SAN FRANCISCO — Pillsbury Winthrop Shaw Pittman and Davis Polk & Wardwell are harmonizing with data storage company Violin Memory Inc. on its $180 million IPO.

The Santa Clara-based flash memory startup is expected to go public on the New York Stock Exchange this month. In a filing this week, Violin disclosed plans to sell 18 million shares at a range of $8 to $10 each. It initially filed confidentially with the SEC last year, and it has harbored plans to go public since at least 2011.