Hi, thought someone would find this useful. I added sysfs support to the AM335x kernel TPS65217 driver so I can select the analog mux output selection from user space. I wanted to be able to read the various signals using the AM335x ADC inputs.
Forum won't let us upload .patch files...so here it is as .txt.
1643.tps65217_analog_mux_sysfs.txt
Index: linux-3.2.0-psp05.06.00.00/drivers/mfd/tps65217.c
===================================================================
--- linux-3.2.0-psp05.06.00.00/drivers/mfd/tps65217.c (revision 26)
+++ linux-3.2.0-psp05.06.00.00/drivers/mfd/tps65217.c (working copy)
@@ -137,6 +137,78 @@
.val_bits = 8,
};
+/* Sys Fs Entries */
+static char* tps65217_mux_table[8] = {
+ "none",
+ "vbat",
+ "vsys",
+ "vts",
+ "vicharge",
+ "mux_in",
+ "none_6",
+ "none_7",
+};
+
+static ssize_t tps65217_analog_mux_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct tps65217 *tps = dev_get_drvdata(dev);
+ int mux_value;
+ int ret;
+
+ /* Read and output the current analog mux selection */
+ ret = tps65217_reg_read(tps, TPS65217_REG_MUXCTRL, &mux_value);
+ if (ret)
+ {
+ return sprintf(buf, "error\n");
+ }
+
+ return sprintf(buf, "%s\n", tps65217_mux_table[mux_value]);
+}
+
+static ssize_t tps65217_analog_mux_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ struct tps65217 *tps = dev_get_drvdata(dev);
+ char mux_string[10] = {0};
+ int mux_value = 0;
+ int count = 0;
+ int ret = -EINVAL;
+
+ /* Copy the signal name into our buffer */
+ while((count < size) && (*buf != '0') && (*buf != '\n'))
+ mux_string[count++] = *buf++;
+
+ /* Find the matching parameter in the mux list */
+ while(mux_value < 8)
+ {
+ if(strcmp(mux_string, tps65217_mux_table[mux_value]) == 0)
+ { /* Match found */
+ break;
+ }
+
+ mux_value++;
+ }
+
+ /* Check if parameter is invalid */
+ if(mux_value == 8)
+ {
+ dev_info(tps->dev, "Unknown analog mux selection, %s", buf);
+ return ret;
+ }
+
+ /* Parameter was found, write the value to the mux register */
+ ret = tps65217_reg_write(tps, TPS65217_REG_MUXCTRL, mux_value, 0);
+ if(ret)
+ dev_err(tps->dev, "Bus error writing new mux selection, %s\n", mux_string);
+
+ return size;
+}
+
+static DEVICE_ATTR(analog_mux, 0644, tps65217_analog_mux_show,
+ tps65217_analog_mux_store);
+
static int __devinit tps65217_probe(struct i2c_client *client,
const struct i2c_device_id *ids)
{
@@ -199,6 +271,8 @@
platform_device_add(pdev);
}
+
+ ret = device_create_file(tps->dev, &dev_attr_analog_mux);
return 0;
@@ -212,6 +286,8 @@
{
struct tps65217 *tps = i2c_get_clientdata(client);
int i;
+
+ device_remove_file(tps->dev, &dev_attr_analog_mux);
for (i = 0; i < TPS65217_NUM_REGULATOR; i++)
platform_device_unregister(tps->regulator_pdev[i]);
