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iio: adc: stm32-adc: add support of internal channels
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Add support of ADC2 internal channels VDDCORE, VREFINT and VBAT.
The reserved label name "vddcore", "vrefint" and "vbat" must
be used in Device Tree channel node, to enable the corresponding
internal channel.

Note: This patch does not provide support of internal channels
for F4 and H7.

Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20211014131228.4692-6-olivier.moysan@foss.st.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
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Olivier Moysan authored and Jonathan Cameron committed Oct 20, 2021
1 parent 95bc818 commit aec6e0d
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Showing 3 changed files with 146 additions and 3 deletions.
1 change: 1 addition & 0 deletions drivers/iio/adc/stm32-adc-core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -659,6 +659,7 @@ static int stm32_adc_probe(struct platform_device *pdev)

priv->cfg = (const struct stm32_adc_priv_cfg *)
of_match_device(dev->driver->of_match_table, dev)->data;
spin_lock_init(&priv->common.lock);

res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
priv->common.base = devm_ioremap_resource(&pdev->dev, res);
Expand Down
10 changes: 10 additions & 0 deletions drivers/iio/adc/stm32-adc-core.h
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Original file line number Diff line number Diff line change
Expand Up @@ -102,6 +102,9 @@
#define STM32H7_ADC_CALFACT 0xC4
#define STM32H7_ADC_CALFACT2 0xC8

/* STM32MP1 - ADC2 instance option register */
#define STM32MP1_ADC2_OR 0xD0

/* 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)
Expand Down Expand Up @@ -168,23 +171,30 @@ enum stm32h7_adc_dmngt {
#define STM32H7_EOC_MST BIT(2)

/* STM32H7_ADC_CCR - bit fields */
#define STM32H7_VBATEN BIT(24)
#define STM32H7_VREFEN BIT(22)
#define STM32H7_PRESC_SHIFT 18
#define STM32H7_PRESC_MASK GENMASK(21, 18)
#define STM32H7_CKMODE_SHIFT 16
#define STM32H7_CKMODE_MASK GENMASK(17, 16)

/* STM32MP1_ADC2_OR - bit fields */
#define STM32MP1_VDDCOREEN BIT(0)

/**
* 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)
* @lock: spinlock
*/
struct stm32_adc_common {
void __iomem *base;
phys_addr_t phys_base;
unsigned long rate;
int vref_mv;
spinlock_t lock; /* lock for common register */
};

#endif
138 changes: 135 additions & 3 deletions drivers/iio/adc/stm32-adc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -77,6 +77,30 @@ enum stm32_adc_extsel {
STM32_EXT20,
};

enum stm32_adc_int_ch {
STM32_ADC_INT_CH_NONE = -1,
STM32_ADC_INT_CH_VDDCORE,
STM32_ADC_INT_CH_VREFINT,
STM32_ADC_INT_CH_VBAT,
STM32_ADC_INT_CH_NB,
};

/**
* struct stm32_adc_ic - ADC internal channels
* @name: name of the internal channel
* @idx: internal channel enum index
*/
struct stm32_adc_ic {
const char *name;
u32 idx;
};

static const struct stm32_adc_ic stm32_adc_ic[STM32_ADC_INT_CH_NB] = {
{ "vddcore", STM32_ADC_INT_CH_VDDCORE },
{ "vrefint", STM32_ADC_INT_CH_VREFINT },
{ "vbat", STM32_ADC_INT_CH_VBAT },
};

/**
* struct stm32_adc_trig_info - ADC trigger info
* @name: name of the trigger, corresponding to its source
Expand Down Expand Up @@ -126,6 +150,9 @@ struct stm32_adc_regs {
* @res: resolution selection register & bitfield
* @smpr: smpr1 & smpr2 registers offset array
* @smp_bits: smpr1 & smpr2 index and bitfields
* @or_vdd: option register & vddcore bitfield
* @ccr_vbat: common register & vbat bitfield
* @ccr_vref: common register & vrefint bitfield
*/
struct stm32_adc_regspec {
const u32 dr;
Expand All @@ -139,6 +166,9 @@ struct stm32_adc_regspec {
const struct stm32_adc_regs res;
const u32 smpr[2];
const struct stm32_adc_regs *smp_bits;
const struct stm32_adc_regs or_vdd;
const struct stm32_adc_regs ccr_vbat;
const struct stm32_adc_regs ccr_vref;
};

