Tested on a STM32MP1 communicating with a ksz9563.

Signed-off-by: Ahmad Fatoum <[email protected]>
---
 arch/arm/configs/stm32mp_defconfig |   7 +-
 drivers/spi/Kconfig                |   7 +
 drivers/spi/Makefile               |   1 +
 drivers/spi/stm32_spi.c            | 590 +++++++++++++++++++++++++++++
 4 files changed, 604 insertions(+), 1 deletion(-)
 create mode 100644 drivers/spi/stm32_spi.c

diff --git a/arch/arm/configs/stm32mp_defconfig 
b/arch/arm/configs/stm32mp_defconfig
index 49041b1f48f3..eb3c95b12c48 100644
--- a/arch/arm/configs/stm32mp_defconfig
+++ b/arch/arm/configs/stm32mp_defconfig
@@ -82,6 +82,7 @@ CONFIG_CMD_FLASH=y
 CONFIG_CMD_GPIO=y
 CONFIG_CMD_LED=y
 CONFIG_CMD_POWEROFF=y
+CONFIG_CMD_SPI=y
 CONFIG_CMD_WD=y
 CONFIG_CMD_BAREBOX_UPDATE=y
 CONFIG_CMD_OF_DIFF=y
@@ -102,9 +103,12 @@ CONFIG_DRIVER_NET_DESIGNWARE_STM32=y
 CONFIG_AT803X_PHY=y
 CONFIG_MICREL_PHY=y
 CONFIG_REALTEK_PHY=y
-# CONFIG_SPI is not set
+CONFIG_DRIVER_SPI_STM32=y
 CONFIG_I2C=y
 CONFIG_I2C_STM32=y
+CONFIG_MTD=y
+CONFIG_MTD_M25P80=y
+CONFIG_MTD_SST25L=y
 CONFIG_USB_HOST=y
 CONFIG_USB_DWC2_HOST=y
 CONFIG_USB_DWC2_GADGET=y
@@ -126,6 +130,7 @@ CONFIG_LED_GPIO=y
 CONFIG_LED_PWM=y
 CONFIG_LED_GPIO_OF=y
 CONFIG_LED_TRIGGERS=y
+CONFIG_EEPROM_AT25=y
 CONFIG_EEPROM_AT24=y
 CONFIG_KEYBOARD_GPIO=y
 CONFIG_INPUT_SPECIALKEYS=y
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 323d93efeb1a..d16cec3164fd 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -103,6 +103,13 @@ config SPI_ZYNQ_QSPI
          This enables support for the Zynq Quad SPI controller in master mode.
          This controller only supports SPI memory interface.
 
+config DRIVER_SPI_STM32
+       bool "STM32 SPI driver"
+       depends on ARCH_STM32MP || COMPILE_TEST
+       help
+         Enable the STM32 Serial Peripheral Interface (SPI) driver for STM32MP
+         SoCs.
