[U-Boot] dm: at91: Add driver model support for the spi driver

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index f0258f8..e6b53ce 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -23,6 +23,15 @@  config ALTERA_SPI
 	  IP core. Please find details on the "Embedded Peripherals IP
 	  User Guide" of Altera.
 
+config ATMEL_SPI
+	bool "Atmel SPI driver"
+	depends on ARCH_AT91
+	select SPI_FLASH
+	select SPI_FLASH_ATMEL
+	help
+	  Enable the Atmel SPI driver. This driver can be used to access
+	  the SPI Flash, such as AT25DF321.
+
 config CADENCE_QSPI
 	bool "Cadence QSPI driver"
 	help
diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c
index ed6278b..24d4a52 100644
--- a/drivers/spi/atmel_spi.c
+++ b/drivers/spi/atmel_spi.c
@@ -4,6 +4,8 @@ 
  * SPDX-License-Identifier:	GPL-2.0+
  */
 #include <common.h>
+#include <dm.h>
+#include <fdtdec.h>
 #include <spi.h>
 #include <malloc.h>
 
@@ -11,9 +13,15 @@ 
 
 #include <asm/arch/clk.h>
 #include <asm/arch/hardware.h>
+#include <asm/arch/at91_spi.h>
+#include <asm/gpio.h>
 
 #include "atmel_spi.h"
 
+DECLARE_GLOBAL_DATA_PTR;
+
+#ifndef CONFIG_DM_SPI
+
 static int spi_has_wdrbt(struct atmel_spi_slave *slave)
 {
 	unsigned int ver;
@@ -209,3 +217,249 @@  out:
 
