Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 978 insertions, 0 deletions

diff --git a/drivers/spi/spi-meson-spicc.c b/drivers/spi/spi-meson-spicc.c
new file mode 100644
index 0000000000..43d134f4b4
--- /dev/null
+++ b/drivers/spi/spi-meson-spicc.c
@@ -0,0 +1,978 @@
+/*
+ * Driver for Amlogic Meson SPI communication controller (SPICC)
+ *
+ * Copyright (C) BayLibre, SAS
+ * Author: Neil Armstrong <narmstrong@baylibre.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/types.h>
+#include <linux/interrupt.h>
+#include <linux/reset.h>
+#include <linux/pinctrl/consumer.h>
+
+/*
+ * The Meson SPICC controller could support DMA based transfers, but is not
+ * implemented by the vendor code, and while having the registers documentation
+ * it has never worked on the GXL Hardware.
+ * The PIO mode is the only mode implemented, and due to badly designed HW :
+ * - all transfers are cutted in 16 words burst because the FIFO hangs on
+ *   TX underflow, and there is no TX "Half-Empty" interrupt, so we go by
+ *   FIFO max size chunk only
+ * - CS management is dumb, and goes UP between every burst, so is really a
+ *   "Data Valid" signal than a Chip Select, GPIO link should be used instead
+ *   to have a CS go down over the full transfer
+ */
+
+#define SPICC_MAX_BURST	128
+
+/* Register Map */
+#define SPICC_RXDATA	0x00
+
+#define SPICC_TXDATA	0x04
+
+#define SPICC_CONREG	0x08
+#define SPICC_ENABLE		BIT(0)
+#define SPICC_MODE_MASTER	BIT(1)
+#define SPICC_XCH		BIT(2)
+#define SPICC_SMC		BIT(3)
+#define SPICC_POL		BIT(4)
+#define SPICC_PHA		BIT(5)
+#define SPICC_SSCTL		BIT(6)
+#define SPICC_SSPOL		BIT(7)
+#define SPICC_DRCTL_MASK	GENMASK(9, 8)
+#define SPICC_DRCTL_IGNORE	0
+#define SPICC_DRCTL_FALLING	1
+#define SPICC_DRCTL_LOWLEVEL	2
+#define SPICC_CS_MASK		GENMASK(13, 12)
+#define SPICC_DATARATE_MASK	GENMASK(18, 16)
+#define SPICC_DATARATE_DIV4	0
+#define SPICC_DATARATE_DIV8	1
+#define SPICC_DATARATE_DIV16	2
+#define SPICC_DATARATE_DIV32	3
+#define SPICC_BITLENGTH_MASK	GENMASK(24, 19)
+#define SPICC_BURSTLENGTH_MASK	GENMASK(31, 25)
+
+#define SPICC_INTREG	0x0c
+#define SPICC_TE_EN	BIT(0) /* TX FIFO Empty Interrupt */
+#define SPICC_TH_EN	BIT(1) /* TX FIFO Half-Full Interrupt */
+#define SPICC_TF_EN	BIT(2) /* TX FIFO Full Interrupt */
+#define SPICC_RR_EN	BIT(3) /* RX FIFO Ready Interrupt */
+#define SPICC_RH_EN	BIT(4) /* RX FIFO Half-Full Interrupt */
+#define SPICC_RF_EN	BIT(5) /* RX FIFO Full Interrupt */
+#define SPICC_RO_EN	BIT(6) /* RX FIFO Overflow Interrupt */
+#define SPICC_TC_EN	BIT(7) /* Transfert Complete Interrupt */
+
+#define SPICC_DMAREG	0x10
+#define SPICC_DMA_ENABLE		BIT(0)
+#define SPICC_TXFIFO_THRESHOLD_MASK	GENMASK(5, 1)
+#define SPICC_RXFIFO_THRESHOLD_MASK	GENMASK(10, 6)
+#define SPICC_READ_BURST_MASK		GENMASK(14, 11)
+#define SPICC_WRITE_BURST_MASK		GENMASK(18, 15)
+#define SPICC_DMA_URGENT		BIT(19)
+#define SPICC_DMA_THREADID_MASK		GENMASK(25, 20)
+#define SPICC_DMA_BURSTNUM_MASK		GENMASK(31, 26)
+
+#define SPICC_STATREG	0x14
+#define SPICC_TE	BIT(0) /* TX FIFO Empty Interrupt */
+#define SPICC_TH	BIT(1) /* TX FIFO Half-Full Interrupt */
+#define SPICC_TF	BIT(2) /* TX FIFO Full Interrupt */
+#define SPICC_RR	BIT(3) /* RX FIFO Ready Interrupt */
+#define SPICC_RH	BIT(4) /* RX FIFO Half-Full Interrupt */
+#define SPICC_RF	BIT(5) /* RX FIFO Full Interrupt */
+#define SPICC_RO	BIT(6) /* RX FIFO Overflow Interrupt */
+#define SPICC_TC	BIT(7) /* Transfert Complete Interrupt */