+
 endif
 
 endmenu
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 908d514a01eb..23c1dd19f983 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -13,3 +13,4 @@ obj-$(CONFIG_SPI_ATMEL_QUADSPI) += atmel-quadspi.o
 obj-$(CONFIG_DRIVER_SPI_OMAP3) += omap3_spi.o
 obj-$(CONFIG_DRIVER_SPI_DSPI) += dspi_spi.o
 obj-$(CONFIG_SPI_ZYNQ_QSPI) += zynq_qspi.o
+obj-$(CONFIG_DRIVER_SPI_STM32) += stm32_spi.o
diff --git a/drivers/spi/stm32_spi.c b/drivers/spi/stm32_spi.c
new file mode 100644
index 000000000000..0cb04a968c8a
--- /dev/null
+++ b/drivers/spi/stm32_spi.c
@@ -0,0 +1,590 @@
+// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
+/*
+ * Copyright (C) 2019, STMicroelectronics - All Rights Reserved
+ *
+ * Driver for STMicroelectronics Serial peripheral interface (SPI)
+ */
+
+#include <common.h>
+#include <linux/clk.h>
+#include <driver.h>
+#include <init.h>
+#include <errno.h>
+#include <linux/reset.h>
+#include <spi/spi.h>
+#include <linux/bitops.h>
+#include <clock.h>
+#include <gpio.h>
+#include <of_gpio.h>
+#include <linux/bitfield.h>
+#include <linux/iopoll.h>
+
+/* STM32 SPI registers */
+#define STM32_SPI_CR1          0x00
+#define STM32_SPI_CR2          0x04
+#define STM32_SPI_CFG1         0x08
+#define STM32_SPI_CFG2         0x0C
+#define STM32_SPI_SR           0x14
+#define STM32_SPI_IFCR         0x18
+#define STM32_SPI_TXDR         0x20
+#define STM32_SPI_RXDR         0x30
+#define STM32_SPI_I2SCFGR      0x50
+
+/* STM32_SPI_CR1 bit fields */
+#define SPI_CR1_SPE            BIT(0)
+#define SPI_CR1_MASRX          BIT(8)
+#define SPI_CR1_CSTART         BIT(9)
+#define SPI_CR1_CSUSP          BIT(10)
+#define SPI_CR1_HDDIR          BIT(11)
+#define SPI_CR1_SSI            BIT(12)
+
+/* STM32_SPI_CR2 bit fields */
+#define SPI_CR2_TSIZE          GENMASK(15, 0)
+
+/* STM32_SPI_CFG1 bit fields */
+#define SPI_CFG1_DSIZE         GENMASK(4, 0)
+#define SPI_CFG1_DSIZE_MIN     3
+#define SPI_CFG1_FTHLV_SHIFT   5
+#define SPI_CFG1_FTHLV         GENMASK(8, 5)
+#define SPI_CFG1_MBR_SHIFT     28
+#define SPI_CFG1_MBR           GENMASK(30, 28)
+#define SPI_CFG1_MBR_MIN       0
+#define SPI_CFG1_MBR_MAX       FIELD_GET(SPI_CFG1_MBR, SPI_CFG1_MBR)
+
+/* STM32_SPI_CFG2 bit fields */
+#define SPI_CFG2_COMM_SHIFT    17
+#define SPI_CFG2_COMM          GENMASK(18, 17)
+#define SPI_CFG2_MASTER                BIT(22)
+#define SPI_CFG2_LSBFRST       BIT(23)
+#define SPI_CFG2_CPHA          BIT(24)
+#define SPI_CFG2_CPOL          BIT(25)
+#define SPI_CFG2_SSM           BIT(26)
+#define SPI_CFG2_AFCNTR                BIT(31)
+
+/* STM32_SPI_SR bit fields */
+#define SPI_SR_RXP             BIT(0)
+#define SPI_SR_TXP             BIT(1)
+#define SPI_SR_EOT             BIT(3)
+#define SPI_SR_TXTF            BIT(4)
+#define SPI_SR_OVR             BIT(6)
+#define SPI_SR_SUSP            BIT(11)
+#define SPI_SR_RXPLVL_SHIFT    13
+#define SPI_SR_RXPLVL          GENMASK(14, 13)
+#define SPI_SR_RXWNE           BIT(15)
+
+/* STM32_SPI_IFCR bit fields */
+#define SPI_IFCR_ALL           GENMASK(11, 3)
