mfd: Add MFD driver for ATC260x PMICs

Add initial support for the Actions Semi ATC260x PMICs which integrates
Audio Codec, Power management, Clock generation and GPIO controller
blocks.

For the moment this driver only supports Regulator, Poweroff and Onkey
functionalities for the ATC2603C and ATC2609A chip variants.

Since the PMICs can be accessed using both I2C and SPI buses, the
following driver structure has been adopted:

           -----> atc260x-core.c (Implements core functionalities)
          /
ATC260x --------> atc260x-i2c.c (Implements I2C interface)
          \
           -----> atc260x-spi.c (Implements SPI interface - TODO)

Co-developed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

4 files changed, 395 insertions, 0 deletions

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index b74efa469e90..f9b43f15790b 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -2055,6 +2055,24 @@ config MFD_WCD934X
 	  This driver provides common support WCD934x audio codec and its
 	  associated Pin Controller, Soundwire Controller and Audio codec.
 
+config MFD_ATC260X
+	tristate
+	select MFD_CORE
+	select REGMAP
+	select REGMAP_IRQ
+
+config MFD_ATC260X_I2C
+	tristate "Actions Semi ATC260x PMICs with I2C"
+	select MFD_ATC260X
+	select REGMAP_I2C
+	depends on I2C
+	help
+	  Support for the Actions Semi ATC260x PMICs controlled via I2C.
+
+	  This driver provides common support for accessing the ATC2603C
+	  and ATC2609A chip variants, additional drivers must be enabled
+	  in order to use the functionality of the device.
+
 config MFD_KHADAS_MCU
 	tristate "Support for Khadas System control Microcontroller"
 	depends on I2C
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 834f5463af28..f7872d0bd570 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -268,3 +268,6 @@ obj-$(CONFIG_MFD_ACER_A500_EC)	+= acer-ec-a500.o
 obj-$(CONFIG_SGI_MFD_IOC3)	+= ioc3.o
 obj-$(CONFIG_MFD_SIMPLE_MFD_I2C)	+= simple-mfd-i2c.o
 obj-$(CONFIG_MFD_INTEL_M10_BMC)   += intel-m10-bmc.o
+
+obj-$(CONFIG_MFD_ATC260X)	+= atc260x-core.o
+obj-$(CONFIG_MFD_ATC260X_I2C)	+= atc260x-i2c.o
diff --git a/drivers/mfd/atc260x-core.c b/drivers/mfd/atc260x-core.c
new file mode 100644
index 000000000000..7148ff5b05b1
--- /dev/null
+++ b/drivers/mfd/atc260x-core.c
@@ -0,0 +1,310 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Core support for ATC260x PMICs
+ *
+ * Copyright (C) 2019 Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+ * Copyright (C) 2020 Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
+ */
+
+#include <linux/interrupt.h>
+#include <linux/mfd/atc260x/core.h>
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+
+#define ATC260X_CHIP_REV_MAX	31
+
+struct atc260x_init_regs {
+	unsigned int cmu_devrst;
+	unsigned int cmu_devrst_ints;
+	unsigned int ints_msk;
+	unsigned int pad_en;
+	unsigned int pad_en_extirq;
+};
+
+static void regmap_lock_mutex(void *__mutex)
+{
+	struct mutex *mutex = __mutex;
+
+	/*
+	 * Using regmap within an atomic context (e.g. accessing a PMIC when
+	 * powering system down) is normally allowed only if the regmap type
+	 * is MMIO and the regcache type is either REGCACHE_NONE or
+	 * REGCACHE_FLAT. For slow buses like I2C and SPI, the regmap is
+	 * internally protected by a mutex which is acquired non-atomically.
+	 *
+	 * Let's improve this by using a customized locking scheme inspired
+	 * from I2C atomic transfer. See i2c_in_atomic_xfer_mode() for a
+	 * starting point.
