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>

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>
Jarkko Nikula · Tony Lindgren
1 parent d4c58bf45a
Showing 2 changed files with 48 additions and 10 deletions Side-by-side Diff
Documentation/kernel-parameters.txt
arch/arm/plat-omap/i2c.c
@@ -830,6 +830,10 @@
 	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
@@ -119,7 +119,47 @@
 	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
  * @clkrate: clock rate of the bus in kHz
  
  
@@ -132,20 +172,13 @@
 			  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 > omap_i2c_nr_ports());
  
-	BUG_ON(bus_id < 1 || bus_id > ports);
-
 	if (info) {
 		err = i2c_register_board_info(bus_id, info, len);
 		if (err)
@@ -153,7 +186,8 @@
 	}
  
 	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;
...	...	@@ -830,6 +830,10 @@
830	830	hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
831	831	terminal devices. Valid values: 0..8
832	832
	833	+ i2c_bus= [HW] Override the default board specific I2C bus speed
	834	+ Format:
	835	+ <bus_id>,<clkrate>
	836	+
833	837	i8042.debug [HW] Toggle i8042 debug mode
834	838	i8042.direct [HW] Put keyboard port into non-translated mode
835	839	i8042.dumbkbd [HW] Pretend that controller can only read data from
...	...	@@ -119,7 +119,47 @@
119	119	omap_cfg_reg(scl);
120	120	}
121	121
	122	+static int __init omap_i2c_nr_ports(void)
	123	+{
	124	+ int ports = 0;
	125	+
	126	+ if (cpu_class_is_omap1())
	127	+ ports = 1;
	128	+ else if (cpu_is_omap24xx())
	129	+ ports = 2;
	130	+ else if (cpu_is_omap34xx())
	131	+ ports = 3;
	132	+
	133	+ return ports;
	134	+}
	135	+
122	136	/**
	137	+ * omap_i2c_bus_setup - Process command line options for the I2C bus speed
	138	+ * @str: String of options
	139	+ *
	140	+ * This function allow to override the default I2C bus speed for given I2C
	141	+ * bus with a command line option.
	142	+ *
	143	+ * Format: i2c_bus=bus_id,clkrate (in kHz)
	144	+ *
	145	+ * Returns 1 on success, 0 otherwise.
	146	+ */
	147	+static int __init omap_i2c_bus_setup(char *str)
	148	+{
	149	+ int ports;
	150	+ int ints[3];
	151	+
	152	+ ports = omap_i2c_nr_ports();
	153	+ get_options(str, 3, ints);
	154	+ if (ints[0] < 2 \|\| ints[1] < 1 \|\| ints[1] > ports)
	155	+ return 0;
	156	+ i2c_rate[ints[1] - 1] = ints[2];
	157	+
	158	+ return 1;
	159	+}
	160	+__setup("i2c_bus=", omap_i2c_bus_setup);
	161	+
	162	+/**
123	163	* omap_register_i2c_bus - register I2C bus with device descriptors
124	164	* @bus_id: bus id counting from number 1
125	165	* @clkrate: clock rate of the bus in kHz
126	166
127	167
...	...	@@ -132,20 +172,13 @@
132	172	struct i2c_board_info const *info,
133	173	unsigned len)
134	174	{
135		- int ports, err;
	175	+ int err;
136	176	struct platform_device *pdev;
137	177	struct resource *res;
138	178	resource_size_t base, irq;
139	179
140		- if (cpu_class_is_omap1())
141		- ports = 1;
142		- else if (cpu_is_omap24xx())
143		- ports = 2;
144		- else if (cpu_is_omap34xx())
145		- ports = 3;
	180	+ BUG_ON(bus_id < 1 \|\| bus_id > omap_i2c_nr_ports());
146	181
147		- BUG_ON(bus_id < 1 \|\| bus_id > ports);
148		-
149	182	if (info) {
150	183	err = i2c_register_board_info(bus_id, info, len);
151	184	if (err)
...	...	@@ -153,7 +186,8 @@
153	186	}
154	187
155	188	pdev = &omap_i2c_devices[bus_id - 1];
156		- (u32 )pdev->dev.platform_data = clkrate;
	189	+ if (i2c_rate[bus_id - 1] == 0)
	190	+ i2c_rate[bus_id - 1] = clkrate;
157	191
158	192	if (bus_id == 1) {
159	193	res = pdev->resource;