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authorJarkko Nikula <jarkko.nikula@nokia.com>2009-03-23 18:07:47 -0700
committerTony Lindgren <tony@atomide.com>2009-03-23 18:51:20 -0700
commit3a853fb933ddf9c5ea8c9f7c665dd8def26bceae (patch)
tree7fea1d04ad338993c3109b68f224525332831766
parentd4c58bf45a9a1668cb850e02a2e1aad785bd9325 (diff)
ARM: OMAP: Add command line option for I2C bus speed, v2
This patch adds a new command line option "i2c_bus=bus_id,clkrate" into I2C bus registration helper. Purpose of the option is to override the default board specific bus speed which is supplied by the omap_register_i2c_bus. The default bus speed is typically set to speed of slowest I2C chip on the bus and overriding allow to use some experimental configurations or updated chip versions without any kernel modifications. Cc: linux-i2c@vger.kernel.org Signed-off-by: Jarkko Nikula <jarkko.nikula@nokia.com> Signed-off-by: Tony Lindgren <tony@atomide.com>
-rw-r--r--Documentation/kernel-parameters.txt4
-rw-r--r--arch/arm/plat-omap/i2c.c54
2 files changed, 48 insertions, 10 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 54f21a5c262..d775076d156 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -830,6 +830,10 @@ and is between 256 and 4096 characters. It is defined in the file
hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
terminal devices. Valid values: 0..8
+ i2c_bus= [HW] Override the default board specific I2C bus speed
+ Format:
+ <bus_id>,<clkrate>
+
i8042.debug [HW] Toggle i8042 debug mode
i8042.direct [HW] Put keyboard port into non-translated mode
i8042.dumbkbd [HW] Pretend that controller can only read data from
diff --git a/arch/arm/plat-omap/i2c.c b/arch/arm/plat-omap/i2c.c
index 3e95954e2a8..aa70e435fa7 100644
--- a/arch/arm/plat-omap/i2c.c
+++ b/arch/arm/plat-omap/i2c.c
@@ -119,6 +119,46 @@ static void __init omap_i2c_mux_pins(int bus)
omap_cfg_reg(scl);
}
+static int __init omap_i2c_nr_ports(void)
+{
+ int ports = 0;
+
+ if (cpu_class_is_omap1())
+ ports = 1;
+ else if (cpu_is_omap24xx())
+ ports = 2;
+ else if (cpu_is_omap34xx())
+ ports = 3;
+
+ return ports;
+}
+
+/**
+ * omap_i2c_bus_setup - Process command line options for the I2C bus speed
+ * @str: String of options
+ *
+ * This function allow to override the default I2C bus speed for given I2C
+ * bus with a command line option.
+ *
+ * Format: i2c_bus=bus_id,clkrate (in kHz)
+ *
+ * Returns 1 on success, 0 otherwise.
+ */
+static int __init omap_i2c_bus_setup(char *str)
+{
+ int ports;
+ int ints[3];
+
+ ports = omap_i2c_nr_ports();
+ get_options(str, 3, ints);
+ if (ints[0] < 2 || ints[1] < 1 || ints[1] > ports)
+ return 0;
+ i2c_rate[ints[1] - 1] = ints[2];
+
+ return 1;
+}
+__setup("i2c_bus=", omap_i2c_bus_setup);
+
/**
* omap_register_i2c_bus - register I2C bus with device descriptors
* @bus_id: bus id counting from number 1
@@ -132,19 +172,12 @@ int __init omap_register_i2c_bus(int bus_id, u32 clkrate,
struct i2c_board_info const *info,
unsigned len)
{
- int ports, err;
+ int err;
struct platform_device *pdev;
struct resource *res;
resource_size_t base, irq;
- if (cpu_class_is_omap1())
- ports = 1;
- else if (cpu_is_omap24xx())
- ports = 2;
- else if (cpu_is_omap34xx())
- ports = 3;
-
- BUG_ON(bus_id < 1 || bus_id > ports);
+ BUG_ON(bus_id < 1 || bus_id > omap_i2c_nr_ports());
if (info) {
err = i2c_register_board_info(bus_id, info, len);
@@ -153,7 +186,8 @@ int __init omap_register_i2c_bus(int bus_id, u32 clkrate,
}
pdev = &omap_i2c_devices[bus_id - 1];
- *(u32 *)pdev->dev.platform_data = clkrate;
+ if (i2c_rate[bus_id - 1] == 0)
+ i2c_rate[bus_id - 1] = clkrate;
if (bus_id == 1) {
res = pdev->resource;