[PATCH v7 13/15] i2c: thunderx: Add i2c driver for ThunderX SOC

Jan Glauber
2016-04-25T14:35:43Z

The ThunderX SOC uses the same i2c block as the Octeon SOC.
The main difference is that on ThunderX the device is a PCI device
so device probing is done via PCI, interrupts are MSIX and the
clock is taken from device tree.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
---
drivers/i2c/busses/Kconfig | 10 ++
drivers/i2c/busses/Makefile | 2 +
drivers/i2c/busses/i2c-cavium.h | 16 +-
drivers/i2c/busses/i2c-thunderx-core.c | 267 +++++++++++++++++++++++++++++++++
4 files changed, 292 insertions(+), 3 deletions(-)
create mode 100644 drivers/i2c/busses/i2c-thunderx-core.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index faa8e68..92d23de 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -953,6 +953,16 @@ config I2C_OCTEON
This driver can also be built as a module. If so, the module
will be called i2c-octeon.

+config I2C_THUNDERX
+ tristate "Cavium ThunderX I2C bus support"
+ depends on 64BIT && PCI && !CAVIUM_OCTEON_SOC
+ help
+ Say yes if you want to support the I2C serial bus on Cavium
+ ThunderX SOC.
+
+ This driver can also be built as a module. If so, the module
+ will be called i2c-thunderx.
+
config I2C_XILINX
tristate "Xilinx I2C Controller"
depends on HAS_IOMEM
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 282f781..a32ff14 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -93,6 +93,8 @@ obj-$(CONFIG_I2C_VERSATILE) += i2c-versatile.o
obj-$(CONFIG_I2C_WMT) += i2c-wmt.o
i2c-octeon-objs := i2c-cavium.o i2c-octeon-core.o
obj-$(CONFIG_I2C_OCTEON) += i2c-octeon.o
+i2c-thunderx-objs := i2c-cavium.o i2c-thunderx-core.o
+obj-$(CONFIG_I2C_THUNDERX) += i2c-thunderx.o
obj-$(CONFIG_I2C_XILINX) += i2c-xiic.o
obj-$(CONFIG_I2C_XLR) += i2c-xlr.o
obj-$(CONFIG_I2C_XLP9XX) += i2c-xlp9xx.o
diff --git a/drivers/i2c/busses/i2c-cavium.h b/drivers/i2c/busses/i2c-cavium.h
index 81c6a81..33c7e1f 100644
--- a/drivers/i2c/busses/i2c-cavium.h
+++ b/drivers/i2c/busses/i2c-cavium.h
@@ -8,9 +8,15 @@
#include <linux/pci.h>

/* Register offsets */
-#define SW_TWSI 0x00
-#define TWSI_INT 0x10
-#define SW_TWSI_EXT 0x18
+#if IS_ENABLED(CONFIG_I2C_THUNDERX)
+ #define SW_TWSI 0x1000
+ #define TWSI_INT 0x1010
+ #define SW_TWSI_EXT 0x1018
+#else
+ #define SW_TWSI 0x00
+ #define TWSI_INT 0x10
+ #define SW_TWSI_EXT 0x18
+#endif

/* Controller command patterns */
#define SW_TWSI_V BIT_ULL(63) /* Valid bit */
@@ -94,6 +100,7 @@
struct octeon_i2c {
wait_queue_head_t queue;
struct i2c_adapter adap;
+ struct clk *clk;
int irq;
int hlc_irq; /* For cn7890 only */
u32 twsi_freq;
@@ -109,6 +116,9 @@ struct octeon_i2c {
void (*hlc_int_disable)(struct octeon_i2c *);
atomic_t int_enable_cnt;
atomic_t hlc_int_enable_cnt;
+#if IS_ENABLED(CONFIG_I2C_THUNDERX)
+ struct msix_entry i2c_msix;
+#endif
};