+
+#define SPICC_PERIODREG	0x18
+#define SPICC_PERIOD	GENMASK(14, 0)	/* Wait cycles */
+
+#define SPICC_TESTREG	0x1c
+#define SPICC_TXCNT_MASK	GENMASK(4, 0)	/* TX FIFO Counter */
+#define SPICC_RXCNT_MASK	GENMASK(9, 5)	/* RX FIFO Counter */
+#define SPICC_SMSTATUS_MASK	GENMASK(12, 10)	/* State Machine Status */
+#define SPICC_LBC_RO		BIT(13)	/* Loop Back Control Read-Only */
+#define SPICC_LBC_W1		BIT(14) /* Loop Back Control Write-Only */
+#define SPICC_SWAP_RO		BIT(14) /* RX FIFO Data Swap Read-Only */
+#define SPICC_SWAP_W1		BIT(15) /* RX FIFO Data Swap Write-Only */
+#define SPICC_DLYCTL_RO_MASK	GENMASK(20, 15) /* Delay Control Read-Only */
+#define SPICC_MO_DELAY_MASK	GENMASK(17, 16) /* Master Output Delay */
+#define SPICC_MO_NO_DELAY	0
+#define SPICC_MO_DELAY_1_CYCLE	1
+#define SPICC_MO_DELAY_2_CYCLE	2
+#define SPICC_MO_DELAY_3_CYCLE	3
+#define SPICC_MI_DELAY_MASK	GENMASK(19, 18) /* Master Input Delay */
+#define SPICC_MI_NO_DELAY	0
+#define SPICC_MI_DELAY_1_CYCLE	1
+#define SPICC_MI_DELAY_2_CYCLE	2
+#define SPICC_MI_DELAY_3_CYCLE	3
+#define SPICC_MI_CAP_DELAY_MASK	GENMASK(21, 20) /* Master Capture Delay */
+#define SPICC_CAP_AHEAD_2_CYCLE	0
+#define SPICC_CAP_AHEAD_1_CYCLE	1
+#define SPICC_CAP_NO_DELAY	2
+#define SPICC_CAP_DELAY_1_CYCLE	3
+#define SPICC_FIFORST_RO_MASK	GENMASK(22, 21) /* FIFO Softreset Read-Only */
+#define SPICC_FIFORST_W1_MASK	GENMASK(23, 22) /* FIFO Softreset Write-Only */
+
+#define SPICC_DRADDR	0x20	/* Read Address of DMA */
+
+#define SPICC_DWADDR	0x24	/* Write Address of DMA */
+
+#define SPICC_ENH_CTL0	0x38	/* Enhanced Feature */
+#define SPICC_ENH_CLK_CS_DELAY_MASK	GENMASK(15, 0)
+#define SPICC_ENH_DATARATE_MASK		GENMASK(23, 16)
+#define SPICC_ENH_DATARATE_EN		BIT(24)
+#define SPICC_ENH_MOSI_OEN		BIT(25)
+#define SPICC_ENH_CLK_OEN		BIT(26)
+#define SPICC_ENH_CS_OEN		BIT(27)
+#define SPICC_ENH_CLK_CS_DELAY_EN	BIT(28)
+#define SPICC_ENH_MAIN_CLK_AO		BIT(29)
+
+#define writel_bits_relaxed(mask, val, addr) \
+	writel_relaxed((readl_relaxed(addr) & ~(mask)) | (val), addr)
+
+struct meson_spicc_data {
+	unsigned int			max_speed_hz;
+	unsigned int			min_speed_hz;
+	unsigned int			fifo_size;
+	bool				has_oen;
+	bool				has_enhance_clk_div;
+	bool				has_pclk;
+};
+
+struct meson_spicc_device {
+	struct spi_master		*master;
+	struct platform_device		*pdev;
+	void __iomem			*base;
+	struct clk			*core;
+	struct clk			*pclk;
+	struct clk_divider		pow2_div;
+	struct clk			*clk;
+	struct spi_message		*message;
+	struct spi_transfer		*xfer;
+	struct completion		done;
+	const struct meson_spicc_data	*data;
+	u8				*tx_buf;
+	u8				*rx_buf;
+	unsigned int			bytes_per_word;
+	unsigned long			tx_remain;
+	unsigned long			rx_remain;
+	unsigned long			xfer_remain;
+	struct pinctrl			*pinctrl;
+	struct pinctrl_state		*pins_idle_high;
+	struct pinctrl_state		*pins_idle_low;
+};
+
+#define pow2_clk_to_spicc(_div) container_of(_div, struct meson_spicc_device, pow2_div)
+
+static void meson_spicc_oen_enable(struct meson_spicc_device *spicc)
+{
+	u32 conf;
+
+	if (!spicc->data->has_oen) {
+		/* Try to get pinctrl states for idle high/low */
+		spicc->pins_idle_high = pinctrl_lookup_state(spicc->pinctrl,
+							     "idle-high");
+		if (IS_ERR(spicc->pins_idle_high)) {
+			dev_warn(&spicc->pdev->dev, "can't get idle-high pinctrl\n");
+			spicc->pins_idle_high = NULL;
+		}
+		spicc->pins_idle_low = pinctrl_lookup_state(spicc->pinctrl,
