TPS65911: Comparator: Add comparator driver
Jorge Eduardo Candelaria [Mon, 16 May 2011 23:35:48 +0000 (18:35 -0500)]
This driver adds functionality to the tps65911 chip driver.

Two of the comparators are configurable by software and measures
VCCS voltage to detect high or low voltage scenarios.

Signed-off-by: Jorge Eduardo Candelaria <jedu@slimlogic.co.uk>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

drivers/mfd/tps65911-comparator.c [new file with mode: 0644]
include/linux/mfd/tps65910.h

diff --git a/drivers/mfd/tps65911-comparator.c b/drivers/mfd/tps65911-comparator.c
new file mode 100644 (file)
index 0000000..3d2dc56
--- /dev/null
@@ -0,0 +1,188 @@
+/*
+ * tps65910.c  --  TI TPS6591x
+ *
+ * Copyright 2010 Texas Instruments Inc.
+ *
+ * Author: Jorge Eduardo Candelaria <jedu@slimlogic.co.uk>
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under  the terms of the GNU General  Public License as published by the
+ *  Free Software Foundation;  either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/debugfs.h>
+#include <linux/gpio.h>
+#include <linux/mfd/tps65910.h>
+
+#define COMP                                   0
+#define COMP1                                  1
+#define COMP2                                  2
+
+/* Comparator 1 voltage selection table in milivolts */
+static const u16 COMP_VSEL_TABLE[] = {
+       0, 2500, 2500, 2500, 2500, 2550, 2600, 2650,
+       2700, 2750, 2800, 2850, 2900, 2950, 3000, 3050,
+       3100, 3150, 3200, 3250, 3300, 3350, 3400, 3450,
+       3500,
+};
+
+struct comparator {
+       const char *name;
+       int reg;
+       int uV_max;
+       const u16 *vsel_table;
+};
+
+static struct comparator tps_comparators[] = {
+       {
+               .name = "COMP1",
+               .reg = TPS65911_VMBCH,
+               .uV_max = 3500,
+               .vsel_table = COMP_VSEL_TABLE,
+       },
+       {
+               .name = "COMP2",
+               .reg = TPS65911_VMBCH2,
+               .uV_max = 3500,
+               .vsel_table = COMP_VSEL_TABLE,
+       },
+};
+
+static int comp_threshold_set(struct tps65910 *tps65910, int id, int voltage)
+{
+       struct comparator tps_comp = tps_comparators[id];
+       int curr_voltage = 0;
+       int ret;
+       u8 index = 0, val;
+
+       if (id == COMP)
+               return 0;
+
+       while (curr_voltage < tps_comp.uV_max) {
+               curr_voltage = tps_comp.vsel_table[index];
+               if (curr_voltage >= voltage)
+                       break;
+               else if (curr_voltage < voltage)
+                       index ++;
+       }
+
+       if (curr_voltage > tps_comp.uV_max)
+               return -EINVAL;
+
+       val = index << 1;
+       ret = tps65910->write(tps65910, tps_comp.reg, 1, &val);
+
+       return ret;
+}
+
+static int comp_threshold_get(struct tps65910 *tps65910, int id)
+{
+       struct comparator tps_comp = tps_comparators[id];
+       int ret;
+       u8 val;
+
+       if (id == COMP)
+               return 0;
+
+       ret = tps65910->read(tps65910, tps_comp.reg, 1, &val);
+       if (ret < 0)
+               return ret;
+
+       val >>= 1;
+       return tps_comp.vsel_table[val];
+}
+
+static ssize_t comp_threshold_show(struct device *dev,
+                               struct device_attribute *attr, char *buf)
+{
+       struct tps65910 *tps65910 = dev_get_drvdata(dev->parent);
+       struct attribute comp_attr = attr->attr;
+       int id, uVolt;
+
+       if (!strcmp(comp_attr.name, "comp1_threshold"))
+               id = COMP1;
+       else if (!strcmp(comp_attr.name, "comp2_threshold"))
+               id = COMP2;
+       else
+               return -EINVAL;
+
+       uVolt = comp_threshold_get(tps65910, id);
+
+       return sprintf(buf, "%d\n", uVolt);
+}
+
+static DEVICE_ATTR(comp1_threshold, S_IRUGO, comp_threshold_show, NULL);
+static DEVICE_ATTR(comp2_threshold, S_IRUGO, comp_threshold_show, NULL);
+
+static __devinit int tps65911_comparator_probe(struct platform_device *pdev)
+{
+       struct tps65910 *tps65910 = dev_get_drvdata(pdev->dev.parent);
+       struct tps65910_platform_data *pdata = dev_get_platdata(tps65910->dev);
+       int ret;
+
+       ret = comp_threshold_set(tps65910, COMP1,  pdata->vmbch_threshold);
+       if (ret < 0) {
+               dev_err(&pdev->dev, "cannot set COMP1 threshold\n");
+               return ret;
+       }
+
+       ret = comp_threshold_set(tps65910, COMP2, pdata->vmbch2_threshold);
+       if (ret < 0) {
+               dev_err(&pdev->dev, "cannot set COMP2 theshold\n");
+               return ret;
+       }
+
+       /* Create sysfs entry */
+       ret = device_create_file(&pdev->dev, &dev_attr_comp1_threshold);
+       if (ret < 0)
+               dev_err(&pdev->dev, "failed to add COMP1 sysfs file\n");
+
+       ret = device_create_file(&pdev->dev, &dev_attr_comp2_threshold);
+       if (ret < 0)
+               dev_err(&pdev->dev, "failed to add COMP2 sysfs file\n");
+
+       return ret;
+}
+
+static __devexit int tps65911_comparator_remove(struct platform_device *pdev)
+{
+       struct tps65910 *tps65910;
+
+       tps65910 = dev_get_drvdata(pdev->dev.parent);
+
+       return 0;
+}
+
+static struct platform_driver tps65911_comparator_driver = {
+       .driver = {
+               .name = "tps65911-comparator",
+               .owner = THIS_MODULE,
+       },
+       .probe = tps65911_comparator_probe,
+       .remove = __devexit_p(tps65911_comparator_remove),
+};
+
+static int __init tps65911_comparator_init(void)
+{
+       return platform_driver_register(&tps65911_comparator_driver);
+}
+subsys_initcall(tps65911_comparator_init);
+
+static void __exit tps65911_comparator_exit(void)
+{
+       platform_driver_unregister(&tps65911_comparator_driver);
+}
+module_exit(tps65911_comparator_exit);
+
+MODULE_AUTHOR("Jorge Eduardo Candelaria <jedu@slimlogic.co.uk>");
+MODULE_DESCRIPTION("TPS65911 comparator driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:tps65911-comparator");
index 5f77006..8bb85b9 100644 (file)
 #define TPS65911_LDO6                                  0x35
 #define TPS65911_LDO4                                  0x36
 #define TPS65911_LDO3                                  0x37
+#define TPS65911_VMBCH                                 0x6A
+#define TPS65911_VMBCH2                                        0x6B
 
 /*
  * List of register bitfields for component TPS65910
@@ -746,6 +748,8 @@ struct tps65910_board {
        int gpio_base;
        int irq;
        int irq_base;
+       int vmbch_threshold;
+       int vmbch2_threshold;
        struct regulator_init_data *tps65910_pmic_init_data;
 };