static inline void octeon_i2c_writeq_flush(u64 val, void __iomem *addr)
diff --git a/drivers/i2c/busses/i2c-thunderx-core.c b/drivers/i2c/busses/i2c-thunderx-core.c
new file mode 100644
index 0000000..656b405
--- /dev/null
+++ b/drivers/i2c/busses/i2c-thunderx-core.c
@@ -0,0 +1,267 @@
+/*
+ * Cavium ThunderX i2c driver.
+ *
+ * Copyright (C) 2015,2016 Cavium Inc.
+ * Authors: Fred Martin <fmartin@caviumnetworks.com>
+ * Jan Glauber <jglauber@cavium.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+
+#include "i2c-cavium.h"
+
+#define DRV_NAME "i2c-thunderx"
+
+#define PCI_CFG_REG_BAR_NUM 0
+#define PCI_DEVICE_ID_THUNDER_TWSI 0xa012
+
+#define TWSI_DFL_RATE 100000
+#define SYS_FREQ_DEFAULT 800000000
+
+#define TWSI_INT_ENA_W1C 0x1028
+#define TWSI_INT_ENA_W1S 0x1030
+
+/*
+ * Enable the CORE interrupt.
+ * The interrupt will be asserted when there is non-STAT_IDLE state in the
+ * SW_TWSI_EOP_TWSI_STAT register.
+ */
+static void thunder_i2c_int_enable(struct octeon_i2c *i2c)
+{
+ octeon_i2c_writeq_flush(TWSI_INT_CORE_INT,
+ i2c->twsi_base + TWSI_INT_ENA_W1S);
+}
+
+/*
+ * Disable the CORE interrupt.
+ */
+static void thunder_i2c_int_disable(struct octeon_i2c *i2c)
+{
+ octeon_i2c_writeq_flush(TWSI_INT_CORE_INT,
+ i2c->twsi_base + TWSI_INT_ENA_W1C);
+}
+
+static void thunder_i2c_hlc_int_enable(struct octeon_i2c *i2c)
+{
+ octeon_i2c_writeq_flush(TWSI_INT_ST_INT | TWSI_INT_TS_INT,
+ i2c->twsi_base + TWSI_INT_ENA_W1S);
+}
+
+static void thunder_i2c_hlc_int_disable(struct octeon_i2c *i2c)
+{
+ octeon_i2c_writeq_flush(TWSI_INT_ST_INT | TWSI_INT_TS_INT,
+ i2c->twsi_base + TWSI_INT_ENA_W1C);
+}
+
+static u32 thunderx_i2c_functionality(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) |
+ I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_SMBUS_BLOCK_PROC_CALL;
+}
+
+static const struct i2c_algorithm thunderx_i2c_algo = {
+ .master_xfer = octeon_i2c_xfer,
+ .functionality = thunderx_i2c_functionality,
+};
+
+static struct i2c_adapter thunderx_i2c_ops = {
+ .owner = THIS_MODULE,
+ .name = "ThunderX adapter",
+ .algo = &thunderx_i2c_algo,
+};
+
+static void thunder_i2c_clock_enable(struct device *dev, struct octeon_i2c *i2c)
+{
+ int ret;
+
+ i2c->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(i2c->clk)) {
+ i2c->clk = NULL;
+ goto skip;
+ }
+
+ ret = clk_prepare_enable(i2c->clk);
+ if (ret)
+ goto skip;
+ i2c->sys_freq = clk_get_rate(i2c->clk);
+
+skip:
+ if (!i2c->sys_freq)
+ i2c->sys_freq = SYS_FREQ_DEFAULT;
+
+ dev_info(dev, "Set system clock to %u\n", i2c->sys_freq);
+}
+
+static void thunder_i2c_clock_disable(struct device *dev, struct clk *clk)
+{
+ if (!clk)
+ return;
+ clk_disable_unprepare(clk);
+ devm_clk_put(dev, clk);
+}
+
+static void thunder_i2c_set_name(struct pci_dev *pdev, struct octeon_i2c *i2c,
+ char *name)
+{
+ u8 i2c_bus_id, soc_node;
+ resource_size_t start;
+
+ start = pci_resource_start(pdev, PCI_CFG_REG_BAR_NUM);
+ soc_node = (start >> 44) & 0x3;
+ i2c_bus_id = (start >> 24) & 0x7;
+ snprintf(name, 10, "i2c%d", soc_node * 6 + i2c_bus_id);
+
+ snprintf(i2c->adap.name, sizeof(i2c->adap.name), "thunderx-i2c-%d.%d",
+ soc_node, i2c_bus_id);
+}
+
+static int thunder_i2c_probe_pci(struct pci_dev *pdev,
+ const struct pci_device_id *ent)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *node = NULL;
+ struct octeon_i2c *i2c;
+ char i2c_name[10];
+ int ret = 0;
+
+ i2c = devm_kzalloc(dev, sizeof(*i2c), GFP_KERNEL);
+ if (!i2c)
