[PATCH] spi: mt7621: Move SPI driver out of staging

[PATCH] spi: mt7621: Move SPI driver out of staging

[Stefan Roese]

This patch moves the MT7621 SPI driver, which is used on some Ralink /
MediaTek MT76xx MIPS SoC's, out of the staging directory. No changes to
the source code are done in this patch.

This driver version was tested successfully on an MT7688 based platform
with an SPI NOR on CS0 and an SPI NAND on CS1 without any issues (so
far).

This patch also documents the devicetree bindings for the MT7621 SPI
device driver.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: NeilBrown <neil@brown.name>
Cc: Sankalp Negi <sankalpnegi2310@gmail.com>
Cc: Chuanhong Guo <gch981213@gmail.com>
Cc: John Crispin <john@phrozen.org>
Cc: Armando Miraglia <arma2ff0@gmail.com>
---
 .../devicetree/bindings/spi/spi-mt7621.txt    |  26 ++
 drivers/spi/Kconfig                           |   6 +
 drivers/spi/Makefile                          |   1 +
 drivers/spi/spi-mt7621.c                      | 422 ++++++++++++++++++
 drivers/staging/Kconfig                       |   2 -
 drivers/staging/Makefile                      |   1 -
 drivers/staging/mt7621-spi/Kconfig            |   6 -
 drivers/staging/mt7621-spi/Makefile           |   1 -
 drivers/staging/mt7621-spi/TODO               |   5 -
 drivers/staging/mt7621-spi/spi-mt7621.c       | 422 ------------------
 10 files changed, 455 insertions(+), 437 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/spi/spi-mt7621.txt
 create mode 100644 drivers/spi/spi-mt7621.c
 delete mode 100644 drivers/staging/mt7621-spi/Kconfig
 delete mode 100644 drivers/staging/mt7621-spi/Makefile
 delete mode 100644 drivers/staging/mt7621-spi/TODO
 delete mode 100644 drivers/staging/mt7621-spi/spi-mt7621.c

diff --git a/Documentation/devicetree/bindings/spi/spi-mt7621.txt b/Documentation/devicetree/bindings/spi/spi-mt7621.txt
new file mode 100644
index 000000000000..d5baec0fa56e
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/spi-mt7621.txt
@@ -0,0 +1,26 @@
+Binding for MTK SPI controller (MT7621 MIPS)
+
+Required properties:
+- compatible: Should be one of the following:
+  - "ralink,mt7621-spi": for mt7621/mt7628/mt7688 platforms
+- #address-cells: should be 1.
+- #size-cells: should be 0.
+- reg: Address and length of the register set for the device
+- resets: phandle to the reset controller asserting this device in
+          reset
+  See ../reset/reset.txt for details.
+
+Optional properties:
+- cs-gpios: see spi-bus.txt.
+
+Example:
+
+- SoC Specific Portion:
+spi0: spi@b00 {
+	compatible = "ralink,mt7621-spi";
+	reg = <0xb00 0x100>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+	resets = <&rstctrl 18>;
+	reset-names = "spi";
+};
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index f761655e2a36..202952f9da56 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -426,6 +426,12 @@ config SPI_MT65XX
 	  say Y or M here.If you are not sure, say N.
 	  SPI drivers for Mediatek MT65XX and MT81XX series ARM SoCs.
 
