[PATCH v4 5/9] mfd: max77714: Add driver for Maxim MAX77714 PMIC

From: Luca Ceresoli
Date: Sat Nov 20 2021 - 10:58:32 EST

Add a simple driver for the Maxim MAX77714 PMIC, supporting RTC and
watchdog only.

Signed-off-by: Luca Ceresoli <luca@xxxxxxxxxxxxxxxx>

---

Changes in v4: none

Changes in v3:
- Suggested by Lee Jones:
- move struct mfd_cell to top of file
- remove struct max77714 and its kmalloc, not used after probe
- reword error messages
- add "/* pF */" onto the end of the load_cap line

Changes in v2:
- fix "watchdog" word in heading comment (Guenter Roeck)
- move struct max77714 to .c file (Krzysztof Kozlowski)
- change include guard format (Krzysztof Kozlowski)
- allow building as a module (Krzysztof Kozlowski)
- remove of_match_ptr usage (Krzysztof Kozlowski / lkp)
(Reported-by: kernel test robot <lkp@xxxxxxxxx>)
---
MAINTAINERS | 2 +
drivers/mfd/Kconfig | 14 ++++
drivers/mfd/Makefile | 1 +
drivers/mfd/max77714.c | 152 +++++++++++++++++++++++++++++++++++
include/linux/mfd/max77714.h | 60 ++++++++++++++
5 files changed, 229 insertions(+)
create mode 100644 drivers/mfd/max77714.c
create mode 100644 include/linux/mfd/max77714.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 8e084f9a1d9f..a40db6e6a86b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11576,6 +11576,8 @@ MAXIM MAX77714 PMIC MFD DRIVER
M: Luca Ceresoli <luca@xxxxxxxxxxxxxxxx>
S: Maintained
F: Documentation/devicetree/bindings/mfd/maxim,max77714.yaml
+F: drivers/mfd/max77714.c
+F: include/linux/mfd/max77714.h

MAXIM MAX77802 PMIC REGULATOR DEVICE DRIVER
M: Javier Martinez Canillas <javier@xxxxxxxxxxxx>
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 3fb480818599..1b9d772bdae6 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -855,6 +855,20 @@ config MFD_MAX77693
additional drivers must be enabled in order to use the functionality
of the device.

