[PATCH v9 06/16] drm/imx: dc: Flag CRTC status in GENERALPURPOSE register

[Liu Ying]

Map Display Controller's register GENERALPURPOSE at offset 0x100 and
create an MMIO regmap to access the register.  Create helpers
dc_drv_flag_crtc_{enable,disable}() with the 2 LSB bits in the register
to flag the CRTC enablement/disablement status.  Also, create a helper
dc_drv_crtc_is_enabled() so that the CRTC driver can use it to check
if the CRTC is enabled by a previous boot or not.  This is a preparation
for an upcoming patch to disable display controller at boot if the CRTC
was enabled by the driver during a previous boot instead of a bootloader.

Reviewed-by: Laurentiu Palcu <laurentiu.palcu at oss.nxp.com>
Signed-off-by: Liu Ying <victor.liu at nxp.com>
---
v9:
- Fix typos in patch subject and commit message.  (Sashiko AI bot)
- Set .max_register_is_0 = true in dc_gp_regmap_config.  (Sashiko AI bot)

v8:
- Rename dc_drv_crtc_was_enabled() to dc_drv_crtc_is_enabled().  (Laurentiu)
- Use dev_err_probe() to handle errors returned from several function calls.
  (Laurentiu)
- Collect Laurentiu's R-b tag.

v7:
- Newly introduced in v7 as a preparation for fixing Sashiko AI bot's
  comment on an upcoming patch.  (Sashiko AI bot)
---
 drivers/gpu/drm/imx/dc/dc-drv.c | 76 +++++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/imx/dc/dc-drv.h |  7 ++++
 2 files changed, 83 insertions(+)

diff --git a/drivers/gpu/drm/imx/dc/dc-drv.c b/drivers/gpu/drm/imx/dc/dc-drv.c
index 13795a2ad735..4c0749e5aa09 100644
--- a/drivers/gpu/drm/imx/dc/dc-drv.c
+++ b/drivers/gpu/drm/imx/dc/dc-drv.c
@@ -13,6 +13,7 @@
 #include <linux/platform_device.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
+#include <linux/regmap.h>
 
 #include <drm/clients/drm_client_setup.h>
 #include <drm/drm_atomic_helper.h>
@@ -28,9 +29,22 @@
 #include "dc-drv.h"
 #include "dc-pe.h"
 
+/* General Purpose register offset used to flag driver usage. */
+#define GENERALPURPOSE		0x100
+#define  CRTC_ENABLED(x)	BIT(x)
+
 struct dc_priv {
 	struct drm_device *drm;
 	struct clk *clk_cfg;
+	struct regmap *gp_regmap;
+};
+
+static const struct regmap_config dc_gp_regmap_config = {
+	.reg_bits = 32,
+	.reg_stride = 4,
+	.val_bits = 32,
+	.max_register = 0,
+	.max_register_is_0 = true,
 };
 
 DEFINE_DRM_GEM_DMA_FOPS(dc_drm_driver_fops);
@@ -156,6 +170,8 @@ static int dc_probe(struct platform_device *pdev)
 {
 	struct component_match *match = NULL;
 	struct dc_priv *priv;
+	struct resource *r;
+	void __iomem *base;
 	int ret;
 
 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
@@ -167,6 +183,27 @@ static int dc_probe(struct platform_device *pdev)
 		return dev_err_probe(&pdev->dev, PTR_ERR(priv->clk_cfg),
 				     "failed to get cfg clock\n");
 
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!r)
+		return dev_err_probe(&pdev->dev, -EINVAL,
+				     "failed to get MEM IO resource\n");
+
+	if (!devm_request_mem_region(&pdev->dev, r->start + GENERALPURPOSE, 4,
+				     dev_name(&pdev->dev)))
+		return dev_err_probe(&pdev->dev, -EBUSY,
+				     "failed to request memory region\n");
+
+	base = devm_ioremap(&pdev->dev, r->start + GENERALPURPOSE, 4);
+	if (!base)
+		return dev_err_probe(&pdev->dev, -ENOMEM,
+				     "failed to do ioremap\n");
+
+	priv->gp_regmap = devm_regmap_init_mmio(&pdev->dev, base,
+						&dc_gp_regmap_config);
+	if (IS_ERR(priv->gp_regmap))
+		return dev_err_probe(&pdev->dev, PTR_ERR(priv->gp_regmap),
+				     "failed to init General Purpose regmap\n");
+
 	dev_set_drvdata(&pdev->dev, priv);
 
 	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
@@ -196,6 +233,45 @@ static void dc_remove(struct platform_device *pdev)
 	component_master_del(&pdev->dev, &dc_drm_ops);
 }
 
+void dc_drv_set_crtc_enable(struct dc_drm_device *dc_drm,
+			    unsigned int crtc_index)
+{
+	struct dc_priv *priv = dev_get_drvdata(dc_drm->base.dev);
+
+	if (WARN_ON(crtc_index > 1))
+		return;
+
+	regmap_set_bits(priv->gp_regmap, 0, CRTC_ENABLED(crtc_index));
+}
+
+void dc_drv_set_crtc_disable(struct dc_drm_device *dc_drm,
+			     unsigned int crtc_index)
+{
+	struct dc_priv *priv = dev_get_drvdata(dc_drm->base.dev);
+
+	if (WARN_ON(crtc_index > 1))
+		return;
+
+	regmap_clear_bits(priv->gp_regmap, 0, CRTC_ENABLED(crtc_index));
+}
+
+bool dc_drv_crtc_is_enabled(struct dc_drm_device *dc_drm,
+			    unsigned int crtc_index)
+{
+	struct dc_priv *priv = dev_get_drvdata(dc_drm->base.dev);
+	unsigned int val;
+	int ret;
+
+	if (WARN_ON(crtc_index > 1))
+		return false;
+
+	ret = regmap_read(priv->gp_regmap, 0, &val);
+	if (ret)
+		return false;
+
+	return !!(val & CRTC_ENABLED(crtc_index));
+}
+
 static int dc_runtime_suspend(struct device *dev)
 {
 	struct dc_priv *priv = dev_get_drvdata(dev);
diff --git a/drivers/gpu/drm/imx/dc/dc-drv.h b/drivers/gpu/drm/imx/dc/dc-drv.h
index eb61b8c76269..8283795f3c76 100644
--- a/drivers/gpu/drm/imx/dc/dc-drv.h
+++ b/drivers/gpu/drm/imx/dc/dc-drv.h
@@ -99,4 +99,11 @@ static inline int dc_subdev_get_id(const struct dc_subdev_info *info,
 void dc_de_post_bind(struct dc_drm_device *dc_drm);
 void dc_pe_post_bind(struct dc_drm_device *dc_drm);
 
+void dc_drv_set_crtc_enable(struct dc_drm_device *dc_drm,
+			    unsigned int crtc_index);
+void dc_drv_set_crtc_disable(struct dc_drm_device *dc_drm,
+			     unsigned int crtc_index);
+bool dc_drv_crtc_is_enabled(struct dc_drm_device *dc_drm,
+			    unsigned int crtc_index);
+
 #endif /* __DC_DRV_H__ */

-- 
2.43.0