struct stm32_adc;
Expand Down Expand Up @@ -195,6 +225,7 @@ struct stm32_adc_cfg {
* @cal: optional calibration data on some devices
* @chan_name: channel name array
* @num_diff: number of differential channels
* @int_ch: internal channel indexes array
*/
struct stm32_adc {
struct stm32_adc_common *common;
Expand All @@ -219,6 +250,7 @@ struct stm32_adc {
struct stm32_adc_calib cal;
char chan_name[STM32_ADC_CH_MAX][STM32_ADC_CH_SZ];
u32 num_diff;
int int_ch[STM32_ADC_INT_CH_NB];
};

struct stm32_adc_diff_channel {
Expand Down Expand Up @@ -451,6 +483,24 @@ static const struct stm32_adc_regspec stm32h7_adc_regspec = {
.smp_bits = stm32h7_smp_bits,
};

static const struct stm32_adc_regspec stm32mp1_adc_regspec = {
.dr = STM32H7_ADC_DR,
.ier_eoc = { STM32H7_ADC_IER, STM32H7_EOCIE },
.ier_ovr = { STM32H7_ADC_IER, STM32H7_OVRIE },
.isr_eoc = { STM32H7_ADC_ISR, STM32H7_EOC },
.isr_ovr = { STM32H7_ADC_ISR, STM32H7_OVR },
.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 },
.smpr = { STM32H7_ADC_SMPR1, STM32H7_ADC_SMPR2 },
.smp_bits = stm32h7_smp_bits,
.or_vdd = { STM32MP1_ADC2_OR, STM32MP1_VDDCOREEN },
.ccr_vbat = { STM32H7_ADC_CCR, STM32H7_VBATEN },
.ccr_vref = { STM32H7_ADC_CCR, STM32H7_VREFEN },
};

/*
* STM32 ADC registers access routines
* @adc: stm32 adc instance
Expand Down Expand Up @@ -489,6 +539,14 @@ static void stm32_adc_set_bits(struct stm32_adc *adc, u32 reg, u32 bits)
spin_unlock_irqrestore(&adc->lock, flags);
}

static void stm32_adc_set_bits_common(struct stm32_adc *adc, u32 reg, u32 bits)
{
spin_lock(&adc->common->lock);
writel_relaxed(readl_relaxed(adc->common->base + reg) | bits,
adc->common->base + reg);
spin_unlock(&adc->common->lock);
}

static void stm32_adc_clr_bits(struct stm32_adc *adc, u32 reg, u32 bits)
{
unsigned long flags;
Expand All @@ -498,6 +556,14 @@ static void stm32_adc_clr_bits(struct stm32_adc *adc, u32 reg, u32 bits)
spin_unlock_irqrestore(&adc->lock, flags);
}

static void stm32_adc_clr_bits_common(struct stm32_adc *adc, u32 reg, u32 bits)
{
spin_lock(&adc->common->lock);
writel_relaxed(readl_relaxed(adc->common->base + reg) & ~bits,
adc->common->base + reg);
spin_unlock(&adc->common->lock);
}

/**
* stm32_adc_conv_irq_enable() - Enable end of conversion interrupt
* @adc: stm32 adc instance
Expand Down Expand Up @@ -579,6 +645,60 @@ static int stm32_adc_hw_start(struct device *dev)
return ret;
}

static void stm32_adc_int_ch_enable(struct iio_dev *indio_dev)
{
struct stm32_adc *adc = iio_priv(indio_dev);
u32 i;

for (i = 0; i < STM32_ADC_INT_CH_NB; i++) {
if (adc->int_ch[i] == STM32_ADC_INT_CH_NONE)
continue;

switch (i) {
case STM32_ADC_INT_CH_VDDCORE:
dev_dbg(&indio_dev->dev, "Enable VDDCore\n");
stm32_adc_set_bits(adc, adc->cfg->regs->or_vdd.reg,
adc->cfg->regs->or_vdd.mask);
break;
case STM32_ADC_INT_CH_VREFINT:
dev_dbg(&indio_dev->dev, "Enable VREFInt\n");
stm32_adc_set_bits_common(adc, adc->cfg->regs->ccr_vref.reg,
adc->cfg->regs->ccr_vref.mask);
break;
case STM32_ADC_INT_CH_VBAT:
dev_dbg(&indio_dev->dev, "Enable VBAT\n");
stm32_adc_set_bits_common(adc, adc->cfg->regs->ccr_vbat.reg,
adc->cfg->regs->ccr_vbat.mask);
break;
}
}
}