 	return 0;
 }
+
+#else
+
+#define MAX_CS_COUNT	4
+
+struct atmel_spi_platdata {
+	struct at91_spi *regs;
+};
+
+struct atmel_spi_priv {
+	unsigned int freq;		/* Default frequency */
+	unsigned int mode;
+	struct gpio_desc cs_gpios[MAX_CS_COUNT];
+};
+
+static int atmel_spi_claim_bus(struct udevice *dev)
+{
+	struct udevice *bus = dev_get_parent(dev);
+	struct atmel_spi_platdata *bus_plat = dev_get_platdata(bus);
+	struct atmel_spi_priv *priv = dev_get_priv(bus);
+	struct dm_spi_slave_platdata *slave_plat = dev_get_parent_platdata(dev);
+	struct at91_spi *reg_base = bus_plat->regs;
+	u32 cs = slave_plat->cs;
+	u32 freq = priv->freq;
+	u32 scbr, csrx, mode;
+
+	scbr = (get_spi_clk_rate(0) + freq - 1) / freq;
+	if (scbr > ATMEL_SPI_CSRx_SCBR_MAX)
+		return -EINVAL;
+
+	if (scbr < 1)
+		scbr = 1;
+
+	csrx = ATMEL_SPI_CSRx_SCBR(scbr);
+	csrx |= ATMEL_SPI_CSRx_BITS(ATMEL_SPI_BITS_8);
+
+	if (!(priv->mode & SPI_CPHA))
+		csrx |= ATMEL_SPI_CSRx_NCPHA;
+	if (priv->mode & SPI_CPOL)
+		csrx |= ATMEL_SPI_CSRx_CPOL;
+
+	writel(csrx, &reg_base->csr[cs]);
+
+	mode = ATMEL_SPI_MR_MSTR |
+	       ATMEL_SPI_MR_MODFDIS |
+	       ATMEL_SPI_MR_WDRBT |
+	       ATMEL_SPI_MR_PCS(~(1 << cs));
+
+	writel(mode, &reg_base->mr);
+
+	writel(ATMEL_SPI_CR_SPIEN, &reg_base->cr);
+
+	return 0;
+}
+
+static int atmel_spi_release_bus(struct udevice *dev)
+{
+	struct udevice *bus = dev_get_parent(dev);
+	struct atmel_spi_platdata *bus_plat = dev_get_platdata(bus);
+
+	writel(ATMEL_SPI_CR_SPIDIS, &bus_plat->regs->cr);
+
+	return 0;
+}
+
+static void atmel_spi_cs_activate(struct udevice *dev)
+{
+	struct udevice *bus = dev_get_parent(dev);
+	struct atmel_spi_priv *priv = dev_get_priv(bus);
+	struct dm_spi_slave_platdata *slave_plat = dev_get_parent_platdata(dev);
+	u32 cs = slave_plat->cs;
+
+	dm_gpio_set_value(&priv->cs_gpios[cs], 0);
+}
+
+static void atmel_spi_cs_deactivate(struct udevice *dev)
+{
+	struct udevice *bus = dev_get_parent(dev);
+	struct atmel_spi_priv *priv = dev_get_priv(bus);
+	struct dm_spi_slave_platdata *slave_plat = dev_get_parent_platdata(dev);
+	u32 cs = slave_plat->cs;
+
+	dm_gpio_set_value(&priv->cs_gpios[cs], 1);
+}
+
+static int atmel_spi_xfer(struct udevice *dev, unsigned int bitlen,
+			  const void *dout, void *din, unsigned long flags)
+{
+	struct udevice *bus = dev_get_parent(dev);
+	struct atmel_spi_platdata *bus_plat = dev_get_platdata(bus);
+	struct at91_spi *reg_base = bus_plat->regs;
+
+	u32 len_tx, len_rx, len;
+	u32 status;
+	const u8 *txp = dout;
+	u8 *rxp = din;
+	u8 value;
+
+	if (bitlen == 0)
+		goto out;
+
+	/*
+	 * The controller can do non-multiple-of-8 bit
+	 * transfers, but this driver currently doesn't support it.
+	 *
+	 * It's also not clear how such transfers are supposed to be
+	 * represented as a stream of bytes...this is a limitation of
+	 * the current SPI interface.
+	 */
+	if (bitlen % 8) {
+		/* Errors always terminate an ongoing transfer */
+		flags |= SPI_XFER_END;
+		goto out;
+	}
+
+	len = bitlen / 8;
+
+	/*
+	 * The controller can do automatic CS control, but it is
+	 * somewhat quirky, and it doesn't really buy us much anyway
+	 * in the context of U-Boot.
+	 */
+	if (flags & SPI_XFER_BEGIN) {
+		atmel_spi_cs_activate(dev);
+
+		/*
+		 * sometimes the RDR is not empty when we get here,
+		 * in theory that should not happen, but it DOES happen.
+		 * Read it here to be on the safe side.
+		 * That also clears the OVRES flag. Required if the
+		 * following loop exits due to OVRES!
+		 */
+		readl(&reg_base->rdr);
+	}
+
+	for (len_tx = 0, len_rx = 0; len_rx < len; ) {
+		status = readl(&reg_base->sr);
+
+		if (status & ATMEL_SPI_SR_OVRES)
+			return -1;
+
+		if ((len_tx < len) && (status & ATMEL_SPI_SR_TDRE)) {
+			if (txp)
+				value = *txp++;
+			else
+				value = 0;
+			writel(value, &reg_base->tdr);
+			len_tx++;
+		}
+
+		if (status & ATMEL_SPI_SR_RDRF) {
+			value = readl(&reg_base->rdr);
+			if (rxp)
+				*rxp++ = value;
+			len_rx++;
+		}
+	}
+
+out:
+	if (flags & SPI_XFER_END) {
+		/*
+		 * Wait until the transfer is completely done before
+		 * we deactivate CS.
+		 */
+		do {
+			status = readl(&reg_base->sr);
+		} while (!(status & ATMEL_SPI_SR_TXEMPTY));
+
+		atmel_spi_cs_deactivate(dev);
+	}
+
+	return 0;
+}
+
+static int atmel_spi_set_speed(struct udevice *bus, uint speed)
+{
+	struct atmel_spi_priv *priv = dev_get_priv(bus);
+
+	priv->freq = speed;
+
+	return 0;
+}
+
+static int atmel_spi_set_mode(struct udevice *bus, uint mode)
+{
+	struct atmel_spi_priv *priv = dev_get_priv(bus);
+
+	priv->mode = mode;
+
+	return 0;
+}
+
+static const struct dm_spi_ops atmel_spi_ops = {
+	.claim_bus	= atmel_spi_claim_bus,
+	.release_bus	= atmel_spi_release_bus,
+	.xfer		= atmel_spi_xfer,
+	.set_speed	= atmel_spi_set_speed,
+	.set_mode	= atmel_spi_set_mode,
+	/*
+	 * cs_info is not needed, since we require all chip selects to be
+	 * in the device tree explicitly
+	 */
+};
+
+static int atmel_spi_ofdata_to_platdata(struct udevice *bus)
+{
+	struct atmel_spi_priv *priv = dev_get_priv(bus);
+	int ret;
+
+	ret = gpio_request_list_by_name(bus, "cs-gpios", priv->cs_gpios,
+					ARRAY_SIZE(priv->cs_gpios), 0);
+	if (ret < 0) {
+		error("Can't get %s gpios! Error: %d", bus->name, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int atmel_spi_probe(struct udevice *bus)
+{
+	struct atmel_spi_platdata *bus_plat = dev_get_platdata(bus);
+
+	bus_plat->regs = (struct at91_spi *)dev_get_addr(bus);
+
+	writel(ATMEL_SPI_CR_SWRST, &bus_plat->regs->cr);
+
+	return 0;
+}
+
+static const struct udevice_id atmel_spi_ids[] = {
+	{ .compatible = "atmel,at91rm9200-spi" },
+	{ }
+};
+
+U_BOOT_DRIVER(atmel_spi) = {
+	.name	= "atmel_spi",
+	.id	= UCLASS_SPI,
+	.of_match = atmel_spi_ids,
+	.ops	= &atmel_spi_ops,
+	.ofdata_to_platdata = atmel_spi_ofdata_to_platdata,
+	.platdata_auto_alloc_size = sizeof(struct atmel_spi_platdata),
+	.priv_auto_alloc_size = sizeof(struct atmel_spi_priv),
+	.probe	= atmel_spi_probe,
+};
+#endif