spmi: add a spmi driver for Apple SoC

The connected PMU contains several useful nvmem cells such as RTC offset,
boot failure counters, reboot/shutdown selector, and a few others.
In addition M3+ machines have their USB-PD controller connected via SPMI.

Signed-off-by: Jean-Francois Bortolotti <jeff@borto.fr>
Reviewed-by: Sven Peter <sven@svenpeter.dev>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Co-developed-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
Link: https://lore.kernel.org/r/20250409-spmi-v4-2-eb81ecfd1f64@gmail.com
Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20250518032330.2959766-4-sboyd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/MAINTAINERS b/MAINTAINERS
index 6748b72e7486c05955fc71c85ff0c7c19b69cbfe..78974c485bdc6d1d14eb2915d4e3478feaca2a0c 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2304,6 +2304,7 @@ F:        drivers/pinctrl/pinctrl-apple-gpio.c
 F:     drivers/pwm/pwm-apple.c
 F:     drivers/soc/apple/*
 F:     drivers/spi/spi-apple.c
+F:     drivers/spmi/spmi-apple-controller.c
 F:     drivers/video/backlight/apple_dwi_bl.c
 F:     drivers/watchdog/apple_wdt.c
 F:     include/dt-bindings/interrupt-controller/apple-aic.h

diff --git a/drivers/spmi/Kconfig b/drivers/spmi/Kconfig
index 4ee496491c744f06c8ee892dfb6da7dec741ed5e..a80cf4047b86e38d22d3750b30deacbb00e7059d 100644 (file)
--- a/drivers/spmi/Kconfig
+++ b/drivers/spmi/Kconfig
@@ -11,6 +11,14 @@ menuconfig SPMI
 
 if SPMI
 
+config SPMI_APPLE
+       tristate "Apple SoC SPMI Controller platform driver"
+       depends on ARCH_APPLE || COMPILE_TEST
+       help
+         If you say yes to this option, support will be included for the
+         SPMI controller present on many Apple SoCs, including the
+         t8103 (M1) and t600x (M1 Pro/Max).
+
 config SPMI_HISI3670
        tristate "Hisilicon 3670 SPMI Controller"
        select IRQ_DOMAIN_HIERARCHY

diff --git a/drivers/spmi/Makefile b/drivers/spmi/Makefile
index 7f152167bb05b2c24a0f9669f60278152898eebb..38ac635645ba65aa46cb5e8a50072ed9771e229b 100644 (file)
--- a/drivers/spmi/Makefile
+++ b/drivers/spmi/Makefile
@@ -4,6 +4,7 @@
 #
 obj-$(CONFIG_SPMI)     += spmi.o spmi-devres.o
 
+obj-$(CONFIG_SPMI_APPLE)       += spmi-apple-controller.o
 obj-$(CONFIG_SPMI_HISI3670)    += hisi-spmi-controller.o
 obj-$(CONFIG_SPMI_MSM_PMIC_ARB)        += spmi-pmic-arb.o
 obj-$(CONFIG_SPMI_MTK_PMIF)    += spmi-mtk-pmif.o

