[PATCH v4 2/2] mfd: Add Spreadtrum SC27xx series PMICs driver

[Baolin Wang]

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@xxxxxxxxxxxxxx>
---
Changes since v3:
 - Use memcpy() to copy register offset address into SPI buffer.

Changes since v2:
 - Add more help information.
 - Define macros for irq base and irq number.
 - Use devm_mfd_add_devices() instead of mfd_add_devices(), which means
 we can remove sprd_pmic_remove().
 - Rename local variables in sprd_pmic_probe().

Changes since v1:
 - Add more documentation to introduce Spreadtrum SC27xx series PMICs.
 - Modify compatile string property.
 - Modify reg property.
 - Remove redundant 'pmic' label.
 - Change 'should be' to 'must be' for cells properties.
---
 drivers/mfd/Kconfig           |   16 +++
 drivers/mfd/Makefile          |    1 +
 drivers/mfd/sprd-sc27xx-spi.c |  259 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 276 insertions(+)
 create mode 100644 drivers/mfd/sprd-sc27xx-spi.c

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index fc5e4fe..67091bb 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -1057,6 +1057,22 @@ 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
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index c3d0a1b..a377e0f 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -226,3 +226,4 @@ 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
diff --git a/drivers/mfd/sprd-sc27xx-spi.c b/drivers/mfd/sprd-sc27xx-spi.c
new file mode 100644
index 0000000..56a4782
--- /dev/null
+++ b/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@xxxxxxxxxxxxxx>");
-- 
1.7.9.5