+config MFD_MAX77714
+ tristate "Maxim Semiconductor MAX77714 PMIC Support"
+ depends on I2C
+ depends on OF || COMPILE_TEST
+ select MFD_CORE
+ select REGMAP_I2C
+ help
+ Say yes here to add support for Maxim Semiconductor MAX77714.
+ This is a Power Management IC with 4 buck regulators, 9
+ low-dropout regulators, 8 GPIOs, RTC, watchdog etc. This driver
+ provides common support for accessing the device; additional
+ drivers must be enabled in order to use each functionality of the
+ device.
+
config MFD_MAX77843
bool "Maxim Semiconductor MAX77843 PMIC Support"
depends on I2C=y
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 0b1b629aef3e..03115cf1336b 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -162,6 +162,7 @@ obj-$(CONFIG_MFD_MAX77620) += max77620.o
obj-$(CONFIG_MFD_MAX77650) += max77650.o
obj-$(CONFIG_MFD_MAX77686) += max77686.o
obj-$(CONFIG_MFD_MAX77693) += max77693.o
+obj-$(CONFIG_MFD_MAX77714) += max77714.o
obj-$(CONFIG_MFD_MAX77843) += max77843.o
obj-$(CONFIG_MFD_MAX8907) += max8907.o
max8925-objs := max8925-core.o max8925-i2c.o
diff --git a/drivers/mfd/max77714.c b/drivers/mfd/max77714.c
new file mode 100644
index 000000000000..08dfb69bc6e8
--- /dev/null
+++ b/drivers/mfd/max77714.c
@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Maxim MAX77714 MFD Driver
+ *
+ * Copyright (C) 2021 Luca Ceresoli
+ * Author: Luca Ceresoli <luca@xxxxxxxxxxxxxxxx>
+ */
+
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/max77714.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+
+static const struct mfd_cell max77714_cells[] = {
+ { .name = "max77714-watchdog" },
+ { .name = "max77714-rtc" },
+};
+
+static const struct regmap_range max77714_readable_ranges[] = {
+ regmap_reg_range(MAX77714_INT_TOP, MAX77714_INT_TOP),
+ regmap_reg_range(MAX77714_INT_TOPM, MAX77714_INT_TOPM),
+ regmap_reg_range(MAX77714_32K_STATUS, MAX77714_32K_CONFIG),
+ regmap_reg_range(MAX77714_CNFG_GLBL2, MAX77714_CNFG2_ONOFF),
+};
+
+static const struct regmap_range max77714_writable_ranges[] = {
+ regmap_reg_range(MAX77714_INT_TOPM, MAX77714_INT_TOPM),
+ regmap_reg_range(MAX77714_32K_CONFIG, MAX77714_32K_CONFIG),
+ regmap_reg_range(MAX77714_CNFG_GLBL2, MAX77714_CNFG2_ONOFF),
+};
+
+static const struct regmap_access_table max77714_readable_table = {
+ .yes_ranges = max77714_readable_ranges,
+ .n_yes_ranges = ARRAY_SIZE(max77714_readable_ranges),
+};
+
+static const struct regmap_access_table max77714_writable_table = {
+ .yes_ranges = max77714_writable_ranges,
+ .n_yes_ranges = ARRAY_SIZE(max77714_writable_ranges),
+};
+
+static const struct regmap_config max77714_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = MAX77714_CNFG2_ONOFF,
+ .rd_table = &max77714_readable_table,
+ .wr_table = &max77714_writable_table,
+};
+
+static const struct regmap_irq max77714_top_irqs[] = {
+ REGMAP_IRQ_REG(MAX77714_IRQ_TOP_ONOFF, 0, MAX77714_INT_TOP_ONOFF),
+ REGMAP_IRQ_REG(MAX77714_IRQ_TOP_RTC, 0, MAX77714_INT_TOP_RTC),
+ REGMAP_IRQ_REG(MAX77714_IRQ_TOP_GPIO, 0, MAX77714_INT_TOP_GPIO),
+ REGMAP_IRQ_REG(MAX77714_IRQ_TOP_LDO, 0, MAX77714_INT_TOP_LDO),
+ REGMAP_IRQ_REG(MAX77714_IRQ_TOP_SD, 0, MAX77714_INT_TOP_SD),
+ REGMAP_IRQ_REG(MAX77714_IRQ_TOP_GLBL, 0, MAX77714_INT_TOP_GLBL),
+};
+
+static const struct regmap_irq_chip max77714_irq_chip = {
+ .name = "max77714-pmic",
+ .status_base = MAX77714_INT_TOP,
+ .mask_base = MAX77714_INT_TOPM,
+ .num_regs = 1,
+ .irqs = max77714_top_irqs,
+ .num_irqs = ARRAY_SIZE(max77714_top_irqs),
+};
+
+/*
+ * MAX77714 initially uses the internal, low precision oscillator. Enable
+ * the external oscillator by setting the XOSC_RETRY bit. If the external
+ * oscillator is not OK (probably not installed) this has no effect.
+ */
+static int max77714_setup_xosc(struct device *dev, struct regmap *regmap)
+{
+ /* Internal Crystal Load Capacitance, indexed by value of 32KLOAD bits */
+ static const unsigned int load_cap[4] = {0, 10, 12, 22}; /* pF */
+ unsigned int load_cap_idx;
+ unsigned int status;
