realtek: backport spi-realtek-rtl driver from 5.12 to 5.10

This patch backports "spi-realtek-rtl" driver to Kernel 5.10 from 5.12.
"MACH_REALTEK_RTL" is used as a platform name in upstream, but "RTL838X"
is used in OpenWrt, so update the dependency by the additional patch.

Signed-off-by: INAGAKI Hiroshi <musashino.open@gmail.com>

3 files changed, 322 insertions, 0 deletions

diff --git a/target/linux/realtek/patches-5.10/003-5.12-spi-realtek-rtl838x-rtl839x-spi-controller.patch b/target/linux/realtek/patches-5.10/003-5.12-spi-realtek-rtl838x-rtl839x-spi-controller.patch
new file mode 100644
index 0000000000..035b0e655f
--- /dev/null
+++ b/target/linux/realtek/patches-5.10/003-5.12-spi-realtek-rtl838x-rtl839x-spi-controller.patch
@@ -0,0 +1,63 @@
+From 6acbd614c2c8d3b8de5fb7605d6e24b9b3a8a17b Mon Sep 17 00:00:00 2001
+From: Bert Vermeulen <bert@biot.com>
+Date: Wed, 20 Jan 2021 14:59:27 +0100
+Subject: spi: Realtek RTL838x/RTL839x SPI controller
+
+Signed-off-by: Bert Vermeulen <bert@biot.com>
+Link: https://lore.kernel.org/r/20210120135928.246054-2-bert@biot.com
+Signed-off-by: Mark Brown <broonie@kernel.org>
+---
+ .../devicetree/bindings/spi/realtek,rtl-spi.yaml   | 41 ++++++++++++++++++++++
+ 1 file changed, 41 insertions(+)
+ create mode 100644 Documentation/devicetree/bindings/spi/realtek,rtl-spi.yaml
+
+diff --git a/Documentation/devicetree/bindings/spi/realtek,rtl-spi.yaml b/Documentation/devicetree/bindings/spi/realtek,rtl-spi.yaml
+new file mode 100644
+index 0000000000000..30a62a211984f
+--- /dev/null
++++ b/Documentation/devicetree/bindings/spi/realtek,rtl-spi.yaml
+@@ -0,0 +1,41 @@
++# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
++%YAML 1.2
++---
++$id: http://devicetree.org/schemas/spi/realtek,rtl-spi.yaml#
++$schema: http://devicetree.org/meta-schemas/core.yaml#
++
++title: Realtek RTL838x/RTL839x SPI controller
++
++maintainers:
++  - Bert Vermeulen <bert@biot.com>
++  - Birger Koblitz <mail@birger-koblitz.de>
++
++allOf:
++  - $ref: "spi-controller.yaml#"
++
++properties:
++  compatible:
++    oneOf:
++      - const: realtek,rtl8380-spi
++      - const: realtek,rtl8382-spi
++      - const: realtek,rtl8391-spi
++      - const: realtek,rtl8392-spi
++      - const: realtek,rtl8393-spi
++
++  reg:
++    maxItems: 1
++
++required:
++  - compatible
++  - reg
++
++unevaluatedProperties: false
++
++examples:
++  - |
++    spi: spi@1200 {
++        compatible = "realtek,rtl8382-spi";
++        reg = <0x1200 0x100>;
++        #address-cells = <1>;
++        #size-cells = <0>;
++    };
+-- 
+cgit 1.2.3-1.el7
+
diff --git a/target/linux/realtek/patches-5.10/004-5.12-spi-realtek-rtl-add-support-for-realtek-rtl838x-rtl839x-spi-controllers.patch b/target/linux/realtek/patches-5.10/004-5.12-spi-realtek-rtl-add-support-for-realtek-rtl838x-rtl839x-spi-controllers.patch
new file mode 100644
index 0000000000..090847baad
--- /dev/null
+++ b/target/linux/realtek/patches-5.10/004-5.12-spi-realtek-rtl-add-support-for-realtek-rtl838x-rtl839x-spi-controllers.patch
@@ -0,0 +1,248 @@
+From a8af5cc2ff1e804694629a8ef320935629dd15ba Mon Sep 17 00:00:00 2001
+From: Bert Vermeulen <bert@biot.com>
+Date: Wed, 20 Jan 2021 14:59:28 +0100
+Subject: spi: realtek-rtl: Add support for Realtek RTL838x/RTL839x SPI
+ controllers
+
+This driver likely also supports earlier (RTL8196) and later (RTL93xx)
+SoCs.
