[PATCH v4] lis3: Add axes module parameter for custom axis-mapping

[Takashi Iwai]

The axis-mapping of lis3dev device on many (rather most) HP machines
doesn't follow the standard.  When each new model appears, users need
to adjust again.  Testing this requires the rebuild of kernel, thus
it's not trivial for end-users.

This patch adds a module parameter "axes" to allow a custom
axis-mapping without patching and recompiling the kernel driver.
User can pass the parameter such as axes=3,2,1.  Also it can be
changed via /sys/module/lis3lv02d/parameters/axes.

Acked-by: Ãric Piel <eric.piel@xxxxxxxxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---

v3->v4: use union for axis_mapping to be type-safe
v2->v3: add the sanity-check of the axes parameter values
v1->v2: change lis3_dev.ac to an int array to be written directly via
        module axes parameter

 drivers/hwmon/hp_accel.c      |   30 ++++++++++++++++++------------
 drivers/hwmon/lis3lv02d.c     |   24 ++++++++++++++++++++++++
 drivers/hwmon/lis3lv02d.h     |   11 ++++++-----
 drivers/hwmon/lis3lv02d_i2c.c |    5 ++---
 drivers/hwmon/lis3lv02d_spi.c |    3 ++-
 5 files changed, 52 insertions(+), 21 deletions(-)

diff --git a/drivers/hwmon/hp_accel.c b/drivers/hwmon/hp_accel.c
index 36e9575..31eaaab 100644
--- a/drivers/hwmon/hp_accel.c
+++ b/drivers/hwmon/hp_accel.c
@@ -146,7 +146,7 @@ int lis3lv02d_acpi_write(struct lis3lv02d *lis3, int reg, u8 val)
 
 static int lis3lv02d_dmi_matched(const struct dmi_system_id *dmi)
 {
-	lis3_dev.ac = *((struct axis_conversion *)dmi->driver_data);
+	lis3_dev.ac = *((union axis_conversion *)dmi->driver_data);
 	printk(KERN_INFO DRIVER_NAME ": hardware type %s found.\n", dmi->ident);
 
 	return 1;
@@ -154,16 +154,19 @@ static int lis3lv02d_dmi_matched(const struct dmi_system_id *dmi)
 
 /* Represents, for each axis seen by userspace, the corresponding hw axis (+1).
  * If the value is negative, the opposite of the hw value is used. */
-static struct axis_conversion lis3lv02d_axis_normal = {1, 2, 3};
-static struct axis_conversion lis3lv02d_axis_y_inverted = {1, -2, 3};
-static struct axis_conversion lis3lv02d_axis_x_inverted = {-1, 2, 3};
-static struct axis_conversion lis3lv02d_axis_z_inverted = {1, 2, -3};
-static struct axis_conversion lis3lv02d_axis_xy_swap = {2, 1, 3};
-static struct axis_conversion lis3lv02d_axis_xy_rotated_left = {-2, 1, 3};
-static struct axis_conversion lis3lv02d_axis_xy_rotated_left_usd = {-2, 1, -3};
-static struct axis_conversion lis3lv02d_axis_xy_swap_inverted = {-2, -1, 3};
-static struct axis_conversion lis3lv02d_axis_xy_rotated_right = {2, -1, 3};
-static struct axis_conversion lis3lv02d_axis_xy_swap_yz_inverted = {2, -1, -3};
+#define DEFINE_CONV(name, x, y, z)			      \
+	static union axis_conversion lis3lv02d_axis_##name = \
+		{ .as_array = { x, y, z } }
+DEFINE_CONV(normal, 1, 2, 3);
+DEFINE_CONV(y_inverted, 1, -2, 3);
+DEFINE_CONV(x_inverted, -1, 2, 3);
+DEFINE_CONV(z_inverted, 1, 2, -3);
+DEFINE_CONV(xy_swap, 2, 1, 3);
+DEFINE_CONV(xy_rotated_left, -2, 1, 3);
+DEFINE_CONV(xy_rotated_left_usd, -2, 1, -3);
+DEFINE_CONV(xy_swap_inverted, -2, -1, 3);
+DEFINE_CONV(xy_rotated_right, 2, -1, 3);
+DEFINE_CONV(xy_swap_yz_inverted, 2, -1, -3);
 
 #define AXIS_DMI_MATCH(_ident, _name, _axis) {		\
 	.ident = _ident,				\
@@ -299,7 +302,10 @@ static int lis3lv02d_add(struct acpi_device *device)
 	lis3lv02d_enum_resources(device);
 