+config SPI_MT7621
+	tristate "MediaTek MT7621 SPI Controller"
+	depends on RALINK
+	help
+	  This selects a driver for the MediaTek MT7621 SPI Controller.
+
 config SPI_NPCM_PSPI
 	tristate "Nuvoton NPCM PSPI Controller"
 	depends on ARCH_NPCM || COMPILE_TEST
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index d8fc03c9faa2..369f29a8a6af 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -60,6 +60,7 @@ obj-$(CONFIG_SPI_MPC512x_PSC)		+= spi-mpc512x-psc.o
 obj-$(CONFIG_SPI_MPC52xx_PSC)		+= spi-mpc52xx-psc.o
 obj-$(CONFIG_SPI_MPC52xx)		+= spi-mpc52xx.o
 obj-$(CONFIG_SPI_MT65XX)                += spi-mt65xx.o
+obj-$(CONFIG_SPI_MT7621)		+= spi-mt7621.o
 obj-$(CONFIG_SPI_MXIC)			+= spi-mxic.o
 obj-$(CONFIG_SPI_MXS)			+= spi-mxs.o
 obj-$(CONFIG_SPI_NPCM_PSPI)		+= spi-npcm-pspi.o
diff --git a/drivers/spi/spi-mt7621.c b/drivers/spi/spi-mt7621.c
new file mode 100644
index 000000000000..b509f9fe3346
--- /dev/null
+++ b/drivers/spi/spi-mt7621.c
@@ -0,0 +1,422 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * spi-mt7621.c -- MediaTek MT7621 SPI controller driver
+ *
+ * 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>
+ *
+ * Some parts are based on spi-orion.c:
+ *   Author: Shadi Ammouri <shadi@marvell.com>
+ *   Copyright (C) 2007-2008 Marvell Ltd.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/reset.h>
+#include <linux/spi/spi.h>
+
+#define DRIVER_NAME		"spi-mt7621"
+
+/* in usec */
+#define RALINK_SPI_WAIT_MAX_LOOP 2000
+
+/* SPISTAT register bit field */
+#define SPISTAT_BUSY		BIT(0)
+
+#define MT7621_SPI_TRANS	0x00
+#define SPITRANS_BUSY		BIT(16)
+
+#define MT7621_SPI_OPCODE	0x04
+#define MT7621_SPI_DATA0	0x08
+#define MT7621_SPI_DATA4	0x18
+#define SPI_CTL_TX_RX_CNT_MASK	0xff
+#define SPI_CTL_START		BIT(8)
+
+#define MT7621_SPI_MASTER	0x28
+#define MASTER_MORE_BUFMODE	BIT(2)
+#define MASTER_FULL_DUPLEX	BIT(10)
+#define MASTER_RS_CLK_SEL	GENMASK(27, 16)
+#define MASTER_RS_CLK_SEL_SHIFT	16
+#define MASTER_RS_SLAVE_SEL	GENMASK(31, 29)
+
+#define MT7621_SPI_MOREBUF	0x2c
+#define MT7621_SPI_POLAR	0x38
+#define MT7621_SPI_SPACE	0x3c
+
+#define MT7621_CPHA		BIT(5)
+#define MT7621_CPOL		BIT(4)
+#define MT7621_LSB_FIRST	BIT(3)
+
+struct mt7621_spi {
+	struct spi_master	*master;
+	void __iomem		*base;
+	unsigned int		sys_freq;
+	unsigned int		speed;
+	struct clk		*clk;
+	int			pending_write;
+
+	struct mt7621_spi_ops	*ops;
+};
+
+static inline struct mt7621_spi *spidev_to_mt7621_spi(struct spi_device *spi)
+{
+	return spi_master_get_devdata(spi->master);
+}
+
+static inline u32 mt7621_spi_read(struct mt7621_spi *rs, u32 reg)
+{
+	return ioread32(rs->base + reg);
+}
+
+static inline void mt7621_spi_write(struct mt7621_spi *rs, u32 reg, u32 val)
+{
+	iowrite32(val, rs->base + reg);
+}
+
+static void mt7621_spi_reset(struct mt7621_spi *rs)
+{
+	u32 master = mt7621_spi_read(rs, MT7621_SPI_MASTER);
+
+	/*
+	 * Select SPI device 7, enable "more buffer mode" and disable
+	 * full-duplex (only half-duplex really works on this chip
+	 * reliably)
+	 */
+	master |= MASTER_RS_SLAVE_SEL | MASTER_MORE_BUFMODE;
+	master &= ~MASTER_FULL_DUPLEX;
+
+	mt7621_spi_write(rs, MT7621_SPI_MASTER, master);
+	rs->pending_write = 0;
+}
+
+static void mt7621_spi_set_cs(struct spi_device *spi, int enable)
+{
+	struct mt7621_spi *rs = spidev_to_mt7621_spi(spi);
+	int cs = spi->chip_select;
+	u32 polar = 0;
+
+	mt7621_spi_reset(rs);
+	if (enable)
+		polar = BIT(cs);
+	mt7621_spi_write(rs, MT7621_SPI_POLAR, polar);
+}
+
+static int mt7621_spi_prepare(struct spi_device *spi, unsigned int speed)
+{
+	struct mt7621_spi *rs = spidev_to_mt7621_spi(spi);
+	u32 rate;
+	u32 reg;
+
+	dev_dbg(&spi->dev, "speed:%u\n", speed);
+
+	rate = DIV_ROUND_UP(rs->sys_freq, speed);
+	dev_dbg(&spi->dev, "rate-1:%u\n", rate);
+
+	if (rate > 4097)
+		return -EINVAL;
+
+	if (rate < 2)
+		rate = 2;
+
+	reg = mt7621_spi_read(rs, MT7621_SPI_MASTER);
+	reg &= ~MASTER_RS_CLK_SEL;
+	reg |= (rate - 2) << MASTER_RS_CLK_SEL_SHIFT;
+	rs->speed = speed;
+
+	reg &= ~MT7621_LSB_FIRST;
+	if (spi->mode & SPI_LSB_FIRST)
+		reg |= MT7621_LSB_FIRST;
+
+	/*
+	 * This SPI controller seems to be tested on SPI flash only and some
+	 * bits are swizzled under other SPI modes probably due to incorrect
+	 * wiring inside the silicon. Only mode 0 works correctly.
+	 */
+	reg &= ~(MT7621_CPHA | MT7621_CPOL);
+
+	mt7621_spi_write(rs, MT7621_SPI_MASTER, reg);
+
+	return 0;
+}
+
+static inline int mt7621_spi_wait_till_ready(struct mt7621_spi *rs)
+{
+	int i;
+
+	for (i = 0; i < RALINK_SPI_WAIT_MAX_LOOP; i++) {
+		u32 status;
+
+		status = mt7621_spi_read(rs, MT7621_SPI_TRANS);
+		if ((status & SPITRANS_BUSY) == 0)
+			return 0;
+		cpu_relax();
+		udelay(1);
+	}
+
+	return -ETIMEDOUT;
+}
+
+static void mt7621_spi_read_half_duplex(struct mt7621_spi *rs,
+					int rx_len, u8 *buf)
+{
+	/*
+	 * Combine with any pending write, and perform one or more half-duplex
+	 * transactions reading 'len' bytes. Data to be written is already in
+	 * MT7621_SPI_DATA.
+	 */
+	int tx_len = rs->pending_write;
+
+	rs->pending_write = 0;
+
+	while (rx_len || tx_len) {
+		int i;
+		u32 val = (min(tx_len, 4) * 8) << 24;
+		int rx = min(rx_len, 32);
+
+		if (tx_len > 4)
+			val |= (tx_len - 4) * 8;
+		val |= (rx * 8) << 12;
+		mt7621_spi_write(rs, MT7621_SPI_MOREBUF, val);
+
+		tx_len = 0;
+
+		val = mt7621_spi_read(rs, MT7621_SPI_TRANS);
+		val |= SPI_CTL_START;
+		mt7621_spi_write(rs, MT7621_SPI_TRANS, val);
+
+		mt7621_spi_wait_till_ready(rs);
+
+		for (i = 0; i < rx; i++) {
+			if ((i % 4) == 0)
