[PATCH 3/5] spi: atmel-quadspi: add padcalib, 2xgclk, and dllon capabilities

[Dharma Balasubiramani <dharma.b@microchip.com>]

Introduce capability flags for SoC-specific variations of the QuadSPI
controller:

  - has_padcalib: controller supports pad calibration
  - has_2xgclk: requires GCLK at half the data rate (2x clocking)
  - has_dllon: controller supports DLL clock

Set `has_padcalib` for Octal controllers that provide pad calibration
support. Use `has_2xgclk` for controllers that require the GCLK to run
at twice the data rate. Differentiate SoC integration variants with the
`has_dllon` flag and set it as needed.

Signed-off-by: Varshini Rajendran <varshini.rajendran@microchip.com>
Signed-off-by: Dharma Balasubiramani <dharma.b@microchip.com>
---
 drivers/spi/atmel-quadspi.c | 92 +++++++++++++++++++++++++++++----------------
 1 file changed, 60 insertions(+), 32 deletions(-)

diff --git a/drivers/spi/atmel-quadspi.c b/drivers/spi/atmel-quadspi.c
index 4e9bfd26aa80..83cea5faff78 100644
--- a/drivers/spi/atmel-quadspi.c
+++ b/drivers/spi/atmel-quadspi.c
@@ -262,6 +262,9 @@ struct atmel_qspi_caps {
 	bool has_ricr;
 	bool octal;
 	bool has_dma;
+	bool has_2xgclk;
+	bool has_padcalib;
+	bool has_dllon;
 };
 
 struct atmel_qspi_ops;
@@ -1027,13 +1030,25 @@ static int atmel_qspi_set_pad_calibration(struct atmel_qspi *aq)
 			 aq, QSPI_PCALCFG);
 
 	/* DLL On + start calibration. */
-	atmel_qspi_write(QSPI_CR_DLLON | QSPI_CR_STPCAL, aq, QSPI_CR);
+	if (aq->caps->has_dllon)
+		atmel_qspi_write(QSPI_CR_DLLON | QSPI_CR_STPCAL, aq, QSPI_CR);
+	/* If there is no DLL support only start calibration. */
+	else
+		atmel_qspi_write(QSPI_CR_STPCAL, aq, QSPI_CR);
 
-	/* Check synchronization status before updating configuration. */
-	ret =  readl_poll_timeout(aq->regs + QSPI_SR2, val,
-				  (val & QSPI_SR2_DLOCK) &&
-				  !(val & QSPI_SR2_CALBSY), 40,
-				  ATMEL_QSPI_TIMEOUT);
+	/*
+	 * Check DLL clock lock and synchronization status before updating
+	 * configuration.
+	 */
+	if (aq->caps->has_dllon)
+		ret =  readl_poll_timeout(aq->regs + QSPI_SR2, val,
+					  (val & QSPI_SR2_DLOCK) &&
+					  !(val & QSPI_SR2_CALBSY), 40,
+					  ATMEL_QSPI_TIMEOUT);
+	else
+		ret =  readl_poll_timeout(aq->regs + QSPI_SR2, val,
+					  !(val & QSPI_SR2_CALBSY), 40,
+					  ATMEL_QSPI_TIMEOUT);
 
 	/* Refresh analogic blocks every 1 ms.*/
 	atmel_qspi_write(FIELD_PREP(QSPI_REFRESH_DELAY_COUNTER,
@@ -1049,23 +1064,28 @@ static int atmel_qspi_set_gclk(struct atmel_qspi *aq)
 	int ret;
 
 	/* Disable DLL before setting GCLK */
-	status = atmel_qspi_read(aq, QSPI_SR2);
-	if (status & QSPI_SR2_DLOCK) {
-		atmel_qspi_write(QSPI_CR_DLLOFF, aq, QSPI_CR);
+	if (aq->caps->has_dllon) {
+		status = atmel_qspi_read(aq, QSPI_SR2);
+		if (status & QSPI_SR2_DLOCK) {
+			atmel_qspi_write(QSPI_CR_DLLOFF, aq, QSPI_CR);
+			ret = readl_poll_timeout(aq->regs + QSPI_SR2, val,
+						 !(val & QSPI_SR2_DLOCK), 40,
+						 ATMEL_QSPI_TIMEOUT);
+			if (ret)
+				return ret;
+		}
 
