[PATCH v4 4/9] drm: renesas: rzg2l_mipi_dsi: Add support for DSI PWRRDY

[Biju]

From: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>

The register for controlling power to the DSI region is in the SYSC
(System Controller) block. Add support for controlling the DSI PWRRDY
signal so the driver can efficiently manage power to the DSI region.

Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
---
v3->v4:
 * Dropped pwrrdy variable from struct rzg2l_mipi_dsi_hw_info and instead
   using feature flag RZ_MIPI_DSI_FEATURE_PWRRDY
 * Dropped rzg2l_mipi_dsi_pwrrdy_off() as it is taken care by
   devm_pwrseq_get(). 
v2->v3:
 * Updated powerseq API names.
v1->v2:
 * Switched to power sequence for handling pwrrdy signal.
 * Dropped header file regmap.h and mfd/syscon.h
 * Added header file pwrseq/consumer.h
---
 .../gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c    | 27 +++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
index d67e1230b70c..5263b2b8f1ca 100644
--- a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
+++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
@@ -18,6 +18,7 @@
 #include <linux/of_graph.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/pwrseq/consumer.h>
 #include <linux/reset.h>
 #include <linux/slab.h>
 #include <linux/units.h>
@@ -38,6 +39,7 @@ MODULE_IMPORT_NS("RZV2H_CPG");
 #define RZG2L_DCS_BUF_SIZE	128 /* Maximum DCS buffer size in external memory. */
 
 #define RZ_MIPI_DSI_FEATURE_16BPP	BIT(0)
+#define RZ_MIPI_DSI_FEATURE_PWRRDY	BIT(1)
 
 struct rzg2l_mipi_dsi;
 
@@ -87,6 +89,8 @@ struct rzg2l_mipi_dsi {
 	struct clk *vclk;
 	struct clk *lpclk;
 
+	struct pwrseq_desc *pwrseq;
+
 	enum mipi_dsi_pixel_format format;
 	unsigned int num_data_lanes;
 	unsigned int lanes;
@@ -1396,6 +1400,25 @@ static const struct dev_pm_ops rzg2l_mipi_pm_ops = {
  * Probe & Remove
  */
 
+static int rzg2l_mipi_dsi_pwrrdy_init(struct rzg2l_mipi_dsi *dsi)
+{
+	if (!(dsi->info->features & RZ_MIPI_DSI_FEATURE_PWRRDY))
+		return 0;
+
+	dsi->pwrseq = devm_pwrseq_get(dsi->dev, "dsi-pwrrdy");
+	if (IS_ERR(dsi->pwrseq)) {
+		/*
+		 * This platform requires a sequencer. If we can't get it, we
+		 * must return the error (including -EPROBE_DEFER to wait for
+		 * the provider to appear)
+		 */
+		return dev_err_probe(dsi->dev, PTR_ERR(dsi->pwrseq),
+				     "Failed to get required power sequencer\n");
+	}
+
+	return pwrseq_enable(dsi->pwrseq);
+}
+
 static int rzg2l_mipi_dsi_probe(struct platform_device *pdev)
 {
 	unsigned int num_data_lanes;
@@ -1454,6 +1477,10 @@ static int rzg2l_mipi_dsi_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, dsi);
 
+	ret = rzg2l_mipi_dsi_pwrrdy_init(dsi);
+	if (ret)
+		return ret;
+
 	pm_runtime_enable(dsi->dev);
 
 	ret = pm_runtime_resume_and_get(dsi->dev);
-- 
2.43.0