+				val = mt7621_spi_read(rs, MT7621_SPI_DATA0 + i);
+			*buf++ = val & 0xff;
+			val >>= 8;
+		}
+
+		rx_len -= i;
+	}
+}
+
+static inline void mt7621_spi_flush(struct mt7621_spi *rs)
+{
+	mt7621_spi_read_half_duplex(rs, 0, NULL);
+}
+
+static void mt7621_spi_write_half_duplex(struct mt7621_spi *rs,
+					 int tx_len, const u8 *buf)
+{
+	int val = 0;
+	int len = rs->pending_write;
+
+	if (len & 3) {
+		val = mt7621_spi_read(rs, MT7621_SPI_OPCODE + (len & ~3));
+		if (len < 4) {
+			val <<= (4 - len) * 8;
+			val = swab32(val);
+		}
+	}
+
+	while (tx_len > 0) {
+		if (len >= 36) {
+			rs->pending_write = len;
+			mt7621_spi_flush(rs);
+			len = 0;
+		}
+
+		val |= *buf++ << (8 * (len & 3));
+		len++;
+		if ((len & 3) == 0) {
+			if (len == 4)
+				/* The byte-order of the opcode is weird! */
+				val = swab32(val);
+			mt7621_spi_write(rs, MT7621_SPI_OPCODE + len - 4, val);
+			val = 0;
+		}
+		tx_len -= 1;
+	}
+	if (len & 3) {
+		if (len < 4) {
+			val = swab32(val);
+			val >>= (4 - len) * 8;
+		}
+		mt7621_spi_write(rs, MT7621_SPI_OPCODE + (len & ~3), val);
+	}
+	rs->pending_write = len;
+}
+
+static int mt7621_spi_transfer_one_message(struct spi_master *master,
+					   struct spi_message *m)
+{
+	struct mt7621_spi *rs = spi_master_get_devdata(master);
+	struct spi_device *spi = m->spi;
+	unsigned int speed = spi->max_speed_hz;
+	struct spi_transfer *t = NULL;
+	int status = 0;
+
+	mt7621_spi_wait_till_ready(rs);
+
+	list_for_each_entry(t, &m->transfers, transfer_list)
+		if (t->speed_hz < speed)
+			speed = t->speed_hz;
+
+	if (mt7621_spi_prepare(spi, speed)) {
+		status = -EIO;
+		goto msg_done;
+	}
+
+	mt7621_spi_set_cs(spi, 1);
+	m->actual_length = 0;
+	list_for_each_entry(t, &m->transfers, transfer_list) {
+		if ((t->rx_buf) && (t->tx_buf)) {
+			/* This controller will shift some extra data out
+			 * of spi_opcode if (mosi_bit_cnt > 0) &&
+			 * (cmd_bit_cnt == 0). So the claimed full-duplex
+			 * support is broken since we have no way to read
+			 * the MISO value during that bit.
+			 */
+			status = -EIO;
+			goto msg_done;
+		} else if (t->rx_buf) {
+			mt7621_spi_read_half_duplex(rs, t->len, t->rx_buf);
+		} else if (t->tx_buf) {
+			mt7621_spi_write_half_duplex(rs, t->len, t->tx_buf);
+		}
+		m->actual_length += t->len;
+	}
+	mt7621_spi_flush(rs);
+
+	mt7621_spi_set_cs(spi, 0);
+
+msg_done:
+	m->status = status;
+	spi_finalize_current_message(master);
+
+	return 0;
+}
+
+static int mt7621_spi_setup(struct spi_device *spi)
+{
+	struct mt7621_spi *rs = spidev_to_mt7621_spi(spi);
+
+	if ((spi->max_speed_hz == 0) ||
+		(spi->max_speed_hz > (rs->sys_freq / 2)))
+		spi->max_speed_hz = (rs->sys_freq / 2);
+
+	if (spi->max_speed_hz < (rs->sys_freq / 4097)) {
+		dev_err(&spi->dev, "setup: requested speed is too low %d Hz\n",
+			spi->max_speed_hz);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id mt7621_spi_match[] = {
+	{ .compatible = "ralink,mt7621-spi" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, mt7621_spi_match);
+
+static int mt7621_spi_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *match;
+	struct spi_master *master;
+	struct mt7621_spi *rs;
+	void __iomem *base;
+	struct resource *r;
+	int status = 0;
+	struct clk *clk;
+	struct mt7621_spi_ops *ops;
+	int ret;
+
+	match = of_match_device(mt7621_spi_match, &pdev->dev);
+	if (!match)
+		return -EINVAL;
+	ops = (struct mt7621_spi_ops *)match->data;
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(&pdev->dev, r);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(clk)) {
+		dev_err(&pdev->dev, "unable to get SYS clock, err=%d\n",
+			status);
+		return PTR_ERR(clk);
+	}
+
+	status = clk_prepare_enable(clk);
+	if (status)
+		return status;
+
+	master = spi_alloc_master(&pdev->dev, sizeof(*rs));
+	if (!master) {
+		dev_info(&pdev->dev, "master allocation failed\n");
+		return -ENOMEM;
+	}
+
+	master->mode_bits = SPI_LSB_FIRST;
+
+	master->setup = mt7621_spi_setup;
+	master->transfer_one_message = mt7621_spi_transfer_one_message;
+	master->bits_per_word_mask = SPI_BPW_MASK(8);
+	master->dev.of_node = pdev->dev.of_node;
+	master->num_chipselect = 2;
+
+	dev_set_drvdata(&pdev->dev, master);
+
+	rs = spi_master_get_devdata(master);
+	rs->base = base;
+	rs->clk = clk;
+	rs->master = master;
+	rs->sys_freq = clk_get_rate(rs->clk);
+	rs->ops = ops;
+	rs->pending_write = 0;
+	dev_info(&pdev->dev, "sys_freq: %u\n", rs->sys_freq);
+
+	ret = device_reset(&pdev->dev);
+	if (ret) {
+		dev_err(&pdev->dev, "SPI reset failed!\n");
+		return ret;
+	}
+
+	mt7621_spi_reset(rs);
+
+	return spi_register_master(master);
+}
+
+static int mt7621_spi_remove(struct platform_device *pdev)
+{
+	struct spi_master *master;
+	struct mt7621_spi *rs;
+
+	master = dev_get_drvdata(&pdev->dev);
+	rs = spi_master_get_devdata(master);
+
+	clk_disable(rs->clk);
+	spi_unregister_master(master);
+
+	return 0;
+}
+
+MODULE_ALIAS("platform:" DRIVER_NAME);
+
+static struct platform_driver mt7621_spi_driver = {
+	.driver = {
+		.name = DRIVER_NAME,
+		.of_match_table = mt7621_spi_match,
+	},
+	.probe = mt7621_spi_probe,
+	.remove = mt7621_spi_remove,
+};
+
+module_platform_driver(mt7621_spi_driver);
+
+MODULE_DESCRIPTION("MT7621 SPI driver");
+MODULE_AUTHOR("Felix Fietkau <nbd@nbd.name>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/staging/Kconfig b/drivers/staging/Kconfig
index c0901b96cfe4..3241bd50d139 100644
--- a/drivers/staging/Kconfig
+++ b/drivers/staging/Kconfig
@@ -106,8 +106,6 @@ source "drivers/staging/mt7621-pci-phy/Kconfig"
 