-		ret = readl_poll_timeout(aq->regs + QSPI_SR2, val,
-					 !(val & QSPI_SR2_DLOCK), 40,
-					 ATMEL_QSPI_TIMEOUT);
-		if (ret)
-			return ret;
+		if (aq->target_max_speed_hz > QSPI_DLLCFG_THRESHOLD_FREQ)
+			atmel_qspi_write(QSPI_DLLCFG_RANGE, aq, QSPI_DLLCFG);
+		else
+			atmel_qspi_write(0, aq, QSPI_DLLCFG);
 	}
 
-	if (aq->target_max_speed_hz > QSPI_DLLCFG_THRESHOLD_FREQ)
-		atmel_qspi_write(QSPI_DLLCFG_RANGE, aq, QSPI_DLLCFG);
+	if (aq->caps->has_2xgclk)
+		ret = clk_set_rate(aq->gclk, 2 * aq->target_max_speed_hz);
 	else
-		atmel_qspi_write(0, aq, QSPI_DLLCFG);
+		ret = clk_set_rate(aq->gclk, aq->target_max_speed_hz);
 
-	ret = clk_set_rate(aq->gclk, aq->target_max_speed_hz);
 	if (ret) {
 		dev_err(&aq->pdev->dev, "Failed to set generic clock rate.\n");
 		return ret;
@@ -1088,11 +1108,16 @@ static int atmel_qspi_sama7g5_init(struct atmel_qspi *aq)
 	if (ret)
 		return ret;
 
-	if (aq->caps->octal) {
+	/*
+	 * Check if the SoC supports pad calibration in Octal SPI mode.
+	 * Proceed only if both the capabilities are true.
+	 */
+	if (aq->caps->octal && aq->caps->has_padcalib) {
 		ret = atmel_qspi_set_pad_calibration(aq);
 		if (ret)
 			return ret;
-	} else {
+	/* Start DLL on only if the SoC supports the same */
+	} else if (aq->caps->has_dllon) {
 		atmel_qspi_write(QSPI_CR_DLLON, aq, QSPI_CR);
 		ret =  readl_poll_timeout(aq->regs + QSPI_SR2, val,
 					  (val & QSPI_SR2_DLOCK), 40,
@@ -1458,19 +1483,19 @@ static int atmel_qspi_sama7g5_suspend(struct atmel_qspi *aq)
 
 	clk_disable_unprepare(aq->gclk);
 
-	atmel_qspi_write(QSPI_CR_DLLOFF, aq, QSPI_CR);
-	ret = readl_poll_timeout(aq->regs + QSPI_SR2, val,
-				 !(val & QSPI_SR2_DLOCK), 40,
-				 ATMEL_QSPI_TIMEOUT);
-	if (ret)
-		return ret;
-
-	ret =  readl_poll_timeout(aq->regs + QSPI_SR2, val,
-				  !(val & QSPI_SR2_CALBSY), 40,
-				  ATMEL_QSPI_TIMEOUT);
-	if (ret)
-		return ret;
+	if (aq->caps->has_dllon) {
+		atmel_qspi_write(QSPI_CR_DLLOFF, aq, QSPI_CR);
+		ret = readl_poll_timeout(aq->regs + QSPI_SR2, val,
+					 !(val & QSPI_SR2_DLOCK), 40,
+					 ATMEL_QSPI_TIMEOUT);
+		if (ret)
+			return ret;
+	}
 
+	if (aq->caps->has_padcalib)
+		return readl_poll_timeout(aq->regs + QSPI_SR2, val,
+					  !(val & QSPI_SR2_CALBSY), 40,
+					  ATMEL_QSPI_TIMEOUT);
 	return 0;
 }
 
@@ -1607,12 +1632,15 @@ static const struct atmel_qspi_caps atmel_sama7g5_ospi_caps = {
 	.has_gclk = true,
 	.octal = true,
 	.has_dma = true,
+	.has_padcalib = true,
+	.has_dllon = true,
 };
 
 static const struct atmel_qspi_caps atmel_sama7g5_qspi_caps = {
 	.max_speed_hz = SAMA7G5_QSPI1_SDR_MAX_SPEED_HZ,
 	.has_gclk = true,
 	.has_dma = true,
+	.has_dllon = true,
 };
 
 static const struct of_device_id atmel_qspi_dt_ids[] = {

-- 
2.43.0