drivers: spmi: Add support for Qualcomm SPMI bus driver

Support SPMI arbiter on Qualcomm Snapdragon devices.

Signed-off-by: Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>

doc/device-tree-bindings/spmi/spmi-msm.txt

@@ -0,0 +1,26 @@
+Qualcomm SPMI arbiter/bus driver
+
+This is bus driver for Qualcomm chips that use SPMI to communicate with PMICs.
+
+Required properties:
+- compatible: "qcom,spmi-pmic-arb"
+- reg: Register block adresses and sizes for various parts of device:
+   1) PMIC arbiter channel mapping base (PMIC_ARB_REG_CHNLn)
+   2) SPMI write command (master) registers (PMIC_ARB_CORE_SW_DEC_CHANNELS)
+   3) SPMI read command (observer) registers (PMIC_ARB_CORE_REGISTERS_OBS)
+
+Optional properties (if not set by parent):
+- #address-cells: 0x1 - childs slave ID address
+- #size-cells: 0x1
+
+All PMICs should be placed as a child nodes of bus arbiter.
+Automatic detection of childs is currently not supported.
+
+Example:
+
+spmi@200f000 {
+	compatible = "qcom,spmi-pmic-arb";
+	reg = <0x200f800 0x200 0x2400000 0x400000 0x2c00000 0x400000>;
+	#address-cells = <0x1>;
+	#size-cells = <0x1>;
+};

drivers/spmi/Kconfig

@@ -8,11 +8,16 @@ config SPMI
 	  SPMI (System Power Management Interface) bus is used
 	  to connect PMIC devices on various SoCs.
 
+config SPMI_MSM
+	boolean "Support Qualcomm SPMI bus"
+	depends on SPMI
+	---help---
+	  Support SPMI bus implementation found on Qualcomm Snapdragon SoCs.
+
 config SPMI_SANDBOX
 	boolean "Support for Sandbox SPMI bus"
 	depends on SPMI
 	---help---
 	  Demo SPMI bus implementation. Emulates part of PM8916 as single
           slave (0) on bus. It has 4 GPIO peripherals, pid 0xC0-0xC3.
-
 endmenu

drivers/spmi/Makefile

@@ -5,4 +5,5 @@
 #
 
 obj-$(CONFIG_SPMI)  += spmi-uclass.o
+obj-$(CONFIG_SPMI_MSM) += spmi-msm.o
 obj-$(CONFIG_SPMI_SANDBOX) += spmi-sandbox.o