 source "drivers/staging/mt7621-pinctrl/Kconfig"
 
-source "drivers/staging/mt7621-spi/Kconfig"
-
 source "drivers/staging/mt7621-dma/Kconfig"
 
 source "drivers/staging/ralink-gdma/Kconfig"
diff --git a/drivers/staging/Makefile b/drivers/staging/Makefile
index 57c6bce13ff4..296ff11ecfae 100644
--- a/drivers/staging/Makefile
+++ b/drivers/staging/Makefile
@@ -43,7 +43,6 @@ obj-$(CONFIG_PI433)		+= pi433/
 obj-$(CONFIG_PCI_MT7621)	+= mt7621-pci/
 obj-$(CONFIG_PCI_MT7621_PHY)	+= mt7621-pci-phy/
 obj-$(CONFIG_PINCTRL_RT2880)	+= mt7621-pinctrl/
-obj-$(CONFIG_SPI_MT7621)	+= mt7621-spi/
 obj-$(CONFIG_SOC_MT7621)	+= mt7621-dma/
 obj-$(CONFIG_DMA_RALINK)	+= ralink-gdma/
 obj-$(CONFIG_MTK_MMC)		+= mt7621-mmc/
diff --git a/drivers/staging/mt7621-spi/Kconfig b/drivers/staging/mt7621-spi/Kconfig
deleted file mode 100644
index 0b90f4cfa426..000000000000
--- a/drivers/staging/mt7621-spi/Kconfig
+++ /dev/null
@@ -1,6 +0,0 @@
-config SPI_MT7621
-	tristate "MediaTek MT7621 SPI Controller"
-	depends on RALINK
-	help
-	  This selects a driver for the MediaTek MT7621 SPI Controller.
-
diff --git a/drivers/staging/mt7621-spi/Makefile b/drivers/staging/mt7621-spi/Makefile
deleted file mode 100644
index 3be508f63bac..000000000000
--- a/drivers/staging/mt7621-spi/Makefile
+++ /dev/null
@@ -1 +0,0 @@
-obj-$(CONFIG_SPI_MT7621)		+= spi-mt7621.o
diff --git a/drivers/staging/mt7621-spi/TODO b/drivers/staging/mt7621-spi/TODO
deleted file mode 100644
index fdbc5002c32a..000000000000
--- a/drivers/staging/mt7621-spi/TODO
+++ /dev/null
@@ -1,5 +0,0 @@
-
-- general code review and clean up
-- ensure device-tree requirements are documented
-
-Cc: NeilBrown <neil@brown.name>
diff --git a/drivers/staging/mt7621-spi/spi-mt7621.c b/drivers/staging/mt7621-spi/spi-mt7621.c
deleted file mode 100644
index b509f9fe3346..000000000000
--- a/drivers/staging/mt7621-spi/spi-mt7621.c
+++ /dev/null
@@ -1,422 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * spi-mt7621.c -- MediaTek MT7621 SPI controller driver
- *
- * 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>
- *
- * Some parts are based on spi-orion.c:
- *   Author: Shadi Ammouri <shadi@marvell.com>
- *   Copyright (C) 2007-2008 Marvell Ltd.
- */
-
-#include <linux/clk.h>
-#include <linux/delay.h>
-#include <linux/io.h>
-#include <linux/module.h>
-#include <linux/of_device.h>
-#include <linux/reset.h>
-#include <linux/spi/spi.h>
-
-#define DRIVER_NAME		"spi-mt7621"
-
-/* in usec */
-#define RALINK_SPI_WAIT_MAX_LOOP 2000
-
-/* SPISTAT register bit field */
-#define SPISTAT_BUSY		BIT(0)
-
-#define MT7621_SPI_TRANS	0x00
-#define SPITRANS_BUSY		BIT(16)
-
-#define MT7621_SPI_OPCODE	0x04
-#define MT7621_SPI_DATA0	0x08
-#define MT7621_SPI_DATA4	0x18
-#define SPI_CTL_TX_RX_CNT_MASK	0xff
-#define SPI_CTL_START		BIT(8)
-
-#define MT7621_SPI_MASTER	0x28
-#define MASTER_MORE_BUFMODE	BIT(2)
-#define MASTER_FULL_DUPLEX	BIT(10)
-#define MASTER_RS_CLK_SEL	GENMASK(27, 16)
-#define MASTER_RS_CLK_SEL_SHIFT	16
-#define MASTER_RS_SLAVE_SEL	GENMASK(31, 29)
-
-#define MT7621_SPI_MOREBUF	0x2c
-#define MT7621_SPI_POLAR	0x38
-#define MT7621_SPI_SPACE	0x3c
-
-#define MT7621_CPHA		BIT(5)
-#define MT7621_CPOL		BIT(4)
-#define MT7621_LSB_FIRST	BIT(3)
-
-struct mt7621_spi {
-	struct spi_master	*master;
-	void __iomem		*base;
-	unsigned int		sys_freq;
-	unsigned int		speed;
-	struct clk		*clk;
-	int			pending_write;
-
-	struct mt7621_spi_ops	*ops;
-};
-
-static inline struct mt7621_spi *spidev_to_mt7621_spi(struct spi_device *spi)
-{
-	return spi_master_get_devdata(spi->master);
-}
-
-static inline u32 mt7621_spi_read(struct mt7621_spi *rs, u32 reg)
-{
-	return ioread32(rs->base + reg);
-}
-
-static inline void mt7621_spi_write(struct mt7621_spi *rs, u32 reg, u32 val)
-{
-	iowrite32(val, rs->base + reg);
-}
-
-static void mt7621_spi_reset(struct mt7621_spi *rs)
-{
-	u32 master = mt7621_spi_read(rs, MT7621_SPI_MASTER);
-
-	/*
-	 * Select SPI device 7, enable "more buffer mode" and disable
