The SPI controller has the following characteristics:
- Full-duplex synchronous serial data transmission
- Support up to 4 variable length byte transmission
- Main mode support
- Mode failure generates an error flag and issues an interrupt request
- Double buffer receiver
- Serial clock with programmable polarity and phase
- SPI can be controlled in wait mode
- Support boot from SPI
Use mtd_debug tool to earse/write/read /dev/mtd0 on development.
eg:
[root@linux mtd-utils-1.0.0]# mtd_debug erase /dev/mtd0 0x20000 0x40000
Erased 262144 bytes from address 0x00020000 in flash
[root@linux mtd-utils-1.0.0]# mtd_debug write /dev/mtd0 0x20000 13 1.img
Copied 13 bytes from 1.img to address 0x00020000 in flash
[root@linux mtd-utils-1.0.0]# mtd_debug read /dev/mtd0 0x20000 13 2.img
Copied 13 bytes from address 0x00020000 in flash to 2.img
[root@linux mtd-utils-1.0.0]# cmp -l 1.img 2.img
Signed-off-by: Qing Zhang <zhangqing@xxxxxxxxxxx>
---
v2:
- keep Kconfig and Makefile sorted
- make the entire comment a C++ one so things look more intentional
- Fix unclear indentation
- make conditional statements to improve legibility
- Don't use static inline
- the core handle message queue
- Add a new binding document
- Fix probe part mixed pdev and PCI
v3:
- expose set_cs to the core and let it handle things
- replace transfer_one_message to transfer_one
- replace spi_alloc_master to devm_spi_alloc_master
- split out into prepare/unprepare_message
- releases pci regions before unregister master
v4:
- names used in the manual
- rename ls7a_spi_do_transfer to ls7a_spi_setup_transfer
- change read the spcr and sper outside of this function
- mode configuration moved to prepare instead
- remove redundancy code about unprepare/prepare_message
- used 0x4 instead of 0x1,WFEMPTY instead of RFEMPTY
---
drivers/spi/Kconfig | 7 ++
drivers/spi/Makefile | 1 +
drivers/spi/spi-ls7a.c | 283 +++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 291 insertions(+)
create mode 100644 drivers/spi/spi-ls7a.c
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index aadaea0..af7c0d4 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -413,6 +413,13 @@ config SPI_LP8841_RTC
Say N here unless you plan to run the kernel on an ICP DAS
LP-8x4x industrial computer.
+config SPI_LS7A
+ tristate "Loongson LS7A SPI Controller Support"
+ depends on CPU_LOONGSON64 || COMPILE_TEST
+ help
+ This drivers supports the Loongson LS7A SPI controller in master
+ SPI mode.
+
config SPI_MPC52xx
tristate "Freescale MPC52xx SPI (non-PSC) controller support"
depends on PPC_MPC52xx
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 6fea582..d015cf2 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -61,6 +61,7 @@ obj-$(CONFIG_SPI_LANTIQ_SSC) += spi-lantiq-ssc.o
obj-$(CONFIG_SPI_JCORE) += spi-jcore.o
obj-$(CONFIG_SPI_LM70_LLP) += spi-lm70llp.o
obj-$(CONFIG_SPI_LP8841_RTC) += spi-lp8841-rtc.o
+obj-$(CONFIG_SPI_LS7A) += spi-ls7a.o
obj-$(CONFIG_SPI_MESON_SPICC) += spi-meson-spicc.o
obj-$(CONFIG_SPI_MESON_SPIFC) += spi-meson-spifc.o
obj-$(CONFIG_SPI_MPC512x_PSC) += spi-mpc512x-psc.o
diff --git a/drivers/spi/spi-ls7a.c b/drivers/spi/spi-ls7a.c
new file mode 100644
index 0000000..d2be370
--- /dev/null
+++ b/drivers/spi/spi-ls7a.c
@@ -0,0 +1,283 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// Loongson LS7A SPI Controller driver
+//
+// Copyright (C) 2020 Loongson Technology Corporation Limited.