static void stm32_adc_int_ch_disable(struct stm32_adc *adc)
{
u32 i;

for (i = 0; i < STM32_ADC_INT_CH_NB; i++) {
if (adc->int_ch[i] == STM32_ADC_INT_CH_NONE)
continue;

switch (i) {
case STM32_ADC_INT_CH_VDDCORE:
stm32_adc_clr_bits(adc, adc->cfg->regs->or_vdd.reg,
adc->cfg->regs->or_vdd.mask);
break;
case STM32_ADC_INT_CH_VREFINT:
stm32_adc_clr_bits_common(adc, adc->cfg->regs->ccr_vref.reg,
adc->cfg->regs->ccr_vref.mask);
break;
case STM32_ADC_INT_CH_VBAT:
stm32_adc_clr_bits_common(adc, adc->cfg->regs->ccr_vbat.reg,
adc->cfg->regs->ccr_vbat.mask);
break;
}
}
}

/**
* stm32f4_adc_start_conv() - Start conversions for regular channels.
* @indio_dev: IIO device instance
Expand Down Expand Up @@ -947,11 +1067,13 @@ static int stm32h7_adc_prepare(struct iio_dev *indio_dev)
goto pwr_dwn;
calib = ret;

stm32_adc_int_ch_enable(indio_dev);

stm32_adc_writel(adc, STM32H7_ADC_DIFSEL, adc->difsel);

ret = stm32h7_adc_enable(indio_dev);
if (ret)
goto pwr_dwn;
goto ch_disable;

/* Either restore or read calibration result for future reference */
if (calib)
Expand All @@ -967,6 +1089,8 @@ static int stm32h7_adc_prepare(struct iio_dev *indio_dev)

disable:
stm32h7_adc_disable(indio_dev);
ch_disable:
stm32_adc_int_ch_disable(adc);
pwr_dwn:
stm32h7_adc_enter_pwr_down(adc);

Expand All @@ -978,6 +1102,7 @@ static void stm32h7_adc_unprepare(struct iio_dev *indio_dev)
struct stm32_adc *adc = iio_priv(indio_dev);

stm32h7_adc_disable(indio_dev);
stm32_adc_int_ch_disable(adc);
stm32h7_adc_enter_pwr_down(adc);
}

Expand Down Expand Up @@ -1800,7 +1925,7 @@ static int stm32_adc_generic_chan_init(struct iio_dev *indio_dev,
const struct stm32_adc_info *adc_info = adc->cfg->adc_info;
struct device_node *child;
const char *name;
int val, scan_index = 0, ret;
int val, scan_index = 0, ret, i;
bool differential;
u32 vin[2];

Expand All @@ -1820,6 +1945,10 @@ static int stm32_adc_generic_chan_init(struct iio_dev *indio_dev,
return -EINVAL;
}
strncpy(adc->chan_name[val], name, STM32_ADC_CH_SZ);
for (i = 0; i < STM32_ADC_INT_CH_NB; i++) {
if (!strncmp(stm32_adc_ic[i].name, name, STM32_ADC_CH_SZ))
adc->int_ch[i] = val;
}
} else if (ret != -EINVAL) {
dev_err(&indio_dev->dev, "Invalid label %d\n", ret);
goto err;
Expand Down Expand Up @@ -1869,6 +1998,9 @@ static int stm32_adc_chan_of_init(struct iio_dev *indio_dev, bool timestamping)
u32 smp = 0;
bool legacy = false;

for (i = 0; i < STM32_ADC_INT_CH_NB; i++)
adc->int_ch[i] = STM32_ADC_INT_CH_NONE;

num_channels = of_get_available_child_count(node);
/* If no channels have been found, fallback to channels legacy properties. */
if (!num_channels) {
Expand Down Expand Up @@ -2219,7 +2351,7 @@ static const struct stm32_adc_cfg stm32h7_adc_cfg = {
};

static const struct stm32_adc_cfg stm32mp1_adc_cfg = {
.regs = &stm32h7_adc_regspec,
.regs = &stm32mp1_adc_regspec,
.adc_info = &stm32h7_adc_info,
.trigs = stm32h7_adc_trigs,
.has_vregready = true,
Expand Down

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