+							     "idle-low");
+		if (IS_ERR(spicc->pins_idle_low)) {
+			dev_warn(&spicc->pdev->dev, "can't get idle-low pinctrl\n");
+			spicc->pins_idle_low = NULL;
+		}
+		return;
+	}
+
+	conf = readl_relaxed(spicc->base + SPICC_ENH_CTL0) |
+		SPICC_ENH_MOSI_OEN | SPICC_ENH_CLK_OEN | SPICC_ENH_CS_OEN;
+
+	writel_relaxed(conf, spicc->base + SPICC_ENH_CTL0);
+}
+
+static inline bool meson_spicc_txfull(struct meson_spicc_device *spicc)
+{
+	return !!FIELD_GET(SPICC_TF,
+			   readl_relaxed(spicc->base + SPICC_STATREG));
+}
+
+static inline bool meson_spicc_rxready(struct meson_spicc_device *spicc)
+{
+	return FIELD_GET(SPICC_RH | SPICC_RR | SPICC_RF,
+			 readl_relaxed(spicc->base + SPICC_STATREG));
+}
+
+static inline u32 meson_spicc_pull_data(struct meson_spicc_device *spicc)
+{
+	unsigned int bytes = spicc->bytes_per_word;
+	unsigned int byte_shift = 0;
+	u32 data = 0;
+	u8 byte;
+
+	while (bytes--) {
+		byte = *spicc->tx_buf++;
+		data |= (byte & 0xff) << byte_shift;
+		byte_shift += 8;
+	}
+
+	spicc->tx_remain--;
+	return data;
+}
+
+static inline void meson_spicc_push_data(struct meson_spicc_device *spicc,
+					 u32 data)
+{
+	unsigned int bytes = spicc->bytes_per_word;
+	unsigned int byte_shift = 0;
+	u8 byte;
+
+	while (bytes--) {
+		byte = (data >> byte_shift) & 0xff;
+		*spicc->rx_buf++ = byte;
+		byte_shift += 8;
+	}
+
+	spicc->rx_remain--;
+}
+
+static inline void meson_spicc_rx(struct meson_spicc_device *spicc)
+{
+	/* Empty RX FIFO */
+	while (spicc->rx_remain &&
+	       meson_spicc_rxready(spicc))
+		meson_spicc_push_data(spicc,
+				readl_relaxed(spicc->base + SPICC_RXDATA));
+}
+
+static inline void meson_spicc_tx(struct meson_spicc_device *spicc)
+{
+	/* Fill Up TX FIFO */
+	while (spicc->tx_remain &&
+	       !meson_spicc_txfull(spicc))
+		writel_relaxed(meson_spicc_pull_data(spicc),
+			       spicc->base + SPICC_TXDATA);
+}
+
+static inline void meson_spicc_setup_burst(struct meson_spicc_device *spicc)
+{
+
+	unsigned int burst_len = min_t(unsigned int,
+				       spicc->xfer_remain /
+				       spicc->bytes_per_word,
+				       spicc->data->fifo_size);
+	/* Setup Xfer variables */
+	spicc->tx_remain = burst_len;
+	spicc->rx_remain = burst_len;
+	spicc->xfer_remain -= burst_len * spicc->bytes_per_word;
+
+	/* Setup burst length */
+	writel_bits_relaxed(SPICC_BURSTLENGTH_MASK,
+			FIELD_PREP(SPICC_BURSTLENGTH_MASK,
+				burst_len - 1),
+			spicc->base + SPICC_CONREG);
+
+	/* Fill TX FIFO */
+	meson_spicc_tx(spicc);
+}
+
+static irqreturn_t meson_spicc_irq(int irq, void *data)
+{
+	struct meson_spicc_device *spicc = (void *) data;
+
+	writel_bits_relaxed(SPICC_TC, SPICC_TC, spicc->base + SPICC_STATREG);
+
+	/* Empty RX FIFO */
+	meson_spicc_rx(spicc);
+
+	if (!spicc->xfer_remain) {
+		/* Disable all IRQs */
+		writel(0, spicc->base + SPICC_INTREG);
+
+		complete(&spicc->done);
+
+		return IRQ_HANDLED;
+	}
+
+	/* Setup burst */
+	meson_spicc_setup_burst(spicc);
+
+	/* Start burst */
+	writel_bits_relaxed(SPICC_XCH, SPICC_XCH, spicc->base + SPICC_CONREG);
+
+	return IRQ_HANDLED;
+}
+
+static void meson_spicc_auto_io_delay(struct meson_spicc_device *spicc)
+{
+	u32 div, hz;
+	u32 mi_delay, cap_delay;
+	u32 conf;
+
+	if (spicc->data->has_enhance_clk_div) {
+		div = FIELD_GET(SPICC_ENH_DATARATE_MASK,
+				readl_relaxed(spicc->base + SPICC_ENH_CTL0));
+		div++;
+		div <<= 1;
+	} else {
+		div = FIELD_GET(SPICC_DATARATE_MASK,
+				readl_relaxed(spicc->base + SPICC_CONREG));