+//
+
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/spi/spi.h>
+
+/* define spi register */
+#define SPCR 0x00
+#define SPSR 0x01
+#define FIFO 0x02
+#define SPER 0x03
+#define SFC_PARAM 0x04
+#define SFC_SOFTCS 0x05
+#define SFC_TIMING 0x06
+
+struct ls7a_spi {
+ struct spi_master *master;
+ void __iomem *base;
+ unsigned int hz;
+ unsigned int mode;
+};
+
+static void ls7a_spi_write_reg(struct ls7a_spi *spi,
+ unsigned char reg,
+ unsigned char data)
+{
+ writeb(data, spi->base + reg);
+}
+
+static char ls7a_spi_read_reg(struct ls7a_spi *spi, unsigned char reg)
+{
+ return readb(spi->base + reg);
+}
+
+static int ls7a_spi_prepare_message(struct spi_master *master,
+ struct spi_message *msg)
+{
+ struct ls7a_spi *ls7a_spi;
+ struct spi_device *spi = msg->spi;
+ unsigned char val;
+
+ ls7a_spi = spi_master_get_devdata(master);
+
+ if (ls7a_spi->mode != spi->mode) {
+ val = ls7a_spi_read_reg(ls7a_spi, SPCR);
+ val &= ~0xc;
+ if (spi->mode & SPI_CPOL)
+ val |= 8;
+ if (spi->mode & SPI_CPHA)
+ val |= 4;
+ ls7a_spi_write_reg(ls7a_spi, SPCR, val);
+ val = ls7a_spi_read_reg(ls7a_spi, SPER);
+ ls7a_spi_write_reg(ls7a_spi, SPER, val);
+ ls7a_spi->mode = spi->mode;
+ }
+ return 0;
+}
+
+static void ls7a_spi_set_cs(struct spi_device *spi, bool enable)
+{
+ struct ls7a_spi *ls7a_spi;
+ int cs;
+
+ ls7a_spi = spi_master_get_devdata(spi->master);
+
+ cs = ls7a_spi_read_reg(ls7a_spi, SFC_SOFTCS) & ~(0x11 << spi->chip_select);
+
+ if (!!(spi->mode & SPI_CS_HIGH) == enable)
+ ls7a_spi_write_reg(ls7a_spi, SFC_SOFTCS, (0x1 << spi->chip_select) | cs);
+ else
+ ls7a_spi_write_reg(ls7a_spi, SFC_SOFTCS, (0x11 << spi->chip_select) | cs);
+}
+
+static int ls7a_spi_setup_transfer(struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ unsigned int hz;
+ unsigned int div, div_tmp;
+ unsigned int bit;
+ unsigned long clk;
+ unsigned char val;
+ unsigned char spcr, sper;
+ const char rdiv[12] = {0, 1, 4, 2, 3, 5, 6, 7, 8, 9, 10, 11};
+ struct ls7a_spi *ls7a_spi;
+
+ ls7a_spi = spi_master_get_devdata(spi->master);
+
+ if (t) {
+ hz = t->speed_hz;
+ if (!hz)
+ hz = spi->max_speed_hz;
+ } else {
+ hz = spi->max_speed_hz;
+ }
+
+ if (hz & (ls7a_spi->hz != hz)) {
+ clk = 100000000;
+
+ div = DIV_ROUND_UP(clk, hz);
+ if (div < 2)
+ div = 2;
+ if (div > 4096)
+ div = 4096;
+
+ bit = fls(div) - 1;
+ if ((1 << bit) == div)
+ bit--;
+ div_tmp = rdiv[bit];
+
+ dev_dbg(&spi->dev, "clk = %ld hz = %d div_tmp = %d bit = %d\n",
+ clk, hz, div_tmp, bit);
+
+ ls7a_spi->hz = hz;
+ spcr = div_tmp & 3;
+ sper = (div_tmp >> 2) & 3;
+
+ val = ls7a_spi_read_reg(ls7a_spi, SPCR);
+ ls7a_spi_write_reg(ls7a_spi, SPCR, (val & ~3) | spcr);
+ val = ls7a_spi_read_reg(ls7a_spi, SPER);
+ ls7a_spi_write_reg(ls7a_spi, SPER, (val & ~3) | sper);
+ }
+ return 0;
+}
+
+static int ls7a_spi_setup(struct spi_device *spi)
+{
+ return ls7a_spi_setup_transfer(spi, NULL);
+}
+
+static int ls7a_spi_write_read_8bit(struct spi_device *spi,
+ const u8 **tx_buf, u8 **rx_buf,
+ unsigned int num)
+{
+ struct ls7a_spi *ls7a_spi;
+
+ ls7a_spi = spi_master_get_devdata(spi->master);
+
+ if (tx_buf && *tx_buf) {
+ ls7a_spi_write_reg(ls7a_spi, FIFO, *((*tx_buf)++));
