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+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * SPI interface.
+ *
+ * Copyright (c) 2017-2020, Silicon Laboratories, Inc.
+ * Copyright (c) 2011, Sagrad Inc.
+ * Copyright (c) 2010, ST-Ericsson
+ */
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/spi/spi.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/of.h>
+
+#include "bus.h"
+#include "wfx.h"
+#include "hwio.h"
+#include "main.h"
+#include "bh.h"
+
+#define SET_WRITE 0x7FFF /* usage: and operation */
+#define SET_READ 0x8000 /* usage: or operation */
+
+#define WFX_RESET_INVERTED 1
+
+static const struct wfx_platform_data wfx_spi_pdata = {
+ .file_fw = "wfm_wf200",
+ .file_pds = "wf200.pds",
+ .use_rising_clk = true,
+};
+
+struct wfx_spi_priv {
+ struct spi_device *func;
+ struct wfx_dev *core;
+ struct gpio_desc *gpio_reset;
+ bool need_swab;
+};
+
+/* WFx chip read data 16bits at time and place them directly into (little
+ * endian) CPU register. So, chip expect byte order like "B1 B0 B3 B2" (while
+ * LE is "B0 B1 B2 B3" and BE is "B3 B2 B1 B0")
+ *
+ * A little endian host with bits_per_word == 16 should do the right job
+ * natively. The code below to support big endian host and commonly used SPI
+ * 8bits.
+ */
+static int wfx_spi_copy_from_io(void *priv, unsigned int addr,
+ void *dst, size_t count)
+{
+ struct wfx_spi_priv *bus = priv;
+ u16 regaddr = (addr << 12) | (count / 2) | SET_READ;
+ struct spi_message m;
+ struct spi_transfer t_addr = {
+ .tx_buf = ®addr,
+ .len = sizeof(regaddr),
+ };
+ struct spi_transfer t_msg = {
+ .rx_buf = dst,
+ .len = count,
+ };
+ u16 *dst16 = dst;
+ int ret, i;
+
+ WARN(count % 2, "buffer size must be a multiple of 2");
+
+ cpu_to_le16s(®addr);
+ if (bus->need_swab)
+ swab16s(®addr);
+
+ spi_message_init(&m);
+ spi_message_add_tail(&t_addr, &m);
+ spi_message_add_tail(&t_msg, &m);
+ ret = spi_sync(bus->func, &m);
+
+ if (bus->need_swab && addr == WFX_REG_CONFIG)
+ for (i = 0; i < count / 2; i++)
+ swab16s(&dst16[i]);
+ return ret;
+}
+
+static int wfx_spi_copy_to_io(void *priv, unsigned int addr,
+ const void *src, size_t count)
+{
+ struct wfx_spi_priv *bus = priv;
+ u16 regaddr = (addr << 12) | (count / 2);
+ /* FIXME: use a bounce buffer */
+ u16 *src16 = (void *)src;
+ int ret, i;
+ struct spi_message m;
+ struct spi_transfer t_addr = {
+ .tx_buf = ®addr,
+ .len = sizeof(regaddr),
+ };
+ struct spi_transfer t_msg = {
+ .tx_buf = src,
+ .len = count,
+ };
+
+ WARN(count % 2, "buffer size must be a multiple of 2");
+ WARN(regaddr & SET_READ, "bad addr or size overflow");
+
+ cpu_to_le16s(®addr);
+
+ /* Register address and CONFIG content always use 16bit big endian
+ * ("BADC" order)
+ */
+ if (bus->need_swab)
+ swab16s(®addr);
+ if (bus->need_swab && addr == WFX_REG_CONFIG)
+ for (i = 0; i < count / 2; i++)
+ swab16s(&src16[i]);
+
+ spi_message_init(&m);
+ spi_message_add_tail(&t_addr, &m);
+ spi_message_add_tail(&t_msg, &m);
+ ret = spi_sync(bus->func, &m);
+
+ if (bus->need_swab && addr == WFX_REG_CONFIG)
+ for (i = 0; i < count / 2; i++)
+ swab16s(&src16[i]);
+ return ret;
+}
+
+static void wfx_spi_lock(void *priv)
+{
+}
+
+static void wfx_spi_unlock(void *priv)
+{
+}
+
+static irqreturn_t wfx_spi_irq_handler(int irq, void *priv)
+{
+ struct wfx_spi_priv *bus = priv;
+
+ wfx_bh_request_rx(bus->core);
+ return IRQ_HANDLED;
+}
+
+static int wfx_spi_irq_subscribe(void *priv)
+{
+ struct wfx_spi_priv *bus = priv;
+ u32 flags;
+
+ flags = irq_get_trigger_type(bus->func->irq);