 	/* If possible use a "standard" axes order */
-	if (dmi_check_system(lis3lv02d_dmi_ids) == 0) {
+	if (lis3_dev.ac.x && lis3_dev.ac.y && lis3_dev.ac.z) {
+		printk(KERN_INFO DRIVER_NAME ": Using custom axes %d,%d,%d\n",
+		       lis3_dev.ac.x, lis3_dev.ac.y, lis3_dev.ac.z);
+	} else if (dmi_check_system(lis3lv02d_dmi_ids) == 0) {
 		printk(KERN_INFO DRIVER_NAME ": laptop model unknown, "
 				 "using default axes configuration\n");
 		lis3_dev.ac = lis3lv02d_axis_normal;
diff --git a/drivers/hwmon/lis3lv02d.c b/drivers/hwmon/lis3lv02d.c
index 6138f03..bfd203e 100644
--- a/drivers/hwmon/lis3lv02d.c
+++ b/drivers/hwmon/lis3lv02d.c
@@ -75,6 +75,30 @@ struct lis3lv02d lis3_dev = {
 
 EXPORT_SYMBOL_GPL(lis3_dev);
 
+/* just like param_set_int() but does sanity-check so that it won't point
+ * over the axis array size
+ */
+static int param_set_axis(const char *val, const struct kernel_param *kp)
+{
+	int ret = param_set_int(val, kp);
+	if (!ret) {
+		int val = *(int *)kp->arg;
+		if (val < 0)
+			val = -val;
+		if (!val || val > 3)
+			return -EINVAL;
+	}
+	return ret;
+}
+
+static struct kernel_param_ops param_ops_axis = {
+	.set = param_set_axis,
+	.get = param_get_int,
+};
+
+module_param_array_named(axes, lis3_dev.ac.as_array, axis, NULL, 0644);
+MODULE_PARM_DESC(axes, "Axis-mapping for x,y,z directions");
+
 static s16 lis3lv02d_read_8(struct lis3lv02d *lis3, int reg)
 {
 	s8 lo;
diff --git a/drivers/hwmon/lis3lv02d.h b/drivers/hwmon/lis3lv02d.h
index 8540913..951d6ff 100644
--- a/drivers/hwmon/lis3lv02d.h
+++ b/drivers/hwmon/lis3lv02d.h
@@ -206,10 +206,11 @@ enum lis3lv02d_click_src_8b {
 	CLICK_IA	= 0x40,
 };
 
-struct axis_conversion {
-	s8	x;
-	s8	y;
-	s8	z;
+union axis_conversion {
+	struct {
+		int x, y, z;
+	};
+	int as_array[3];
 };
 
 struct lis3lv02d {
@@ -232,7 +233,7 @@ struct lis3lv02d {
 	struct input_polled_dev	*idev;     /* input device */
 	struct platform_device	*pdev;     /* platform device */
 	atomic_t		count;     /* interrupt count after last read */
-	struct axis_conversion	ac;        /* hw -> logical axis */
+	union axis_conversion	ac;        /* hw -> logical axis */
 	int			mapped_btns[3];
 
 	u32			irq;       /* IRQ number */
diff --git a/drivers/hwmon/lis3lv02d_i2c.c b/drivers/hwmon/lis3lv02d_i2c.c
index 8e5933b..c6f3f34 100644
--- a/drivers/hwmon/lis3lv02d_i2c.c
+++ b/drivers/hwmon/lis3lv02d_i2c.c
@@ -61,9 +61,8 @@ static int lis3_i2c_init(struct lis3lv02d *lis3)
 }
 
 /* Default axis mapping but it can be overwritten by platform data */
-static struct axis_conversion lis3lv02d_axis_map = { LIS3_DEV_X,
-						     LIS3_DEV_Y,
-						     LIS3_DEV_Z };
+static union axis_conversion lis3lv02d_axis_map =
+	{ .as_array = { LIS3_DEV_X, LIS3_DEV_Y, LIS3_DEV_Z } };
 
 static int __devinit lis3lv02d_i2c_probe(struct i2c_client *client,
 					const struct i2c_device_id *id)
diff --git a/drivers/hwmon/lis3lv02d_spi.c b/drivers/hwmon/lis3lv02d_spi.c
index b9be5e3..955544b 100644
--- a/drivers/hwmon/lis3lv02d_spi.c
+++ b/drivers/hwmon/lis3lv02d_spi.c
@@ -54,7 +54,8 @@ static int lis3_spi_init(struct lis3lv02d *lis3)
 	return lis3->write(lis3, CTRL_REG1, reg);
 }
 
-static struct axis_conversion lis3lv02d_axis_normal = { 1, 2, 3 };
+static union axis_conversion lis3lv02d_axis_normal =
+	{ .as_array = { 1, 2, 3 } };
 
 static int __devinit lis302dl_spi_probe(struct spi_device *spi)
 {
-- 
1.7.2.2

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