[U-Boot] [PATCH v2] dm: at91: Add driver model support for the spi driver

[Wenyou Yang]

Add driver model support while retaining the existing legacy code.
This allows the driver to support boards that have converted to
driver model as well as those that have not.

Signed-off-by: Wenyou Yang <wenyou.yang at atmel.com>
---

Changes in v2:
 - Add clock support.

 drivers/spi/Kconfig     |   9 ++
 drivers/spi/atmel_spi.c | 311 +++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 319 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index b7fd8e5..2ac145c 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -32,6 +32,15 @@ config ATH79_SPI
 	  uses driver model and requires a device tree binding to operate.
 	  please refer to doc/device-tree-bindings/spi/spi-ath79.txt.
 
+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..66b8580 100644
--- a/drivers/spi/atmel_spi.c
+++ b/drivers/spi/atmel_spi.c
@@ -4,16 +4,24 @@
  * SPDX-License-Identifier:	GPL-2.0+
  */
 #include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <fdtdec.h>
 #include <spi.h>
 #include <malloc.h>
 
 #include <asm/io.h>
 
-#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 +217,304 @@ 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;
+	ulong bus_clk_rate;
+	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 = (priv->bus_clk_rate + 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_enable_clk(struct udevice *bus)
+{
+	struct atmel_spi_priv *priv = dev_get_priv(bus);
+	struct udevice *clkdev;
+	ulong clk_rate;
+	int periph;
+	int ret;
+
+	ret = clk_get_by_index(bus, 0, &clkdev);
+	if (ret) {
+		dev_err(bus, "Failed to find peripheral clock node\n");
+		return -EINVAL;
+	}
+
+	periph = fdtdec_get_uint(gd->fdt_blob, clkdev->of_offset, "reg", -1);
+	if (periph < 0) {
+		dev_err(bus, "Failed to find peripheral id\n");
+		return -EINVAL;
+	}
+
+	clkdev = dev_get_parent(clkdev);
+	if (!clkdev) {
+		dev_err(bus, "Failed to find parent node\n");
+		return -ENODEV;
+	}
+
+	ret = clk_enable(clkdev, periph);
+	if (ret) {
+		dev_err(bus, "Failed to enable peripheral clock\n");
+		return ret;
+	}
+
+	ret = clk_get_by_index(clkdev, 0, &clkdev);
+	if (ret) {
+		dev_err(bus, "Failed to find bus clock node\n");
+		return ret;
+	}
+
+	clk_rate = clk_get_rate(clkdev);
+	if (!clk_rate) {
+		dev_err(bus, "Failed to get bus clock rate\n");
+		return -ENODEV;
+	}
+
+	priv->bus_clk_rate = clk_rate;
+
+	return 0;
+}
+
+static int atmel_spi_probe(struct udevice *bus)
+{
+	struct atmel_spi_platdata *bus_plat = dev_get_platdata(bus);
+	int ret;
+
+	ret = atmel_spi_enable_clk(bus);
+	if (ret)
+		return ret;
+
+	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
-- 
2.7.4