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Groups > linux.kernel > #1486705

[PATCH 25/26] drm/rockchip: dw-mipi-dsi: add reset control

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In order to fully reset the state of the MIPI controller we must assert
this reset.

This is slightly more complicated than it could be in order to maintain
compatibility with device trees that do not specify the reset property.

Signed-off-by: John Keeping <john@metanate.com>
---
 drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
index d93e620adea6..d0b2f6e9517d 100644
--- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/regmap.h>
+#include <linux/reset.h>
 #include <linux/mfd/syscon.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc.h>
@@ -1134,6 +1135,7 @@ static int dw_mipi_dsi_bind(struct device *dev, struct device *master,
 			of_match_device(dw_mipi_dsi_dt_ids, dev);
 	const struct dw_mipi_dsi_plat_data *pdata = of_id->data;
 	struct platform_device *pdev = to_platform_device(dev);
+	struct reset_control *apb_rst;
 	struct drm_device *drm = data;
 	struct dw_mipi_dsi *dsi;
 	struct resource *res;
@@ -1172,6 +1174,34 @@ static int dw_mipi_dsi_bind(struct device *dev, struct device *master,
 		return ret;
 	}
 
+	/*
+	 * Note that the reset was not defined in the initial device tree, so
+	 * we have to be prepared for it not being found.
+	 */
+	apb_rst = devm_reset_control_get(dev, "apb");
+	if (IS_ERR(apb_rst)) {
+		if (PTR_ERR(apb_rst) == -ENODEV) {
+			apb_rst = NULL;
+		} else {
+			dev_err(dev, "Unable to get reset control: %d\n", ret);
+			return PTR_ERR(apb_rst);
+		}
+	}
+
+	if (apb_rst) {
+		ret = clk_prepare_enable(dsi->pclk);
+		if (ret) {
+			dev_err(dev, "%s: Failed to enable pclk\n", __func__);
+			return ret;
+		}
+
+		reset_control_assert(apb_rst);
+		usleep_range(10, 20);
+		reset_control_deassert(apb_rst);
+
+		clk_disable_unprepare(dsi->pclk);
+	}
+
 	ret = clk_prepare_enable(dsi->pllref_clk);
 	if (ret) {
 		dev_err(dev, "%s: Failed to enable pllref_clk\n", __func__);
-- 
2.10.0.278.g4f427b1.dirty

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[PATCH 00/27] drm/rockchip: MIPI fixes & improvements John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 07/26] drm/rockchip: dw-mipi-dsi: avoid out-of-bounds read on tx_buf John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 15/26] drm/rockchip: dw-mipi-dsi: ensure PHY is reset John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 14/26] drm/rockchip: dw-mipi-dsi: fix escape clock rate John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 21/27] drm/rockchip: dw-mipi-dsi: improve PLL configuration John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 09/26] drm/rockchip: dw-mipi-dsi: respect message flags John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 22/26] drm/rockchip: vop: test for P{H,V}SYNC John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 18/26] drm/rockchip: dw-mipi-dsi: properly configure PHY timing John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 11/26] drm/rockchip: dw-mipi-dsi: don't assume buffer is aligned John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 15/27] drm/rockchip: dw-mipi-dsi: use positive check for N{H,V}SYNC John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 22/27] drm/rockchip: dw-mipi-dsi: defer probe if panel is not loaded John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 18/27] drm/rockchip: dw-mipi-dsi: configure bias and bandgap before enable John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 25/26] drm/rockchip: dw-mipi-dsi: add reset control John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 16/26] drm/rockchip: dw-mipi-dsi: configure bias and bandgap before enable John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  Re: [PATCH 00/27] drm/rockchip: MIPI fixes & improvements John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 02/26] drm/rockchip: dw-mipi-dsi: pass new mode into MIPI mode set John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 14/27] drm/rockchip: dw-mipi-dsi: use specific poll helper John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 20/27] drm/rockchip: dw-mipi-dsi: properly configure PHY timing John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 23/26] drm/rockchip: dw-mipi-dsi: defer probe if panel is not loaded John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 16/27] drm/rockchip: dw-mipi-dsi: fix escape clock rate John Keeping <john@metanate.com> - 2016-09-19 19:30 +0200
  [PATCH 24/26] drm/rockchip: dw-mipi-dsi: support non-burst modes John Keeping <john@metanate.com> - 2016-09-19 19:40 +0200
  [PATCH 23/27] drm/rockchip: dw-mipi-dsi: support non-burst modes John Keeping <john@metanate.com> - 2016-09-19 19:40 +0200
  [PATCH 24/27] drm/rockchip: vop: test for P{H,V}SYNC John Keeping <john@metanate.com> - 2016-09-19 19:40 +0200

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