-	 * full-duplex (only half-duplex really works on this chip
-	 * reliably)
-	 */
-	master |= MASTER_RS_SLAVE_SEL | MASTER_MORE_BUFMODE;
-	master &= ~MASTER_FULL_DUPLEX;
-
-	mt7621_spi_write(rs, MT7621_SPI_MASTER, master);
-	rs->pending_write = 0;
-}
-
-static void mt7621_spi_set_cs(struct spi_device *spi, int enable)
-{
-	struct mt7621_spi *rs = spidev_to_mt7621_spi(spi);
-	int cs = spi->chip_select;
-	u32 polar = 0;
-
-	mt7621_spi_reset(rs);
-	if (enable)
-		polar = BIT(cs);
-	mt7621_spi_write(rs, MT7621_SPI_POLAR, polar);
-}
-
-static int mt7621_spi_prepare(struct spi_device *spi, unsigned int speed)
-{
-	struct mt7621_spi *rs = spidev_to_mt7621_spi(spi);
-	u32 rate;
-	u32 reg;
-
-	dev_dbg(&spi->dev, "speed:%u\n", speed);
-
-	rate = DIV_ROUND_UP(rs->sys_freq, speed);
-	dev_dbg(&spi->dev, "rate-1:%u\n", rate);
-
-	if (rate > 4097)
-		return -EINVAL;
-
-	if (rate < 2)
-		rate = 2;
-
-	reg = mt7621_spi_read(rs, MT7621_SPI_MASTER);
-	reg &= ~MASTER_RS_CLK_SEL;
-	reg |= (rate - 2) << MASTER_RS_CLK_SEL_SHIFT;
-	rs->speed = speed;
-
-	reg &= ~MT7621_LSB_FIRST;
-	if (spi->mode & SPI_LSB_FIRST)
-		reg |= MT7621_LSB_FIRST;
-
-	/*
-	 * This SPI controller seems to be tested on SPI flash only and some
-	 * bits are swizzled under other SPI modes probably due to incorrect
-	 * wiring inside the silicon. Only mode 0 works correctly.
-	 */
-	reg &= ~(MT7621_CPHA | MT7621_CPOL);
-
-	mt7621_spi_write(rs, MT7621_SPI_MASTER, reg);
-
-	return 0;
-}
-
-static inline int mt7621_spi_wait_till_ready(struct mt7621_spi *rs)
-{
-	int i;
-
-	for (i = 0; i < RALINK_SPI_WAIT_MAX_LOOP; i++) {
-		u32 status;
-
-		status = mt7621_spi_read(rs, MT7621_SPI_TRANS);
-		if ((status & SPITRANS_BUSY) == 0)
-			return 0;
-		cpu_relax();
-		udelay(1);
-	}
-
-	return -ETIMEDOUT;
-}
-
-static void mt7621_spi_read_half_duplex(struct mt7621_spi *rs,
-					int rx_len, u8 *buf)
-{
-	/*
-	 * Combine with any pending write, and perform one or more half-duplex
-	 * transactions reading 'len' bytes. Data to be written is already in
-	 * MT7621_SPI_DATA.
-	 */
-	int tx_len = rs->pending_write;
-
-	rs->pending_write = 0;
-
-	while (rx_len || tx_len) {
-		int i;
-		u32 val = (min(tx_len, 4) * 8) << 24;
-		int rx = min(rx_len, 32);
-
-		if (tx_len > 4)
-			val |= (tx_len - 4) * 8;
-		val |= (rx * 8) << 12;
-		mt7621_spi_write(rs, MT7621_SPI_MOREBUF, val);
-
-		tx_len = 0;
-
-		val = mt7621_spi_read(rs, MT7621_SPI_TRANS);
-		val |= SPI_CTL_START;
-		mt7621_spi_write(rs, MT7621_SPI_TRANS, val);
-
-		mt7621_spi_wait_till_ready(rs);
-
-		for (i = 0; i < rx; i++) {
-			if ((i % 4) == 0)
-				val = mt7621_spi_read(rs, MT7621_SPI_DATA0 + i);
-			*buf++ = val & 0xff;
-			val >>= 8;
-		}
-
-		rx_len -= i;
-	}
-}
-
-static inline void mt7621_spi_flush(struct mt7621_spi *rs)
-{
-	mt7621_spi_read_half_duplex(rs, 0, NULL);
-}
-
-static void mt7621_spi_write_half_duplex(struct mt7621_spi *rs,
-					 int tx_len, const u8 *buf)
-{
-	int val = 0;
-	int len = rs->pending_write;
-
-	if (len & 3) {
-		val = mt7621_spi_read(rs, MT7621_SPI_OPCODE + (len & ~3));
-		if (len < 4) {
-			val <<= (4 - len) * 8;
-			val = swab32(val);
-		}
-	}
-
-	while (tx_len > 0) {
-		if (len >= 36) {
-			rs->pending_write = len;
-			mt7621_spi_flush(rs);
-			len = 0;
-		}
-
-		val |= *buf++ << (8 * (len & 3));
-		len++;
-		if ((len & 3) == 0) {
-			if (len == 4)
-				/* The byte-order of the opcode is weird! */
-				val = swab32(val);
-			mt7621_spi_write(rs, MT7621_SPI_OPCODE + len - 4, val);
-			val = 0;
-		}
-		tx_len -= 1;
-	}
-	if (len & 3) {
-		if (len < 4) {
-			val = swab32(val);
-			val >>= (4 - len) * 8;
-		}
-		mt7621_spi_write(rs, MT7621_SPI_OPCODE + (len & ~3), val);
-	}
-	rs->pending_write = len;
-}
-
-static int mt7621_spi_transfer_one_message(struct spi_master *master,
-					   struct spi_message *m)
-{
-	struct mt7621_spi *rs = spi_master_get_devdata(master);
-	struct spi_device *spi = m->spi;
-	unsigned int speed = spi->max_speed_hz;
-	struct spi_transfer *t = NULL;
-	int status = 0;