+
+/* STM32_SPI_I2SCFGR bit fields */
+#define SPI_I2SCFGR_I2SMOD     BIT(0)
+
+/* SPI Master Baud Rate min/max divisor */
+#define STM32_MBR_DIV_MIN      (2 << SPI_CFG1_MBR_MIN)
+#define STM32_MBR_DIV_MAX      (2 << SPI_CFG1_MBR_MAX)
+
+/* SPI Communication mode */
+#define SPI_FULL_DUPLEX                0
+#define SPI_SIMPLEX_TX         1
+#define SPI_SIMPLEX_RX         2
+#define SPI_HALF_DUPLEX                3
+
+struct stm32_spi_priv {
+       struct spi_master       master;
+       int                     *cs_gpios;
+       void __iomem            *base;
+       struct clk              *clk;
+       ulong                   bus_clk_rate;
+       unsigned int            fifo_size;
+       unsigned int            cur_bpw;
+       unsigned int            cur_hz;
+       unsigned int            cur_xferlen;    /* current transfer length in 
bytes */
+       unsigned int            tx_len;         /* number of data to be written 
in bytes */
+       unsigned int            rx_len;         /* number of data to be read in 
bytes */
+       const void              *tx_buf;        /* data to be written, or NULL 
*/
+       void                    *rx_buf;        /* data to be read, or NULL */
+       u32                     cur_mode;
+};
+
+static inline struct stm32_spi_priv *to_stm32_spi_priv(struct spi_master 
*master)
+{
+       return container_of(master, struct stm32_spi_priv, master);
+}
+
+static void stm32_spi_write_txfifo(struct stm32_spi_priv *priv)
+{
+       while ((priv->tx_len > 0) &&
+              (readl(priv->base + STM32_SPI_SR) & SPI_SR_TXP)) {
+               u32 offs = priv->cur_xferlen - priv->tx_len;
+
+               if (priv->tx_len >= sizeof(u32) &&
+                   IS_ALIGNED((uintptr_t)(priv->tx_buf + offs), sizeof(u32))) {
+                       const u32 *tx_buf32 = (const u32 *)(priv->tx_buf + 
offs);
+
+                       writel(*tx_buf32, priv->base + STM32_SPI_TXDR);
+                       priv->tx_len -= sizeof(u32);
+               } else if (priv->tx_len >= sizeof(u16) &&
+                          IS_ALIGNED((uintptr_t)(priv->tx_buf + offs), 
sizeof(u16))) {
+                       const u16 *tx_buf16 = (const u16 *)(priv->tx_buf + 
offs);
+
+                       writew(*tx_buf16, priv->base + STM32_SPI_TXDR);
+                       priv->tx_len -= sizeof(u16);
+               } else {
+                       const u8 *tx_buf8 = (const u8 *)(priv->tx_buf + offs);
+
+                       writeb(*tx_buf8, priv->base + STM32_SPI_TXDR);
+                       priv->tx_len -= sizeof(u8);
+               }
+       }
+
+       dev_dbg(priv->master.dev, "%d bytes left\n", priv->tx_len);
+}
+
+static void stm32_spi_read_rxfifo(struct stm32_spi_priv *priv)
+{
+       u32 sr = readl(priv->base + STM32_SPI_SR);
+       u32 rxplvl = (sr & SPI_SR_RXPLVL) >> SPI_SR_RXPLVL_SHIFT;
+
+       while ((priv->rx_len > 0) &&
+              ((sr & SPI_SR_RXP) ||
+              ((sr & SPI_SR_EOT) && ((sr & SPI_SR_RXWNE) || (rxplvl > 0))))) {
