[PATCH v2 05/10] iio: adc: at91-sama5d2-adc: add support for separate end of conversion registers

Eugen Hristev
2021-08-24T11:59:28Z

Some platforms have separated the end-of-conversion information from the
usual ISR/IMR/IER/IDR registers, into EOC_ISR/EOC_IMR/EOC_IER/EOC_IDR.
To cope with both variants, helpers are being added, that will make
code more clear and more easy to read.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
---
drivers/iio/adc/at91-sama5d2_adc.c | 66 ++++++++++++++++++++++++++----
1 file changed, 59 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
index 8ede18b8d789..23be7cec063e 100644
--- a/drivers/iio/adc/at91-sama5d2_adc.c
+++ b/drivers/iio/adc/at91-sama5d2_adc.c
@@ -117,6 +117,14 @@ struct at91_adc_reg_layout {
u16 IMR;
/* Interrupt Status Register */
u16 ISR;
+/* End of Conversion Interrupt Enable Register */
+ u16 EOC_IER;
+/* End of Conversion Interrupt Disable Register */
+ u16 EOC_IDR;
+/* End of Conversion Interrupt Mask Register */
+ u16 EOC_IMR;
+/* End of Conversion Interrupt Status Register */
+ u16 EOC_ISR;
/* Interrupt Status Register - Pen touching sense status */
#define AT91_SAMA5D2_ISR_PENS BIT(31)
/* Last Channel Trigger Mode Register */
@@ -581,6 +589,44 @@ static unsigned int at91_adc_active_scan_mask_to_reg(struct iio_dev *indio_dev)
return mask & GENMASK(st->soc_info.platform->nr_channels, 0);
}

+static void at91_adc_irq_status(struct at91_adc_state *st, u32 *status,
+ u32 *eoc)
+{
+ *status = at91_adc_readl(st, ISR);
+ if (st->soc_info.platform->layout->EOC_ISR)
+ *eoc = at91_adc_readl(st, EOC_ISR);
+ else
+ *eoc = *status;
+}
+
+static void at91_adc_irq_mask(struct at91_adc_state *st, u32 *status, u32 *eoc)
+{
+ *status = at91_adc_readl(st, IMR);
+ if (st->soc_info.platform->layout->EOC_IMR)
+ *eoc = at91_adc_readl(st, EOC_IMR);
+ else
+ *eoc = *status;
+}
+
+static void at91_adc_eoc_dis(struct at91_adc_state *st, unsigned int channel)
+{
+ /*
+ * On some products having the EOC bits in a separate register,
+ * errata recommends not writing this register (EOC_IDR).
+ * On products having the EOC bits in the IDR register, it's fine to write it.
+ */
+ if (!st->soc_info.platform->layout->EOC_IDR)
+ at91_adc_writel(st, IDR, BIT(channel));
+}
+
+static void at91_adc_eoc_ena(struct at91_adc_state *st, unsigned int channel)
+{
+ if (!st->soc_info.platform->layout->EOC_IDR)
+ at91_adc_writel(st, IER, BIT(channel));
+ else
+ at91_adc_writel(st, EOC_IER, BIT(channel));
+}
+
static void at91_adc_config_emr(struct at91_adc_state *st)
{
/* configure the extended mode register */
@@ -1100,13 +1146,15 @@ static void at91_adc_trigger_handler_nodma(struct iio_dev *indio_dev,
u8 bit;
u32 mask = at91_adc_active_scan_mask_to_reg(indio_dev);
unsigned int timeout = 50;
+ u32 status, imr, eoc = 0, eoc_imr;

/*
* Check if the conversion is ready. If not, wait a little bit, and
* in case of timeout exit with an error.
*/
- while ((at91_adc_readl(st, ISR) & mask) != mask &&
- timeout) {
+ while (((eoc & mask) != mask) && timeout) {
+ at91_adc_irq_status(st, &status, &eoc);
+ at91_adc_irq_mask(st, &imr, &eoc_imr);
usleep_range(50, 100);
timeout--;
}
@@ -1342,12 +1390,14 @@ static irqreturn_t at91_adc_interrupt(int irq, void *private)
{
struct iio_dev *indio = private;
struct at91_adc_state *st = iio_priv(indio);
- u32 status = at91_adc_readl(st, ISR);
- u32 imr = at91_adc_readl(st, IMR);
+ u32 status, eoc, imr, eoc_imr;
u32 rdy_mask = AT91_SAMA5D2_IER_XRDY | AT91_SAMA5D2_IER_YRDY |
AT91_SAMA5D2_IER_PRDY;

- if (!(status & imr))
+ at91_adc_irq_status(st, &status, &eoc);
+ at91_adc_irq_mask(st, &imr, &eoc_imr);
+
+ if (!(status & imr) && !(eoc & eoc_imr))
return IRQ_NONE;
if (status & AT91_SAMA5D2_IER_PEN) {
/* pen detected IRQ */
@@ -1441,7 +1491,7 @@ static int at91_adc_read_info_raw(struct iio_dev *indio_dev,

at91_adc_writel(st, COR, cor);
at91_adc_writel(st, CHER, BIT(chan->channel));
- at91_adc_writel(st, IER, BIT(chan->channel));
+ at91_adc_eoc_ena(st, chan->channel);
at91_adc_writel(st, CR, AT91_SAMA5D2_CR_START);

ret = wait_event_interruptible_timeout(st->wq_data_available,
@@ -1458,7 +1508,7 @@ static int at91_adc_read_info_raw(struct iio_dev *indio_dev,
st->conversion_done = false;
}

- at91_adc_writel(st, IDR, BIT(chan->channel));
+ at91_adc_eoc_dis(st, st->chan->channel);
at91_adc_writel(st, CHDR, BIT(chan->channel));

/* Needed to ACK the DRDY interruption */
@@ -1676,6 +1726,8 @@ static void at91_adc_hw_init(struct iio_dev *indio_dev)
struct at91_adc_state *st = iio_priv(indio_dev);

at91_adc_writel(st, CR, AT91_SAMA5D2_CR_SWRST);
+ if (st->soc_info.platform->layout->EOC_IDR)
+ at91_adc_writel(st, EOC_IDR, 0xffffffff);
at91_adc_writel(st, IDR, 0xffffffff);
/*
* Transfer field must be set to 2 according to the datasheet and