This I2C module is integrated into the Loongson-2K SoC and the Loongson
LS7A bridge chip.
Initialize the i2c controller early. This is required in order to ensure
that core system devices such as the display controller(DC) attached via
I2C are available early in boot.
Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
Signed-off-by: Binbin Zhou <zhoubinbin@xxxxxxxxxxx>
---
drivers/i2c/busses/Kconfig | 7 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-ls2x.c | 364 ++++++++++++++++++++++++++++++++++
3 files changed, 372 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-ls2x.c
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 7284206b278b..a4687a6abe75 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -887,6 +887,13 @@ config I2C_OWL
Say Y here if you want to use the I2C bus controller on
the Actions Semiconductor Owl SoC's.
+config I2C_LS2X
+ tristate "Loongson LS2X I2C adapter"
+ depends on MACH_LOONGSON64 || COMPILE_TEST
+ help
+ If you say yes to this option, support will be included for the
+ I2C interface on the Loongson's LS2K/LS7A Platform-Bridge.
+
config I2C_PASEMI
tristate "PA Semi SMBus interface"
depends on PPC_PASEMI && PCI
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index c5cac15f075c..721841361e34 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -86,6 +86,7 @@ obj-$(CONFIG_I2C_MV64XXX) += i2c-mv64xxx.o
obj-$(CONFIG_I2C_MXS) += i2c-mxs.o
obj-$(CONFIG_I2C_NOMADIK) += i2c-nomadik.o
obj-$(CONFIG_I2C_NPCM) += i2c-npcm7xx.o
+obj-$(CONFIG_I2C_LS2X) += i2c-ls2x.o
obj-$(CONFIG_I2C_OCORES) += i2c-ocores.o
obj-$(CONFIG_I2C_OMAP) += i2c-omap.o
obj-$(CONFIG_I2C_OWL) += i2c-owl.o
diff --git a/drivers/i2c/busses/i2c-ls2x.c b/drivers/i2c/busses/i2c-ls2x.c
new file mode 100644
index 000000000000..80d8f1e12876
--- /dev/null
+++ b/drivers/i2c/busses/i2c-ls2x.c
@@ -0,0 +1,364 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Loongson-2K/7A I2C master mode driver
+ *
+ * Copyright (C) 2013 Loongson Technology Corporation Limited
+ * Copyright (C) 2014-2017 Lemote, Inc.
+ *
+ * Originally written by liushaozong
+ */
+
+#include <linux/i2c.h>
+#include <linux/acpi.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/completion.h>
+#include <linux/platform_device.h>
+
+#define LS2X_I2C_PRER_LO_REG 0x0
+#define LS2X_I2C_PRER_HI_REG 0x1
+#define LS2X_I2C_CTR_REG 0x2
+#define LS2X_I2C_TXR_REG 0x3
+#define LS2X_I2C_RXR_REG 0x3
+#define LS2X_I2C_CR_REG 0x4
+#define LS2X_I2C_SR_REG 0x4
+
+#define LS2X_I2C_CMD_START BIT(7)
+#define LS2X_I2C_CMD_STOP BIT(6)
+#define LS2X_I2C_CMD_READ BIT(5)
+#define LS2X_I2C_CMD_WRITE BIT(4)
+#define LS2X_I2C_CMD_ACK BIT(3)
+#define LS2X_I2C_CMD_IACK BIT(0)
+
+#define LS2X_I2C_SR_NOACK BIT(7)
+#define LS2X_I2C_SR_BUSY BIT(6)
+#define LS2X_I2C_SR_AL BIT(5)
+#define LS2X_I2C_SR_TIP BIT(1)
+#define LS2X_I2C_SR_IF BIT(0)
+
+#define I2C_MAX_RETRIES 5
+
+/* I2C clock frequency 50M */
+#define I2C_CLK_RATE_50M (50 * 1000000)
+
+#define i2c_readb(addr) readb(dev->base + addr)
+#define i2c_writeb(val, addr) writeb(val, dev->base + addr)
+
+struct ls2x_i2c_dev {
+ unsigned int suspended:1;
+ struct device *dev;
+ void __iomem *base;
+ int irq;
+ u32 bus_freq_hz;
+ struct completion cmd_complete;
+ struct i2c_adapter adapter;
+};
+
+static void i2c_stop(struct ls2x_i2c_dev *dev)