+               u32 offs = priv->cur_xferlen - priv->rx_len;
+
+               if (IS_ALIGNED((uintptr_t)(priv->rx_buf + offs), sizeof(u32)) &&
+                   (priv->rx_len >= sizeof(u32) || (sr & SPI_SR_RXWNE))) {
+                       u32 *rx_buf32 = (u32 *)(priv->rx_buf + offs);
+
+                       *rx_buf32 = readl(priv->base + STM32_SPI_RXDR);
+                       priv->rx_len -= sizeof(u32);
+               } else if (IS_ALIGNED((uintptr_t)(priv->rx_buf + offs), 
sizeof(u16)) &&
+                          (priv->rx_len >= sizeof(u16) ||
+                           (!(sr & SPI_SR_RXWNE) &&
+                           (rxplvl >= 2 || priv->cur_bpw > 8)))) {
+                       u16 *rx_buf16 = (u16 *)(priv->rx_buf + offs);
+
+                       *rx_buf16 = readw(priv->base + STM32_SPI_RXDR);
+                       priv->rx_len -= sizeof(u16);
+               } else {
+                       u8 *rx_buf8 = (u8 *)(priv->rx_buf + offs);
+
+                       *rx_buf8 = readb(priv->base + STM32_SPI_RXDR);
+                       priv->rx_len -= sizeof(u8);
+               }
+
+               sr = readl(priv->base + STM32_SPI_SR);
+               rxplvl = (sr & SPI_SR_RXPLVL) >> SPI_SR_RXPLVL_SHIFT;
+       }
+
+       dev_dbg(priv->master.dev, "%d bytes left\n", priv->rx_len);
+}
+
+static void stm32_spi_enable(struct stm32_spi_priv *priv)
+{
+       setbits_le32(priv->base + STM32_SPI_CR1, SPI_CR1_SPE);
+}
+
+static void stm32_spi_disable(struct stm32_spi_priv *priv)
+{
+       clrbits_le32(priv->base + STM32_SPI_CR1, SPI_CR1_SPE);
+}
+
+static void stm32_spi_stopxfer(struct stm32_spi_priv *priv)
+{
+       struct device_d *dev = priv->master.dev;
+       u32 cr1, sr;
+       int ret;
+
+       dev_dbg(dev, "%s\n", __func__);
+
+       cr1 = readl(priv->base + STM32_SPI_CR1);
+
+       if (!(cr1 & SPI_CR1_SPE))
+               return;
+
+       /* Wait on EOT or suspend the flow */
+       ret = readl_poll_timeout(priv->base + STM32_SPI_SR, sr,
+                                !(sr & SPI_SR_EOT), USEC_PER_SEC);
+       if (ret < 0) {
+               if (cr1 & SPI_CR1_CSTART) {
+                       writel(cr1 | SPI_CR1_CSUSP, priv->base + STM32_SPI_CR1);
+                       if (readl_poll_timeout(priv->base + STM32_SPI_SR,
+                                              sr, !(sr & SPI_SR_SUSP),
+                                              100000) < 0)
+                               dev_err(dev, "Suspend request timeout\n");
+               }
+       }
+
+       /* clear status flags */
+       setbits_le32(priv->base + STM32_SPI_IFCR, SPI_IFCR_ALL);
+}
+
+static void stm32_spi_set_cs(struct spi_device *spi, bool en)
+{
+       struct stm32_spi_priv *priv = to_stm32_spi_priv(spi->master);
+       int gpio = priv->cs_gpios[spi->chip_select];
+       int ret = -EINVAL;
+
+       dev_dbg(priv->master.dev, "cs=%d en=%d\n", gpio, en);
+
+       if (gpio_is_valid(gpio))
+               ret = gpio_direction_output(gpio, (spi->mode & SPI_CS_HIGH) ? 
