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path: root/drivers/gpu/drm/tiny/simpledrm.c
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Diffstat (limited to 'drivers/gpu/drm/tiny/simpledrm.c')
-rw-r--r--drivers/gpu/drm/tiny/simpledrm.c105
1 files changed, 105 insertions, 0 deletions
diff --git a/drivers/gpu/drm/tiny/simpledrm.c b/drivers/gpu/drm/tiny/simpledrm.c
index 8ea120eb86..5fefc895bc 100644
--- a/drivers/gpu/drm/tiny/simpledrm.c
+++ b/drivers/gpu/drm/tiny/simpledrm.c
@@ -6,6 +6,7 @@
#include <linux/of_address.h>
#include <linux/platform_data/simplefb.h>
#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
#include <linux/regulator/consumer.h>
#include <drm/drm_aperture.h>
@@ -227,6 +228,12 @@ struct simpledrm_device {
unsigned int regulator_count;
struct regulator **regulators;
#endif
+ /* power-domains */
+#if defined CONFIG_OF && defined CONFIG_PM_GENERIC_DOMAINS
+ int pwr_dom_count;
+ struct device **pwr_dom_devs;
+ struct device_link **pwr_dom_links;
+#endif
/* simplefb settings */
struct drm_display_mode mode;
@@ -468,6 +475,101 @@ static int simpledrm_device_init_regulators(struct simpledrm_device *sdev)
}
#endif
+#if defined CONFIG_OF && defined CONFIG_PM_GENERIC_DOMAINS
+/*
+ * Generic power domain handling code.
+ *
+ * Here we handle the power-domains properties of our "simple-framebuffer"
+ * dt node. This is only necessary if there is more than one power-domain.
+ * A single power-domains is handled automatically by the driver core. Multiple
+ * power-domains have to be handled by drivers since the driver core can't know
+ * the correct power sequencing. Power sequencing is not an issue for simpledrm
+ * since the bootloader has put the power domains already in the correct state.
+ * simpledrm has only to ensure they remain active for its lifetime.
+ *
+ * When the driver unloads, we detach from the power-domains.
+ *
+ * We only complain about errors here, no action is taken as the most likely
+ * error can only happen due to a mismatch between the bootloader which set
+ * up the "simple-framebuffer" dt node, and the PM domain providers in the
+ * device tree. Chances are that there are no adverse effects, and if there are,
+ * a clean teardown of the fb probe will not help us much either. So just
+ * complain and carry on, and hope that the user actually gets a working fb at
+ * the end of things.
+ */
+static void simpledrm_device_detach_genpd(void *res)
+{
+ int i;
+ struct simpledrm_device *sdev = res;
+
+ if (sdev->pwr_dom_count <= 1)
+ return;
+
+ for (i = sdev->pwr_dom_count - 1; i >= 0; i--) {
+ if (sdev->pwr_dom_links[i])
+ device_link_del(sdev->pwr_dom_links[i]);
+ if (!IS_ERR_OR_NULL(sdev->pwr_dom_devs[i]))
+ dev_pm_domain_detach(sdev->pwr_dom_devs[i], true);
+ }
+}
+
+static int simpledrm_device_attach_genpd(struct simpledrm_device *sdev)
+{
+ struct device *dev = sdev->dev.dev;
+ int i;
+
+ sdev->pwr_dom_count = of_count_phandle_with_args(dev->of_node, "power-domains",
+ "#power-domain-cells");
+ /*
+ * Single power-domain devices are handled by driver core nothing to do
+ * here. The same for device nodes without "power-domains" property.
+ */
+ if (sdev->pwr_dom_count <= 1)
+ return 0;
+
+ sdev->pwr_dom_devs = devm_kcalloc(dev, sdev->pwr_dom_count,
+ sizeof(*sdev->pwr_dom_devs),
+ GFP_KERNEL);
+ if (!sdev->pwr_dom_devs)
+ return -ENOMEM;
+
+ sdev->pwr_dom_links = devm_kcalloc(dev, sdev->pwr_dom_count,
+ sizeof(*sdev->pwr_dom_links),
+ GFP_KERNEL);
+ if (!sdev->pwr_dom_links)
+ return -ENOMEM;
+
+ for (i = 0; i < sdev->pwr_dom_count; i++) {
+ sdev->pwr_dom_devs[i] = dev_pm_domain_attach_by_id(dev, i);
+ if (IS_ERR(sdev->pwr_dom_devs[i])) {
+ int ret = PTR_ERR(sdev->pwr_dom_devs[i]);
+ if (ret == -EPROBE_DEFER) {
+ simpledrm_device_detach_genpd(sdev);
+ return ret;
+ }
+ drm_warn(&sdev->dev,
+ "pm_domain_attach_by_id(%u) failed: %d\n", i, ret);
+ continue;
+ }
+
+ sdev->pwr_dom_links[i] = device_link_add(dev,
+ sdev->pwr_dom_devs[i],
+ DL_FLAG_STATELESS |
+ DL_FLAG_PM_RUNTIME |
+ DL_FLAG_RPM_ACTIVE);
+ if (!sdev->pwr_dom_links[i])
+ drm_warn(&sdev->dev, "failed to link power-domain %d\n", i);
+ }
+
+ return devm_add_action_or_reset(dev, simpledrm_device_detach_genpd, sdev);
+}
+#else
+static int simpledrm_device_attach_genpd(struct simpledrm_device *sdev)
+{
+ return 0;
+}
+#endif
+
/*
* Modesetting
*/
@@ -653,6 +755,9 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv,
ret = simpledrm_device_init_regulators(sdev);
if (ret)
return ERR_PTR(ret);
+ ret = simpledrm_device_attach_genpd(sdev);
+ if (ret)
+ return ERR_PTR(ret);
if (pd) {
width = simplefb_get_width_pd(dev, pd);