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path: root/drivers/mfd/max14577.c
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Diffstat (limited to 'drivers/mfd/max14577.c')
-rw-r--r--drivers/mfd/max14577.c95
1 files changed, 95 insertions, 0 deletions
diff --git a/drivers/mfd/max14577.c b/drivers/mfd/max14577.c
index 6599407b5624..b8af263be594 100644
--- a/drivers/mfd/max14577.c
+++ b/drivers/mfd/max14577.c
@@ -26,6 +26,87 @@
#include <linux/mfd/max14577.h>
#include <linux/mfd/max14577-private.h>
+/*
+ * Table of valid charger currents for different Maxim chipsets.
+ * It is placed here because it is used by both charger and regulator driver.
+ */
+const struct maxim_charger_current maxim_charger_currents[] = {
+ [MAXIM_DEVICE_TYPE_UNKNOWN] = { 0, 0, 0, 0 },
+ [MAXIM_DEVICE_TYPE_MAX14577] = {
+ .min = MAX14577_CHARGER_CURRENT_LIMIT_MIN,
+ .high_start = MAX14577_CHARGER_CURRENT_LIMIT_HIGH_START,
+ .high_step = MAX14577_CHARGER_CURRENT_LIMIT_HIGH_STEP,
+ .max = MAX14577_CHARGER_CURRENT_LIMIT_MAX,
+ },
+ [MAXIM_DEVICE_TYPE_MAX77836] = {
+ .min = MAX77836_CHARGER_CURRENT_LIMIT_MIN,
+ .high_start = MAX77836_CHARGER_CURRENT_LIMIT_HIGH_START,
+ .high_step = MAX77836_CHARGER_CURRENT_LIMIT_HIGH_STEP,
+ .max = MAX77836_CHARGER_CURRENT_LIMIT_MAX,
+ },
+};
+EXPORT_SYMBOL_GPL(maxim_charger_currents);
+
+/*
+ * maxim_charger_calc_reg_current - Calculate register value for current
+ * @limits: constraints for charger, matching the MBCICHWRC register
+ * @min_ua: minimal requested current, micro Amps
+ * @max_ua: maximum requested current, micro Amps
+ * @dst: destination to store calculated register value
+ *
+ * Calculates the value of MBCICHWRC (Fast Battery Charge Current) register
+ * for given current and stores it under pointed 'dst'. The stored value
+ * combines low bit (MBCICHWRCL) and high bits (MBCICHWRCH). It is also
+ * properly shifted.
+ *
+ * The calculated register value matches the current which:
+ * - is always between <limits.min, limits.max>;
+ * - is always less or equal to max_ua;
+ * - is the highest possible value;
+ * - may be lower than min_ua.
+ *
+ * On success returns 0. On error returns -EINVAL (requested min/max current
+ * is outside of given charger limits) and 'dst' is not set.
+ */
+int maxim_charger_calc_reg_current(const struct maxim_charger_current *limits,
+ unsigned int min_ua, unsigned int max_ua, u8 *dst)
+{
+ unsigned int current_bits = 0xf;
+
+ if (min_ua > max_ua)
+ return -EINVAL;
+
+ if (min_ua > limits->max || max_ua < limits->min)
+ return -EINVAL;
+
+ if (max_ua < limits->high_start) {
+ /*
+ * Less than high_start, so set the minimal current
+ * (turn Low Bit off, 0 as high bits).
+ */
+ *dst = 0x0;
+ return 0;
+ }
+
+ /* max_ua is in range: <high_start, infinite>, cut it to limits.max */
+ max_ua = min(limits->max, max_ua);
+ max_ua -= limits->high_start;
+ /*
+ * There is no risk of overflow 'max_ua' here because:
+ * - max_ua >= limits.high_start
+ * - BUILD_BUG checks that 'limits' are: max >= high_start + high_step
+ */
+ current_bits = max_ua / limits->high_step;
+
+ /* Turn Low Bit on (use range <limits.high_start, limits.max>) ... */
+ *dst = 0x1 << CHGCTRL4_MBCICHWRCL_SHIFT;
+ /* and set proper High Bits */
+ *dst |= current_bits << CHGCTRL4_MBCICHWRCH_SHIFT;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(maxim_charger_calc_reg_current);
+
static const struct mfd_cell max14577_devs[] = {
{
.name = "max14577-muic",
@@ -466,6 +547,20 @@ static int __init max14577_i2c_init(void)
BUILD_BUG_ON(ARRAY_SIZE(max14577_i2c_id) != MAXIM_DEVICE_TYPE_NUM);
BUILD_BUG_ON(ARRAY_SIZE(max14577_dt_match) != MAXIM_DEVICE_TYPE_NUM);
+ /* Valid charger current values must be provided for each chipset */
+ BUILD_BUG_ON(ARRAY_SIZE(maxim_charger_currents) != MAXIM_DEVICE_TYPE_NUM);
+
+ /* Check for valid values for charger */
+ BUILD_BUG_ON(MAX14577_CHARGER_CURRENT_LIMIT_HIGH_START +
+ MAX14577_CHARGER_CURRENT_LIMIT_HIGH_STEP * 0xf !=
+ MAX14577_CHARGER_CURRENT_LIMIT_MAX);
+ BUILD_BUG_ON(MAX14577_CHARGER_CURRENT_LIMIT_HIGH_STEP == 0);
+
+ BUILD_BUG_ON(MAX77836_CHARGER_CURRENT_LIMIT_HIGH_START +
+ MAX77836_CHARGER_CURRENT_LIMIT_HIGH_STEP * 0xf !=
+ MAX77836_CHARGER_CURRENT_LIMIT_MAX);
+ BUILD_BUG_ON(MAX77836_CHARGER_CURRENT_LIMIT_HIGH_STEP == 0);
+
return i2c_add_driver(&max14577_i2c_driver);
}
subsys_initcall(max14577_i2c_init);