Applied "spi: add driver for ar934x spi controller" to the spi tree

[Mark Brown <broonie@kernel.org>]

The patch

   spi: add driver for ar934x spi controller

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.7

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

From 047980c582af665e1581e60ebf3e57977e621c23 Mon Sep 17 00:00:00 2001
From: Chuanhong Guo <gch981213@gmail.com>
Date: Mon, 10 Feb 2020 11:41:51 +0800
Subject: [PATCH] spi: add driver for ar934x spi controller

This patch adds driver for SPI controller found in Qualcomm Atheros
AR934x/QCA95xx SoCs.
This controller is a superset of the already supported qca,ar7100-spi.
Besides the bit-bang mode in spi-ath79.c, this new controller added
a new "shift register" mode, allowing faster spi operations.

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
Link: https://lore.kernel.org/r/20200210034152.49063-2-gch981213@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/Kconfig      |   7 ++
 drivers/spi/Makefile     |   1 +
 drivers/spi/spi-ar934x.c | 235 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 243 insertions(+)
 create mode 100644 drivers/spi/spi-ar934x.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index d6ed0c355954..0434614d8201 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -62,6 +62,13 @@ config SPI_ALTERA
 	help
 	  This is the driver for the Altera SPI Controller.
 
+config SPI_AR934X
+	tristate "Qualcomm Atheros AR934X/QCA95XX SPI controller driver"
+	depends on ATH79 || COMPILE_TEST
+	help
+	  This enables support for the SPI controller present on the
+	  Qualcomm Atheros AR934X/QCA95XX SoCs.
+
 config SPI_ATH79
 	tristate "Atheros AR71XX/AR724X/AR913X SPI controller driver"
 	depends on ATH79 || COMPILE_TEST
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 9b65ec5afc5e..9892bdfab15e 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_SPI_LOOPBACK_TEST)		+= spi-loopback-test.o
 