+{
+again:
+ i2c_writeb(LS2X_I2C_CMD_STOP, LS2X_I2C_CR_REG);
+ wait_for_completion(&dev->cmd_complete);
+
+ i2c_readb(LS2X_I2C_SR_REG);
+
+ while (i2c_readb(LS2X_I2C_SR_REG) & LS2X_I2C_SR_BUSY)
+ goto again;
+}
+
+static int ls2x_i2c_start(struct ls2x_i2c_dev *dev,
+ int dev_addr, int flags)
+{
+ int retry = I2C_MAX_RETRIES;
+ unsigned char addr = (dev_addr & 0x7f) << 1;
+
+ addr |= (flags & I2C_M_RD) ? 1 : 0;
+start:
+ mdelay(1);
+ i2c_writeb(addr, LS2X_I2C_TXR_REG);
+ dev_dbg(dev->dev, "%s <line%d>: i2c device address: 0x%x\n",
+ __func__, __LINE__, addr);
+
+ i2c_writeb((LS2X_I2C_CMD_START | LS2X_I2C_CMD_WRITE),
+ LS2X_I2C_CR_REG);
+ wait_for_completion(&dev->cmd_complete);
+
+ if (i2c_readb(LS2X_I2C_SR_REG) & LS2X_I2C_SR_NOACK) {
+ i2c_stop(dev);
+ while (retry--)
+ goto start;
+ dev_info(dev->dev, "There is no i2c device ack\n");
+ return 0;
+ }
+
+ return 1;
+}
+
+static void ls2x_i2c_reginit(struct ls2x_i2c_dev *dev)
+{
+ u16 val = 0x12c;
+
+ if (dev->bus_freq_hz)
+ val = I2C_CLK_RATE_50M / (5 * dev->bus_freq_hz) - 1;
+
+ i2c_writeb(0, LS2X_I2C_CTR_REG);
+ i2c_writeb(val & 0xff, LS2X_I2C_PRER_LO_REG);
+ i2c_writeb((val & 0xff00) >> 8, LS2X_I2C_PRER_HI_REG);
+ i2c_writeb(0xc0, LS2X_I2C_CTR_REG);
+}
+
+static int ls2x_i2c_read(struct ls2x_i2c_dev *dev,
+ unsigned char *buf, int count)
+{
+ int i;
+ int cmd = LS2X_I2C_CMD_READ;
+
+ for (i = 0; i < count; i++) {
+ if (i == count - 1)
+ cmd |= LS2X_I2C_CMD_ACK;
+
+ i2c_writeb(cmd, LS2X_I2C_CR_REG);
+ wait_for_completion(&dev->cmd_complete);
+
+ buf[i] = i2c_readb(LS2X_I2C_RXR_REG);
+ dev_dbg(dev->dev, "%s <line%d>: read buf[%d] <= %02x\n",
+ __func__, __LINE__, i, buf[i]);
+ }
+
+ return i;
+}
+
+static int ls2x_i2c_write(struct ls2x_i2c_dev *dev,
+ unsigned char *buf, int count)
+{
+ int i;
+
+ for (i = 0; i < count; i++) {
+ i2c_writeb(buf[i], LS2X_I2C_TXR_REG);
+ dev_dbg(dev->dev, "%s <line%d>: write buf[%d] => %02x\n",
+ __func__, __LINE__, i, buf[i]);
+
+ i2c_writeb(LS2X_I2C_CMD_WRITE, LS2X_I2C_CR_REG);
+ wait_for_completion(&dev->cmd_complete);
+
+ if (i2c_readb(LS2X_I2C_SR_REG) & LS2X_I2C_SR_NOACK) {
+ dev_dbg(dev->dev, "%s <line%d>: device no ack\n",
+ __func__, __LINE__);
+ i2c_stop(dev);
+ return 0;
+ }
+ }
+
+ return i;
+}
+
+static int ls2x_i2c_doxfer(struct ls2x_i2c_dev *dev,
+ struct i2c_msg *msgs, int num)
+{
+ int i;
+ struct i2c_msg *m = msgs;
+
+ for (i = 0; i < num; i++) {
+ reinit_completion(&dev->cmd_complete);
+ if (!ls2x_i2c_start(dev, m->addr, m->flags))
+ return 0;
+
+ if (m->flags & I2C_M_RD)
+ ls2x_i2c_read(dev, m->buf, m->len);
+ else
+ ls2x_i2c_write(dev, m->buf, m->len);
+ ++m;
+ }
+
+ i2c_stop(dev);
+
+ return i;
+}
+
+static int ls2x_i2c_xfer(struct i2c_adapter *adap,
+ struct i2c_msg *msgs, int num)
+{
+ int ret, retry;
+ struct ls2x_i2c_dev *dev;
+
+ dev = i2c_get_adapdata(adap);
+ for (retry = 0; retry < adap->retries; retry++) {
+ ret = ls2x_i2c_doxfer(dev, msgs, num);
+ if (ret != -EAGAIN)
+ return ret;
+
+ udelay(100);
+ }
+
+ return -EREMOTEIO;
+}
+
+static unsigned int ls2x_i2c_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm ls2x_i2c_algo = {
+ .master_xfer = ls2x_i2c_xfer,
+ .functionality = ls2x_i2c_func,
+};
+
+/*
+ * Interrupt service routine. This gets called whenever an I2C interrupt
+ * occurs.