en : !en);
+
+       if (ret)
+               dev_warn(priv->master.dev, "couldn't toggle cs#%u\n", 
spi->chip_select);
+}
+
+static void stm32_spi_set_mode(struct stm32_spi_priv *priv, unsigned mode)
+{
+       u32 cfg2_clrb = 0, cfg2_setb = 0;
+
+       dev_dbg(priv->master.dev, "mode=%d\n", mode);
+
+       if (mode & SPI_CPOL)
+               cfg2_setb |= SPI_CFG2_CPOL;
+       else
+               cfg2_clrb |= SPI_CFG2_CPOL;
+
+       if (mode & SPI_CPHA)
+               cfg2_setb |= SPI_CFG2_CPHA;
+       else
+               cfg2_clrb |= SPI_CFG2_CPHA;
+
+       if (mode & SPI_LSB_FIRST)
+               cfg2_setb |= SPI_CFG2_LSBFRST;
+       else
+               cfg2_clrb |= SPI_CFG2_LSBFRST;
+
+       if (cfg2_clrb || cfg2_setb)
+               clrsetbits_le32(priv->base + STM32_SPI_CFG2,
+                               cfg2_clrb, cfg2_setb);
+}
+
+static void stm32_spi_set_fthlv(struct stm32_spi_priv *priv, u32 xfer_len)
+{
+       u32 fthlv, half_fifo;
+
+       /* data packet should not exceed 1/2 of fifo space */
+       half_fifo = (priv->fifo_size / 2);
+
+       /* data_packet should not exceed transfer length */
+       fthlv = (half_fifo > xfer_len) ? xfer_len : half_fifo;
+
+       /* align packet size with data registers access */
+       fthlv -= (fthlv % 4);
+
+       if (!fthlv)
+               fthlv = 1;
+       clrsetbits_le32(priv->base + STM32_SPI_CFG1, SPI_CFG1_FTHLV,
+                       (fthlv - 1) << SPI_CFG1_FTHLV_SHIFT);
+}
+
+static int stm32_spi_set_speed(struct stm32_spi_priv *priv, uint hz)
+{
+       u32 mbrdiv;
+       long div;
+
+       dev_dbg(priv->master.dev, "hz=%d\n", hz);
+
+       if (priv->cur_hz == hz)
+               return 0;
+
+       div = DIV_ROUND_UP(priv->bus_clk_rate, hz);
+
+       if (div < STM32_MBR_DIV_MIN || div > STM32_MBR_DIV_MAX)
+               return -EINVAL;
+
+       /* Determine the first power of 2 greater than or equal to div */
+       if (div & (div - 1))
+               mbrdiv = fls(div);
+       else
+               mbrdiv = fls(div) - 1;
+
+       if (!mbrdiv)
+               return -EINVAL;
+
+       clrsetbits_le32(priv->base + STM32_SPI_CFG1, SPI_CFG1_MBR,
+                       (mbrdiv - 1) << SPI_CFG1_MBR_SHIFT);
+
+       priv->cur_hz = hz;
+
+       return 0;
+}
+
+static int stm32_spi_setup(struct spi_device *spi)
+{
+       struct stm32_spi_priv *priv = to_stm32_spi_priv(spi->master);
+       int ret;
+
+       stm32_spi_set_cs(spi, false);
+       stm32_spi_enable(priv);
+
+       stm32_spi_set_mode(priv, spi->mode);
+
+       ret = stm32_spi_set_speed(priv, spi->max_speed_hz);
+       if (ret)
+               goto out;
+
+       priv->cur_bpw = spi->bits_per_word;
+       clrsetbits_le32(priv->base + STM32_SPI_CFG1, SPI_CFG1_DSIZE,
+                       priv->cur_bpw - 1);
+
+       dev_dbg(priv->master.dev, "%s mode 0x%08x bits_per_word: %d speed: 
%d\n",
+               __func__, spi->mode, spi->bits_per_word,
+               spi->max_speed_hz);
+out:
+       stm32_spi_disable(priv);
+       return ret;
+}
+
+static int stm32_spi_transfer_one(struct stm32_spi_priv *priv,
+                                 struct spi_transfer *t)
+{
+       struct device_d *dev = priv->master.dev;
+       u32 sr;
+       u32 ifcr = 0;
+       u32 mode;
+       int xfer_status = 0;
+
+       if (t->len <= SPI_CR2_TSIZE)
+               writel(t->len, priv->base + STM32_SPI_CR2);
+       else
+               return -EMSGSIZE;
+
+       priv->tx_buf = t->tx_buf;
+       priv->rx_buf = t->rx_buf;
