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path: root/drivers/spi/ath79_spi.c
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Diffstat (limited to 'drivers/spi/ath79_spi.c')
-rw-r--r--drivers/spi/ath79_spi.c228
1 files changed, 228 insertions, 0 deletions
diff --git a/drivers/spi/ath79_spi.c b/drivers/spi/ath79_spi.c
new file mode 100644
index 0000000..b18c733
--- /dev/null
+++ b/drivers/spi/ath79_spi.c
@@ -0,0 +1,228 @@
+/*
+ * Copyright (C) 2015-2016 Wills Wang <wills.wang@live.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <spi.h>
+#include <dm.h>
+#include <div64.h>
+#include <errno.h>
+#include <asm/io.h>
+#include <asm/addrspace.h>
+#include <asm/types.h>
+#include <dm/pinctrl.h>
+#include <mach/ar71xx_regs.h>
+
+/* CLOCK_DIVIDER = 3 (SPI clock = 200 / 8 ~ 25 MHz) */
+#define ATH79_SPI_CLK_DIV(x) (((x) >> 1) - 1)
+#define ATH79_SPI_RRW_DELAY_FACTOR 12000
+#define ATH79_SPI_MHZ (1000 * 1000)
+
+struct ath79_spi_priv {
+ void __iomem *regs;
+ u32 rrw_delay;
+};
+
+static void spi_cs_activate(struct udevice *dev)
+{
+ struct udevice *bus = dev_get_parent(dev);
+ struct ath79_spi_priv *priv = dev_get_priv(bus);
+
+ writel(AR71XX_SPI_FS_GPIO, priv->regs + AR71XX_SPI_REG_FS);
+ writel(AR71XX_SPI_IOC_CS_ALL, priv->regs + AR71XX_SPI_REG_IOC);
+}
+
+static void spi_cs_deactivate(struct udevice *dev)
+{
+ struct udevice *bus = dev_get_parent(dev);
+ struct ath79_spi_priv *priv = dev_get_priv(bus);
+
+ writel(AR71XX_SPI_IOC_CS_ALL, priv->regs + AR71XX_SPI_REG_IOC);
+ writel(0, priv->regs + AR71XX_SPI_REG_FS);
+}
+
+static int ath79_spi_claim_bus(struct udevice *dev)
+{
+ return 0;
+}
+
+static int ath79_spi_release_bus(struct udevice *dev)
+{
+ return 0;
+}
+
+static int ath79_spi_xfer(struct udevice *dev, unsigned int bitlen,
+ const void *dout, void *din, unsigned long flags)
+{
+ struct udevice *bus = dev_get_parent(dev);
+ struct ath79_spi_priv *priv = dev_get_priv(bus);
+ struct dm_spi_slave_platdata *slave = dev_get_parent_platdata(dev);
+ u8 *rx = din;
+ const u8 *tx = dout;
+ u8 curbyte, curbitlen, restbits;
+ u32 bytes = bitlen / 8;
+ u32 out, in;
+ u64 tick;
+
+ if (flags & SPI_XFER_BEGIN)
+ spi_cs_activate(dev);
+
+ restbits = (bitlen % 8);
+ if (restbits)
+ bytes++;
+
+ out = AR71XX_SPI_IOC_CS_ALL & ~(AR71XX_SPI_IOC_CS(slave->cs));
+ while (bytes > 0) {
+ bytes--;
+ curbyte = 0;
+ if (tx)
+ curbyte = *tx++;
+
+ if (restbits && !bytes) {
+ curbitlen = restbits;
+ curbyte <<= 8 - restbits;
+ } else {
+ curbitlen = 8;
+ }
+
+ for (curbyte <<= (8 - curbitlen); curbitlen; curbitlen--) {
+ if (curbyte & 0x80)
+ out |= AR71XX_SPI_IOC_DO;
+ else
+ out &= ~(AR71XX_SPI_IOC_DO);
+
+ writel(out, priv->regs + AR71XX_SPI_REG_IOC);
+
+ /* delay for low level */