+ return -ENOMEM;
+
+ i2c->dev = dev;
+ pci_set_drvdata(pdev, i2c);
+ ret = pci_enable_device(pdev);
+ if (ret) {
+ dev_err(dev, "Failed to enable PCI device\n");
+ goto out_free_i2c;
+ }
+
+ ret = pci_request_regions(pdev, DRV_NAME);
+ if (ret) {
+ dev_err(dev, "PCI request regions failed 0x%x\n", ret);
+ goto out_disable_device;
+ }
+
+ i2c->twsi_base = pci_ioremap_bar(pdev, PCI_CFG_REG_BAR_NUM);
+ if (!i2c->twsi_base) {
+ dev_err(dev, "Cannot map CSR memory space\n");
+ ret = -EINVAL;
+ goto out_release_regions;
+ }
+
+ thunder_i2c_clock_enable(dev, i2c);
+
+ thunder_i2c_set_name(pdev, i2c, i2c_name);
+ node = of_find_node_by_name(NULL, i2c_name);
+ if (!node || of_property_read_u32(node, "clock-frequency",
+ &i2c->twsi_freq))
+ i2c->twsi_freq = TWSI_DFL_RATE;
+
+ init_waitqueue_head(&i2c->queue);
+
+ i2c->int_enable = thunder_i2c_int_enable;
+ i2c->int_disable = thunder_i2c_int_disable;
+ i2c->hlc_int_enable = thunder_i2c_hlc_int_enable;
+ i2c->hlc_int_disable = thunder_i2c_hlc_int_disable;
+
+ ret = pci_enable_msix(pdev, &i2c->i2c_msix, 1);
+ if (ret) {
+ dev_err(dev, "Unable to enable MSI-X\n");
+ goto out_unmap;
+ }
+
+ ret = devm_request_irq(dev, i2c->i2c_msix.vector, octeon_i2c_isr, 0,
+ DRV_NAME, i2c);
+ if (ret < 0) {
+ dev_err(dev, "Failed to attach i2c interrupt\n");
+ goto out_msix;
+ }
+
+ ret = octeon_i2c_init_lowlevel(i2c);
+ if (ret) {
+ dev_err(dev, "Init low level failed\n");
+ goto out_msix;
+ }
+
+ octeon_i2c_set_clock(i2c);
+
+ i2c->adap = thunderx_i2c_ops;
+ i2c->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
+ i2c->adap.timeout = msecs_to_jiffies(5);
+ i2c->adap.retries = 5;
+ i2c->adap.bus_recovery_info = &octeon_i2c_recovery_info;
+ i2c->adap.dev.parent = dev;
+ i2c->adap.dev.of_node = pdev->dev.of_node;
+ i2c_set_adapdata(&i2c->adap, i2c);
+
+ ret = i2c_add_adapter(&i2c->adap);
+ if (ret < 0) {
+ dev_err(dev, "Failed to add i2c adapter\n");
+ goto out_irq;
+ }
+
+ dev_info(i2c->dev, "probed\n");
+ return 0;
+
+out_irq:
+ devm_free_irq(dev, i2c->i2c_msix.vector, i2c);
+out_msix:
+ pci_disable_msix(pdev);
+out_unmap:
+ iounmap(i2c->twsi_base);
+ thunder_i2c_clock_disable(dev, i2c->clk);
+out_release_regions:
+ pci_release_regions(pdev);
+out_disable_device:
+ pci_disable_device(pdev);
+out_free_i2c:
+ pci_set_drvdata(pdev, NULL);
+ devm_kfree(dev, i2c);
+ return ret;
+}
+
+static void thunder_i2c_remove_pci(struct pci_dev *pdev)
+{
+ struct octeon_i2c *i2c = pci_get_drvdata(pdev);
+ struct device *dev;
+
+ if (!i2c)
+ return;
+
+ dev = i2c->dev;
+ thunder_i2c_clock_disable(dev, i2c->clk);
+ i2c_del_adapter(&i2c->adap);
+ devm_free_irq(dev, i2c->i2c_msix.vector, i2c);
+ pci_disable_msix(pdev);
+ iounmap(i2c->twsi_base);
+ pci_release_regions(pdev);
+ pci_disable_device(pdev);
+ pci_set_drvdata(pdev, NULL);
+ devm_kfree(dev, i2c);
+}
+
+static const struct pci_device_id thunder_i2c_pci_id_table[] = {
+ { PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, PCI_DEVICE_ID_THUNDER_TWSI) },
+ { 0, }
+};
+
+MODULE_DEVICE_TABLE(pci, thunder_i2c_pci_id_table);
+
+static struct pci_driver thunder_i2c_pci_driver = {
+ .name = DRV_NAME,
+ .id_table = thunder_i2c_pci_id_table,
+ .probe = thunder_i2c_probe_pci,
+ .remove = thunder_i2c_remove_pci,
+};
+
+module_pci_driver(thunder_i2c_pci_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Fred Martin <fmartin@caviumnetworks.com>");
+MODULE_DESCRIPTION("I2C-Bus adapter for Cavium ThunderX SOC");
--
1.9.1