+       priv->tx_len = priv->tx_buf ? t->len : 0;
+       priv->rx_len = priv->rx_buf ? t->len : 0;
+
+       mode = SPI_FULL_DUPLEX;
+       if (!priv->tx_buf)
+               mode = SPI_SIMPLEX_RX;
+       else if (!priv->rx_buf)
+               mode = SPI_SIMPLEX_TX;
+
+       if (priv->cur_xferlen != t->len || priv->cur_mode != mode) {
+               priv->cur_mode = mode;
+               priv->cur_xferlen = t->len;
+
+               /* Disable the SPI hardware to unlock CFG1/CFG2 registers */
+               stm32_spi_disable(priv);
+
+               clrsetbits_le32(priv->base + STM32_SPI_CFG2, SPI_CFG2_COMM,
+                               mode << SPI_CFG2_COMM_SHIFT);
+
+               stm32_spi_set_fthlv(priv, t->len);
+
+               /* Enable the SPI hardware */
+               stm32_spi_enable(priv);
+       }
+
+       dev_dbg(dev, "priv->tx_len=%d priv->rx_len=%d\n",
+               priv->tx_len, priv->rx_len);
+
+       /* Be sure to have data in fifo before starting data transfer */
+       if (priv->tx_buf)
+               stm32_spi_write_txfifo(priv);
+
+       setbits_le32(priv->base + STM32_SPI_CR1, SPI_CR1_CSTART);
+
+       while (1) {
+               sr = readl(priv->base + STM32_SPI_SR);
+
+               if (sr & SPI_SR_OVR) {
+                       dev_err(dev, "Overrun: RX data lost\n");
+                       xfer_status = -EIO;
+                       break;
+               }
+
+               if (sr & SPI_SR_SUSP) {
+                       dev_warn(dev, "System too slow is limiting data 
throughput\n");
+
+                       if (priv->rx_buf && priv->rx_len > 0)
+                               stm32_spi_read_rxfifo(priv);
+
+                       ifcr |= SPI_SR_SUSP;
+               }
+
+               if (sr & SPI_SR_TXTF)
+                       ifcr |= SPI_SR_TXTF;
+
+               if (sr & SPI_SR_TXP)
+                       if (priv->tx_buf && priv->tx_len > 0)
+                               stm32_spi_write_txfifo(priv);
+
+               if (sr & SPI_SR_RXP)
+                       if (priv->rx_buf && priv->rx_len > 0)
+                               stm32_spi_read_rxfifo(priv);
+
+               if (sr & SPI_SR_EOT) {
+                       if (priv->rx_buf && priv->rx_len > 0)
+                               stm32_spi_read_rxfifo(priv);
+                       break;
+               }
+
+               writel(ifcr, priv->base + STM32_SPI_IFCR);
+       }
+
+       /* clear status flags */
+       setbits_le32(priv->base + STM32_SPI_IFCR, SPI_IFCR_ALL);
+       stm32_spi_stopxfer(priv);
+
+       return xfer_status;
+}
+
+static int stm32_spi_transfer(struct spi_device *spi, struct spi_message *mesg)
+{
+       struct stm32_spi_priv *priv = to_stm32_spi_priv(spi->master);
+       struct spi_transfer *t;
+       unsigned int cs_change;
+       const int nsecs = 50;
+       int ret = 0;
+
+       stm32_spi_enable(priv);
+
+       stm32_spi_set_cs(spi, true);
+
+       cs_change = 0;
+
+       mesg->actual_length = 0;
+
+       list_for_each_entry(t, &mesg->transfers, transfer_list) {
+               if (cs_change) {
+                       ndelay(nsecs);
+                       stm32_spi_set_cs(spi, false);
+                       ndelay(nsecs);
+                       stm32_spi_set_cs(spi, true);
+               }
+
+               cs_change = t->cs_change;
+
+               ret = stm32_spi_transfer_one(priv, t);
+               if (ret)
+                       goto out;
+
+               mesg->actual_length += t->len;
+
+               if (cs_change)
