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Subject[PATCH 1/3] iio: adc: stm32-adc: move self-calibration to prepare routine
Date
Move self-calibration routine to prepare routine.
- This is precursor patch to ease power management handling.
- This also allow to factorize few error cases (error handling).

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
---
drivers/iio/adc/stm32-adc.c | 59 ++++++++++++++++++---------------------------
1 file changed, 24 insertions(+), 35 deletions(-)

diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index 3784118..dca8733 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -199,11 +199,13 @@ struct stm32_adc_trig_info {
* @calfact_s: Calibration offset for single ended channels
* @calfact_d: Calibration offset in differential
* @lincalfact: Linearity calibration factor
+ * @calibrated: Indicates calibration status
*/
struct stm32_adc_calib {
u32 calfact_s;
u32 calfact_d;
u32 lincalfact[STM32H7_LINCALFACT_NUM];
+ bool calibrated;
};

/**
@@ -251,7 +253,6 @@ struct stm32_adc_regspec {
* @trigs: external trigger sources
* @clk_required: clock is required
* @has_vregready: vregready status flag presence
- * @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
@@ -264,7 +265,6 @@ struct stm32_adc_cfg {
struct stm32_adc_trig_info *trigs;
bool clk_required;
bool has_vregready;
- int (*selfcalib)(struct stm32_adc *);
int (*prepare)(struct stm32_adc *);
void (*start_conv)(struct stm32_adc *, bool dma);
void (*stop_conv)(struct stm32_adc *);
@@ -777,6 +777,7 @@ static void stm32h7_adc_disable(struct stm32_adc *adc)
/**
* stm32h7_adc_read_selfcalib() - read calibration shadow regs, save result
* @adc: stm32 adc instance
+ * Note: Must be called once ADC is enabled, so LINCALRDYW[1..6] are writable
*/
static int stm32h7_adc_read_selfcalib(struct stm32_adc *adc)
{
@@ -784,11 +785,6 @@ static int stm32h7_adc_read_selfcalib(struct stm32_adc *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--) {
@@ -801,7 +797,7 @@ static int stm32h7_adc_read_selfcalib(struct stm32_adc *adc)
100, STM32_ADC_TIMEOUT_US);
if (ret) {
dev_err(&indio_dev->dev, "Failed to read calfact\n");
- goto disable;
+ return ret;
}

val = stm32_adc_readl(adc, STM32H7_ADC_CALFACT2);
@@ -817,11 +813,9 @@ static int stm32h7_adc_read_selfcalib(struct stm32_adc *adc)
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;
+ adc->cal.calibrated = true;

-disable:
- stm32h7_adc_disable(adc);
-
- return ret;
+ return 0;
}

/**
@@ -898,9 +892,9 @@ static int stm32h7_adc_restore_selfcalib(struct stm32_adc *adc)
#define STM32H7_ADC_CALIB_TIMEOUT_US 100000

/**
- * stm32h7_adc_selfcalib() - Procedure to calibrate ADC (from power down)
+ * stm32h7_adc_selfcalib() - Procedure to calibrate ADC
* @adc: stm32 adc instance
- * Exit from power down, calibrate ADC, then return to power down.
+ * Note: Must be called once ADC is out of power down.
*/
static int stm32h7_adc_selfcalib(struct stm32_adc *adc)
{
@@ -908,9 +902,8 @@ static int stm32h7_adc_selfcalib(struct stm32_adc *adc)
int ret;
u32 val;

- ret = stm32h7_adc_exit_pwr_down(adc);
- if (ret)
- return ret;
+ if (adc->cal.calibrated)
+ return adc->cal.calibrated;

/*
* Select calibration mode:
@@ -927,7 +920,7 @@ static int stm32h7_adc_selfcalib(struct stm32_adc *adc)
STM32H7_ADC_CALIB_TIMEOUT_US);
if (ret) {
dev_err(&indio_dev->dev, "calibration failed\n");
- goto pwr_dwn;
+ goto out;
}

/*
@@ -944,18 +937,13 @@ static int stm32h7_adc_selfcalib(struct stm32_adc *adc)
STM32H7_ADC_CALIB_TIMEOUT_US);
if (ret) {
dev_err(&indio_dev->dev, "calibration failed\n");
- goto pwr_dwn;
+ goto out;
}

+out:
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;
}

@@ -972,19 +960,28 @@ static int stm32h7_adc_selfcalib(struct stm32_adc *adc)
*/
static int stm32h7_adc_prepare(struct stm32_adc *adc)
{
- int ret;
+ int calib, ret;

ret = stm32h7_adc_exit_pwr_down(adc);
if (ret)
return ret;

+ ret = stm32h7_adc_selfcalib(adc);
+ if (ret < 0)
+ goto pwr_dwn;
+ calib = ret;
+
stm32_adc_writel(adc, STM32H7_ADC_DIFSEL, adc->difsel);

ret = stm32h7_adc_enable(adc);
if (ret)
goto pwr_dwn;

- ret = stm32h7_adc_restore_selfcalib(adc);
+ /* Either restore or read calibration result for future reference */
+ if (calib)
+ ret = stm32h7_adc_restore_selfcalib(adc);
+ else
+ ret = stm32h7_adc_read_selfcalib(adc);
if (ret)
goto disable;

@@ -1880,12 +1877,6 @@ 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;
@@ -1961,7 +1952,6 @@ static int stm32_adc_remove(struct platform_device *pdev)
.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,
@@ -1974,7 +1964,6 @@ static int stm32_adc_remove(struct platform_device *pdev)
.adc_info = &stm32h7_adc_info,
.trigs = stm32h7_adc_trigs,
.has_vregready = true,
- .selfcalib = stm32h7_adc_selfcalib,
.start_conv = stm32h7_adc_start_conv,
.stop_conv = stm32h7_adc_stop_conv,
.prepare = stm32h7_adc_prepare,
--
1.9.1
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