mfd: Add Spreadtrum SC27xx series PMICs driver

This patch adds support for Spreadtrum SC27xx series PMIC MFD core, and It
provides communication through the SPI interfaces. The SC27xx series PMICs
contains the following 6 major components:
- DCDCs
- LDOs
- Battery management system
- Audio codec
- User interface function, such as indicator, flash LED
- IC level function, such as power on/off, type-c

Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/Kconfig

@@ -1070,6 +1070,22 @@ config MFD_SMSC
         To compile this driver as a module, choose M here: the
         module will be called smsc.
 
+config MFD_SC27XX_PMIC
+	tristate "Spreadtrum SC27xx PMICs"
+	depends on ARCH_SPRD || COMPILE_TEST
+	depends on SPI_MASTER
+	select MFD_CORE
+	select REGMAP_SPI
+	select REGMAP_IRQ
+	help
+	  This enables support for the Spreadtrum SC27xx PMICs with SPI
+	  interface. The SC27xx series PMICs integrate power management,
+	  audio codec, battery management and user interface support
+	  function (such as RTC, Typec, indicator and so on) in a single chip.
+
+	  This driver provides common support for accessing the SC27xx PMICs,
+	  and it also adds the irq_chip parts for handling the PMIC chip events.
+
 config ABX500_CORE
 	bool "ST-Ericsson ABX500 Mixed Signal Circuit register functions"
 	default y if ARCH_U300 || ARCH_U8500 || COMPILE_TEST

drivers/mfd/Makefile

@@ -227,3 +227,4 @@ obj-$(CONFIG_MFD_SUN4I_GPADC)	+= sun4i-gpadc.o
 obj-$(CONFIG_MFD_STM32_LPTIMER)	+= stm32-lptimer.o
 obj-$(CONFIG_MFD_STM32_TIMERS) 	+= stm32-timers.o
 obj-$(CONFIG_MFD_MXS_LRADC)     += mxs-lradc.o
+obj-$(CONFIG_MFD_SC27XX_PMIC)	+= sprd-sc27xx-spi.o

