+static void lpss_ssp_select_cs(struct driver_data *drv_data,
+ const struct lpss_config *config)
+{
+ u32 value, cs;
+
+ if (!config->cs_sel_mask)
+ return;
+
+ value = __lpss_ssp_read_priv(drv_data, config->reg_cs_ctrl);
+
+ cs = drv_data->cur_msg->spi->chip_select;
+ cs <<= config->cs_sel_shift;
+ if (cs != (value & config->cs_sel_mask)) {
+ /*
+ * When switching another chip select output active the
+ * output must be selected first and wait 2 ssp_clk cycles
+ * before changing state to active. Otherwise a short
+ * glitch will occur on the previous chip select since
+ * output select is latched but state control is not.
+ */
+ value &= ~config->cs_sel_mask;
+ value |= cs;
+ __lpss_ssp_write_priv(drv_data,
+ config->reg_cs_ctrl, value);
+ ndelay(1000000000 /
+ (drv_data->master->max_speed_hz / 2));
+ }
+}
+