spi: mt7621: Move SPI driver out of staging

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>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/spi/spi-mt7621.txt

+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";
+};

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 || COMPILE_TEST
+	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

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

drivers/staging/mt7621-spi/spi-mt7621.c → drivers/spi/spi-mt7621.c

 // 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.
- */
+//
+// 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>
@@ -52,7 +51,7 @@
 #define MT7621_LSB_FIRST	BIT(3)
 
 struct mt7621_spi {
-	struct spi_master	*master;
+	struct spi_controller	*master;
 	void __iomem		*base;
 	unsigned int		sys_freq;
 	unsigned int		speed;
@@ -64,7 +63,7 @@ struct mt7621_spi {
 
 static inline struct mt7621_spi *spidev_to_mt7621_spi(struct spi_device *spi)
 {
-	return spi_master_get_devdata(spi->master);
+	return spi_controller_get_devdata(spi->master);
 }
 
 static inline u32 mt7621_spi_read(struct mt7621_spi *rs, u32 reg)
@@ -77,29 +76,25 @@ 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)
+static void mt7621_spi_set_cs(struct spi_device *spi, int enable)
 {
-	u32 master = mt7621_spi_read(rs, MT7621_SPI_MASTER);
+	struct mt7621_spi *rs = spidev_to_mt7621_spi(spi);
+	int cs = spi->chip_select;
+	u32 polar = 0;
+	u32 master;
 
 	/*
 	 * Select SPI device 7, enable "more buffer mode" and disable
 	 * full-duplex (only half-duplex really works on this chip
 	 * reliably)
 	 */
+	master = mt7621_spi_read(rs, MT7621_SPI_MASTER);
 	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;
+	rs->pending_write = 0;
 
-	mt7621_spi_reset(rs);
 	if (enable)
 		polar = BIT(cs);
 	mt7621_spi_write(rs, MT7621_SPI_POLAR, polar);
@@ -163,13 +158,14 @@ static inline int mt7621_spi_wait_till_ready(struct mt7621_spi *rs)
 static void mt7621_spi_read_half_duplex(struct mt7621_spi *rs,
 					int rx_len, u8 *buf)
 {
+	int tx_len;
+
 	/*
 	 * 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;
-
+	tx_len = rs->pending_write;
 	rs->pending_write = 0;
 
 	while (rx_len || tx_len) {
@@ -209,8 +205,8 @@ static inline void mt7621_spi_flush(struct mt7621_spi *rs)
 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;
+	int val = 0;
 
 	if (len & 3) {
 		val = mt7621_spi_read(rs, MT7621_SPI_OPCODE + (len & ~3));
@@ -238,6 +234,7 @@ static void mt7621_spi_write_half_duplex(struct mt7621_spi *rs,
 		}
 		tx_len -= 1;
 	}
+
 	if (len & 3) {
 		if (len < 4) {
 			val = swab32(val);
@@ -245,13 +242,14 @@ static void mt7621_spi_write_half_duplex(struct mt7621_spi *rs,
 		}
 		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,
+static int mt7621_spi_transfer_one_message(struct spi_controller *master,
 					   struct spi_message *m)
 {
-	struct mt7621_spi *rs = spi_master_get_devdata(master);
+	struct mt7621_spi *rs = spi_controller_get_devdata(master);
 	struct spi_device *spi = m->spi;
 	unsigned int speed = spi->max_speed_hz;
 	struct spi_transfer *t = NULL;
@@ -268,11 +266,14 @@ static int mt7621_spi_transfer_one_message(struct spi_master *master,
 		goto msg_done;
 	}
 
+	/* Assert CS */
 	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
+			/*
+			 * 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
@@ -287,8 +288,9 @@ static int mt7621_spi_transfer_one_message(struct spi_master *master,
 		}
 		m->actual_length += t->len;
 	}
-	mt7621_spi_flush(rs);
 
+	/* Flush data and deassert CS */
+	mt7621_spi_flush(rs);
 	mt7621_spi_set_cs(spi, 0);
 
 msg_done:
@@ -324,7 +326,7 @@ 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 spi_controller *master;
 	struct mt7621_spi *rs;
 	void __iomem *base;
 	struct resource *r;
@@ -361,7 +363,7 @@ static int mt7621_spi_probe(struct platform_device *pdev)
 	}
 
 	master->mode_bits = SPI_LSB_FIRST;
-
+	master->flags = SPI_CONTROLLER_HALF_DUPLEX;
 	master->setup = mt7621_spi_setup;
 	master->transfer_one_message = mt7621_spi_transfer_one_message;
 	master->bits_per_word_mask = SPI_BPW_MASK(8);
@@ -370,7 +372,7 @@ static int mt7621_spi_probe(struct platform_device *pdev)
 
 	dev_set_drvdata(&pdev->dev, master);
 
-	rs = spi_master_get_devdata(master);
+	rs = spi_controller_get_devdata(master);
 	rs->base = base;
 	rs->clk = clk;
 	rs->master = master;
@@ -385,21 +387,18 @@ static int mt7621_spi_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	mt7621_spi_reset(rs);
-
-	return spi_register_master(master);
+	return devm_spi_register_controller(&pdev->dev, master);
 }
 
 static int mt7621_spi_remove(struct platform_device *pdev)
 {
-	struct spi_master *master;
+	struct spi_controller *master;
 	struct mt7621_spi *rs;
 
 	master = dev_get_drvdata(&pdev->dev);
-	rs = spi_master_get_devdata(master);
+	rs = spi_controller_get_devdata(master);
 
-	clk_disable(rs->clk);
-	spi_unregister_master(master);
+	clk_disable_unprepare(rs->clk);
 
 	return 0;
 }

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"

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/

drivers/staging/mt7621-spi/Kconfig

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

drivers/staging/mt7621-spi/Makefile

-obj-$(CONFIG_SPI_MT7621)		+= spi-mt7621.o

drivers/staging/mt7621-spi/TODO

-
-- general code review and clean up
-- ensure device-tree requirements are documented
-
-Cc: NeilBrown <neil@brown.name>