ARM: OMAP: Add method to register additional I2C busses on the command line, v2

This patch extends command line option "i2c_bus=bus_id,clkrate" so that
it allow to register additional I2C busses that are not registered with
omap_register_i2c_bus from board initialization code.

Purpose of this is to register additional board busses which are routed
to external connectors only without any on board I2C devices.

Cc: linux-i2c@vger.kernel.org
Signed-off-by: Jarkko Nikula <jarkko.nikula@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

2 files changed, 54 insertions, 21 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index d775076d1563..ef9827f7c84e 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -831,6 +831,8 @@ and is between 256 and 4096 characters. It is defined in the file
                                terminal devices. Valid values: 0..8
 
         i2c_bus=        [HW] Override the default board specific I2C bus speed
+                             or register an additional I2C bus that is not
+                             registered from board initialization code.
                              Format:
                              <bus_id>,<clkrate>
 
diff --git a/arch/arm/plat-omap/i2c.c b/arch/arm/plat-omap/i2c.c
index aa70e435fa79..a303071d5e36 100644
--- a/arch/arm/plat-omap/i2c.c
+++ b/arch/arm/plat-omap/i2c.c
@@ -98,6 +98,8 @@ static const int omap34xx_pins[][2] = {
 static const int omap34xx_pins[][2] = {};
 #endif
 
+#define OMAP_I2C_CMDLINE_SETUP  (BIT(31))
+
 static void __init omap_i2c_mux_pins(int bus)
 {
         int scl, sda;
@@ -133,6 +135,31 @@ static int __init omap_i2c_nr_ports(void)
         return ports;
 }
 
+static int __init omap_i2c_add_bus(int bus_id)
+{
+        struct platform_device *pdev;
+        struct resource *res;
+        resource_size_t base, irq;
+
+        pdev = &omap_i2c_devices[bus_id - 1];
+        if (bus_id == 1) {
+                res = pdev->resource;
+                if (cpu_class_is_omap1()) {
+                        base = OMAP1_I2C_BASE;
+                        irq = INT_I2C;
+                } else {
+                        base = OMAP2_I2C_BASE1;
+                        irq = INT_24XX_I2C1_IRQ;
+                }
+                res[0].start = base;
+                res[0].end = base + OMAP_I2C_SIZE;
+                res[1].start = irq;
+        }
+
+        omap_i2c_mux_pins(bus_id - 1);
+        return platform_device_register(pdev);
+}
+
 /**
  * omap_i2c_bus_setup - Process command line options for the I2C bus speed
  * @str: String of options
@@ -154,11 +181,33 @@ static int __init omap_i2c_bus_setup(char *str)
         if (ints[0] < 2 || ints[1] < 1 || ints[1] > ports)
                 return 0;
         i2c_rate[ints[1] - 1] = ints[2];
+        i2c_rate[ints[1] - 1] |= OMAP_I2C_CMDLINE_SETUP;
 
         return 1;
 }
 __setup("i2c_bus=", omap_i2c_bus_setup);
 
+/*
+ * Register busses defined in command line but that are not registered with
+ * omap_register_i2c_bus from board initialization code.
+ */
+static int __init omap_register_i2c_bus_cmdline(void)
+{
+        int i, err = 0;
+
+        for (i = 0; i < ARRAY_SIZE(i2c_rate); i++)
+                if (i2c_rate[i] & OMAP_I2C_CMDLINE_SETUP) {
+                        i2c_rate[i] &= ~OMAP_I2C_CMDLINE_SETUP;
+                        err = omap_i2c_add_bus(i + 1);
+                        if (err)
+                                goto out;
+                }
+
+out:
+        return err;
+}
+subsys_initcall(omap_register_i2c_bus_cmdline);
+
 /**
  * omap_register_i2c_bus - register I2C bus with device descriptors
  * @bus_id: bus id counting from number 1
@@ -173,9 +222,6 @@ int __init omap_register_i2c_bus(int bus_id, u32 clkrate,
                           unsigned len)
 {
         int err;
-        struct platform_device *pdev;
-        struct resource *res;
-        resource_size_t base, irq;
 
         BUG_ON(bus_id < 1 || bus_id > omap_i2c_nr_ports());
 
@@ -185,24 +231,9 @@ int __init omap_register_i2c_bus(int bus_id, u32 clkrate,
                         return err;
         }
 
-        pdev = &omap_i2c_devices[bus_id - 1];
-        if (i2c_rate[bus_id - 1] == 0)
+        if (!i2c_rate[bus_id - 1])
                 i2c_rate[bus_id - 1] = clkrate;
+        i2c_rate[bus_id - 1] &= ~OMAP_I2C_CMDLINE_SETUP;
 
-        if (bus_id == 1) {
-                res = pdev->resource;
-                if (cpu_class_is_omap1()) {
-                        base = OMAP1_I2C_BASE;
-                        irq = INT_I2C;
-                } else {
-                        base = OMAP2_I2C_BASE1;
-                        irq = INT_24XX_I2C1_IRQ;
-                }
-                res[0].start = base;
-                res[0].end = base + OMAP_I2C_SIZE;
-                res[1].start = irq;
-        }
-
-        omap_i2c_mux_pins(bus_id - 1);
-        return platform_device_register(pdev);
+        return omap_i2c_add_bus(bus_id);
 }