[PATCH] ARM: OMAP: Add command line option for I2C bus speed

[PATCH] ARM: OMAP: Add command line option for I2C bus speed

[Jarkko Nikula]

From: Jarkko Nikula <jarkko.nikula@nokia.com>

This patch adds a new command line option "i2c_rate=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.

Signed-off-by: Jarkko Nikula <jarkko.nikula@nokia.com>
---
 arch/arm/plat-omap/i2c.c |   52 ++++++++++++++++++++++++++++++++++++++--------
 1 files changed, 43 insertions(+), 9 deletions(-)

diff --git a/arch/arm/plat-omap/i2c.c b/arch/arm/plat-omap/i2c.c
index 467531e..0724fbd 100644
--- a/arch/arm/plat-omap/i2c.c
+++ b/arch/arm/plat-omap/i2c.c
@@ -119,14 +119,9 @@ static void __init omap_i2c_mux_pins(int bus)
 	omap_cfg_reg(scl);
 }
 
-int __init omap_register_i2c_bus(int bus_id, u32 clkrate,
-			  struct i2c_board_info const *info,
-			  unsigned len)
+static int __init omap_i2c_nr_ports(void)
 {
-	int ports, err;
-	struct platform_device *pdev;
-	struct resource *res;
-	resource_size_t base, irq;
+	int ports = 0;
 
 	if (cpu_class_is_omap1())
 		ports = 1;
@@ -135,7 +130,45 @@ int __init omap_register_i2c_bus(int bus_id, u32 clkrate,
 	else if (cpu_is_omap34xx())
 		ports = 3;
 
-	BUG_ON(bus_id < 1 || bus_id > ports);
+	return ports;
+}
+
+/**
+ * omap_i2c_rate_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_rate=bus_id,clkrate
+ *
+ * Returns 1 on success, 0 otherwise.
+ */
+static int __init omap_i2c_rate_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_rate=", omap_i2c_rate_setup);
+
+int __init omap_register_i2c_bus(int bus_id, u32 clkrate,
+			  struct i2c_board_info const *info,
+			  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());
 
 	if (info) {
 		err = i2c_register_board_info(bus_id, info, len);
@@ -144,7 +177,8 @@ 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;
-- 
1.5.6.5

[REPOST][PATCH 0/3] ARM: OMAP: Add command line option for I2C bus speed

[Jarkko Nikula]

Hi

I'm reposting this patch[set] adding command line option for I2C bus speed.
First version was

http://marc.info/?l=linux-omap&m=123289314421984&w=2

With this set, the option name is now i2c_bus instead of i2c_rate and this
version allow to register busses from command line as well. Idea of the set
is mostly for EVM boards where bus speed may depend on use case and extra
components connected into it.

With this it should be possible to revert one Dirk Behme's patch 

commit bae4b6a716ccf3247a1991d3c20b5e58ddd52890
Author: Dirk Behme <dirk.behme@gmail.com>
Date:   Tue Aug 5 14:09:15 2008 +0300

    ARM: OMAP3: Make I2C bus 2 configurable for BeagleBoard
 

This is tested only with unmodified Beagle so I'm interested to hear if one
has e.g. a Beagle with extra I2C devices connected into second I2C bus and
those starts working just by adding "i2c_bus=2,100" on the kernel command line.


-- 
Jarkko

[PATCH] ARM: OMAP: Add documentation for function omap_register_i2c_bus

[Jarkko Nikula]

From: Jarkko Nikula <jarkko.nikula@nokia.com>

Signed-off-by: Jarkko Nikula <jarkko.nikula@nokia.com>
---
 arch/arm/plat-omap/i2c.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/arch/arm/plat-omap/i2c.c b/arch/arm/plat-omap/i2c.c
index 467531e..3e95954 100644
--- a/arch/arm/plat-omap/i2c.c
+++ b/arch/arm/plat-omap/i2c.c
@@ -119,6 +119,15 @@ static void __init omap_i2c_mux_pins(int bus)
 	omap_cfg_reg(scl);
 }
 
+/**
+ * omap_register_i2c_bus - register I2C bus with device descriptors
+ * @bus_id: bus id counting from number 1
+ * @clkrate: clock rate of the bus in kHz
+ * @info: pointer into I2C device descriptor table or NULL
+ * @len: number of descriptors in the table
+ *
+ * Returns 0 on success or an error code.
+ */
 int __init omap_register_i2c_bus(int bus_id, u32 clkrate,
 			  struct i2c_board_info const *info,
 			  unsigned len)
-- 
1.5.6.5

[PATCH] ARM: OMAP: Add command line option for I2C bus speed

[Jarkko Nikula]

From: Jarkko Nikula <jarkko.nikula@nokia.com>

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.

Signed-off-by: Jarkko Nikula <jarkko.nikula@nokia.com>
---
 arch/arm/plat-omap/i2c.c |   54 +++++++++++++++++++++++++++++++++++++--------
 1 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/arch/arm/plat-omap/i2c.c b/arch/arm/plat-omap/i2c.c
index 3e95954..aa70e43 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;
-- 
1.5.6.5