+                       stm32_spi_set_cs(spi, true);
+       }
+
+       if (!cs_change)
+               stm32_spi_set_cs(spi, false);
+
+out:
+       stm32_spi_disable(priv);
+       return ret;
+}
+
+static int stm32_spi_get_fifo_size(struct stm32_spi_priv *priv)
+{
+       u32 count = 0;
+
+       stm32_spi_enable(priv);
+
+       while (readl(priv->base + STM32_SPI_SR) & SPI_SR_TXP)
+               writeb(++count, priv->base + STM32_SPI_TXDR);
+
+       stm32_spi_disable(priv);
+
+       dev_dbg(priv->master.dev, "%d x 8-bit fifo size\n", count);
+
+       return count;
+}
+
+static void stm32_spi_dt_probe(struct stm32_spi_priv *priv)
+{
+       struct device_node *node = priv->master.dev->device_node;
+       int i;
+
+       priv->master.num_chipselect = of_gpio_named_count(node, "cs-gpios");
+       priv->cs_gpios = xzalloc(sizeof(u32) * priv->master.num_chipselect);
+
+       for (i = 0; i < priv->master.num_chipselect; i++)
+               priv->cs_gpios[i] = of_get_named_gpio(node, "cs-gpios", i);
+}
+
+static int stm32_spi_probe(struct device_d *dev)
+{
+       struct resource *iores;
+       struct spi_master *master;
+       struct stm32_spi_priv *priv;
+       int ret;
+
+       iores = dev_request_mem_resource(dev, 0);
+       if (IS_ERR(iores))
+               return PTR_ERR(iores);
+
+       priv = dev->priv = xzalloc(sizeof(*priv));
+
+       priv->base = IOMEM(iores->start);
+
+       master = &priv->master;
+       master->dev = dev;
+
+       master->setup = stm32_spi_setup;
+       master->transfer = stm32_spi_transfer;
+
+       master->bus_num = -1;
+       stm32_spi_dt_probe(priv);
+
+       priv->clk = clk_get(dev, NULL);
+       if (IS_ERR(priv->clk))
+               return PTR_ERR(priv->clk);
+
+       ret = clk_enable(priv->clk);
+       if (ret)
+               return ret;
+
+       priv->bus_clk_rate = clk_get_rate(priv->clk);
+
+       ret = device_reset_us(dev, 2);
+       if (ret)
+               return ret;
+
+       priv->fifo_size = stm32_spi_get_fifo_size(priv);
+
+       priv->cur_mode = SPI_FULL_DUPLEX;
+       priv->cur_xferlen = 0;
+
+       /* Ensure I2SMOD bit is kept cleared */
+       clrbits_le32(priv->base + STM32_SPI_I2SCFGR, SPI_I2SCFGR_I2SMOD);
+
+       /*
+        * - SS input value high
+        * - transmitter half duplex direction
+        * - automatic communication suspend when RX-Fifo is full
+        */
+       setbits_le32(priv->base + STM32_SPI_CR1,
+                    SPI_CR1_SSI | SPI_CR1_HDDIR | SPI_CR1_MASRX);
+
+       /*
+        * - Set the master mode (default Motorola mode)
+        * - Consider 1 master/n slaves configuration and
+        *   SS input value is determined by the SSI bit
+        * - keep control of all associated GPIOs
+        */
+       setbits_le32(priv->base + STM32_SPI_CFG2,
+                    SPI_CFG2_MASTER | SPI_CFG2_SSM | SPI_CFG2_AFCNTR);
+
+       return spi_register_master(master);
+}
+
+static void stm32_spi_remove(struct device_d *dev)
+{
+       struct stm32_spi_priv *priv = dev->priv;
+
+       stm32_spi_stopxfer(priv);
+       stm32_spi_disable(priv);
+};
+
+static const struct of_device_id stm32_spi_ids[] = {
+       { .compatible = "st,stm32h7-spi", },
+       { /* sentinel */ }
+};
+
+static struct driver_d stm32_spi_driver = {
+       .name  = "stm32_spi",
+       .probe = stm32_spi_probe,
+       .remove = stm32_spi_remove,
+       .of_compatible = stm32_spi_ids,
+};
+coredevice_platform_driver(stm32_spi_driver);
-- 
2.30.2


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