drivers/spmi/spmi-msm.c

@@ -0,0 +1,189 @@
+/*
+ * Qualcomm SPMI bus driver
+ *
+ * (C) Copyright 2015 Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
+ *
+ * Loosely based on Little Kernel driver
+ *
+ * SPDX-License-Identifier:	BSD-3-Clause
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <fdtdec.h>
+#include <asm/io.h>
+#include <spmi/spmi.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define ARB_CHANNEL_OFFSET(n)		(0x4 * (n))
+#define SPMI_CH_OFFSET(chnl)		((chnl) * 0x8000)
+
+#define SPMI_REG_CMD0			0x0
+#define SPMI_REG_CONFIG			0x4
+#define SPMI_REG_STATUS			0x8
+#define SPMI_REG_WDATA			0x10
+#define SPMI_REG_RDATA			0x18
+
+#define SPMI_CMD_OPCODE_SHIFT		27
+#define SPMI_CMD_SLAVE_ID_SHIFT		20
+#define SPMI_CMD_ADDR_SHIFT		12
+#define SPMI_CMD_ADDR_OFFSET_SHIFT	4
+#define SPMI_CMD_BYTE_CNT_SHIFT		0
+
+#define SPMI_CMD_EXT_REG_WRITE_LONG	0x00
+#define SPMI_CMD_EXT_REG_READ_LONG	0x01
+
+#define SPMI_STATUS_DONE		0x1
+
+#define SPMI_MAX_CHANNELS	128
+#define SPMI_MAX_SLAVES		16
+#define SPMI_MAX_PERIPH		256
+
+struct msm_spmi_priv {
+	phys_addr_t arb_chnl; /* ARB channel mapping base */
+	phys_addr_t spmi_core; /* SPMI core */
+	phys_addr_t spmi_obs; /* SPMI observer */
+	/* SPMI channel map */
+	uint8_t channel_map[SPMI_MAX_SLAVES][SPMI_MAX_PERIPH];
+};
+
+static int msm_spmi_write(struct udevice *dev, int usid, int pid, int off,
+			  uint8_t val)
+{
+	struct msm_spmi_priv *priv = dev_get_priv(dev);
+	unsigned channel;
+	uint32_t reg = 0;
+
+	if (usid >= SPMI_MAX_SLAVES)
+		return -EIO;
+	if (pid >= SPMI_MAX_PERIPH)
+		return -EIO;
+
+	channel = priv->channel_map[usid][pid];
+
+	/* Disable IRQ mode for the current channel*/
+	writel(0x0, priv->spmi_core + SPMI_CH_OFFSET(channel) +
+	       SPMI_REG_CONFIG);
+
+	/* Write single byte */
+	writel(val, priv->spmi_core + SPMI_CH_OFFSET(channel) + SPMI_REG_WDATA);
+
+	/* Prepare write command */
+	reg |= SPMI_CMD_EXT_REG_WRITE_LONG << SPMI_CMD_OPCODE_SHIFT;
+	reg |= (usid << SPMI_CMD_SLAVE_ID_SHIFT);
+	reg |= (pid << SPMI_CMD_ADDR_SHIFT);
+	reg |= (off << SPMI_CMD_ADDR_OFFSET_SHIFT);
+	reg |= 1; /* byte count */
+
+	/* Send write command */
+	writel(reg, priv->spmi_core + SPMI_CH_OFFSET(channel) + SPMI_REG_CMD0);
+
+	/* Wait till CMD DONE status */
+	reg = 0;
+	while (!reg) {
+		reg = readl(priv->spmi_core + SPMI_CH_OFFSET(channel) +
+			    SPMI_REG_STATUS);
+	}
+
+	if (reg ^ SPMI_STATUS_DONE) {
+		printf("SPMI write failure.\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int msm_spmi_read(struct udevice *dev, int usid, int pid, int off)
+{
+	struct msm_spmi_priv *priv = dev_get_priv(dev);
+	unsigned channel;
+	uint32_t reg = 0;
+
+	if (usid >= SPMI_MAX_SLAVES)
+		return -EIO;
+	if (pid >= SPMI_MAX_PERIPH)
+		return -EIO;
+
+	channel = priv->channel_map[usid][pid];
+
+	/* Disable IRQ mode for the current channel*/
+	writel(0x0, priv->spmi_obs + SPMI_CH_OFFSET(channel) + SPMI_REG_CONFIG);
+
+	/* Prepare read command */
+	reg |= SPMI_CMD_EXT_REG_READ_LONG << SPMI_CMD_OPCODE_SHIFT;
+	reg |= (usid << SPMI_CMD_SLAVE_ID_SHIFT);
+	reg |= (pid << SPMI_CMD_ADDR_SHIFT);
+	reg |= (off << SPMI_CMD_ADDR_OFFSET_SHIFT);
+	reg |= 1; /* byte count */
+
+	/* Request read */
+	writel(reg, priv->spmi_obs + SPMI_CH_OFFSET(channel) + SPMI_REG_CMD0);
+
+	/* Wait till CMD DONE status */
+	reg = 0;
+	while (!reg) {
+		reg = readl(priv->spmi_obs + SPMI_CH_OFFSET(channel) +
+			    SPMI_REG_STATUS);
+	}
+
+	if (reg ^ SPMI_STATUS_DONE) {
+		printf("SPMI read failure.\n");
+		return -EIO;
+	}
+
+	/* Read the data */
+	return readl(priv->spmi_obs + SPMI_CH_OFFSET(channel) +
+		     SPMI_REG_RDATA) & 0xFF;
+}
+
+static struct dm_spmi_ops msm_spmi_ops = {
+	.read = msm_spmi_read,
+	.write = msm_spmi_write,
+};
+
+static int msm_spmi_probe(struct udevice *dev)
+{
+	struct udevice *parent = dev->parent;
+	struct msm_spmi_priv *priv = dev_get_priv(dev);
+	int i;
+
+	priv->arb_chnl = dev_get_addr(dev);
+	priv->spmi_core = fdtdec_get_addr_size_auto_parent(gd->fdt_blob,
+							   parent->of_offset,
+							   dev->of_offset,
+							   "reg", 1, NULL);
+	priv->spmi_obs = fdtdec_get_addr_size_auto_parent(gd->fdt_blob,
+							  parent->of_offset,
+							  dev->of_offset, "reg",
+							  2, NULL);
+	if (priv->arb_chnl == FDT_ADDR_T_NONE ||
+	    priv->spmi_core == FDT_ADDR_T_NONE ||
+	    priv->spmi_obs == FDT_ADDR_T_NONE)
+		return -EINVAL;
+
+	/* Scan peripherals connected to each SPMI channel */
+	for (i = 0; i < SPMI_MAX_CHANNELS ; i++) {
+		uint32_t periph = readl(priv->arb_chnl + ARB_CHANNEL_OFFSET(i));
+		uint8_t slave_id = (periph & 0xf0000) >> 16;
+		uint8_t pid = (periph & 0xff00) >> 8;
+
+		priv->channel_map[slave_id][pid] = i;
+	}
+	return 0;
+}
+
+static const struct udevice_id msm_spmi_ids[] = {
+	{ .compatible = "qcom,spmi-pmic-arb" },
+	{ }
+};
+
+U_BOOT_DRIVER(msm_spmi) = {
+	.name = "msm_spmi",
+	.id = UCLASS_SPMI,
+	.of_match = msm_spmi_ids,
+	.ops = &msm_spmi_ops,
+	.probe = msm_spmi_probe,
+	.priv_auto_alloc_size = sizeof(struct msm_spmi_priv),
+};