| Message ID | 20170224125506.21533-24-john@metanate.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
+ devicetree Hi, On Fri, Feb 24, 2017 at 12:55:06PM +0000, John Keeping wrote: > 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> > --- > v4: > - Fix error check for devm_reset_control_get() to use ENOENT > v3: > - Add Chris' Reviewed-by > Unchanged in v2 > --- > drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 31 +++++++++++++++++++++++++++++++ > 1 file changed, 31 insertions(+) > > diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c > index 0c4bae711e84..30da75667334 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> > @@ -1144,6 +1145,7 @@ 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; > @@ -1182,6 +1184,35 @@ 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"); Did this reset ever get documented in the device tree bindings? I couldn't find it. Perhaps a follow-up patch is in order? [...] Brian
Oh, one more thing: On Fri, Feb 24, 2017 at 12:55:06PM +0000, John Keeping wrote: > diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c > index 0c4bae711e84..30da75667334 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> > @@ -1144,6 +1145,7 @@ 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; > @@ -1182,6 +1184,35 @@ 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)) { > + ret = PTR_ERR(apb_rst); > + if (ret == -ENOENT) { > + apb_rst = NULL; > + } else { > + dev_err(dev, "Unable to get reset control: %d\n", ret); Might want to check for -EPROBE_DEFER before printing an error? Brian > + return ret; > + } > + } > + > + 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__);
diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c index 0c4bae711e84..30da75667334 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> @@ -1144,6 +1145,7 @@ 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; @@ -1182,6 +1184,35 @@ 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)) { + ret = PTR_ERR(apb_rst); + if (ret == -ENOENT) { + apb_rst = NULL; + } else { + dev_err(dev, "Unable to get reset control: %d\n", ret); + return ret; + } + } + + 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__);