diff options
Diffstat (limited to 'drivers/gpu/drm/tiny/simpledrm.c')
| -rw-r--r-- | drivers/gpu/drm/tiny/simpledrm.c | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/drivers/gpu/drm/tiny/simpledrm.c b/drivers/gpu/drm/tiny/simpledrm.c index 8ea120eb8674..5fefc895bca2 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); |