-
-	mt7621_spi_wait_till_ready(rs);
-
-	list_for_each_entry(t, &m->transfers, transfer_list)
-		if (t->speed_hz < speed)
-			speed = t->speed_hz;
-
-	if (mt7621_spi_prepare(spi, speed)) {
-		status = -EIO;
-		goto msg_done;
-	}
-
-	mt7621_spi_set_cs(spi, 1);
-	m->actual_length = 0;
-	list_for_each_entry(t, &m->transfers, transfer_list) {
-		if ((t->rx_buf) && (t->tx_buf)) {
-			/* This controller will shift some extra data out
-			 * of spi_opcode if (mosi_bit_cnt > 0) &&
-			 * (cmd_bit_cnt == 0). So the claimed full-duplex
-			 * support is broken since we have no way to read
-			 * the MISO value during that bit.
-			 */
-			status = -EIO;
-			goto msg_done;
-		} else if (t->rx_buf) {
-			mt7621_spi_read_half_duplex(rs, t->len, t->rx_buf);
-		} else if (t->tx_buf) {
-			mt7621_spi_write_half_duplex(rs, t->len, t->tx_buf);
-		}
-		m->actual_length += t->len;
-	}
-	mt7621_spi_flush(rs);
-
-	mt7621_spi_set_cs(spi, 0);
-
-msg_done:
-	m->status = status;
-	spi_finalize_current_message(master);
-
-	return 0;
-}
-
-static int mt7621_spi_setup(struct spi_device *spi)
-{
-	struct mt7621_spi *rs = spidev_to_mt7621_spi(spi);
-
-	if ((spi->max_speed_hz == 0) ||
-		(spi->max_speed_hz > (rs->sys_freq / 2)))
-		spi->max_speed_hz = (rs->sys_freq / 2);
-
-	if (spi->max_speed_hz < (rs->sys_freq / 4097)) {
-		dev_err(&spi->dev, "setup: requested speed is too low %d Hz\n",
-			spi->max_speed_hz);
-		return -EINVAL;
-	}
-
-	return 0;
-}
-
-static const struct of_device_id mt7621_spi_match[] = {
-	{ .compatible = "ralink,mt7621-spi" },
-	{},
-};
-MODULE_DEVICE_TABLE(of, mt7621_spi_match);
-
-static int mt7621_spi_probe(struct platform_device *pdev)
-{
-	const struct of_device_id *match;
-	struct spi_master *master;
-	struct mt7621_spi *rs;
-	void __iomem *base;
-	struct resource *r;
-	int status = 0;
-	struct clk *clk;
-	struct mt7621_spi_ops *ops;
-	int ret;
-
-	match = of_match_device(mt7621_spi_match, &pdev->dev);
-	if (!match)
-		return -EINVAL;
-	ops = (struct mt7621_spi_ops *)match->data;
-
-	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	base = devm_ioremap_resource(&pdev->dev, r);
-	if (IS_ERR(base))
-		return PTR_ERR(base);
-
-	clk = devm_clk_get(&pdev->dev, NULL);
-	if (IS_ERR(clk)) {
-		dev_err(&pdev->dev, "unable to get SYS clock, err=%d\n",
-			status);
-		return PTR_ERR(clk);
-	}
-
-	status = clk_prepare_enable(clk);
-	if (status)
-		return status;
-
-	master = spi_alloc_master(&pdev->dev, sizeof(*rs));
-	if (!master) {
-		dev_info(&pdev->dev, "master allocation failed\n");
-		return -ENOMEM;
-	}
-
-	master->mode_bits = SPI_LSB_FIRST;
-
-	master->setup = mt7621_spi_setup;
-	master->transfer_one_message = mt7621_spi_transfer_one_message;
-	master->bits_per_word_mask = SPI_BPW_MASK(8);
-	master->dev.of_node = pdev->dev.of_node;
-	master->num_chipselect = 2;
-
-	dev_set_drvdata(&pdev->dev, master);
-
-	rs = spi_master_get_devdata(master);
-	rs->base = base;
-	rs->clk = clk;
-	rs->master = master;
-	rs->sys_freq = clk_get_rate(rs->clk);
-	rs->ops = ops;
-	rs->pending_write = 0;
-	dev_info(&pdev->dev, "sys_freq: %u\n", rs->sys_freq);
-
-	ret = device_reset(&pdev->dev);
-	if (ret) {
-		dev_err(&pdev->dev, "SPI reset failed!\n");
-		return ret;
-	}
-
-	mt7621_spi_reset(rs);
-
-	return spi_register_master(master);
-}
-
-static int mt7621_spi_remove(struct platform_device *pdev)
-{
-	struct spi_master *master;
-	struct mt7621_spi *rs;
-
-	master = dev_get_drvdata(&pdev->dev);
-	rs = spi_master_get_devdata(master);
-
-	clk_disable(rs->clk);
-	spi_unregister_master(master);
-
-	return 0;
-}
-
-MODULE_ALIAS("platform:" DRIVER_NAME);
-
-static struct platform_driver mt7621_spi_driver = {
-	.driver = {
-		.name = DRIVER_NAME,
-		.of_match_table = mt7621_spi_match,
-	},
-	.probe = mt7621_spi_probe,
-	.remove = mt7621_spi_remove,
-};
-
-module_platform_driver(mt7621_spi_driver);
-
-MODULE_DESCRIPTION("MT7621 SPI driver");
-MODULE_AUTHOR("Felix Fietkau <nbd@nbd.name>");
-MODULE_LICENSE("GPL");
-- 
2.21.0