+		div += 2;
+		div = 1 << div;
+	}
+
+	mi_delay = SPICC_MI_NO_DELAY;
+	cap_delay = SPICC_CAP_AHEAD_2_CYCLE;
+	hz = clk_get_rate(spicc->clk);
+
+	if (hz >= 100000000)
+		cap_delay = SPICC_CAP_DELAY_1_CYCLE;
+	else if (hz >= 80000000)
+		cap_delay = SPICC_CAP_NO_DELAY;
+	else if (hz >= 40000000)
+		cap_delay = SPICC_CAP_AHEAD_1_CYCLE;
+	else if (div >= 16)
+		mi_delay = SPICC_MI_DELAY_3_CYCLE;
+	else if (div >= 8)
+		mi_delay = SPICC_MI_DELAY_2_CYCLE;
+	else if (div >= 6)
+		mi_delay = SPICC_MI_DELAY_1_CYCLE;
+
+	conf = readl_relaxed(spicc->base + SPICC_TESTREG);
+	conf &= ~(SPICC_MO_DELAY_MASK | SPICC_MI_DELAY_MASK
+		  | SPICC_MI_CAP_DELAY_MASK);
+	conf |= FIELD_PREP(SPICC_MI_DELAY_MASK, mi_delay);
+	conf |= FIELD_PREP(SPICC_MI_CAP_DELAY_MASK, cap_delay);
+	writel_relaxed(conf, spicc->base + SPICC_TESTREG);
+}
+
+static void meson_spicc_setup_xfer(struct meson_spicc_device *spicc,
+				   struct spi_transfer *xfer)
+{
+	u32 conf, conf_orig;
+
+	/* Read original configuration */
+	conf = conf_orig = readl_relaxed(spicc->base + SPICC_CONREG);
+
+	/* Setup word width */
+	conf &= ~SPICC_BITLENGTH_MASK;
+	conf |= FIELD_PREP(SPICC_BITLENGTH_MASK,
+			   (spicc->bytes_per_word << 3) - 1);
+
+	/* Ignore if unchanged */
+	if (conf != conf_orig)
+		writel_relaxed(conf, spicc->base + SPICC_CONREG);
+
+	clk_set_rate(spicc->clk, xfer->speed_hz);
+
+	meson_spicc_auto_io_delay(spicc);
+
+	writel_relaxed(0, spicc->base + SPICC_DMAREG);
+}
+
+static void meson_spicc_reset_fifo(struct meson_spicc_device *spicc)
+{
+	if (spicc->data->has_oen)
+		writel_bits_relaxed(SPICC_ENH_MAIN_CLK_AO,
+				    SPICC_ENH_MAIN_CLK_AO,
+				    spicc->base + SPICC_ENH_CTL0);
+
+	writel_bits_relaxed(SPICC_FIFORST_W1_MASK, SPICC_FIFORST_W1_MASK,
+			    spicc->base + SPICC_TESTREG);
+
+	while (meson_spicc_rxready(spicc))
+		readl_relaxed(spicc->base + SPICC_RXDATA);
+
+	if (spicc->data->has_oen)
+		writel_bits_relaxed(SPICC_ENH_MAIN_CLK_AO, 0,
+				    spicc->base + SPICC_ENH_CTL0);
+}
+
+static int meson_spicc_transfer_one(struct spi_master *master,
+				    struct spi_device *spi,
+				    struct spi_transfer *xfer)
+{
+	struct meson_spicc_device *spicc = spi_master_get_devdata(master);
+	uint64_t timeout;
+
+	/* Store current transfer */
+	spicc->xfer = xfer;
+
+	/* Setup transfer parameters */
+	spicc->tx_buf = (u8 *)xfer->tx_buf;
+	spicc->rx_buf = (u8 *)xfer->rx_buf;
+	spicc->xfer_remain = xfer->len;
+
+	/* Pre-calculate word size */
+	spicc->bytes_per_word =
+	   DIV_ROUND_UP(spicc->xfer->bits_per_word, 8);
+
+	if (xfer->len % spicc->bytes_per_word)
+		return -EINVAL;
+
+	/* Setup transfer parameters */
+	meson_spicc_setup_xfer(spicc, xfer);
+
+	meson_spicc_reset_fifo(spicc);
+
+	/* Setup burst */
+	meson_spicc_setup_burst(spicc);
+
+	/* Setup wait for completion */
+	reinit_completion(&spicc->done);
+
+	/* For each byte we wait for 8 cycles of the SPI clock */
+	timeout = 8LL * MSEC_PER_SEC * xfer->len;
+	do_div(timeout, xfer->speed_hz);
+
+	/* Add 10us delay between each fifo bursts */
+	timeout += ((xfer->len >> 4) * 10) / MSEC_PER_SEC;
+
+	/* Increase it twice and add 200 ms tolerance */
+	timeout += timeout + 200;
+
+	/* Start burst */
+	writel_bits_relaxed(SPICC_XCH, SPICC_XCH, spicc->base + SPICC_CONREG);
+
+	/* Enable interrupts */
+	writel_relaxed(SPICC_TC_EN, spicc->base + SPICC_INTREG);
+
+	if (!wait_for_completion_timeout(&spicc->done, msecs_to_jiffies(timeout)))