+
+The SPI hardware in these SoCs is specifically intended for connecting NOR
+bootflash chips, and only used for that in dozens of examined devices.
+However boiled down to basics, it's really just a half-duplex SPI
+controller.
+
+The hardware appears to have a vestigial second chip-select control, but
+it hasn't been seen in the wild and is thus not supported.
+
+Signed-off-by: Bert Vermeulen <bert@biot.com>
+Link: https://lore.kernel.org/r/20210120135928.246054-3-bert@biot.com
+Signed-off-by: Mark Brown <broonie@kernel.org>
+---
+ drivers/spi/Makefile          |   1 +
+ drivers/spi/spi-realtek-rtl.c | 209 ++++++++++++++++++++++++++++++++++++++++++
+ 2 files changed, 210 insertions(+)
+ create mode 100644 drivers/spi/spi-realtek-rtl.c
+
+--- a/drivers/spi/Makefile
++++ b/drivers/spi/Makefile
+@@ -94,6 +94,7 @@ obj-$(CONFIG_SPI_QCOM_QSPI)		+= spi-qcom
+ obj-$(CONFIG_SPI_QUP)			+= spi-qup.o
+ obj-$(CONFIG_SPI_ROCKCHIP)		+= spi-rockchip.o
+ obj-$(CONFIG_SPI_RB4XX)			+= spi-rb4xx.o
++obj-$(CONFIG_MACH_REALTEK_RTL)		+= spi-realtek-rtl.o
+ obj-$(CONFIG_SPI_RPCIF)			+= spi-rpc-if.o
+ obj-$(CONFIG_SPI_RSPI)			+= spi-rspi.o
+ obj-$(CONFIG_SPI_S3C24XX)		+= spi-s3c24xx-hw.o
+--- /dev/null
++++ b/drivers/spi/spi-realtek-rtl.c
+@@ -0,0 +1,209 @@
++// SPDX-License-Identifier: GPL-2.0-only
++
++#include <linux/module.h>
++#include <linux/platform_device.h>
++#include <linux/mod_devicetable.h>
++#include <linux/spi/spi.h>
++
++struct rtspi {
++	void __iomem *base;
++};
++
++/* SPI Flash Configuration Register */
++#define RTL_SPI_SFCR			0x00
++#define RTL_SPI_SFCR_RBO		BIT(28)
++#define RTL_SPI_SFCR_WBO		BIT(27)
++
++/* SPI Flash Control and Status Register */
++#define RTL_SPI_SFCSR			0x08
++#define RTL_SPI_SFCSR_CSB0		BIT(31)
++#define RTL_SPI_SFCSR_CSB1		BIT(30)
++#define RTL_SPI_SFCSR_RDY		BIT(27)
++#define RTL_SPI_SFCSR_CS		BIT(24)
++#define RTL_SPI_SFCSR_LEN_MASK		~(0x03 << 28)
++#define RTL_SPI_SFCSR_LEN1		(0x00 << 28)
++#define RTL_SPI_SFCSR_LEN4		(0x03 << 28)
++
++/* SPI Flash Data Register */
++#define RTL_SPI_SFDR			0x0c
++
++#define REG(x)		(rtspi->base + x)
++
++
++static void rt_set_cs(struct spi_device *spi, bool active)
++{
++	struct rtspi *rtspi = spi_controller_get_devdata(spi->controller);
++	u32 value;
++
++	/* CS0 bit is active low */
++	value = readl(REG(RTL_SPI_SFCSR));
++	if (active)
++		value |= RTL_SPI_SFCSR_CSB0;
++	else
++		value &= ~RTL_SPI_SFCSR_CSB0;