drivers/mfd/sprd-sc27xx-spi.c

@@ -0,0 +1,259 @@
+/*
+ * Copyright (C) 2017 Spreadtrum Communications Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mfd/core.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+
+#define SPRD_PMIC_INT_MASK_STATUS	0x0
+#define SPRD_PMIC_INT_RAW_STATUS	0x4
+#define SPRD_PMIC_INT_EN		0x8
+
+#define SPRD_SC2731_IRQ_BASE		0x140
+#define SPRD_SC2731_IRQ_NUMS		16
+
+struct sprd_pmic {
+	struct regmap *regmap;
+	struct device *dev;
+	struct regmap_irq *irqs;
+	struct regmap_irq_chip irq_chip;
+	struct regmap_irq_chip_data *irq_data;
+	int irq;
+};
+
+struct sprd_pmic_data {
+	u32 irq_base;
+	u32 num_irqs;
+};
+
+/*
+ * Since different PMICs of SC27xx series can have different interrupt
+ * base address and irq number, we should save irq number and irq base
+ * in the device data structure.
+ */
+static const struct sprd_pmic_data sc2731_data = {
+	.irq_base = SPRD_SC2731_IRQ_BASE,
+	.num_irqs = SPRD_SC2731_IRQ_NUMS,
+};
+
+static const struct mfd_cell sprd_pmic_devs[] = {
+	{
+		.name = "sc27xx-wdt",
+		.of_compatible = "sprd,sc27xx-wdt",
+	}, {
+		.name = "sc27xx-rtc",
+		.of_compatible = "sprd,sc27xx-rtc",
+	}, {
+		.name = "sc27xx-charger",
+		.of_compatible = "sprd,sc27xx-charger",
+	}, {
+		.name = "sc27xx-chg-timer",
+		.of_compatible = "sprd,sc27xx-chg-timer",
+	}, {
+		.name = "sc27xx-fast-chg",
+		.of_compatible = "sprd,sc27xx-fast-chg",
+	}, {
+		.name = "sc27xx-chg-wdt",
+		.of_compatible = "sprd,sc27xx-chg-wdt",
+	}, {
+		.name = "sc27xx-typec",
+		.of_compatible = "sprd,sc27xx-typec",
+	}, {
+		.name = "sc27xx-flash",
+		.of_compatible = "sprd,sc27xx-flash",
+	}, {
+		.name = "sc27xx-eic",
+		.of_compatible = "sprd,sc27xx-eic",
+	}, {
+		.name = "sc27xx-efuse",
+		.of_compatible = "sprd,sc27xx-efuse",
+	}, {
+		.name = "sc27xx-thermal",
+		.of_compatible = "sprd,sc27xx-thermal",
+	}, {
+		.name = "sc27xx-adc",
+		.of_compatible = "sprd,sc27xx-adc",
+	}, {
+		.name = "sc27xx-audio-codec",
+		.of_compatible = "sprd,sc27xx-audio-codec",
+	}, {
+		.name = "sc27xx-regulator",
+		.of_compatible = "sprd,sc27xx-regulator",
+	}, {
+		.name = "sc27xx-vibrator",
+		.of_compatible = "sprd,sc27xx-vibrator",
+	}, {
+		.name = "sc27xx-keypad-led",
+		.of_compatible = "sprd,sc27xx-keypad-led",
+	}, {
+		.name = "sc27xx-bltc",
+		.of_compatible = "sprd,sc27xx-bltc",
+	}, {
+		.name = "sc27xx-fgu",
+		.of_compatible = "sprd,sc27xx-fgu",
+	}, {
+		.name = "sc27xx-7sreset",
+		.of_compatible = "sprd,sc27xx-7sreset",
+	}, {
+		.name = "sc27xx-poweroff",
+		.of_compatible = "sprd,sc27xx-poweroff",
+	},
+};
+
+static int sprd_pmic_spi_write(void *context, const void *data, size_t count)
+{
+	struct device *dev = context;
+	struct spi_device *spi = to_spi_device(dev);
+
+	return spi_write(spi, data, count);
+}
+
+static int sprd_pmic_spi_read(void *context,
+			      const void *reg, size_t reg_size,
+			      void *val, size_t val_size)
+{
+	struct device *dev = context;
+	struct spi_device *spi = to_spi_device(dev);
+	u32 rx_buf[2] = { 0 };
+	int ret;
+
+	/* Now we only support one PMIC register to read every time. */
+	if (reg_size != sizeof(u32) || val_size != sizeof(u32))
+		return -EINVAL;
+
+	/* Copy address to read from into first element of SPI buffer. */
+	memcpy(rx_buf, reg, sizeof(u32));
+	ret = spi_read(spi, rx_buf, 1);
+	if (ret < 0)
+		return ret;
+
+	memcpy(val, rx_buf, val_size);
+	return 0;
+}
+
+static struct regmap_bus sprd_pmic_regmap = {
+	.write = sprd_pmic_spi_write,
+	.read = sprd_pmic_spi_read,
+	.reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
+	.val_format_endian_default = REGMAP_ENDIAN_NATIVE,
+};
+
+static const struct regmap_config sprd_pmic_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.max_register = 0xffff,
+};
+
+static int sprd_pmic_probe(struct spi_device *spi)
+{
+	struct sprd_pmic *ddata;
+	const struct sprd_pmic_data *pdata;
+	int ret, i;
+
+	pdata = of_device_get_match_data(&spi->dev);
+	if (!pdata) {
+		dev_err(&spi->dev, "No matching driver data found\n");
+		return -EINVAL;
+	}
+
+	ddata = devm_kzalloc(&spi->dev, sizeof(*ddata), GFP_KERNEL);
+	if (!ddata)
+		return -ENOMEM;
+
+	ddata->regmap = devm_regmap_init(&spi->dev, &sprd_pmic_regmap,
+					 &spi->dev, &sprd_pmic_config);
+	if (IS_ERR(ddata->regmap)) {
+		ret = PTR_ERR(ddata->regmap);
+		dev_err(&spi->dev, "Failed to allocate register map %d\n", ret);
+		return ret;
+	}
+
+	spi_set_drvdata(spi, ddata);
+	ddata->dev = &spi->dev;
+	ddata->irq = spi->irq;
+
+	ddata->irq_chip.name = dev_name(&spi->dev);
+	ddata->irq_chip.status_base =
+		pdata->irq_base + SPRD_PMIC_INT_MASK_STATUS;
+	ddata->irq_chip.mask_base = pdata->irq_base + SPRD_PMIC_INT_EN;
+	ddata->irq_chip.ack_base = 0;
+	ddata->irq_chip.num_regs = 1;
+	ddata->irq_chip.num_irqs = pdata->num_irqs;
+	ddata->irq_chip.mask_invert = true;
+
+	ddata->irqs = devm_kzalloc(&spi->dev, sizeof(struct regmap_irq) *
+				   pdata->num_irqs, GFP_KERNEL);
+	if (!ddata->irqs)
+		return -ENOMEM;
+
+	ddata->irq_chip.irqs = ddata->irqs;
+	for (i = 0; i < pdata->num_irqs; i++) {
+		ddata->irqs[i].reg_offset = i / pdata->num_irqs;
+		ddata->irqs[i].mask = BIT(i % pdata->num_irqs);
+	}
+
+	ret = devm_regmap_add_irq_chip(&spi->dev, ddata->regmap, ddata->irq,
+				       IRQF_ONESHOT | IRQF_NO_SUSPEND, 0,
+				       &ddata->irq_chip, &ddata->irq_data);
+	if (ret) {
+		dev_err(&spi->dev, "Failed to add PMIC irq chip %d\n", ret);
+		return ret;
+	}
+
+	ret = devm_mfd_add_devices(&spi->dev, PLATFORM_DEVID_AUTO,
+				   sprd_pmic_devs, ARRAY_SIZE(sprd_pmic_devs),
+				   NULL, 0,
+				   regmap_irq_get_domain(ddata->irq_data));
+	if (ret) {
+		dev_err(&spi->dev, "Failed to register device %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id sprd_pmic_match[] = {
+	{ .compatible = "sprd,sc2731", .data = &sc2731_data },
+	{},
+};
+MODULE_DEVICE_TABLE(of, sprd_pmic_match);
+
+static struct spi_driver sprd_pmic_driver = {
+	.driver = {
+		.name = "sc27xx-pmic",
+		.bus = &spi_bus_type,
+		.of_match_table = sprd_pmic_match,
+	},
+	.probe = sprd_pmic_probe,
+};
+
+static int __init sprd_pmic_init(void)
+{
+	return spi_register_driver(&sprd_pmic_driver);
+}
+subsys_initcall(sprd_pmic_init);
+
+static void __exit sprd_pmic_exit(void)
+{
+	spi_unregister_driver(&sprd_pmic_driver);
+}
+module_exit(sprd_pmic_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Spreadtrum SC27xx PMICs driver");
+MODULE_AUTHOR("Baolin Wang <baolin.wang@spreadtrum.com>");