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+static int meson_spicc_prepare_message(struct spi_master *master,
+				       struct spi_message *message)
+{
+	struct meson_spicc_device *spicc = spi_master_get_devdata(master);
+	struct spi_device *spi = message->spi;
+	u32 conf = readl_relaxed(spicc->base + SPICC_CONREG) & SPICC_DATARATE_MASK;
+
+	/* Store current message */
+	spicc->message = message;
+
+	/* Enable Master */
+	conf |= SPICC_ENABLE;
+	conf |= SPICC_MODE_MASTER;
+
+	/* SMC = 0 */
+
+	/* Setup transfer mode */
+	if (spi->mode & SPI_CPOL)
+		conf |= SPICC_POL;
+	else
+		conf &= ~SPICC_POL;
+
+	if (!spicc->data->has_oen) {
+		if (spi->mode & SPI_CPOL) {
+			if (spicc->pins_idle_high)
+				pinctrl_select_state(spicc->pinctrl, spicc->pins_idle_high);
+		} else {
+			if (spicc->pins_idle_low)
+				pinctrl_select_state(spicc->pinctrl, spicc->pins_idle_low);
+		}
+	}
+
+	if (spi->mode & SPI_CPHA)
+		conf |= SPICC_PHA;
+	else
+		conf &= ~SPICC_PHA;
+
+	/* SSCTL = 0 */
+
+	if (spi->mode & SPI_CS_HIGH)
+		conf |= SPICC_SSPOL;
+	else
+		conf &= ~SPICC_SSPOL;
+
+	if (spi->mode & SPI_READY)
+		conf |= FIELD_PREP(SPICC_DRCTL_MASK, SPICC_DRCTL_LOWLEVEL);
+	else
+		conf |= FIELD_PREP(SPICC_DRCTL_MASK, SPICC_DRCTL_IGNORE);
+
+	/* Select CS */
+	conf |= FIELD_PREP(SPICC_CS_MASK, spi_get_chipselect(spi, 0));
+
+	/* Default 8bit word */
+	conf |= FIELD_PREP(SPICC_BITLENGTH_MASK, 8 - 1);
+
+	writel_relaxed(conf, spicc->base + SPICC_CONREG);
+
+	/* Setup no wait cycles by default */
+	writel_relaxed(0, spicc->base + SPICC_PERIODREG);
+
+	writel_bits_relaxed(SPICC_LBC_W1, 0, spicc->base + SPICC_TESTREG);
+
+	return 0;
+}
+
+static int meson_spicc_unprepare_transfer(struct spi_master *master)
+{
+	struct meson_spicc_device *spicc = spi_master_get_devdata(master);
+	u32 conf = readl_relaxed(spicc->base + SPICC_CONREG) & SPICC_DATARATE_MASK;
+
+	/* Disable all IRQs */
+	writel(0, spicc->base + SPICC_INTREG);
+
+	device_reset_optional(&spicc->pdev->dev);
+
+	/* Set default configuration, keeping datarate field */
+	writel_relaxed(conf, spicc->base + SPICC_CONREG);
+
+	if (!spicc->data->has_oen)
+		pinctrl_select_default_state(&spicc->pdev->dev);
+
+	return 0;
+}
+
+static int meson_spicc_setup(struct spi_device *spi)
+{
+	if (!spi->controller_state)
+		spi->controller_state = spi_master_get_devdata(spi->master);
+
+	return 0;
+}
+
+static void meson_spicc_cleanup(struct spi_device *spi)
+{
+	spi->controller_state = NULL;
+}
+
+/*
+ * The Clock Mux
+ *            x-----------------x   x------------x    x------\
+ *        |---| pow2 fixed div  |---| pow2 div   |----|      |
+ *        |   x-----------------x   x------------x    |      |
+ * src ---|                                           | mux  |-- out
+ *        |   x-----------------x   x------------x    |      |
+ *        |---| enh fixed div   |---| enh div    |0---|      |
+ *            x-----------------x   x------------x    x------/
+ *
+ * Clk path for GX series:
+ *    src -> pow2 fixed div -> pow2 div -> out
+ *
+ * Clk path for AXG series:
+ *    src -> pow2 fixed div -> pow2 div -> mux -> out
+ *    src -> enh fixed div -> enh div -> mux -> out
+ *
+ * Clk path for G12A series:
+ *    pclk -> pow2 fixed div -> pow2 div -> mux -> out
+ *    pclk -> enh fixed div -> enh div -> mux -> out
+ *
+ * The pow2 divider is tied to the controller HW state, and the
+ * divider is only valid when the controller is initialized.