++	writel(value, REG(RTL_SPI_SFCSR));
++}
++
++static void set_size(struct rtspi *rtspi, int size)
++{
++	u32 value;
++
++	value = readl(REG(RTL_SPI_SFCSR));
++	value &= RTL_SPI_SFCSR_LEN_MASK;
++	if (size == 4)
++		value |= RTL_SPI_SFCSR_LEN4;
++	else if (size == 1)
++		value |= RTL_SPI_SFCSR_LEN1;
++	writel(value, REG(RTL_SPI_SFCSR));
++}
++
++static inline void wait_ready(struct rtspi *rtspi)
++{
++	while (!(readl(REG(RTL_SPI_SFCSR)) & RTL_SPI_SFCSR_RDY))
++		cpu_relax();
++}
++static void send4(struct rtspi *rtspi, const u32 *buf)
++{
++	wait_ready(rtspi);
++	set_size(rtspi, 4);
++	writel(*buf, REG(RTL_SPI_SFDR));
++}
++
++static void send1(struct rtspi *rtspi, const u8 *buf)
++{
++	wait_ready(rtspi);
++	set_size(rtspi, 1);
++	writel(buf[0] << 24, REG(RTL_SPI_SFDR));
++}
++
++static void rcv4(struct rtspi *rtspi, u32 *buf)
++{
++	wait_ready(rtspi);
++	set_size(rtspi, 4);
++	*buf = readl(REG(RTL_SPI_SFDR));
++}
++
++static void rcv1(struct rtspi *rtspi, u8 *buf)
++{
++	wait_ready(rtspi);
++	set_size(rtspi, 1);
++	*buf = readl(REG(RTL_SPI_SFDR)) >> 24;
++}
++
++static int transfer_one(struct spi_controller *ctrl, struct spi_device *spi,
++			struct spi_transfer *xfer)
++{
++	struct rtspi *rtspi = spi_controller_get_devdata(ctrl);
++	void *rx_buf;
++	const void *tx_buf;
++	int cnt;
++
++	tx_buf = xfer->tx_buf;
++	rx_buf = xfer->rx_buf;
++	cnt = xfer->len;
++	if (tx_buf) {
++		while (cnt >= 4) {
++			send4(rtspi, tx_buf);
++			tx_buf += 4;
++			cnt -= 4;
++		}
++		while (cnt) {
++			send1(rtspi, tx_buf);
++			tx_buf++;
++			cnt--;
++		}
++	} else if (rx_buf) {
++		while (cnt >= 4) {
++			rcv4(rtspi, rx_buf);
++			rx_buf += 4;
++			cnt -= 4;
++		}
++		while (cnt) {
++			rcv1(rtspi, rx_buf);
++			rx_buf++;
++			cnt--;
++		}
++	}
++
++	spi_finalize_current_transfer(ctrl);
++
++	return 0;
++}
++
++static void init_hw(struct rtspi *rtspi)
++{
++	u32 value;
++
++	/* Turn on big-endian byte ordering */
++	value = readl(REG(RTL_SPI_SFCR));
++	value |= RTL_SPI_SFCR_RBO | RTL_SPI_SFCR_WBO;
++	writel(value, REG(RTL_SPI_SFCR));
++
++	value = readl(REG(RTL_SPI_SFCSR));
++	/* Permanently disable CS1, since it's never used */
++	value |= RTL_SPI_SFCSR_CSB1;
++	/* Select CS0 for use */
++	value &= RTL_SPI_SFCSR_CS;
++	writel(value, REG(RTL_SPI_SFCSR));
++}
++
++static int realtek_rtl_spi_probe(struct platform_device *pdev)
++{
++	struct spi_controller *ctrl;
++	struct rtspi *rtspi;
