As ospi reset is consumed by both OMM and OSPI drivers, use the reset
acquire/release mechanism which ensure exclusive reset usage.

This avoid to call reset_control_get/put() in OMM driver each time
we need to reset OSPI children and guarantee the reset line stays
deasserted.

During resume, OMM driver takes temporarily control of reset.

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
---
Changes in v4:
  - Add a comment about reset sharing between OSPI and OMM drivers durig resume.
  - Link to v3: https://lore.kernel.org/r/20250507-b4-upstream_ospi_reset_update-v3-1-7e46a8797572@foss.st.com

Changes in v3:
  - Remove previous patch 1/2 as already merged.
  - Keep the reset control acquired from probe() to remove().
  - Link to v2: https://lore.kernel.org/r/20250411-b4-upstream_ospi_reset_update-v2-0-4de7f5dd2a91@foss.st.com

Changes in v2:
  - Rebased on spi/for-next (7a978d8fcf57).
  - Remove useless check on reset.
  - Add error handling on reset_control_acquire().
  - Link to v1: https://lore.kernel.org/all/20250410-b4-upstream_ospi_reset_update-v1-0-74126a8ceb9c@foss.st.com/
---
 drivers/spi/spi-stm32-ospi.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi-stm32-ospi.c b/drivers/spi/spi-stm32-ospi.c
index 668022098b1eac3628f0677e6d786e5a267346be..b2597b52beb1133155e0d6f601b0632ad4b8e8f5 100644
--- a/drivers/spi/spi-stm32-ospi.c
+++ b/drivers/spi/spi-stm32-ospi.c
@@ -804,7 +804,7 @@ static int stm32_ospi_get_resources(struct platform_device *pdev)
 		return ret;
 	}
 
-	ospi->rstc = devm_reset_control_array_get_optional_exclusive(dev);
+	ospi->rstc = devm_reset_control_array_get_exclusive_released(dev);
 	if (IS_ERR(ospi->rstc))
 		return dev_err_probe(dev, PTR_ERR(ospi->rstc),
 				     "Can't get reset\n");
@@ -936,11 +936,13 @@ static int stm32_ospi_probe(struct platform_device *pdev)
 	if (ret < 0)
 		goto err_pm_enable;
 
-	if (ospi->rstc) {
-		reset_control_assert(ospi->rstc);
-		udelay(2);
-		reset_control_deassert(ospi->rstc);
-	}
+	ret = reset_control_acquire(ospi->rstc);
+	if (ret)
+		return dev_err_probe(dev, ret, "Can not acquire reset %d\n", ret);
+
+	reset_control_assert(ospi->rstc);
+	udelay(2);
+	reset_control_deassert(ospi->rstc);
 
 	ret = spi_register_controller(ctrl);
 	if (ret) {
@@ -983,6 +985,8 @@ static void stm32_ospi_remove(struct platform_device *pdev)
 	if (ospi->dma_chrx)
 		dma_release_channel(ospi->dma_chrx);
 
+	reset_control_release(ospi->rstc);
+
 	pm_runtime_put_sync_suspend(ospi->dev);
 	pm_runtime_force_suspend(ospi->dev);
 }
@@ -993,6 +997,8 @@ static int __maybe_unused stm32_ospi_suspend(struct device *dev)
 
 	pinctrl_pm_select_sleep_state(dev);
 
+	reset_control_release(ospi->rstc);
+
 	return pm_runtime_force_suspend(ospi->dev);
 }
 
@@ -1012,6 +1018,12 @@ static int __maybe_unused stm32_ospi_resume(struct device *dev)
 	if (ret < 0)
 		return ret;
 
+	ret = reset_control_acquire(ospi->rstc);
+	if (ret) {
+		dev_err(dev, "Can not acquire reset\n");
+		return ret;
+	}
+
 	writel_relaxed(ospi->cr_reg, regs_base + OSPI_CR);
 	writel_relaxed(ospi->dcr_reg, regs_base + OSPI_DCR1);
 	pm_runtime_mark_last_busy(ospi->dev);

---
base-commit: 1c64de886b8893c0158097edd6ba08d527a2c97a
change-id: 20250411-b4-upstream_ospi_reset_update-596ce245ada1

Best regards,
-- 
Patrice Chotard <patrice.chotard@foss.st.com>

On Mon, May 12, 2025 at 09:01:04AM +0200, Patrice Chotard wrote:
> As ospi reset is consumed by both OMM and OSPI drivers, use the reset
> acquire/release mechanism which ensure exclusive reset usage.

This doesn't apply against current code, please check and resend.

On 5/12/25 14:11, Mark Brown wrote:
> On Mon, May 12, 2025 at 09:01:04AM +0200, Patrice Chotard wrote:
>> As ospi reset is consumed by both OMM and OSPI drivers, use the reset
>> acquire/release mechanism which ensure exclusive reset usage.
> 
> This doesn't apply against current code, please check and resend.

Hi Mark

This patch has been submitted on top of reset tag reset-for-v6.16
due to dependency with new reset API devm_reset_control_array_get_exclusive_released().

How do you want to proceed ? Philipp can take it on its reset tree ?

Patrice

On Tue, May 13, 2025 at 11:47:16AM +0200, Patrice CHOTARD wrote:
> On 5/12/25 14:11, Mark Brown wrote:

> > This doesn't apply against current code, please check and resend.

> This patch has been submitted on top of reset tag reset-for-v6.16
> due to dependency with new reset API devm_reset_control_array_get_exclusive_released().

> How do you want to proceed ? Philipp can take it on its reset tree ?

There was no mention about the dependency in the patch, please resend
with information about this tag included.