+ *
+ * A set of clock ops is added to make sure we don't read/set this
+ * clock rate while the controller is in an unknown state.
+ */
+
+static unsigned long meson_spicc_pow2_recalc_rate(struct clk_hw *hw,
+						  unsigned long parent_rate)
+{
+	struct clk_divider *divider = to_clk_divider(hw);
+	struct meson_spicc_device *spicc = pow2_clk_to_spicc(divider);
+
+	if (!spicc->master->cur_msg)
+		return 0;
+
+	return clk_divider_ops.recalc_rate(hw, parent_rate);
+}
+
+static int meson_spicc_pow2_determine_rate(struct clk_hw *hw,
+					   struct clk_rate_request *req)
+{
+	struct clk_divider *divider = to_clk_divider(hw);
+	struct meson_spicc_device *spicc = pow2_clk_to_spicc(divider);
+
+	if (!spicc->master->cur_msg)
+		return -EINVAL;
+
+	return clk_divider_ops.determine_rate(hw, req);
+}
+
+static int meson_spicc_pow2_set_rate(struct clk_hw *hw, unsigned long rate,
+				     unsigned long parent_rate)
+{
+	struct clk_divider *divider = to_clk_divider(hw);
+	struct meson_spicc_device *spicc = pow2_clk_to_spicc(divider);
+
+	if (!spicc->master->cur_msg)
+		return -EINVAL;
+
+	return clk_divider_ops.set_rate(hw, rate, parent_rate);
+}
+
+static const struct clk_ops meson_spicc_pow2_clk_ops = {
+	.recalc_rate = meson_spicc_pow2_recalc_rate,
+	.determine_rate = meson_spicc_pow2_determine_rate,
+	.set_rate = meson_spicc_pow2_set_rate,
+};
+
+static int meson_spicc_pow2_clk_init(struct meson_spicc_device *spicc)
+{
+	struct device *dev = &spicc->pdev->dev;
+	struct clk_fixed_factor *pow2_fixed_div;
+	struct clk_init_data init;
+	struct clk *clk;
+	struct clk_parent_data parent_data[2];
+	char name[64];
+
+	memset(&init, 0, sizeof(init));
+	memset(&parent_data, 0, sizeof(parent_data));
+
+	init.parent_data = parent_data;
+
+	/* algorithm for pow2 div: rate = freq / 4 / (2 ^ N) */
+
+	pow2_fixed_div = devm_kzalloc(dev, sizeof(*pow2_fixed_div), GFP_KERNEL);
+	if (!pow2_fixed_div)
+		return -ENOMEM;
+
+	snprintf(name, sizeof(name), "%s#pow2_fixed_div", dev_name(dev));
+	init.name = name;
+	init.ops = &clk_fixed_factor_ops;
+	init.flags = 0;
+	if (spicc->data->has_pclk)
+		parent_data[0].hw = __clk_get_hw(spicc->pclk);
+	else
+		parent_data[0].hw = __clk_get_hw(spicc->core);
+	init.num_parents = 1;
+
+	pow2_fixed_div->mult = 1,
+	pow2_fixed_div->div = 4,
+	pow2_fixed_div->hw.init = &init;
+
+	clk = devm_clk_register(dev, &pow2_fixed_div->hw);
+	if (WARN_ON(IS_ERR(clk)))
+		return PTR_ERR(clk);
+
+	snprintf(name, sizeof(name), "%s#pow2_div", dev_name(dev));
+	init.name = name;
+	init.ops = &meson_spicc_pow2_clk_ops;
+	/*
+	 * Set NOCACHE here to make sure we read the actual HW value
+	 * since we reset the HW after each transfer.
