commit 58a52e878b35a936e7ab9210aac04c9cb016ad88
author Simon Glass <sjg@chromium.org> Thu Jan 21 19:44:10 2016 -0700
committer Simon Glass <sjg@chromium.org> Thu Jan 21 20:42:36 2016 -0700
tree bbda67b252c8fac81d39036470677d5be3f751c4
parent 9c73e74d737bec2b4dd87aade387056373b9b924

rockchip: spi: Implement the delays

Some devices need delays before and after activiation. Implement these
features in the SPI driver so that we will be able to enable the Chrome
OS EC.

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/spi/rk_spi.c

diff --git a/drivers/spi/rk_spi.c b/drivers/spi/rk_spi.c
index 3418f9b..35b528f 100644
--- a/drivers/spi/rk_spi.c
+++ b/drivers/spi/rk_spi.c
@@ -32,6 +32,7 @@
 	s32 frequency;		/* Default clock frequency, -1 for none */
 	fdt_addr_t base;
 	uint deactivate_delay_us;	/* Delay to wait after deactivate */
+	uint activate_delay_us;		/* Delay to wait after activate */
 };
 
 struct rockchip_spi_priv {
@@ -101,16 +102,32 @@
 	return 0;
 }
 
-static void spi_cs_activate(struct rockchip_spi *regs, uint cs)
+static void spi_cs_activate(struct udevice *dev, uint cs)
 {
+	struct udevice *bus = dev->parent;
+	struct rockchip_spi_platdata *plat = bus->platdata;
+	struct rockchip_spi_priv *priv = dev_get_priv(bus);
+	struct rockchip_spi *regs = priv->regs;
+
 	debug("activate cs%u\n", cs);
 	writel(1 << cs, &regs->ser);
+	if (plat->activate_delay_us)
+		udelay(plat->activate_delay_us);
 }
 
-static void spi_cs_deactivate(struct rockchip_spi *regs, uint cs)
+static void spi_cs_deactivate(struct udevice *dev, uint cs)
 {
+	struct udevice *bus = dev->parent;
+	struct rockchip_spi_platdata *plat = bus->platdata;
+	struct rockchip_spi_priv *priv = dev_get_priv(bus);
+	struct rockchip_spi *regs = priv->regs;
+
 	debug("deactivate cs%u\n", cs);
 	writel(0, &regs->ser);
+
+	/* Remember time of this transaction so we can honour the bus delay */
+	if (plat->deactivate_delay_us)
+		priv->last_transaction_us = timer_get_us();
 }
 
 static int rockchip_spi_ofdata_to_platdata(struct udevice *bus)
@@ -145,6 +162,8 @@
 					 50000000);
 	plat->deactivate_delay_us = fdtdec_get_int(blob, node,
 					"spi-deactivate-delay", 0);
+	plat->activate_delay_us = fdtdec_get_int(blob, node,
+						 "spi-activate-delay", 0);
 	debug("%s: base=%x, periph_id=%d, max-frequency=%d, deactivate_delay=%d\n",
 	      __func__, (uint)plat->base, plat->periph_id, plat->frequency,
 	      plat->deactivate_delay_us);
@@ -290,7 +309,7 @@
 
 	/* Assert CS before transfer */
 	if (flags & SPI_XFER_BEGIN)
-		spi_cs_activate(regs, slave_plat->cs);
+		spi_cs_activate(dev, slave_plat->cs);
 
 	while (len > 0) {
 		int todo = min(len, 0xffff);
@@ -324,7 +343,7 @@
 
 	/* Deassert CS after transfer */
 	if (flags & SPI_XFER_END)
-		spi_cs_deactivate(regs, slave_plat->cs);
+		spi_cs_deactivate(dev, slave_plat->cs);
 
 	rkspi_enable_chip(regs, false);