++	int err;
++
++	ctrl = devm_spi_alloc_master(&pdev->dev, sizeof(*rtspi));
++	if (!ctrl) {
++		dev_err(&pdev->dev, "Error allocating SPI controller\n");
++		return -ENOMEM;
++	}
++	platform_set_drvdata(pdev, ctrl);
++	rtspi = spi_controller_get_devdata(ctrl);
++
++	rtspi->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
++	if (IS_ERR(rtspi->base)) {
++		dev_err(&pdev->dev, "Could not map SPI register address");
++		return -ENOMEM;
++	}
++
++	init_hw(rtspi);
++
++	ctrl->dev.of_node = pdev->dev.of_node;
++	ctrl->flags = SPI_CONTROLLER_HALF_DUPLEX;
++	ctrl->set_cs = rt_set_cs;
++	ctrl->transfer_one = transfer_one;
++
++	err = devm_spi_register_controller(&pdev->dev, ctrl);
++	if (err) {
++		dev_err(&pdev->dev, "Could not register SPI controller\n");
++		return -ENODEV;
++	}
++
++	return 0;
++}
++
++
++static const struct of_device_id realtek_rtl_spi_of_ids[] = {
++	{ .compatible = "realtek,rtl8380-spi" },
++	{ .compatible = "realtek,rtl8382-spi" },
++	{ .compatible = "realtek,rtl8391-spi" },
++	{ .compatible = "realtek,rtl8392-spi" },
++	{ .compatible = "realtek,rtl8393-spi" },
++	{ /* sentinel */ }
++};
++MODULE_DEVICE_TABLE(of, realtek_rtl_spi_of_ids);
++
++static struct platform_driver realtek_rtl_spi_driver = {
++	.probe = realtek_rtl_spi_probe,
++	.driver = {
++		.name = "realtek-rtl-spi",
++		.of_match_table = realtek_rtl_spi_of_ids,
++	},
++};
++
++module_platform_driver(realtek_rtl_spi_driver);
++
++MODULE_LICENSE("GPL v2");
++MODULE_AUTHOR("Bert Vermeulen <bert@biot.com>");
++MODULE_DESCRIPTION("Realtek RTL SPI driver");
diff --git a/target/linux/realtek/patches-5.10/304-spi-update-dependency-for-spi-realtek-rtl.patch b/target/linux/realtek/patches-5.10/304-spi-update-dependency-for-spi-realtek-rtl.patch
new file mode 100644
index 0000000000..6975bfd228
--- /dev/null
+++ b/target/linux/realtek/patches-5.10/304-spi-update-dependency-for-spi-realtek-rtl.patch
@@ -0,0 +1,11 @@
+--- a/drivers/spi/Makefile
++++ b/drivers/spi/Makefile
+@@ -94,7 +94,7 @@ obj-$(CONFIG_SPI_QCOM_QSPI)		+= spi-qcom
+ obj-$(CONFIG_SPI_QUP)			+= spi-qup.o
+ obj-$(CONFIG_SPI_ROCKCHIP)		+= spi-rockchip.o
+ obj-$(CONFIG_SPI_RB4XX)			+= spi-rb4xx.o
+-obj-$(CONFIG_MACH_REALTEK_RTL)		+= spi-realtek-rtl.o
++obj-$(CONFIG_RTL838X)			+= spi-realtek-rtl.o
+ obj-$(CONFIG_SPI_RPCIF)			+= spi-rpc-if.o
+ obj-$(CONFIG_SPI_RSPI)			+= spi-rspi.o
+ obj-$(CONFIG_SPI_S3C24XX)		+= spi-s3c24xx-hw.o