--- /dev/null
+// 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);
OSDN Git Service
