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Subject[PATCH 5/5] iio: adc: stm32: add support for STM32H7
Date
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 <fabrice.gasnier@st.com>
---
drivers/iio/adc/stm32-adc-core.c | 171 +++++++++++-
drivers/iio/adc/stm32-adc-core.h | 2 +
drivers/iio/adc/stm32-adc.c | 552 ++++++++++++++++++++++++++++++++++++++-
3 files changed, 721 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c
index c5d292c..e09233b 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 int stm32f4_adc_clk_sel(struct platform_device *pdev,
.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);
@@ -341,11 +498,19 @@ static int stm32_adc_remove(struct platform_device *pdev)
.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
+ }, {
},
};
MODULE_DEVICE_TABLE(of, stm32_adc_of_match);
diff --git a/drivers/iio/adc/stm32-adc-core.h b/drivers/iio/adc/stm32-adc-core.h
index 2ec7abb..250ee95 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 ad8fdb9..dba89c7 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -31,6 +31,7 @@
#include <linux/iio/triggered_buffer.h>
#include <linux/interrupt.h>
#include <linux/io.h>
+#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/of.h>
@@ -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))
@@ -122,6 +195,18 @@ struct stm32_adc_trig_info {
};

/**
+ * 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
* @mask: bitfield mask
@@ -161,16 +246,22 @@ struct stm32_adc_regspec {
* @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;
};

/**
@@ -269,6 +364,42 @@ struct stm32_adc_info {
.num_res = ARRAY_SIZE(stm32f4_adc_resolutions),
};

+/* Input definitions for stm32h7 */
+static const struct stm32_adc_chan_spec stm32h7_adc_channels[] = {
+ { IIO_VOLTAGE, 0, "in0" },
+ { IIO_VOLTAGE, 1, "in1" },
+ { IIO_VOLTAGE, 2, "in2" },
+ { IIO_VOLTAGE, 3, "in3" },
+ { IIO_VOLTAGE, 4, "in4" },
+ { IIO_VOLTAGE, 5, "in5" },
+ { IIO_VOLTAGE, 6, "in6" },
+ { IIO_VOLTAGE, 7, "in7" },
+ { IIO_VOLTAGE, 8, "in8" },
+ { IIO_VOLTAGE, 9, "in9" },
+ { IIO_VOLTAGE, 10, "in10" },
+ { IIO_VOLTAGE, 11, "in11" },
+ { IIO_VOLTAGE, 12, "in12" },
+ { 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 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 = stm32h7_adc_channels,
+ .max_channels = ARRAY_SIZE(stm32h7_adc_channels),
+ .resolutions = stm32h7_adc_resolutions,
+ .num_res = ARRAY_SIZE(stm32h7_adc_resolutions),
+};
+
/**
* stm32f4_sq - describe regular sequence registers
* - L: sequence len (register & bit field)
@@ -327,6 +458,58 @@ struct stm32_adc_info {
.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
@@ -340,6 +523,12 @@ 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);
@@ -436,6 +625,324 @@ 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
@@ -606,6 +1113,12 @@ 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;
@@ -637,6 +1150,9 @@ 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;
}

@@ -861,10 +1377,16 @@ 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);
@@ -892,6 +1414,9 @@ static int stm32_adc_buffer_postenable(struct iio_dev *indio_dev)
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;
}
@@ -915,6 +1440,9 @@ 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;
}

@@ -1002,6 +1530,7 @@ static void stm32_adc_chan_init_one(struct iio_dev *indio_dev,
{
struct stm32_adc *adc = iio_priv(indio_dev);

+ /* Initialize IIO channel */
chan->type = channel->type;
chan->channel = channel->channel;
chan->datasheet_name = channel->name;
@@ -1013,6 +1542,9 @@ 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)
@@ -1166,6 +1698,12 @@ 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;
@@ -1236,8 +1774,20 @@ static int stm32_adc_remove(struct platform_device *pdev)
.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);
--
1.9.1
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