[PATCH v2 1/4] mfd: max77620: Add backup battery charger support

Mark Zhang
2019-01-29T08:56:13Z

Add PMIC configurations for backup battery charger, which
is a constant voltage and constant current style charger
with a series output resistance.

The max77620 register CNFGBBC(addr: 0x04) defines the
parameters of backup battery charger. This patch adds
support for it.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Venkat Reddy Talla <vreddytalla@nvidia.com>
Signed-off-by: Mark Zhang <markz@nvidia.com>
---
drivers/mfd/max77620.c | 80 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 80 insertions(+)

diff --git a/drivers/mfd/max77620.c b/drivers/mfd/max77620.c
index d8ddd1a6f304..f58143103185 100644
--- a/drivers/mfd/max77620.c
+++ b/drivers/mfd/max77620.c
@@ -398,6 +398,82 @@ static int max77620_initialise_fps(struct max77620_chip *chip)
return 0;
}

+static int max77620_init_backup_battery_charging(struct max77620_chip *chip)
+{
+ struct device *dev = chip->dev;
+ struct device_node *np;
+ u32 pval;
+ u8 config;
+ int charging_current;
+ int charging_voltage;
+ int resistor;
+ int ret;
+
+ np = of_get_child_by_name(dev->of_node, "backup-battery");
+ if (!np) {
+ dev_info(dev, "Backup battery charging support disabled\n");
+ ret = regmap_update_bits(chip->rmap, MAX77620_REG_CNFGBBC,
+ MAX77620_CNFGBBC_ENABLE, 0);
+ if (ret < 0)
+ dev_err(dev, "Failed to update CNFGBBC: %d\n", ret);
+ return ret;
+ }
+
+ ret = of_property_read_u32(np,
+ "maxim,backup-battery-charging-current", &pval);
+ charging_current = (!ret) ? pval : 50;
+
+ ret = of_property_read_u32(np,
+ "maxim,backup-battery-charging-voltage", &pval);
+ charging_voltage = (!ret) ? pval : 2500000;
+ charging_voltage /= 1000;
+
+ ret = of_property_read_u32(np,
+ "maxim,backup-battery-output-resister", &pval);
+ resistor = (!ret) ? pval : 1000;
+
+ config = MAX77620_CNFGBBC_ENABLE;
+ if (charging_current <= 50)
+ config |= 0 << MAX77620_CNFGBBC_CURRENT_SHIFT;
+ else if (charging_current <= 100)
+ config |= 3 << MAX77620_CNFGBBC_CURRENT_SHIFT;
+ else if (charging_current <= 200)
+ config |= 0 << MAX77620_CNFGBBC_CURRENT_SHIFT;
+ else if (charging_current <= 400)
+ config |= 3 << MAX77620_CNFGBBC_CURRENT_SHIFT;
+ else if (charging_current <= 600)
+ config |= 1 << MAX77620_CNFGBBC_CURRENT_SHIFT;
+ else
+ config |= 2 << MAX77620_CNFGBBC_CURRENT_SHIFT;
+
+ if (charging_current > 100)
+ config |= MAX77620_CNFGBBC_LOW_CURRENT_DISABLE;
+
+ if (charging_voltage <= 2500)
+ config |= 0 << MAX77620_CNFGBBC_VOLTAGE_SHIFT;
+ else if (charging_voltage <= 3000)
+ config |= 1 << MAX77620_CNFGBBC_VOLTAGE_SHIFT;
+ else if (charging_voltage <= 3300)
+ config |= 2 << MAX77620_CNFGBBC_VOLTAGE_SHIFT;
+ else
+ config |= 3 << MAX77620_CNFGBBC_VOLTAGE_SHIFT;
+
+ if (resistor <= 100)
+ config |= 0 << MAX77620_CNFGBBC_RESISTOR_SHIFT;
+ else if (resistor <= 1000)
+ config |= 1 << MAX77620_CNFGBBC_RESISTOR_SHIFT;
+ else if (resistor <= 3000)
+ config |= 2 << MAX77620_CNFGBBC_RESISTOR_SHIFT;
+ else if (resistor <= 6000)
+ config |= 3 << MAX77620_CNFGBBC_RESISTOR_SHIFT;
+
+ ret = regmap_write(chip->rmap, MAX77620_REG_CNFGBBC, config);
+ if (ret < 0)
+ dev_err(dev, "Reg 0x%02x write failed, %d\n",
+ MAX77620_REG_CNFGBBC, ret);
+ return ret;
+}
+
static int max77620_read_es_version(struct max77620_chip *chip)
{
unsigned int val;
@@ -483,6 +559,10 @@ static int max77620_probe(struct i2c_client *client,
if (ret < 0)
return ret;

+ ret = max77620_init_backup_battery_charging(chip);
+ if (ret < 0)
+ return ret;
+
ret = devm_mfd_add_devices(chip->dev, PLATFORM_DEVID_NONE,
mfd_cells, n_mfd_cells, NULL, 0,
regmap_irq_get_domain(chip->top_irq_data));
--
2.19.2