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 <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Fabrice Gasnier 2017-05-29 11:28:20 +02:00 committed by Jonathan Cameron
parent 204a6a25db
commit 95e339b6e8
3 changed files with 701 additions and 4 deletions

View file

@ -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
}, {
},
};

View file

@ -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;
};

View file

@ -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))
@ -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 @@ 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;
}
@ -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);