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Groups > linux.kernel > #1569213

[PATCH v3 23/24] 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>
Reviewed-by: Chris Zhong <zyw@rock-chips.com>
---
v3:
- Add Chris' Reviewed-by
Unchanged in v2

 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 58cb8ace2fe8..cf3ca6b0cbdb 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>
@@ -1124,6 +1125,7 @@ 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;
@@ -1162,6 +1164,34 @@ 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__);
-- 
2.11.0.197.gb556de5.dirty

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Thread

[PATCH v3 00/24] drm/rockchip: MIPI fixes & improvements John Keeping <john@metanate.com> - 2017-01-29 15:10 +0100
  [PATCH v3 08/24] drm/rockchip: dw-mipi-dsi: respect message flags John Keeping <john@metanate.com> - 2017-01-29 15:10 +0100
    Re: [PATCH v3 08/24] drm/rockchip: dw-mipi-dsi: respect message flags Sean Paul <seanpaul@chromium.org> - 2017-01-30 19:30 +0100
  [PATCH v3 01/24] drm/rockchip: dw-mipi-dsi: don't configure hardware in mode_set for MIPI John Keeping <john@metanate.com> - 2017-01-29 15:10 +0100
    Re: [PATCH v3 01/24] drm/rockchip: dw-mipi-dsi: don't configure  hardware in mode_set for MIPI Sean Paul <seanpaul@chromium.org> - 2017-01-30 16:40 +0100
  [PATCH v3 24/24] drm/rockchip: dw-mipi-dsi: support read commands John Keeping <john@metanate.com> - 2017-01-29 15:50 +0100
    Re: [PATCH v3 24/24] drm/rockchip: dw-mipi-dsi: support read commands Sean Paul <seanpaul@chromium.org> - 2017-01-30 16:40 +0100
      Re: [PATCH v3 24/24] drm/rockchip: dw-mipi-dsi: support read  commands John Keeping <john@metanate.com> - 2017-01-30 19:40 +0100
  [PATCH v3 11/24] drm/rockchip: dw-mipi-dsi: prepare panel after phy init John Keeping <john@metanate.com> - 2017-01-29 15:50 +0100
  [PATCH v3 05/24] drm/rockchip: dw-mipi-dsi: fix generic packet status check John Keeping <john@metanate.com> - 2017-01-29 15:50 +0100
    Re: [PATCH v3 05/24] drm/rockchip: dw-mipi-dsi: fix generic packet  status check Sean Paul <seanpaul@chromium.org> - 2017-01-30 19:30 +0100
  [PATCH v3 07/24] drm/rockchip: dw-mipi-dsi: include bad value in error message John Keeping <john@metanate.com> - 2017-01-29 15:50 +0100
    Re: [PATCH v3 07/24] drm/rockchip: dw-mipi-dsi: include bad value in  error message Sean Paul <seanpaul@chromium.org> - 2017-01-30 19:10 +0100
  [PATCH v3 20/24] drm/rockchip: vop: test for P{H,V}SYNC John Keeping <john@metanate.com> - 2017-01-29 15:50 +0100
  [PATCH v3 12/24] drm/rockchip: dw-mipi-dsi: allow commands in panel_disable John Keeping <john@metanate.com> - 2017-01-29 15:50 +0100
  [PATCH v3 13/24] drm/rockchip: dw-mipi-dsi: fix escape clock rate John Keeping <john@metanate.com> - 2017-01-29 15:50 +0100
  [PATCH v3 18/24] drm/rockchip: dw-mipi-dsi: use specific poll helper John Keeping <john@metanate.com> - 2017-01-29 15:50 +0100
  [PATCH v3 04/24] drm/rockchip: dw-mipi-dsi: fix command header writes John Keeping <john@metanate.com> - 2017-01-29 15:50 +0100
    Re: [PATCH v3 04/24] drm/rockchip: dw-mipi-dsi: fix command header  writes Sean Paul <seanpaul@chromium.org> - 2017-01-30 17:00 +0100
  [PATCH v3 15/24] drm/rockchip: dw-mipi-dsi: configure PHY before enabling John Keeping <john@metanate.com> - 2017-01-29 15:50 +0100
  [PATCH v3 19/24] drm/rockchip: dw-mipi-dsi: use positive check for N{H,V}SYNC John Keeping <john@metanate.com> - 2017-01-29 16:20 +0100
  [PATCH v3 17/24] drm/rockchip: dw-mipi-dsi: improve PLL configuration John Keeping <john@metanate.com> - 2017-01-29 16:20 +0100
  [PATCH v3 23/24] drm/rockchip: dw-mipi-dsi: add reset control John Keeping <john@metanate.com> - 2017-01-29 16:30 +0100
  [PATCH v3 03/24] drm/rockchip: dw-mipi-dsi: remove mode_set hook John Keeping <john@metanate.com> - 2017-01-29 16:30 +0100
    Re: [PATCH v3 03/24] drm/rockchip: dw-mipi-dsi: remove mode_set hook Sean Paul <seanpaul@chromium.org> - 2017-01-30 16:50 +0100
  [PATCH v3 22/24] drm/rockchip: dw-mipi-dsi: support non-burst modes John Keeping <john@metanate.com> - 2017-01-29 16:30 +0100

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