Re: [PATCH] spi: mt7621: Move SPI driver out of staging

[Mark Brown]

[-- Attachment #1.1: Type: text/plain, Size: 2084 bytes --]

On Thu, Mar 14, 2019 at 12:52:12PM +0100, Stefan Roese wrote:

This looks pretty good, a few trivial issues below but nothing major I
think.

> +config SPI_MT7621
> +	tristate "MediaTek MT7621 SPI Controller"
> +	depends on RALINK
> +	help
> +	  This selects a driver for the MediaTek MT7621 SPI Controller.
> +

I'm not seeing any build time dependency on this, please add an ||
COMPILE_TEST to help with build testing.

> @@ -0,0 +1,422 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * spi-mt7621.c -- MediaTek MT7621 SPI controller driver
> + *

Please make the entire comment a C++ one to 

> + * Some parts are based on spi-orion.c:
> + *   Author: Shadi Ammouri <shadi@marvell.com>
> + *   Copyright (C) 2007-2008 Marvell Ltd.

That driver dates from 2008 AFAICT, and had some changes after then?

> +static void mt7621_spi_set_cs(struct spi_device *spi, int enable)
> +{
> +	struct mt7621_spi *rs = spidev_to_mt7621_spi(spi);
> +	int cs = spi->chip_select;
> +	u32 polar = 0;
> +
> +	mt7621_spi_reset(rs);
> +	if (enable)
> +		polar = BIT(cs);
> +	mt7621_spi_write(rs, MT7621_SPI_POLAR, polar);
> +}

Will doing a reset mess up the rate configuration and stuff that's done
in _prepare(), or is _reset() perhaps not an entirely accurate name?

