Non-selective, calcium-permeable cation channel. Also transports maganese. Contributes to both spontaneous and receptor stimulation-induced cationic currents. Receptor stimulation, including that of G(q)-coupled or receptor tyrosine kinase pathways, triggers phospholipase C (PLC)-mediated hydrolysis of phosphatidylinositides, producing diacylglycerol (DAG) that activates TRPC7. May also be activated by depletion of intracellular calcium stores. Mediates depolarization of intrinsically photosensitive retinal ganglion cells (ipRGCs) in response to light-induced melanopsin (OPN4)-mediated phototransduction via G(q)-PLC signaling, likely by forming heteromeric TRPC6-TRPC7 channels. . This is the function of TRPC7 (transient receptor potential cation channel subfamily C member 7, Ensembl gene identifier ENSG00000069018).