+	 */
+	if (system_state > SYSTEM_RUNNING && irqs_disabled())
+		mutex_trylock(mutex);
+	else
+		mutex_lock(mutex);
+}
+
+static void regmap_unlock_mutex(void *__mutex)
+{
+	struct mutex *mutex = __mutex;
+
+	mutex_unlock(mutex);
+}
+
+static const struct regmap_config atc2603c_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 16,
+	.max_register = ATC2603C_SADDR,
+	.cache_type = REGCACHE_NONE,
+};
+
+static const struct regmap_config atc2609a_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 16,
+	.max_register = ATC2609A_SADDR,
+	.cache_type = REGCACHE_NONE,
+};
+
+static const struct regmap_irq atc2603c_regmap_irqs[] = {
+	REGMAP_IRQ_REG(ATC2603C_IRQ_AUDIO,	0, ATC2603C_INTS_MSK_AUDIO),
+	REGMAP_IRQ_REG(ATC2603C_IRQ_OV,		0, ATC2603C_INTS_MSK_OV),
+	REGMAP_IRQ_REG(ATC2603C_IRQ_OC,		0, ATC2603C_INTS_MSK_OC),
+	REGMAP_IRQ_REG(ATC2603C_IRQ_OT,		0, ATC2603C_INTS_MSK_OT),
+	REGMAP_IRQ_REG(ATC2603C_IRQ_UV,		0, ATC2603C_INTS_MSK_UV),
+	REGMAP_IRQ_REG(ATC2603C_IRQ_ALARM,	0, ATC2603C_INTS_MSK_ALARM),
+	REGMAP_IRQ_REG(ATC2603C_IRQ_ONOFF,	0, ATC2603C_INTS_MSK_ONOFF),
+	REGMAP_IRQ_REG(ATC2603C_IRQ_SGPIO,	0, ATC2603C_INTS_MSK_SGPIO),
+	REGMAP_IRQ_REG(ATC2603C_IRQ_IR,		0, ATC2603C_INTS_MSK_IR),
+	REGMAP_IRQ_REG(ATC2603C_IRQ_REMCON,	0, ATC2603C_INTS_MSK_REMCON),
+	REGMAP_IRQ_REG(ATC2603C_IRQ_POWER_IN,	0, ATC2603C_INTS_MSK_POWERIN),
+};
+
+static const struct regmap_irq atc2609a_regmap_irqs[] = {
+	REGMAP_IRQ_REG(ATC2609A_IRQ_AUDIO,	0, ATC2609A_INTS_MSK_AUDIO),
+	REGMAP_IRQ_REG(ATC2609A_IRQ_OV,		0, ATC2609A_INTS_MSK_OV),
+	REGMAP_IRQ_REG(ATC2609A_IRQ_OC,		0, ATC2609A_INTS_MSK_OC),
+	REGMAP_IRQ_REG(ATC2609A_IRQ_OT,		0, ATC2609A_INTS_MSK_OT),
+	REGMAP_IRQ_REG(ATC2609A_IRQ_UV,		0, ATC2609A_INTS_MSK_UV),
+	REGMAP_IRQ_REG(ATC2609A_IRQ_ALARM,	0, ATC2609A_INTS_MSK_ALARM),
+	REGMAP_IRQ_REG(ATC2609A_IRQ_ONOFF,	0, ATC2609A_INTS_MSK_ONOFF),
+	REGMAP_IRQ_REG(ATC2609A_IRQ_WKUP,	0, ATC2609A_INTS_MSK_WKUP),
+	REGMAP_IRQ_REG(ATC2609A_IRQ_IR,		0, ATC2609A_INTS_MSK_IR),
+	REGMAP_IRQ_REG(ATC2609A_IRQ_REMCON,	0, ATC2609A_INTS_MSK_REMCON),
+	REGMAP_IRQ_REG(ATC2609A_IRQ_POWER_IN,	0, ATC2609A_INTS_MSK_POWERIN),
+};
+
+static const struct regmap_irq_chip atc2603c_regmap_irq_chip = {
+	.name = "atc2603c",
+	.irqs = atc2603c_regmap_irqs,
+	.num_irqs = ARRAY_SIZE(atc2603c_regmap_irqs),
+	.num_regs = 1,
+	.status_base = ATC2603C_INTS_PD,
+	.mask_base = ATC2603C_INTS_MSK,
+	.mask_invert = true,
+};
+
+static const struct regmap_irq_chip atc2609a_regmap_irq_chip = {
+	.name = "atc2609a",
+	.irqs = atc2609a_regmap_irqs,
+	.num_irqs = ARRAY_SIZE(atc2609a_regmap_irqs),
+	.num_regs = 1,
+	.status_base = ATC2609A_INTS_PD,
+	.mask_base = ATC2609A_INTS_MSK,
+	.mask_invert = true,
+};
+
+static const struct resource atc2603c_onkey_resources[] = {
+	DEFINE_RES_IRQ(ATC2603C_IRQ_ONOFF),
+};
+
+static const struct resource atc2609a_onkey_resources[] = {
+	DEFINE_RES_IRQ(ATC2609A_IRQ_ONOFF),
+};
+
+static const struct mfd_cell atc2603c_mfd_cells[] = {
+	{ .name = "atc260x-regulator" },
+	{ .name = "atc260x-pwrc" },
+	{
+		.name = "atc260x-onkey",
+		.num_resources = ARRAY_SIZE(atc2603c_onkey_resources),
+		.resources = atc2603c_onkey_resources,
+	},
+};
+
+static const struct mfd_cell atc2609a_mfd_cells[] = {
+	{ .name = "atc260x-regulator" },
+	{ .name = "atc260x-pwrc" },
+	{
+		.name = "atc260x-onkey",
+		.num_resources = ARRAY_SIZE(atc2609a_onkey_resources),
+		.resources = atc2609a_onkey_resources,
+	},
+};
+
