i2c: thunderx: Add SMBUS alert support

Add SMBUS alert interrupt support. For now only device tree is
supported for specifying the alert. In case of ACPI an error
is returned.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

3 files changed, 50 insertions, 0 deletions

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index d69a3420c8dc..1f3239ead037 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -959,6 +959,7 @@ config I2C_OCTEON
 config I2C_THUNDERX
         tristate "Cavium ThunderX I2C bus support"
         depends on 64BIT && PCI && (ARM64 || COMPILE_TEST)
+        select I2C_SMBUS
         help
           Say yes if you want to support the I2C serial bus on Cavium
           ThunderX SOC.
diff --git a/drivers/i2c/busses/i2c-octeon-core.h b/drivers/i2c/busses/i2c-octeon-core.h
index 33c7e1fb178c..2ed6f7a36b88 100644
--- a/drivers/i2c/busses/i2c-octeon-core.h
+++ b/drivers/i2c/busses/i2c-octeon-core.h
@@ -3,6 +3,7 @@
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/i2c.h>
+#include <linux/i2c-smbus.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/pci.h>
@@ -119,6 +120,8 @@ struct octeon_i2c {
 #if IS_ENABLED(CONFIG_I2C_THUNDERX)
         struct msix_entry i2c_msix;
 #endif
+        struct i2c_smbus_alert_setup alert_data;
+        struct i2c_client *ara;
 };
 
 static inline void octeon_i2c_writeq_flush(u64 val, void __iomem *addr)
diff --git a/drivers/i2c/busses/i2c-thunderx-pcidrv.c b/drivers/i2c/busses/i2c-thunderx-pcidrv.c
index 0dcebe2a5c4f..e8c3ce0eaf4d 100644
--- a/drivers/i2c/busses/i2c-thunderx-pcidrv.c
+++ b/drivers/i2c/busses/i2c-thunderx-pcidrv.c
@@ -14,9 +14,11 @@
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/i2c.h>
+#include <linux/i2c-smbus.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/of_irq.h>
 #include <linux/pci.h>
 
 #include "i2c-octeon-core.h"
@@ -107,6 +109,44 @@ static void thunder_i2c_clock_disable(struct device *dev, struct clk *clk)
         clk_put(clk);
 }
 
+static int thunder_i2c_smbus_setup_of(struct octeon_i2c *i2c,
+                                      struct device_node *node)
+{
+        u32 type;
+
+        if (!node)
+                return -EINVAL;
+
+        i2c->alert_data.irq = irq_of_parse_and_map(node, 0);
+        if (!i2c->alert_data.irq)
+                return -EINVAL;
+
+        type = irqd_get_trigger_type(irq_get_irq_data(i2c->alert_data.irq));
+        i2c->alert_data.alert_edge_triggered =
+                (type & IRQ_TYPE_LEVEL_MASK) ? 1 : 0;
+
+        i2c->ara = i2c_setup_smbus_alert(&i2c->adap, &i2c->alert_data);
+        if (!i2c->ara)
+                return -ENODEV;
+        return 0;
+}
+
+static int thunder_i2c_smbus_setup(struct octeon_i2c *i2c,
+                                   struct device_node *node)
+{
+        /* TODO: ACPI support */
+        if (!acpi_disabled)
+                return -EOPNOTSUPP;
+
+        return thunder_i2c_smbus_setup_of(i2c, node);
+}
+
+static void thunder_i2c_smbus_remove(struct octeon_i2c *i2c)
+{
+        if (i2c->ara)
+                i2c_unregister_device(i2c->ara);
+}
+
 static int thunder_i2c_probe_pci(struct pci_dev *pdev,
                                  const struct pci_device_id *ent)
 {
@@ -173,6 +213,11 @@ static int thunder_i2c_probe_pci(struct pci_dev *pdev,
                 goto error;
 
         dev_info(i2c->dev, "Probed. Set system clock to %u\n", i2c->sys_freq);
+
+        ret = thunder_i2c_smbus_setup(i2c, pdev->dev.of_node);
+        if (ret)
+                dev_info(dev, "SMBUS alert not active on this bus\n");
+
         return 0;
 
 error:
@@ -184,6 +229,7 @@ static void thunder_i2c_remove_pci(struct pci_dev *pdev)
 {
         struct octeon_i2c *i2c = pci_get_drvdata(pdev);
 
+        thunder_i2c_smbus_remove(i2c);
         thunder_i2c_clock_disable(&pdev->dev, i2c->clk);
         i2c_del_adapter(&i2c->adap);
 }