+ int err;
+
+ err = regmap_update_bits(regmap, MAX77714_32K_CONFIG,
+ MAX77714_32K_CONFIG_XOSC_RETRY,
+ MAX77714_32K_CONFIG_XOSC_RETRY);
+ if (err)
+ return dev_err_probe(dev, err, "Failed to configure the external oscillator\n");
+
+ err = regmap_read(regmap, MAX77714_32K_STATUS, &status);
+ if (err)
+ return dev_err_probe(dev, err, "Failed to read external oscillator status\n");
+
+ load_cap_idx = (status >> MAX77714_32K_STATUS_32KLOAD_SHF)
+ & MAX77714_32K_STATUS_32KLOAD_MSK;
+
+ dev_info(dev, "Using %s oscillator, %d pF load cap\n",
+ status & MAX77714_32K_STATUS_32KSOURCE ? "internal" : "external",
+ load_cap[load_cap_idx]);
+
+ return 0;
+}
+
+static int max77714_probe(struct i2c_client *client)
+{
+ struct device *dev = &client->dev;
+ struct regmap *regmap;
+ struct regmap_irq_chip_data *irq_data;
+ int err;
+
+ regmap = devm_regmap_init_i2c(client, &max77714_regmap_config);
+ if (IS_ERR(regmap))
+ return dev_err_probe(dev, PTR_ERR(regmap),
+ "Failed to initialise regmap\n");
+
+ err = max77714_setup_xosc(dev, regmap);
+ if (err)
+ return err;
+
+ err = devm_regmap_add_irq_chip(dev, regmap, client->irq,
+ IRQF_ONESHOT | IRQF_SHARED, 0,
+ &max77714_irq_chip, &irq_data);
+ if (err)
+ return dev_err_probe(dev, err, "Failed to add PMIC IRQ chip\n");
+
+ err = devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
+ max77714_cells, ARRAY_SIZE(max77714_cells),
+ NULL, 0, NULL);
+ if (err)
+ return dev_err_probe(dev, err, "Failed to register child devices\n");
+
+ return 0;
+}
+
+static const struct of_device_id max77714_dt_match[] = {
+ { .compatible = "maxim,max77714" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, max77714_dt_match);
+
+static struct i2c_driver max77714_driver = {
+ .driver = {
+ .name = "max77714",
+ .of_match_table = max77714_dt_match,
+ },
+ .probe_new = max77714_probe,
+};
+module_i2c_driver(max77714_driver);
+
+MODULE_DESCRIPTION("Maxim MAX77714 MFD core driver");
+MODULE_AUTHOR("Luca Ceresoli <luca@xxxxxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/mfd/max77714.h b/include/linux/mfd/max77714.h
new file mode 100644
index 000000000000..4a274592d4f2
--- /dev/null
+++ b/include/linux/mfd/max77714.h
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Maxim MAX77714 Register and data structures definition.
+ *
+ * Copyright (C) 2021 Luca Ceresoli
+ * Author: Luca Ceresoli <luca@xxxxxxxxxxxxxxxx>
+ */
+
+#ifndef __LINUX_MFD_MAX77714_H_
+#define __LINUX_MFD_MAX77714_H_
+
+#include <linux/bits.h>
+
+#define MAX77714_INT_TOP 0x00
+#define MAX77714_INT_TOPM 0x07 /* Datasheet says "read only", but it is RW */
+
+#define MAX77714_INT_TOP_ONOFF BIT(1)
+#define MAX77714_INT_TOP_RTC BIT(3)
+#define MAX77714_INT_TOP_GPIO BIT(4)
+#define MAX77714_INT_TOP_LDO BIT(5)
+#define MAX77714_INT_TOP_SD BIT(6)
+#define MAX77714_INT_TOP_GLBL BIT(7)
+
+#define MAX77714_32K_STATUS 0x30
+#define MAX77714_32K_STATUS_SIOSCOK BIT(5)
+#define MAX77714_32K_STATUS_XOSCOK BIT(4)
+#define MAX77714_32K_STATUS_32KSOURCE BIT(3)
+#define MAX77714_32K_STATUS_32KLOAD_MSK 0x3
+#define MAX77714_32K_STATUS_32KLOAD_SHF 1
+#define MAX77714_32K_STATUS_CRYSTAL_CFG BIT(0)
+
+#define MAX77714_32K_CONFIG 0x31
+#define MAX77714_32K_CONFIG_XOSC_RETRY BIT(4)
+
+#define MAX77714_CNFG_GLBL2 0x91
+#define MAX77714_WDTEN BIT(2)
+#define MAX77714_WDTSLPC BIT(3)
+#define MAX77714_TWD_MASK 0x3
+#define MAX77714_TWD_2s 0x0
+#define MAX77714_TWD_16s 0x1
+#define MAX77714_TWD_64s 0x2
+#define MAX77714_TWD_128s 0x3
+
+#define MAX77714_CNFG_GLBL3 0x92
+#define MAX77714_WDTC BIT(0)
+
+#define MAX77714_CNFG2_ONOFF 0x94
+#define MAX77714_WD_RST_WK BIT(5)
+
+/* Interrupts */
+enum {
+ MAX77714_IRQ_TOP_ONOFF,
+ MAX77714_IRQ_TOP_RTC, /* Real-time clock */
+ MAX77714_IRQ_TOP_GPIO, /* GPIOs */
+ MAX77714_IRQ_TOP_LDO, /* Low-dropout regulators */
+ MAX77714_IRQ_TOP_SD, /* Step-down regulators */
+ MAX77714_IRQ_TOP_GLBL, /* "Global resources": Low-Battery, overtemp... */
+};
+
+#endif /* __LINUX_MFD_MAX77714_H_ */
--
2.25.1