spi: ep93xx: Convert to let spi core handle checking transfer speed

By setting master->max_speed_hz and master->min_speed_hz, spi core will handle
checking transfer speed. So we can remove the same checking in this driver.

Signed-off-by: Axel Lin <[e-mail]>
Acked-by: Mika Westerberg <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

drivers/spi/spi-ep93xx.c

···
  * @clk: clock for the controller
  * @regs_base: pointer to ioremap()'d registers
  * @sspdr_phys: physical address of the SSPDR register
- * @min_rate: minimum clock rate (in Hz) supported by the controller
- * @max_rate: maximum clock rate (in Hz) supported by the controller
  * @wait: wait here until given transfer is completed
  * @current_msg: message that is currently processed (or %NULL if none)
  * @tx: current byte in transfer to transmit
···
 	struct clk			*clk;
 	void __iomem			*regs_base;
 	unsigned long			sspdr_phys;
-	unsigned long			min_rate;
-	unsigned long			max_rate;
 	struct completion		wait;
 	struct spi_message		*current_msg;
 	size_t				tx;
···
  * @div_scr: pointer to return the scr divider
  */
 static int ep93xx_spi_calc_divisors(const struct ep93xx_spi *espi,
-				    unsigned long rate,
-				    u8 *div_cpsr, u8 *div_scr)
+				    u32 rate, u8 *div_cpsr, u8 *div_scr)
 {
+	struct spi_master *master = platform_get_drvdata(espi->pdev);
 	unsigned long spi_clk_rate = clk_get_rate(espi->clk);
 	int cpsr, scr;
 
···
 	 * controller. Note that minimum value is already checked in
 	 * ep93xx_spi_transfer_one_message().
 	 */
-	rate = clamp(rate, espi->min_rate, espi->max_rate);
+	rate = clamp(rate, master->min_speed_hz, master->max_speed_hz);
 
 	/*
 	 * Calculate divisors so that we can get speed according the
···
 					   struct spi_message *msg)
 {
 	struct ep93xx_spi *espi = spi_master_get_devdata(master);
-	struct spi_transfer *t;
-
-	/* first validate each transfer */
-	list_for_each_entry(t, &msg->transfers, transfer_list) {
-		if (t->speed_hz < espi->min_rate)
-			return -EINVAL;
-	}
 
 	msg->state = NULL;
 	msg->status = 0;
···
 	 * Calculate maximum and minimum supported clock rates
 	 * for the controller.
 	 */
-	espi->max_rate = clk_get_rate(espi->clk) / 2;
-	espi->min_rate = clk_get_rate(espi->clk) / (254 * 256);
+	master->max_speed_hz = clk_get_rate(espi->clk) / 2;
+	master->min_speed_hz = clk_get_rate(espi->clk) / (254 * 256);
 	espi->pdev = pdev;
 
 	espi->sspdr_phys = res->start + SSPDR;