+ */
+static irqreturn_t ls2x_i2c_isr(int this_irq, void *dev_id)
+{
+ unsigned char iflag;
+ struct ls2x_i2c_dev *dev = dev_id;
+
+ iflag = i2c_readb(LS2X_I2C_SR_REG);
+
+ if (iflag & LS2X_I2C_SR_IF) {
+ i2c_writeb(LS2X_I2C_CMD_IACK, LS2X_I2C_CR_REG);
+ complete(&dev->cmd_complete);
+ } else
+ return IRQ_NONE;
+
+ return IRQ_HANDLED;
+}
+
+static int ls2x_i2c_probe(struct platform_device *pdev)
+{
+ int r;
+ struct ls2x_i2c_dev *dev;
+ struct i2c_adapter *adap;
+
+ dev = devm_kzalloc(&pdev->dev, sizeof(struct ls2x_i2c_dev), GFP_KERNEL);
+ if (unlikely(!dev))
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, dev);
+ init_completion(&dev->cmd_complete);
+ dev->dev = &pdev->dev;
+
+ /* Map hardware registers */
+ dev->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(dev->base))
+ return PTR_ERR(dev->base);
+
+ r = platform_get_irq(pdev, 0);
+ if (unlikely(r <= 0))
+ return -ENODEV;
+ dev->irq = r;
+
+ r = devm_request_irq(&pdev->dev, dev->irq, ls2x_i2c_isr,
+ IRQF_SHARED, "ls2x-i2c", dev);
+ if (unlikely(r)) {
+ dev_err(dev->dev, "failure requesting irq %i\n", dev->irq);
+ return r;
+ }
+
+ dev->bus_freq_hz = i2c_acpi_find_bus_speed(&pdev->dev);
+ if (!dev->bus_freq_hz)
+ device_property_read_u32(&pdev->dev, "clock-frequency",
+ &dev->bus_freq_hz);
+
+ ls2x_i2c_reginit(dev);
+
+ /* Add the i2c adapter */
+ adap = &dev->adapter;
+ i2c_set_adapdata(adap, dev);
+ adap->nr = pdev->id;
+ strscpy(adap->name, pdev->name, sizeof(adap->name));
+ adap->owner = THIS_MODULE;
+ adap->class = I2C_CLASS_HWMON;
+ adap->retries = I2C_MAX_RETRIES;
+ adap->algo = &ls2x_i2c_algo;
+ adap->dev.parent = &pdev->dev;
+ adap->dev.of_node = pdev->dev.of_node;
+ ACPI_COMPANION_SET(&adap->dev, ACPI_COMPANION(&pdev->dev));
+
+ /* i2c device drivers may be active on return from add_adapter() */
+ r = i2c_add_adapter(adap);
+ if (r) {
+ dev_err(dev->dev, "failure adding adapter\n");
+ return r;
+ }
+
+ return 0;
+}
+
+static int ls2x_i2c_remove(struct platform_device *pdev)
+{
+ struct ls2x_i2c_dev *dev = platform_get_drvdata(pdev);
+
+ i2c_del_adapter(&dev->adapter);
+ return 0;
+}
+
+static int __maybe_unused ls2x_i2c_suspend_noirq(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct ls2x_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
+
+ i2c_dev->suspended = 1;
+
+ return 0;
+}
+
+static int __maybe_unused ls2x_i2c_resume(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct ls2x_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
+
+ i2c_dev->suspended = 0;
+ ls2x_i2c_reginit(i2c_dev);
+
+ return 0;
+}
+
+static const struct dev_pm_ops ls2x_i2c_dev_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(ls2x_i2c_suspend_noirq, ls2x_i2c_resume)
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id ls2x_i2c_id_table[] = {
+ {.compatible = "loongson,ls2k-i2c"},
+ {.compatible = "loongson,ls7a-i2c"},
+ {},
+};
+MODULE_DEVICE_TABLE(of, ls2x_i2c_id_table);
+#endif
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id ls2x_i2c_acpi_match[] = {
+ {"LOON0004"},
+ {}
+};
+MODULE_DEVICE_TABLE(acpi, ls2x_i2c_acpi_match);
+#endif
+
+static struct platform_driver ls2x_i2c_driver = {
+ .probe = ls2x_i2c_probe,
+ .remove = ls2x_i2c_remove,
+ .driver = {
+ .name = "ls2x-i2c",
+ .owner = THIS_MODULE,
+ .pm = &ls2x_i2c_dev_pm_ops,
+ .of_match_table = of_match_ptr(ls2x_i2c_id_table),
+ .acpi_match_table = ACPI_PTR(ls2x_i2c_acpi_match),
+ },
+};
+
+static int __init ls2x_i2c_init_driver(void)
+{
+ return platform_driver_register(&ls2x_i2c_driver);
+}
+subsys_initcall(ls2x_i2c_init_driver);
+
+static void __exit ls2x_i2c_exit_driver(void)
+{
+ platform_driver_unregister(&ls2x_i2c_driver);
+}
+module_exit(ls2x_i2c_exit_driver);
+
+MODULE_AUTHOR("Loongson Technology Corporation Limited");
+MODULE_DESCRIPTION("Loongson LS2X I2C bus adapter");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ls2x-i2c");
--
2.31.1