+	 */
+	init.flags = CLK_SET_RATE_PARENT | CLK_GET_RATE_NOCACHE;
+	parent_data[0].hw = &pow2_fixed_div->hw;
+	init.num_parents = 1;
+
+	spicc->pow2_div.shift = 16,
+	spicc->pow2_div.width = 3,
+	spicc->pow2_div.flags = CLK_DIVIDER_POWER_OF_TWO,
+	spicc->pow2_div.reg = spicc->base + SPICC_CONREG;
+	spicc->pow2_div.hw.init = &init;
+
+	spicc->clk = devm_clk_register(dev, &spicc->pow2_div.hw);
+	if (WARN_ON(IS_ERR(spicc->clk)))
+		return PTR_ERR(spicc->clk);
+
+	return 0;
+}
+
+static int meson_spicc_enh_clk_init(struct meson_spicc_device *spicc)
+{
+	struct device *dev = &spicc->pdev->dev;
+	struct clk_fixed_factor *enh_fixed_div;
+	struct clk_divider *enh_div;
+	struct clk_mux *mux;
+	struct clk_init_data init;
+	struct clk *clk;
+	struct clk_parent_data parent_data[2];
+	char name[64];
+
+	memset(&init, 0, sizeof(init));
+	memset(&parent_data, 0, sizeof(parent_data));
+
+	init.parent_data = parent_data;
+
+	/* algorithm for enh div: rate = freq / 2 / (N + 1) */
+
+	enh_fixed_div = devm_kzalloc(dev, sizeof(*enh_fixed_div), GFP_KERNEL);
+	if (!enh_fixed_div)
+		return -ENOMEM;
+
+	snprintf(name, sizeof(name), "%s#enh_fixed_div", dev_name(dev));
+	init.name = name;
+	init.ops = &clk_fixed_factor_ops;
+	init.flags = 0;
+	if (spicc->data->has_pclk)
+		parent_data[0].hw = __clk_get_hw(spicc->pclk);
+	else
+		parent_data[0].hw = __clk_get_hw(spicc->core);
+	init.num_parents = 1;
+
+	enh_fixed_div->mult = 1,
+	enh_fixed_div->div = 2,
+	enh_fixed_div->hw.init = &init;
+
+	clk = devm_clk_register(dev, &enh_fixed_div->hw);
+	if (WARN_ON(IS_ERR(clk)))
+		return PTR_ERR(clk);
+
+	enh_div = devm_kzalloc(dev, sizeof(*enh_div), GFP_KERNEL);
+	if (!enh_div)
+		return -ENOMEM;
+
+	snprintf(name, sizeof(name), "%s#enh_div", dev_name(dev));
+	init.name = name;
+	init.ops = &clk_divider_ops;
+	init.flags = CLK_SET_RATE_PARENT;
+	parent_data[0].hw = &enh_fixed_div->hw;
+	init.num_parents = 1;
+
+	enh_div->shift	= 16,
+	enh_div->width	= 8,
+	enh_div->reg = spicc->base + SPICC_ENH_CTL0;
+	enh_div->hw.init = &init;
+
+	clk = devm_clk_register(dev, &enh_div->hw);
+	if (WARN_ON(IS_ERR(clk)))
+		return PTR_ERR(clk);
+
+	mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
+	if (!mux)
+		return -ENOMEM;
+
+	snprintf(name, sizeof(name), "%s#sel", dev_name(dev));
+	init.name = name;
+	init.ops = &clk_mux_ops;
+	parent_data[0].hw = &spicc->pow2_div.hw;
+	parent_data[1].hw = &enh_div->hw;
+	init.num_parents = 2;
+	init.flags = CLK_SET_RATE_PARENT;
+
+	mux->mask = 0x1,
+	mux->shift = 24,
+	mux->reg = spicc->base + SPICC_ENH_CTL0;
+	mux->hw.init = &init;
+
+	spicc->clk = devm_clk_register(dev, &mux->hw);
+	if (WARN_ON(IS_ERR(spicc->clk)))
+		return PTR_ERR(spicc->clk);
+
+	return 0;
+}
+
+static int meson_spicc_probe(struct platform_device *pdev)
+{
+	struct spi_master *master;
+	struct meson_spicc_device *spicc;
+	int ret, irq;
+
+	master = spi_alloc_master(&pdev->dev, sizeof(*spicc));
+	if (!master) {
+		dev_err(&pdev->dev, "master allocation failed\n");
+		return -ENOMEM;
+	}
+	spicc = spi_master_get_devdata(master);
+	spicc->master = master;
+
+	spicc->data = of_device_get_match_data(&pdev->dev);
+	if (!spicc->data) {
+		dev_err(&pdev->dev, "failed to get match data\n");
+		ret = -EINVAL;
+		goto out_master;
+	}
+
+	spicc->pdev = pdev;
+	platform_set_drvdata(pdev, spicc);
+
+	init_completion(&spicc->done);
+
+	spicc->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(spicc->base)) {
+		dev_err(&pdev->dev, "io resource mapping failed\n");
+		ret = PTR_ERR(spicc->base);
+		goto out_master;
+	}
+
+	/* Set master mode and enable controller */
+	writel_relaxed(SPICC_ENABLE | SPICC_MODE_MASTER,
+		       spicc->base + SPICC_CONREG);
+
+	/* Disable all IRQs */
+	writel_relaxed(0, spicc->base + SPICC_INTREG);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		ret = irq;
+		goto out_master;
+	}
+
+	ret = devm_request_irq(&pdev->dev, irq, meson_spicc_irq,
+			       0, NULL, spicc);
+	if (ret) {
+		dev_err(&pdev->dev, "irq request failed\n");
+		goto out_master;
+	}
+