> +	list_for_each_entry(t, &m->transfers, transfer_list)
> +		if (t->speed_hz < speed)
> +			speed = t->speed_hz;

This should be in the core if it's needed, it's going to be the same for
all drivers.

> +	master->setup = mt7621_spi_setup;
> +	master->transfer_one_message = mt7621_spi_transfer_one_message;
> +	master->bits_per_word_mask = SPI_BPW_MASK(8);
> +	master->dev.of_node = pdev->dev.of_node;
> +	master->num_chipselect = 2;

The driver should set SPI_CONTROLLER_HALF_DUPLEX in flags.

> +	clk_disable(rs->clk);

This needs to be clk_disable_unprepare() to ensure the clock is
unprepared as well as disabled.

> +	spi_unregister_master(master);

Just use devm_spi_register_controller()?  The _master() name is legacy
and devm_ would make life easier.

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Re: [PATCH] spi: mt7621: Move SPI driver out of staging

[Stefan Roese]

On 21.03.19 15:25, Mark Brown wrote:
> On Thu, Mar 14, 2019 at 12:52:12PM +0100, Stefan Roese wrote:
> 
> This looks pretty good, a few trivial issues below but nothing major I
> think.
> 
>> +config SPI_MT7621
>> +	tristate "MediaTek MT7621 SPI Controller"
>> +	depends on RALINK
>> +	help
>> +	  This selects a driver for the MediaTek MT7621 SPI Controller.
>> +
> 
> I'm not seeing any build time dependency on this, please add an ||
> COMPILE_TEST to help with build testing.

Okay, will add in v2.
  
>> @@ -0,0 +1,422 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * spi-mt7621.c -- MediaTek MT7621 SPI controller driver
>> + *
> 
> Please make the entire comment a C++ one to

Will change in v2.
  
>> + * Some parts are based on spi-orion.c:
>> + *   Author: Shadi Ammouri <shadi@marvell.com>
>> + *   Copyright (C) 2007-2008 Marvell Ltd.
> 
> That driver dates from 2008 AFAICT, and had some changes after then?

The spi-orion driver? I didn't check. That's what in the header of
this driver since quite some time. And I didn't want to change any
copyright notices.

BTW: spi-orion still has the same copyright message.
  
>> +static void mt7621_spi_set_cs(struct spi_device *spi, int enable)
>> +{
>> +	struct mt7621_spi *rs = spidev_to_mt7621_spi(spi);
>> +	int cs = spi->chip_select;
>> +	u32 polar = 0;
>> +
>> +	mt7621_spi_reset(rs);
>> +	if (enable)
>> +		polar = BIT(cs);
>> +	mt7621_spi_write(rs, MT7621_SPI_POLAR, polar);
>> +}
> 
> Will doing a reset mess up the rate configuration and stuff that's done
> in _prepare(), or is _reset() perhaps not an entirely accurate name?

You are correct. The function name is not really matching its
implementation. Will change in v2.
  
>> +	list_for_each_entry(t, &m->transfers, transfer_list)
>> +		if (t->speed_hz < speed)
>> +			speed = t->speed_hz;
> 
> This should be in the core if it's needed, it's going to be the same for
> all drivers.

I'm not sure here, other drivers might set the speed individually for
each "spi_transfer" entry. In this driver its set only once: before
beginning to transfer all entries. So should I really move this into
the core and set all speed_hz values to the minimum one of the list?
  
>> +	master->setup = mt7621_spi_setup;
>> +	master->transfer_one_message = mt7621_spi_transfer_one_message;
>> +	master->bits_per_word_mask = SPI_BPW_MASK(8);
>> +	master->dev.of_node = pdev->dev.of_node;
>> +	master->num_chipselect = 2;
> 
> The driver should set SPI_CONTROLLER_HALF_DUPLEX in flags.

Will update in v2.
  
>> +	clk_disable(rs->clk);
> 
> This needs to be clk_disable_unprepare() to ensure the clock is
> unprepared as well as disabled.

Okay, will change in v2.
  
>> +	spi_unregister_master(master);
> 
> Just use devm_spi_register_controller()?  The _master() name is legacy
> and devm_ would make life easier.

Yes, will change in v2.

Thanks for the review.

Thanks,
Stefan

Re: [PATCH] spi: mt7621: Move SPI driver out of staging

[Mark Brown]

[-- Attachment #1.1: Type: text/plain, Size: 787 bytes --]

On Fri, Mar 22, 2019 at 03:02:54PM +0100, Stefan Roese wrote:
> On 21.03.19 15:25, Mark Brown wrote:

> > > +	list_for_each_entry(t, &m->transfers, transfer_list)
> > > +		if (t->speed_hz < speed)
> > > +			speed = t->speed_hz;

> > This should be in the core if it's needed, it's going to be the same for
> > all drivers.

> I'm not sure here, other drivers might set the speed individually for
> each "spi_transfer" entry. In this driver its set only once: before
> beginning to transfer all entries. So should I really move this into
> the core and set all speed_hz values to the minimum one of the list?

Oh, I see what it's doing...  the driver should really be setting the
speed per transfer, though in practice I'm not convinced that anything
ever varies within a single message.

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