+
+ while ((ls7a_spi_read_reg(ls7a_spi, SPSR) & 0x4) == 1)
+
+ ;
+ } else {
+ ls7a_spi_write_reg(ls7a_spi, FIFO, 0);
+
+ while ((ls7a_spi_read_reg(ls7a_spi, SPSR) & 0x1) == 1)
+
+ ;
+ }
+
+ if (rx_buf && *rx_buf)
+ *(*rx_buf)++ = ls7a_spi_read_reg(ls7a_spi, FIFO);
+ else
+ ls7a_spi_read_reg(ls7a_spi, FIFO);
+
+ return 1;
+}
+
+static unsigned int ls7a_spi_write_read(struct spi_device *spi,
+ struct spi_transfer *xfer)
+{
+ unsigned int count;
+ const u8 *tx = xfer->tx_buf;
+
+ u8 *rx = xfer->rx_buf;
+
+ count = xfer->len;
+
+ do {
+ if (ls7a_spi_write_read_8bit(spi, &tx, &rx, count) < 0)
+ goto out;
+ count--;
+ } while (count);
+
+out:
+ return xfer->len - count;
+}
+
+static int ls7a_spi_transfer_one(struct spi_master *master,
+ struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ int status = 0;
+
+ status = ls7a_spi_setup_transfer(spi, t);
+ if (status < 0)
+ return status;
+
+ if (t->len)
+ ls7a_spi_write_read(spi, t);
+
+ return status;
+}
+
+static int ls7a_spi_pci_probe(struct pci_dev *pdev,
+ const struct pci_device_id *ent)
+{
+ struct spi_master *master;
+ struct ls7a_spi *spi;
+ int ret;
+
+ master = devm_spi_alloc_master(&pdev->dev, sizeof(*spi));
+ if (!master)
+ return -ENOMEM;
+
+ spi = spi_master_get_devdata(master);
+ ret = pcim_enable_device(pdev);
+ if (ret)
+ goto err_free_master;
+
+ ret = pci_request_regions(pdev, "ls7a-spi");
+ if (ret)
+ goto err_free_master;
+
+ spi->base = pcim_iomap(pdev, 0, pci_resource_len(pdev, 0));
+ if (!spi->base) {
+ ret = -EINVAL;
+ goto err_free_master;
+ }
+ ls7a_spi_write_reg(spi, SPCR, 0x51);
+ ls7a_spi_write_reg(spi, SPER, 0x00);
+ ls7a_spi_write_reg(spi, SFC_TIMING, 0x01);
+ ls7a_spi_write_reg(spi, SFC_PARAM, 0x40);
+ spi->mode = 0;
+
+ master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
+ master->set_cs = ls7a_spi_set_cs;
+ master->prepare_message = ls7a_spi_prepare_message;
+ master->setup = ls7a_spi_setup;
+ master->transfer_one = ls7a_spi_transfer_one;
+ master->bits_per_word_mask = SPI_BPW_MASK(8);
+ master->num_chipselect = 4;
+ master->dev.of_node = pdev->dev.of_node;
+
+ spi->master = master;
+
+ pci_set_drvdata(pdev, master);
+
+ ret = spi_register_master(master);
+ if (ret)
+ goto err_free_master;
+
+ return 0;
+
+err_free_master:
+ pci_release_regions(pdev);
+ return ret;
+}
+
+static void ls7a_spi_pci_remove(struct pci_dev *pdev)
+{
+ struct spi_master *master = pci_get_drvdata(pdev);
+
+ spi_unregister_master(master);
+ pci_release_regions(pdev);
+}
+
+static const struct pci_device_id ls7a_spi_pci_id_table[] = {
+ { PCI_DEVICE(PCI_VENDOR_ID_LOONGSON, 0x7a0b) },
+ { 0, }
+};
+
+MODULE_DEVICE_TABLE(pci, ls7a_spi_pci_id_table);
+
+static struct pci_driver ls7a_spi_pci_driver = {
+ .name = "ls7a-spi",
+ .id_table = ls7a_spi_pci_id_table,
+ .probe = ls7a_spi_pci_probe,
+ .remove = ls7a_spi_pci_remove,
+};
+
+module_pci_driver(ls7a_spi_pci_driver);
+
+MODULE_AUTHOR("Juxin Gao <gaojuxin@xxxxxxxxxxx>");
+MODULE_AUTHOR("Qing Zhang <zhangqing@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("Loongson LS7A SPI controller driver");
+MODULE_LICENSE("GPL v2");
--
2.1.0
