + + /* Setting DEEPPWD disables ADC vreg and clears ADVREGEN */ + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_DEEPPWD); +} + +static int stm32h7_adc_enable(struct stm32_adc *adc) +{ + struct iio_dev *indio_dev = iio_priv_to_dev(adc); + int ret; + u32 val; + + /* Clear ADRDY by writing one, then enable ADC */ + stm32_adc_set_bits(adc, STM32H7_ADC_ISR, STM32H7_ADRDY); + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADEN); + + /* Poll for ADRDY to be set (after adc startup time) */ + ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_ISR, val, + val & STM32H7_ADRDY, + 100, STM32_ADC_TIMEOUT_US); + if (ret) { + stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_ADEN); + dev_err(&indio_dev->dev, "Failed to enable ADC\n"); + } + + return ret; +} + +static void stm32h7_adc_disable(struct stm32_adc *adc) +{ + struct iio_dev *indio_dev = iio_priv_to_dev(adc); + int ret; + u32 val; + + /* Disable ADC and wait until it's effectively disabled */ + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADDIS); + ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val, + !(val & STM32H7_ADEN), 100, + STM32_ADC_TIMEOUT_US); + if (ret) + dev_warn(&indio_dev->dev, "Failed to disable\n"); +} + +/** + * stm32h7_adc_read_selfcalib() - read calibration shadow regs, save result + * @adc: stm32 adc instance + */ +static int stm32h7_adc_read_selfcalib(struct stm32_adc *adc) +{ + struct iio_dev *indio_dev = iio_priv_to_dev(adc); + int i, ret; + u32 lincalrdyw_mask, val; + + /* Enable adc so LINCALRDYW1..6 bits are writable */ + ret = stm32h7_adc_enable(adc); + if (ret) + return ret; + + /* Read linearity calibration */ + lincalrdyw_mask = STM32H7_LINCALRDYW6; + for (i = STM32H7_LINCALFACT_NUM - 1; i >= 0; i--) { + /* Clear STM32H7_LINCALRDYW[6..1]: transfer calib to CALFACT2 */ + stm32_adc_clr_bits(adc, STM32H7_ADC_CR, lincalrdyw_mask); + + /* Poll: wait calib data to be ready in CALFACT2 register */ + ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val, + !(val & lincalrdyw_mask), + 100, STM32_ADC_TIMEOUT_US); + if (ret) { + dev_err(&indio_dev->dev, "Failed to read calfact\n"); + goto disable; + } + + val = stm32_adc_readl(adc, STM32H7_ADC_CALFACT2); + adc->cal.lincalfact[i] = (val & STM32H7_LINCALFACT_MASK); + adc->cal.lincalfact[i] >>= STM32H7_LINCALFACT_SHIFT; + + lincalrdyw_mask >>= 1; + } + + /* Read offset calibration */ + val = stm32_adc_readl(adc, STM32H7_ADC_CALFACT); + adc->cal.calfact_s = (val & STM32H7_CALFACT_S_MASK); + adc->cal.calfact_s >>= STM32H7_CALFACT_S_SHIFT; + adc->cal.calfact_d = (val & STM32H7_CALFACT_D_MASK); + adc->cal.calfact_d >>= STM32H7_CALFACT_D_SHIFT; + +disable: + stm32h7_adc_disable(adc); + + return ret; +} + +/** + * stm32h7_adc_restore_selfcalib() - Restore saved self-calibration result + * @adc: stm32 adc instance + * Note: ADC must be enabled, with no on-going conversions. + */ +static int stm32h7_adc_restore_selfcalib(struct stm32_adc *adc) +{ + struct iio_dev *indio_dev = iio_priv_to_dev(adc); + int i, ret; + u32 lincalrdyw_mask, val; + + val = (adc->cal.calfact_s << STM32H7_CALFACT_S_SHIFT) | + (adc->cal.calfact_d << STM32H7_CALFACT_D_SHIFT); + stm32_adc_writel(adc, STM32H7_ADC_CALFACT, val); + + lincalrdyw_mask = STM32H7_LINCALRDYW6; + for (i = STM32H7_LINCALFACT_NUM - 1; i >= 0; i--) { + /* + * Write saved calibration data to shadow registers: + * Write CALFACT2, and set LINCALRDYW[6..1] bit to trigger + * data write. Then poll to wait for complete transfer. + */ + val = adc->cal.lincalfact[i] << STM32H7_LINCALFACT_SHIFT; + stm32_adc_writel(adc, STM32H7_ADC_CALFACT2, val); + stm32_adc_set_bits(adc, STM32H7_ADC_CR, lincalrdyw_mask); + ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val, + val & lincalrdyw_mask, + 100, STM32_ADC_TIMEOUT_US); + if (ret) { + dev_err(&indio_dev->dev, "Failed to write calfact\n"); + return ret; + } + + /* + * Read back calibration data, has two effects: + * - It ensures bits LINCALRDYW[6..1] are kept cleared + * for next time calibration needs to be restored. + * - BTW, bit clear triggers a read, then check data has been + * correctly written. + */ + stm32_adc_clr_bits(adc, STM32H7_ADC_CR, lincalrdyw_mask); + ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val, + !(val & lincalrdyw_mask), + 100, STM32_ADC_TIMEOUT_US); + if (ret) { + dev_err(&indio_dev->dev, "Failed to read calfact\n"); + return ret; + } + val = stm32_adc_readl(adc, STM32H7_ADC_CALFACT2); + if (val != adc->cal.lincalfact[i] << STM32H7_LINCALFACT_SHIFT) { + dev_err(&indio_dev->dev, "calfact not consistent\n"); + return -EIO; + } + + lincalrdyw_mask >>= 1; + } + + return 0; +} + +/** + * Fixed timeout value for ADC calibration. + * worst cases: + * - low clock frequency + * - maximum prescalers + * Calibration requires: + * - 131,072 ADC clock cycle for the linear calibration + * - 20 ADC clock cycle for the offset calibration + * + * Set to 100ms for now + */ +#define STM32H7_ADC_CALIB_TIMEOUT_US 100000 + +/** + * stm32h7_adc_selfcalib() - Procedure to calibrate ADC (from power down) + * @adc: stm32 adc instance + * Exit from power down, calibrate ADC, then return to power down. + */ +static int stm32h7_adc_selfcalib(struct stm32_adc *adc) +{ + struct iio_dev *indio_dev = iio_priv_to_dev(adc); + int ret; + u32 val; + + stm32h7_adc_exit_pwr_down(adc); + + /* + * Select calibration mode: + * - Offset calibration for single ended inputs + * - No linearity calibration (do it later, before reading it) + */ + stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_ADCALDIF); + stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_ADCALLIN); + + /* Start calibration, then wait for completion */ + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADCAL); + ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val, + !(val & STM32H7_ADCAL), 100, + STM32H7_ADC_CALIB_TIMEOUT_US); + if (ret) { + dev_err(&indio_dev->dev, "calibration failed\n"); + goto pwr_dwn; + } + + /* + * Select calibration mode, then start calibration: + * - Offset calibration for differential input + * - Linearity calibration (needs to be done only once for single/diff) + * will run simultaneously with offset calibration. + */ + stm32_adc_set_bits(adc, STM32H7_ADC_CR, + STM32H7_ADCALDIF | STM32H7_ADCALLIN); + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADCAL); + ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val, + !(val & STM32H7_ADCAL), 100, + STM32H7_ADC_CALIB_TIMEOUT_US); + if (ret) { + dev_err(&indio_dev->dev, "calibration failed\n"); + goto pwr_dwn; + } + + stm32_adc_clr_bits(adc, STM32H7_ADC_CR, + STM32H7_ADCALDIF | STM32H7_ADCALLIN); + + /* Read calibration result for future reference */ + ret = stm32h7_adc_read_selfcalib(adc); + +pwr_dwn: + stm32h7_adc_enter_pwr_down(adc); + + return ret; +} + +/** + * stm32h7_adc_prepare() - Leave power down mode to enable ADC. + * @adc: stm32 adc instance + * Leave power down mode. + * Enable ADC. + * Restore calibration data. + * Pre-select channels that