+ if (priv->rrw_delay) {
+ tick = get_ticks() + priv->rrw_delay;
+ while (get_ticks() < tick)
+ /*NOP*/;
+ }
+
+ writel(out | AR71XX_SPI_IOC_CLK,
+ priv->regs + AR71XX_SPI_REG_IOC);
+
+ /* delay for high level */
+ if (priv->rrw_delay) {
+ tick = get_ticks() + priv->rrw_delay;
+ while (get_ticks() < tick)
+ /*NOP*/;
+ }
+
+ curbyte <<= 1;
+ }
+
+ if (!bytes)
+ writel(out, priv->regs + AR71XX_SPI_REG_IOC);
+
+ in = readl(priv->regs + AR71XX_SPI_REG_RDS);
+ if (rx) {
+ if (restbits && !bytes)
+ *rx++ = (in << (8 - restbits));
+ else
+ *rx++ = in;
+ }
+ }
+
+ if (flags & SPI_XFER_END)
+ spi_cs_deactivate(dev);
+
+ return 0;
+}
+
+
+static int ath79_spi_set_speed(struct udevice *bus, uint speed)
+{
+ struct ath79_spi_priv *priv = dev_get_priv(bus);
+ u32 val, div = 0;
+ u64 time;
+
+ if (speed)
+ div = get_bus_freq(0) / speed;
+
+ if (div > 63)
+ div = 63;
+
+ if (div < 5)
+ div = 5;
+
+ /* calculate delay */
+ time = get_tbclk();
+ do_div(time, speed / 2);
+ val = get_bus_freq(0) / ATH79_SPI_MHZ;
+ val = ATH79_SPI_RRW_DELAY_FACTOR / val;
+ if (time > val)
+ priv->rrw_delay = time - val + 1;
+ else
+ priv->rrw_delay = 0;
+
+ writel(AR71XX_SPI_FS_GPIO, priv->regs + AR71XX_SPI_REG_FS);
+ clrsetbits_be32(priv->regs + AR71XX_SPI_REG_CTRL,
+ AR71XX_SPI_CTRL_DIV_MASK,
+ ATH79_SPI_CLK_DIV(div));
+ writel(0, priv->regs + AR71XX_SPI_REG_FS);
+ return 0;
+}
+
+static int ath79_spi_set_mode(struct udevice *bus, uint mode)
+{
+ return 0;
+}
+
+static int ath79_spi_probe(struct udevice *bus)
+{
+ struct ath79_spi_priv *priv = dev_get_priv(bus);
+ fdt_addr_t addr;
+
+ addr = dev_get_addr(bus);
+ if (addr == FDT_ADDR_T_NONE)
+ return -EINVAL;
+
+ priv->regs = map_physmem(addr,
+ AR71XX_SPI_SIZE,
+ MAP_NOCACHE);
+
+ /* Init SPI Hardware, disable remap, set clock */
+ writel(AR71XX_SPI_FS_GPIO, priv->regs + AR71XX_SPI_REG_FS);
+ writel(AR71XX_SPI_CTRL_RD | ATH79_SPI_CLK_DIV(8),
+ priv->regs + AR71XX_SPI_REG_CTRL);
+ writel(0, priv->regs + AR71XX_SPI_REG_FS);
+
+ return 0;
+}
+
+static int ath79_cs_info(struct udevice *bus, uint cs,
+ struct spi_cs_info *info)
+{
+ /* Always allow activity on CS 0/1/2 */
+ if (cs >= 3)
+ return -ENODEV;
+
+ return 0;
+}
+
+static const struct dm_spi_ops ath79_spi_ops = {
+ .claim_bus = ath79_spi_claim_bus,
+ .release_bus = ath79_spi_release_bus,
+ .xfer = ath79_spi_xfer,
+ .set_speed = ath79_spi_set_speed,
+ .set_mode = ath79_spi_set_mode,
+ .cs_info = ath79_cs_info,
+};
+
+static const struct udevice_id ath79_spi_ids[] = {
+ { .compatible = "qca,ar7100-spi" },
+ {}
+};
+
+U_BOOT_DRIVER(ath79_spi) = {
+ .name = "ath79_spi",
+ .id = UCLASS_SPI,
+ .of_match = ath79_spi_ids,
+ .ops = &ath79_spi_ops,
+ .priv_auto_alloc_size = sizeof(struct ath79_spi_priv),
+ .probe = ath79_spi_probe,
+};