+	spicc->core = devm_clk_get(&pdev->dev, "core");
+	if (IS_ERR(spicc->core)) {
+		dev_err(&pdev->dev, "core clock request failed\n");
+		ret = PTR_ERR(spicc->core);
+		goto out_master;
+	}
+
+	if (spicc->data->has_pclk) {
+		spicc->pclk = devm_clk_get(&pdev->dev, "pclk");
+		if (IS_ERR(spicc->pclk)) {
+			dev_err(&pdev->dev, "pclk clock request failed\n");
+			ret = PTR_ERR(spicc->pclk);
+			goto out_master;
+		}
+	}
+
+	ret = clk_prepare_enable(spicc->core);
+	if (ret) {
+		dev_err(&pdev->dev, "core clock enable failed\n");
+		goto out_master;
+	}
+
+	ret = clk_prepare_enable(spicc->pclk);
+	if (ret) {
+		dev_err(&pdev->dev, "pclk clock enable failed\n");
+		goto out_core_clk;
+	}
+
+	spicc->pinctrl = devm_pinctrl_get(&pdev->dev);
+	if (IS_ERR(spicc->pinctrl)) {
+		ret = PTR_ERR(spicc->pinctrl);
+		goto out_clk;
+	}
+
+	device_reset_optional(&pdev->dev);
+
+	master->num_chipselect = 4;
+	master->dev.of_node = pdev->dev.of_node;
+	master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_CS_HIGH;
+	master->bits_per_word_mask = SPI_BPW_MASK(32) |
+				     SPI_BPW_MASK(24) |
+				     SPI_BPW_MASK(16) |
+				     SPI_BPW_MASK(8);
+	master->flags = (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX);
+	master->min_speed_hz = spicc->data->min_speed_hz;
+	master->max_speed_hz = spicc->data->max_speed_hz;
+	master->setup = meson_spicc_setup;
+	master->cleanup = meson_spicc_cleanup;
+	master->prepare_message = meson_spicc_prepare_message;
+	master->unprepare_transfer_hardware = meson_spicc_unprepare_transfer;
+	master->transfer_one = meson_spicc_transfer_one;
+	master->use_gpio_descriptors = true;
+
+	meson_spicc_oen_enable(spicc);
+
+	ret = meson_spicc_pow2_clk_init(spicc);
+	if (ret) {
+		dev_err(&pdev->dev, "pow2 clock registration failed\n");
+		goto out_clk;
+	}
+
+	if (spicc->data->has_enhance_clk_div) {
+		ret = meson_spicc_enh_clk_init(spicc);
+		if (ret) {
+			dev_err(&pdev->dev, "clock registration failed\n");
+			goto out_clk;
+		}
+	}
+
+	ret = devm_spi_register_master(&pdev->dev, master);
+	if (ret) {
+		dev_err(&pdev->dev, "spi master registration failed\n");
+		goto out_clk;
+	}
+
+	return 0;
+
+out_clk:
+	clk_disable_unprepare(spicc->pclk);
+
+out_core_clk:
+	clk_disable_unprepare(spicc->core);
+
+out_master:
+	spi_master_put(master);
+
+	return ret;
+}
+
+static void meson_spicc_remove(struct platform_device *pdev)
+{
+	struct meson_spicc_device *spicc = platform_get_drvdata(pdev);
+
+	/* Disable SPI */
+	writel(0, spicc->base + SPICC_CONREG);
+
+	clk_disable_unprepare(spicc->core);
+	clk_disable_unprepare(spicc->pclk);
+
+	spi_master_put(spicc->master);
+}
+
+static const struct meson_spicc_data meson_spicc_gx_data = {
+	.max_speed_hz		= 30000000,
+	.min_speed_hz		= 325000,
+	.fifo_size		= 16,
+};
+
+static const struct meson_spicc_data meson_spicc_axg_data = {
+	.max_speed_hz		= 80000000,
+	.min_speed_hz		= 325000,
+	.fifo_size		= 16,
+	.has_oen		= true,
+	.has_enhance_clk_div	= true,
+};
+
+static const struct meson_spicc_data meson_spicc_g12a_data = {
+	.max_speed_hz		= 166666666,
+	.min_speed_hz		= 50000,
+	.fifo_size		= 15,
+	.has_oen		= true,
+	.has_enhance_clk_div	= true,
+	.has_pclk		= true,
+};
+
+static const struct of_device_id meson_spicc_of_match[] = {
+	{
+		.compatible	= "amlogic,meson-gx-spicc",
+		.data		= &meson_spicc_gx_data,
+	},
+	{
+		.compatible = "amlogic,meson-axg-spicc",
+		.data		= &meson_spicc_axg_data,
+	},
+	{
+		.compatible = "amlogic,meson-g12a-spicc",
+		.data		= &meson_spicc_g12a_data,
+	},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, meson_spicc_of_match);
+
+static struct platform_driver meson_spicc_driver = {
+	.probe   = meson_spicc_probe,
+	.remove_new = meson_spicc_remove,
+	.driver  = {
+		.name = "meson-spicc",
+		.of_match_table = of_match_ptr(meson_spicc_of_match),
+	},
+};
+
+module_platform_driver(meson_spicc_driver);
+
+MODULE_DESCRIPTION("Meson SPI Communication Controller driver");
+MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
+MODULE_LICENSE("GPL");