may be used in PCSEL (required by input MUX / IO). + */ +static int stm32h7_adc_prepare(struct stm32_adc *adc) +{ + int ret; + + stm32h7_adc_exit_pwr_down(adc); + + ret = stm32h7_adc_enable(adc); + if (ret) + goto pwr_dwn; + + ret = stm32h7_adc_restore_selfcalib(adc); + if (ret) + goto disable; + + stm32_adc_writel(adc, STM32H7_ADC_PCSEL, adc->pcsel); + + return 0; + +disable: + stm32h7_adc_disable(adc); +pwr_dwn: + stm32h7_adc_enter_pwr_down(adc); + + return ret; +} + +static void stm32h7_adc_unprepare(struct stm32_adc *adc) +{ + stm32h7_adc_disable(adc); + stm32h7_adc_enter_pwr_down(adc); +} + /** * stm32_adc_conf_scan_seq() - Build regular channels scan sequence * @indio_dev: IIO device @@ -609,6 +1097,12 @@ static int stm32_adc_single_conv(struct iio_dev *indio_dev, adc->bufi = 0; + if (adc->cfg->prepare) { + ret = adc->cfg->prepare(adc); + if (ret) + return ret; + } + /* Program chan number in regular sequence (SQ1) */ val = stm32_adc_readl(adc, regs->sqr[1].reg); val &= ~regs->sqr[1].mask; @@ -640,6 +1134,9 @@ static int stm32_adc_single_conv(struct iio_dev *indio_dev, stm32_adc_conv_irq_disable(adc); + if (adc->cfg->unprepare) + adc->cfg->unprepare(adc); + return ret; } @@ -864,10 +1361,16 @@ static int stm32_adc_buffer_postenable(struct iio_dev *indio_dev) struct stm32_adc *adc = iio_priv(indio_dev); int ret; + if (adc->cfg->prepare) { + ret = adc->cfg->prepare(adc); + if (ret) + return ret; + } + ret = stm32_adc_set_trig(indio_dev, indio_dev->trig); if (ret) { dev_err(&indio_dev->dev, "Can't set trigger\n"); - return ret; + goto err_unprepare; } ret = stm32_adc_dma_start(indio_dev); @@ -895,6 +1398,9 @@ err_stop_dma: dmaengine_terminate_all(adc->dma_chan); err_clr_trig: stm32_adc_set_trig(indio_dev, NULL); +err_unprepare: + if (adc->cfg->unprepare) + adc->cfg->unprepare(adc); return ret; } @@ -918,6 +1424,9 @@ static int stm32_adc_buffer_predisable(struct iio_dev *indio_dev) if (stm32_adc_set_trig(indio_dev, NULL)) dev_err(&indio_dev->dev, "Can't clear trigger\n"); + if (adc->cfg->unprepare) + adc->cfg->unprepare(adc); + return ret; } @@ -1016,6 +1525,9 @@ static void stm32_adc_chan_init_one(struct iio_dev *indio_dev, chan->scan_type.realbits = adc->cfg->adc_info->resolutions[adc->res]; chan->scan_type.storagebits = 16; chan->ext_info = stm32_adc_ext_info; + + /* pre-build selected channels mask */ + adc->pcsel |= BIT(chan->channel); } static int stm32_adc_chan_of_init(struct iio_dev *indio_dev) @@ -1169,6 +1681,12 @@ static int stm32_adc_probe(struct platform_device *pdev) goto err_clk_disable; stm32_adc_set_res(adc); + if (adc->cfg->selfcalib) { + ret = adc->cfg->selfcalib(adc); + if (ret) + goto err_clk_disable; + } + ret = stm32_adc_chan_of_init(indio_dev); if (ret < 0) goto err_clk_disable; @@ -1239,8 +1757,20 @@ static const struct stm32_adc_cfg stm32f4_adc_cfg = { .stop_conv = stm32f4_adc_stop_conv, }; +static const struct stm32_adc_cfg stm32h7_adc_cfg = { + .regs = &stm32h7_adc_regspec, + .adc_info = &stm32h7_adc_info, + .trigs = stm32h7_adc_trigs, + .selfcalib = stm32h7_adc_selfcalib, + .start_conv = stm32h7_adc_start_conv, + .stop_conv = stm32h7_adc_stop_conv, + .prepare = stm32h7_adc_prepare, + .unprepare = stm32h7_adc_unprepare, +}; + static const struct of_device_id stm32_adc_of_match[] = { { .compatible = "st,stm32f4-adc", .data = (void *)&stm32f4_adc_cfg }, + { .compatible = "st,stm32h7-adc", .data = (void *)&stm32h7_adc_cfg }, {}, }; MODULE_DEVICE_TABLE(of, stm32_adc_of_match); -- 2.20.1