+ if (!flags)
+ flags = IRQF_TRIGGER_HIGH;
+ flags |= IRQF_ONESHOT;
+ return devm_request_threaded_irq(&bus->func->dev, bus->func->irq, NULL,
+ wfx_spi_irq_handler, IRQF_ONESHOT,
+ "wfx", bus);
+}
+
+static int wfx_spi_irq_unsubscribe(void *priv)
+{
+ struct wfx_spi_priv *bus = priv;
+
+ devm_free_irq(&bus->func->dev, bus->func->irq, bus);
+ return 0;
+}
+
+static size_t wfx_spi_align_size(void *priv, size_t size)
+{
+ /* Most of SPI controllers avoid DMA if buffer size is not 32bit aligned
+ */
+ return ALIGN(size, 4);
+}
+
+static const struct hwbus_ops wfx_spi_hwbus_ops = {
+ .copy_from_io = wfx_spi_copy_from_io,
+ .copy_to_io = wfx_spi_copy_to_io,
+ .irq_subscribe = wfx_spi_irq_subscribe,
+ .irq_unsubscribe = wfx_spi_irq_unsubscribe,
+ .lock = wfx_spi_lock,
+ .unlock = wfx_spi_unlock,
+ .align_size = wfx_spi_align_size,
+};
+
+static int wfx_spi_probe(struct spi_device *func)
+{
+ struct wfx_spi_priv *bus;
+ int ret;
+
+ if (!func->bits_per_word)
+ func->bits_per_word = 16;
+ ret = spi_setup(func);
+ if (ret)
+ return ret;
+ /* Trace below is also displayed by spi_setup() if compiled with DEBUG */
+ dev_dbg(&func->dev, "SPI params: CS=%d, mode=%d bits/word=%d speed=%d\n",
+ func->chip_select, func->mode, func->bits_per_word,
+ func->max_speed_hz);
+ if (func->bits_per_word != 16 && func->bits_per_word != 8)
+ dev_warn(&func->dev, "unusual bits/word value: %d\n",
+ func->bits_per_word);
+ if (func->max_speed_hz > 50000000)
+ dev_warn(&func->dev, "%dHz is a very high speed\n",
+ func->max_speed_hz);
+
+ bus = devm_kzalloc(&func->dev, sizeof(*bus), GFP_KERNEL);
+ if (!bus)
+ return -ENOMEM;
+ bus->func = func;
+ if (func->bits_per_word == 8 || IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
+ bus->need_swab = true;
+ spi_set_drvdata(func, bus);
+
+ bus->gpio_reset = devm_gpiod_get_optional(&func->dev, "reset",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(bus->gpio_reset))
+ return PTR_ERR(bus->gpio_reset);
+ if (!bus->gpio_reset) {
+ dev_warn(&func->dev,
+ "gpio reset is not defined, trying to load firmware anyway\n");
+ } else {
+ gpiod_set_consumer_name(bus->gpio_reset, "wfx reset");
+ if (spi_get_device_id(func)->driver_data & WFX_RESET_INVERTED)
+ gpiod_toggle_active_low(bus->gpio_reset);
+ gpiod_set_value_cansleep(bus->gpio_reset, 1);
+ usleep_range(100, 150);
+ gpiod_set_value_cansleep(bus->gpio_reset, 0);
+ usleep_range(2000, 2500);
+ }
+
+ bus->core = wfx_init_common(&func->dev, &wfx_spi_pdata,
+ &wfx_spi_hwbus_ops, bus);
+ if (!bus->core)
+ return -EIO;
+
+ return wfx_probe(bus->core);
+}
+
+static int wfx_spi_remove(struct spi_device *func)
+{
+ struct wfx_spi_priv *bus = spi_get_drvdata(func);
+
+ wfx_release(bus->core);
+ return 0;
+}
+
+/* For dynamic driver binding, kernel does not use OF to match driver. It only
+ * use modalias and modalias is a copy of 'compatible' DT node with vendor
+ * stripped.
+ */
+static const struct spi_device_id wfx_spi_id[] = {
+ { "wfx-spi", WFX_RESET_INVERTED },
+ { "wf200", 0 },
+ { },
+};
+MODULE_DEVICE_TABLE(spi, wfx_spi_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id wfx_spi_of_match[] = {
+ { .compatible = "silabs,wfx-spi", .data = (void *)WFX_RESET_INVERTED },
+ { .compatible = "silabs,wf200" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, wfx_spi_of_match);
+#endif
+
+struct spi_driver wfx_spi_driver = {
+ .driver = {
+ .name = "wfx-spi",
+ .of_match_table = of_match_ptr(wfx_spi_of_match),
+ },
+ .id_table = wfx_spi_id,
+ .probe = wfx_spi_probe,
+ .remove = wfx_spi_remove,
+};