+static const struct atc260x_init_regs atc2603c_init_regs = {
+	.cmu_devrst = ATC2603C_CMU_DEVRST,
+	.cmu_devrst_ints = ATC2603C_CMU_DEVRST_INTS,
+	.ints_msk = ATC2603C_INTS_MSK,
+	.pad_en = ATC2603C_PAD_EN,
+	.pad_en_extirq = ATC2603C_PAD_EN_EXTIRQ,
+};
+
+static const struct atc260x_init_regs atc2609a_init_regs = {
+	.cmu_devrst = ATC2609A_CMU_DEVRST,
+	.cmu_devrst_ints = ATC2609A_CMU_DEVRST_INTS,
+	.ints_msk = ATC2609A_INTS_MSK,
+	.pad_en = ATC2609A_PAD_EN,
+	.pad_en_extirq = ATC2609A_PAD_EN_EXTIRQ,
+};
+
+static void atc260x_cmu_reset(struct atc260x *atc260x)
+{
+	const struct atc260x_init_regs *regs = atc260x->init_regs;
+
+	/* Assert reset */
+	regmap_update_bits(atc260x->regmap, regs->cmu_devrst,
+			   regs->cmu_devrst_ints, ~regs->cmu_devrst_ints);
+
+	/* De-assert reset */
+	regmap_update_bits(atc260x->regmap, regs->cmu_devrst,
+			   regs->cmu_devrst_ints, regs->cmu_devrst_ints);
+}
+
+static void atc260x_dev_init(struct atc260x *atc260x)
+{
+	const struct atc260x_init_regs *regs = atc260x->init_regs;
+
+	/* Initialize interrupt block */
+	atc260x_cmu_reset(atc260x);
+
+	/* Disable all interrupt sources */
+	regmap_write(atc260x->regmap, regs->ints_msk, 0);
+
+	/* Enable EXTIRQ pad */
+	regmap_update_bits(atc260x->regmap, regs->pad_en,
+			   regs->pad_en_extirq, regs->pad_en_extirq);
+}
+
+/**
+ * atc260x_match_device(): Setup ATC260x variant related fields
+ *
+ * @atc260x: ATC260x device to setup (.dev field must be set)
+ * @regmap_cfg: regmap config associated with this ATC260x device
+ *
+ * This lets the ATC260x core configure the MFD cells and register maps
+ * for later use.
+ */
+int atc260x_match_device(struct atc260x *atc260x, struct regmap_config *regmap_cfg)
+{
+	struct device *dev = atc260x->dev;
+	const void *of_data;
+
+	of_data = of_device_get_match_data(dev);
+	if (!of_data)
+		return -ENODEV;
+
+	atc260x->ic_type = (unsigned long)of_data;
+
+	switch (atc260x->ic_type) {
+	case ATC2603C:
+		*regmap_cfg = atc2603c_regmap_config;
+		atc260x->regmap_irq_chip = &atc2603c_regmap_irq_chip;
+		atc260x->cells = atc2603c_mfd_cells;
+		atc260x->nr_cells = ARRAY_SIZE(atc2603c_mfd_cells);
+		atc260x->type_name = "atc2603c";
+		atc260x->rev_reg = ATC2603C_CHIP_VER;
+		atc260x->init_regs = &atc2603c_init_regs;
+		break;
+	case ATC2609A:
+		*regmap_cfg = atc2609a_regmap_config;
+		atc260x->regmap_irq_chip = &atc2609a_regmap_irq_chip;
+		atc260x->cells = atc2609a_mfd_cells;
+		atc260x->nr_cells = ARRAY_SIZE(atc2609a_mfd_cells);
+		atc260x->type_name = "atc2609a";
+		atc260x->rev_reg = ATC2609A_CHIP_VER;
+		atc260x->init_regs = &atc2609a_init_regs;
+		break;
+	default:
+		dev_err(dev, "Unsupported ATC260x device type: %u\n",
+			atc260x->ic_type);
+		return -EINVAL;
+	}
+
+	atc260x->regmap_mutex = devm_kzalloc(dev, sizeof(*atc260x->regmap_mutex),
+					     GFP_KERNEL);
+	if (!atc260x->regmap_mutex)
+		return -ENOMEM;
+
+	mutex_init(atc260x->regmap_mutex);
+
+	regmap_cfg->lock = regmap_lock_mutex,
+	regmap_cfg->unlock = regmap_unlock_mutex,
+	regmap_cfg->lock_arg = atc260x->regmap_mutex;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(atc260x_match_device);
+
+/**
+ * atc260x_device_probe(): Probe a configured ATC260x device
+ *
+ * @atc260x: ATC260x device to probe (must be configured)
+ *
+ * This function lets the ATC260x core register the ATC260x MFD devices
+ * and IRQCHIP. The ATC260x device passed in must be fully configured
+ * with atc260x_match_device, its IRQ set, and regmap created.
+ */
