media: camss: Split power domain management

There are three cases of power domain management on supported platforms:
1) CAMSS on MSM8916, where a single VFE power domain is operated outside
of the camss device driver,
2) CAMSS on MSM8996 and SDM630/SDM660, where two VFE power domains are
managed separately by the camss device driver, the power domains are
linked and unlinked on demand by their functions vfe_pm_domain_on()
and vfe_pm_domain_off() respectively,
3) CAMSS on SDM845 and SM8250 platforms, and there are two VFE power
domains and their parent power domain TITAN_TOP, the latter one
shall be turned on prior to turning on any of VFE power domains.

Due to a previously missing link between TITAN_TOP and VFEx power domains
in the latter case, which is now fixed by [1], it was decided always to
turn on all found VFE power domains and TITAN_TOP power domain, even if
just one particular VFE is needed to be enabled or none of VFE power
domains are required, for instance the latter case is when vfe_lite is in
use. This misusage becomes more incovenient and clumsy, if next generations
are to be supported, for instance CAMSS on SM8450 has three VFE power
domains.

The change splits the power management support for platforms with TITAN_TOP
parent power domain, and, since 'power-domain-names' property is not
present in camss device tree nodes, the assumption is that the first
N power domains from the 'power-domains' list correspond to VFE power
domains, and, if the number of power domains is greater than number of
non-lite VFEs, then the last power domain from the list is the TITAN_TOP
power domain.

Signed-off-by: Vladimir Zapolskiy <[e-mail]>
Reviewed-by: Robert Foss <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/platform/qcom/camss/camss-vfe-170.c

···
  */
 static void vfe_pm_domain_off(struct vfe_device *vfe)
 {
-	/* nop */
+	struct camss *camss = vfe->camss;
+
+	if (vfe->id >= camss->vfe_num)
+		return;
+
+	device_link_del(camss->genpd_link[vfe->id]);
 }
 
 /*
···
  */
 static int vfe_pm_domain_on(struct vfe_device *vfe)
 {
+	struct camss *camss = vfe->camss;
+	enum vfe_line_id id = vfe->id;
+
+	if (id >= camss->vfe_num)
+		return 0;
+
+	camss->genpd_link[id] = device_link_add(camss->dev, camss->genpd[id],
+						DL_FLAG_STATELESS |
+						DL_FLAG_PM_RUNTIME |
+						DL_FLAG_RPM_ACTIVE);
+	if (!camss->genpd_link[id])
+		return -EINVAL;
+
 	return 0;
 }
 

drivers/media/platform/qcom/camss/camss-vfe-480.c

···
  */
 static void vfe_pm_domain_off(struct vfe_device *vfe)
 {
-	/* nop */
+	struct camss *camss = vfe->camss;
+
+	if (vfe->id >= camss->vfe_num)
+		return;
+
+	device_link_del(camss->genpd_link[vfe->id]);
 }
 
 /*
···
  */
 static int vfe_pm_domain_on(struct vfe_device *vfe)
 {
+	struct camss *camss = vfe->camss;
+	enum vfe_line_id id = vfe->id;
+
+	if (id >= camss->vfe_num)
+		return 0;
+
+	camss->genpd_link[id] = device_link_add(camss->dev, camss->genpd[id],
+						DL_FLAG_STATELESS |
+						DL_FLAG_PM_RUNTIME |
+						DL_FLAG_RPM_ACTIVE);
+	if (!camss->genpd_link[id])
+		return -EINVAL;
+
 	return 0;
 }
 

drivers/media/platform/qcom/camss/camss.c

···
 static int camss_configure_pd(struct camss *camss)
 {
 	struct device *dev = camss->dev;
-	int last_pm_domain = 0;
 	int i;
 	int ret;
 
···
 	if (!camss->genpd_link)
 		return -ENOMEM;
 
+	/*
+	 * VFE power domains are in the beginning of the list, and while all
+	 * power domains should be attached, only if TITAN_TOP power domain is
+	 * found in the list, it should be linked over here.
+	 */
 	for (i = 0; i < camss->genpd_num; i++) {
 		camss->genpd[i] = dev_pm_domain_attach_by_id(camss->dev, i);
 		if (IS_ERR(camss->genpd[i])) {
 			ret = PTR_ERR(camss->genpd[i]);
 			goto fail_pm;
 		}
+	}
 
-		camss->genpd_link[i] = device_link_add(camss->dev, camss->genpd[i],
-						       DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME |
-						       DL_FLAG_RPM_ACTIVE);
-		if (!camss->genpd_link[i]) {
-			dev_pm_domain_detach(camss->genpd[i], true);
+	if (i > camss->vfe_num) {
+		camss->genpd_link[i - 1] = device_link_add(camss->dev, camss->genpd[i - 1],
+							   DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME |
+							   DL_FLAG_RPM_ACTIVE);
+		if (!camss->genpd_link[i - 1]) {
 			ret = -EINVAL;
 			goto fail_pm;
 		}
-
-		last_pm_domain = i;
 	}
 
 	return 0;
 
 fail_pm:
-	for (i = 0; i < last_pm_domain; i++) {
-		device_link_del(camss->genpd_link[i]);
+	for (--i ; i >= 0; i--)
 		dev_pm_domain_detach(camss->genpd[i], true);
-	}
 
 	return ret;
 }
···
 	if (camss->genpd_num == 1)
 		return;
 
-	for (i = 0; i < camss->genpd_num; i++) {
-		device_link_del(camss->genpd_link[i]);
+	if (camss->genpd_num > camss->vfe_num)
+		device_link_del(camss->genpd_link[camss->genpd_num - 1]);
+
+	for (i = 0; i < camss->genpd_num; i++)
 		dev_pm_domain_detach(camss->genpd[i], true);
-	}
 }
 
 /*