The charts always render with 5 evenly-spaced gridlines when using a continuous axis, and each gridline gets a label. Setting the viewWindowMode to 'maximized' will render the first and last points on the edges of the chart area, but there is no guarantee that they will have labels. The only way to achieve what you want (while using a continuous axis) would be to deliberately restrict your data sets to those which produce labels where you want them.
If your data is evenly spaced (ie, 1 data point per day, 1 per hour, something like that), then you can switch to a discrete axis, which would get you your labels, but you would lose the gridlines.