+int atc260x_device_probe(struct atc260x *atc260x)
+{
+	struct device *dev = atc260x->dev;
+	unsigned int chip_rev;
+	int ret;
+
+	if (!atc260x->irq) {
+		dev_err(dev, "No interrupt support\n");
+		return -EINVAL;
+	}
+
+	/* Initialize the hardware */
+	atc260x_dev_init(atc260x);
+
+	ret = regmap_read(atc260x->regmap, atc260x->rev_reg, &chip_rev);
+	if (ret) {
+		dev_err(dev, "Failed to get chip revision\n");
+		return ret;
+	}
+
+	if (chip_rev > ATC260X_CHIP_REV_MAX) {
+		dev_err(dev, "Unknown chip revision: %u\n", chip_rev);
+		return -EINVAL;
+	}
+
+	atc260x->ic_ver = __ffs(chip_rev + 1U);
+
+	dev_info(dev, "Detected chip type %s rev.%c\n",
+		 atc260x->type_name, 'A' + atc260x->ic_ver);
+
+	ret = devm_regmap_add_irq_chip(dev, atc260x->regmap, atc260x->irq, IRQF_ONESHOT,
+				       -1, atc260x->regmap_irq_chip, &atc260x->irq_data);
+	if (ret) {
+		dev_err(dev, "Failed to add IRQ chip: %d\n", ret);
+		return ret;
+	}
+
+	ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
+				   atc260x->cells, atc260x->nr_cells, NULL, 0,
+				   regmap_irq_get_domain(atc260x->irq_data));
+	if (ret) {
+		dev_err(dev, "Failed to add child devices: %d\n", ret);
+		regmap_del_irq_chip(atc260x->irq, atc260x->irq_data);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(atc260x_device_probe);
+
+MODULE_DESCRIPTION("ATC260x PMICs Core support");
+MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
+MODULE_AUTHOR("Cristian Ciocaltea <cristian.ciocaltea@gmail.com>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/mfd/atc260x-i2c.c b/drivers/mfd/atc260x-i2c.c
new file mode 100644
index 000000000000..362005703367
--- /dev/null
+++ b/drivers/mfd/atc260x-i2c.c
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * I2C bus interface for ATC260x PMICs
+ *
+ * Copyright (C) 2019 Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+ * Copyright (C) 2020 Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
+ */
+
+#include <linux/i2c.h>
+#include <linux/mfd/atc260x/core.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+
+static int atc260x_i2c_probe(struct i2c_client *client,
+			     const struct i2c_device_id *id)
+{
+	struct atc260x *atc260x;
+	struct regmap_config regmap_cfg;
+	int ret;
+
+	atc260x = devm_kzalloc(&client->dev, sizeof(*atc260x), GFP_KERNEL);
+	if (!atc260x)
+		return -ENOMEM;
+
+	atc260x->dev = &client->dev;
+	atc260x->irq = client->irq;
+
+	ret = atc260x_match_device(atc260x, &regmap_cfg);
+	if (ret)
+		return ret;
+
+	i2c_set_clientdata(client, atc260x);
+
+	atc260x->regmap = devm_regmap_init_i2c(client, &regmap_cfg);
+	if (IS_ERR(atc260x->regmap)) {
+		ret = PTR_ERR(atc260x->regmap);
+		dev_err(&client->dev, "failed to init regmap: %d\n", ret);
+		return ret;
+	}
+
+	return atc260x_device_probe(atc260x);
+}
+
+const struct of_device_id atc260x_i2c_of_match[] = {
+	{ .compatible = "actions,atc2603c", .data = (void *)ATC2603C },
+	{ .compatible = "actions,atc2609a", .data = (void *)ATC2609A },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, atc260x_i2c_of_match);
+
+static struct i2c_driver atc260x_i2c_driver = {
+	.driver = {
+		.name = "atc260x",
+		.of_match_table	= of_match_ptr(atc260x_i2c_of_match),
+	},
+	.probe = atc260x_i2c_probe,
+};
+module_i2c_driver(atc260x_i2c_driver);
+
+MODULE_DESCRIPTION("ATC260x PMICs I2C bus interface");
+MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
+MODULE_AUTHOR("Cristian Ciocaltea <cristian.ciocaltea@gmail.com>");
+MODULE_LICENSE("GPL");