ath79: add new ar934x spi driver

A new shift mode was introduced since ar934x which has a way better
performance than current bitbang driver and can handle higher spi
clock properly. This commit adds a new driver to make use of this
new feature.
This new driver has chipselect properly configured and we don't need
cs-gpios hack in dts anymore. Remove them.

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>

1 files changed, 277 insertions, 0 deletions

diff --git a/target/linux/ath79/patches-4.19/0051-spi-add-driver-for-ar934x-spi-controller.patch b/target/linux/ath79/patches-4.19/0051-spi-add-driver-for-ar934x-spi-controller.patch
new file mode 100644
index 0000000000..9dbc3dbd4e
--- /dev/null
+++ b/target/linux/ath79/patches-4.19/0051-spi-add-driver-for-ar934x-spi-controller.patch
@@ -0,0 +1,277 @@
+From b518f18f89dbd49fe9403a8c92230f1af59219bc Mon Sep 17 00:00:00 2001
+From: Chuanhong Guo <gch981213@gmail.com>
+Date: Wed, 5 Feb 2020 18:25:37 +0800
+Subject: [PATCH 1/2] 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>
+---
+ drivers/spi/Kconfig      |   7 ++
+ drivers/spi/Makefile     |   1 +
+ drivers/spi/spi-ar934x.c | 229 +++++++++++++++++++++++++++++++++++++++
+ 3 files changed, 237 insertions(+)
+ create mode 100644 drivers/spi/spi-ar934x.c
+
+--- a/drivers/spi/Kconfig
++++ b/drivers/spi/Kconfig
+@@ -61,6 +61,13 @@ 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 && GPIOLIB
+--- a/drivers/spi/Makefile
++++ b/drivers/spi/Makefile
+@@ -14,6 +14,7 @@ obj-$(CONFIG_SPI_LOOPBACK_TEST)		+= spi-
+ 
+ # SPI master controller drivers (bus)
+ obj-$(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_ATH79)			+= spi-ath79.o
+--- /dev/null
++++ b/drivers/spi/spi-ar934x.c
+@@ -0,0 +1,229 @@
++// 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_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;
++	}
++
++	iowrite32(AR934X_SPI_ENABLE, base + AR934X_SPI_REG_FS);
++
++	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);