 # SPI master controller drivers (bus)
 obj-$(CONFIG_SPI_ALTERA)		+= spi-altera.o
+obj-$(CONFIG_SPI_AR934X)		+= spi-ar934x.o
 obj-$(CONFIG_SPI_ARMADA_3700)		+= spi-armada-3700.o
 obj-$(CONFIG_SPI_ATMEL)			+= spi-atmel.o
 obj-$(CONFIG_SPI_ATMEL_QUADSPI)		+= atmel-quadspi.o
diff --git a/drivers/spi/spi-ar934x.c b/drivers/spi/spi-ar934x.c
new file mode 100644
index 000000000000..d08dec09d423
--- /dev/null
+++ b/drivers/spi/spi-ar934x.c
@@ -0,0 +1,235 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// SPI controller driver for Qualcomm Atheros AR934x/QCA95xx SoCs
+//
+// Copyright (C) 2020 Chuanhong Guo <gch981213@gmail.com>
+//
+// Based on spi-mt7621.c:
+// Copyright (C) 2011 Sergiy <piratfm@gmail.com>
+// Copyright (C) 2011-2013 Gabor Juhos <juhosg@openwrt.org>
+// Copyright (C) 2014-2015 Felix Fietkau <nbd@nbd.name>
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/spi/spi.h>
+
+#define DRIVER_NAME "spi-ar934x"
+
+#define AR934X_SPI_REG_FS		0x00
+#define AR934X_SPI_ENABLE		BIT(0)
+
+#define AR934X_SPI_REG_IOC		0x08
+#define AR934X_SPI_IOC_INITVAL		0x70000
+
+#define AR934X_SPI_REG_CTRL		0x04
+#define AR934X_SPI_CLK_MASK		GENMASK(5, 0)
+
+#define AR934X_SPI_DATAOUT		0x10
+
+#define AR934X_SPI_REG_SHIFT_CTRL	0x14
+#define AR934X_SPI_SHIFT_EN		BIT(31)
+#define AR934X_SPI_SHIFT_CS(n)		BIT(28 + (n))
+#define AR934X_SPI_SHIFT_TERM		26
+#define AR934X_SPI_SHIFT_VAL(cs, term, count)			\
+	(AR934X_SPI_SHIFT_EN | AR934X_SPI_SHIFT_CS(cs) |	\
+	(term) << AR934X_SPI_SHIFT_TERM | (count))
+
+#define AR934X_SPI_DATAIN 0x18
+
+struct ar934x_spi {
+	struct spi_controller *ctlr;
+	void __iomem *base;
+	struct clk *clk;
+	unsigned int clk_freq;
+};
+
+static inline int ar934x_spi_clk_div(struct ar934x_spi *sp, unsigned int freq)
+{
+	int div = DIV_ROUND_UP(sp->clk_freq, freq * 2) - 1;
+
+	if (div < 0)
+		return 0;
+	else if (div > AR934X_SPI_CLK_MASK)
+		return -EINVAL;
+	else
+		return div;
+}
+
+static int ar934x_spi_setup(struct spi_device *spi)
+{
+	struct ar934x_spi *sp = spi_controller_get_devdata(spi->master);
+
+	if ((spi->max_speed_hz == 0) ||
+	    (spi->max_speed_hz > (sp->clk_freq / 2))) {
+		spi->max_speed_hz = sp->clk_freq / 2;
+	} else if (spi->max_speed_hz < (sp->clk_freq / 128)) {
+		dev_err(&spi->dev, "spi clock is too low\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int ar934x_spi_transfer_one_message(struct spi_controller *master,
+					   struct spi_message *m)
+{
+	struct ar934x_spi *sp = spi_controller_get_devdata(master);
+	struct spi_transfer *t = NULL;
+	struct spi_device *spi = m->spi;
+	unsigned long trx_done, trx_cur;
+	int stat = 0;
+	u8 term = 0;
+	int div, i;
+	u32 reg;
+	const u8 *tx_buf;
+	u8 *buf;
+
+	m->actual_length = 0;
+	list_for_each_entry(t, &m->transfers, transfer_list) {
+		if (t->speed_hz)
+			div = ar934x_spi_clk_div(sp, t->speed_hz);
+		else
+			div = ar934x_spi_clk_div(sp, spi->max_speed_hz);
+		if (div < 0) {
+			stat = -EIO;
+			goto msg_done;
+		}
+
+		reg = ioread32(sp->base + AR934X_SPI_REG_CTRL);
+		reg &= ~AR934X_SPI_CLK_MASK;
+		reg |= div;
+		iowrite32(reg, sp->base + AR934X_SPI_REG_CTRL);
+		iowrite32(0, sp->base + AR934X_SPI_DATAOUT);
+
+		for (trx_done = 0; trx_done < t->len; trx_done += 4) {
+			trx_cur = t->len - trx_done;
+			if (trx_cur > 4)
+				trx_cur = 4;
+			else if (list_is_last(&t->transfer_list, &m->transfers))
+				term = 1;
+
+			if (t->tx_buf) {
+				tx_buf = t->tx_buf + trx_done;
+				reg = tx_buf[0];
+				for (i = 1; i < trx_cur; i++)
+					reg = reg << 8 | tx_buf[i];
+				iowrite32(reg, sp->base + AR934X_SPI_DATAOUT);
+			}
+
+			reg = AR934X_SPI_SHIFT_VAL(spi->chip_select, term,
+						   trx_cur * 8);
+			iowrite32(reg, sp->base + AR934X_SPI_REG_SHIFT_CTRL);
+			stat = readl_poll_timeout(
+				sp->base + AR934X_SPI_REG_SHIFT_CTRL, reg,
+				!(reg & AR934X_SPI_SHIFT_EN), 0, 5);
+			if (stat < 0)
+				goto msg_done;
+
+			if (t->rx_buf) {
+				reg = ioread32(sp->base + AR934X_SPI_DATAIN);
+				buf = t->rx_buf + trx_done;
+				for (i = 0; i < trx_cur; i++) {
+					buf[trx_cur - i - 1] = reg & 0xff;
+					reg >>= 8;
+				}
+			}
+		}
+		m->actual_length += t->len;
+	}
+
+msg_done:
+	m->status = stat;
+	spi_finalize_current_message(master);
+
+	return 0;
+}
+
+static const struct of_device_id ar934x_spi_match[] = {
+	{ .compatible = "qca,ar934x-spi" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ar934x_spi_match);
+
+static int ar934x_spi_probe(struct platform_device *pdev)
+{
+	struct spi_controller *ctlr;
+	struct ar934x_spi *sp;
+	void __iomem *base;
+	struct clk *clk;
+	int ret;
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(clk)) {
+		dev_err(&pdev->dev, "failed to get clock\n");
+		return PTR_ERR(clk);
+	}
+
+	ret = clk_prepare_enable(clk);
+	if (ret)
+		return ret;
+
+	ctlr = spi_alloc_master(&pdev->dev, sizeof(*sp));
+	if (!ctlr) {
+		dev_info(&pdev->dev, "failed to allocate spi controller\n");
+		return -ENOMEM;
+	}
+
+	/* disable flash mapping and expose spi controller registers */
+	iowrite32(AR934X_SPI_ENABLE, base + AR934X_SPI_REG_FS);
+	/* restore pins to default state: CSn=1 DO=CLK=0 */
+	iowrite32(AR934X_SPI_IOC_INITVAL, base + AR934X_SPI_REG_IOC);
+
+	ctlr->mode_bits = SPI_LSB_FIRST;
+	ctlr->setup = ar934x_spi_setup;
+	ctlr->transfer_one_message = ar934x_spi_transfer_one_message;
+	ctlr->bits_per_word_mask = SPI_BPW_MASK(8);
+	ctlr->dev.of_node = pdev->dev.of_node;
+	ctlr->num_chipselect = 3;
+
+	dev_set_drvdata(&pdev->dev, ctlr);
+
+	sp = spi_controller_get_devdata(ctlr);
+	sp->base = base;
+	sp->clk = clk;
+	sp->clk_freq = clk_get_rate(clk);
+	sp->ctlr = ctlr;
+
+	return devm_spi_register_controller(&pdev->dev, ctlr);
+}
+
+static int ar934x_spi_remove(struct platform_device *pdev)
+{
+	struct spi_controller *ctlr;
+	struct ar934x_spi *sp;
+
+	ctlr = dev_get_drvdata(&pdev->dev);
+	sp = spi_controller_get_devdata(ctlr);
+
+	clk_disable_unprepare(sp->clk);
+
+	return 0;
+}
+
+static struct platform_driver ar934x_spi_driver = {
+	.driver = {
+		.name = DRIVER_NAME,
+		.of_match_table = ar934x_spi_match,
+	},
+	.probe = ar934x_spi_probe,
+	.remove = ar934x_spi_remove,
+};
+
+module_platform_driver(ar934x_spi_driver);
+
+MODULE_DESCRIPTION("SPI controller driver for Qualcomm Atheros AR934x/QCA95xx");
+MODULE_AUTHOR("Chuanhong Guo <gch981213@gmail.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRIVER_NAME);
-- 
2.20.1