diff --git a/drivers/spmi/spmi-apple-controller.c b/drivers/spmi/spmi-apple-controller.c
new file mode 100644 (file)
index 0000000..697b3e8
--- /dev/null
+++ b/drivers/spmi/spmi-apple-controller.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Apple SoC SPMI device driver
+ *
+ * Copyright The Asahi Linux Contributors
+ *
+ * Inspired by:
+ *             OpenBSD support Copyright (c) 2021 Mark Kettenis <kettenis@openbsd.org>
+ *             Correllium support Copyright (C) 2021 Corellium LLC
+ *             hisi-spmi-controller.c
+ *             spmi-pmic-arb.c Copyright (c) 2021, The Linux Foundation.
+ */
+
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/spmi.h>
+
+/* SPMI Controller Registers */
+#define SPMI_STATUS_REG 0
+#define SPMI_CMD_REG 0x4
+#define SPMI_RSP_REG 0x8
+
+#define SPMI_RX_FIFO_EMPTY BIT(24)
+
+#define REG_POLL_INTERVAL_US 10000
+#define REG_POLL_TIMEOUT_US (REG_POLL_INTERVAL_US * 5)
+
+struct apple_spmi {
+       void __iomem *regs;
+};
+
+#define poll_reg(spmi, reg, val, cond) \
+       readl_poll_timeout((spmi)->regs + (reg), (val), (cond), \
+                          REG_POLL_INTERVAL_US, REG_POLL_TIMEOUT_US)
+
+static inline u32 apple_spmi_pack_cmd(u8 opc, u8 sid, u16 saddr, size_t len)
+{
+       return opc | sid << 8 | saddr << 16 | (len - 1) | (1 << 15);
+}
+
+/* Wait for Rx FIFO to have something */
+static int apple_spmi_wait_rx_not_empty(struct spmi_controller *ctrl)
+{
+       struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl);
+       int ret;
+       u32 status;
+
+       ret = poll_reg(spmi, SPMI_STATUS_REG, status, !(status & SPMI_RX_FIFO_EMPTY));
+       if (ret) {
+               dev_err(&ctrl->dev,
+                       "failed to wait for RX FIFO not empty\n");
+               return ret;
+       }
+
+       return 0;
+}
+
+static int spmi_read_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
+                        u16 saddr, u8 *buf, size_t len)
+{
+       struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl);
+       u32 spmi_cmd = apple_spmi_pack_cmd(opc, sid, saddr, len);
+       u32 rsp;
+       size_t len_read = 0;
+       u8 i;
+       int ret;
+
+       writel(spmi_cmd, spmi->regs + SPMI_CMD_REG);
+
+       ret = apple_spmi_wait_rx_not_empty(ctrl);
+       if (ret)
+               return ret;
+
+       /* Discard SPMI reply status */
+       readl(spmi->regs + SPMI_RSP_REG);
+
+       /* Read SPMI data reply */
+       while (len_read < len) {
+               rsp = readl(spmi->regs + SPMI_RSP_REG);
+               i = 0;
+               while ((len_read < len) && (i < 4)) {
+                       buf[len_read++] = ((0xff << (8 * i)) & rsp) >> (8 * i);
+                       i += 1;
+               }
+       }
+
+       return 0;
+}
+
+static int spmi_write_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
+                         u16 saddr, const u8 *buf, size_t len)
+{
+       struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl);
+       u32 spmi_cmd = apple_spmi_pack_cmd(opc, sid, saddr, len);
+       size_t i = 0, j;
+       int ret;
+
+       writel(spmi_cmd, spmi->regs + SPMI_CMD_REG);
+
+       while (i < len) {
+               j = 0;
+               spmi_cmd = 0;
+               while ((j < 4) & (i < len))
+                       spmi_cmd |= buf[i++] << (j++ * 8);
+
+               writel(spmi_cmd, spmi->regs + SPMI_CMD_REG);
+       }
+
+       ret = apple_spmi_wait_rx_not_empty(ctrl);
+       if (ret)
+               return ret;
+
+       /* Discard */
+       readl(spmi->regs + SPMI_RSP_REG);
+
+       return 0;
+}
+
+static int apple_spmi_probe(struct platform_device *pdev)
+{
+       struct apple_spmi *spmi;
+       struct spmi_controller *ctrl;
+       int ret;
+
+       ctrl = devm_spmi_controller_alloc(&pdev->dev, sizeof(*spmi));
+       if (IS_ERR(ctrl))
+               return -ENOMEM;
+
+       spmi = spmi_controller_get_drvdata(ctrl);
+
+       spmi->regs = devm_platform_ioremap_resource(pdev, 0);
+       if (IS_ERR(spmi->regs))
+               return PTR_ERR(spmi->regs);
+
+       ctrl->dev.of_node = pdev->dev.of_node;
+
+       ctrl->read_cmd = spmi_read_cmd;
+       ctrl->write_cmd = spmi_write_cmd;
+
+       ret = devm_spmi_controller_add(&pdev->dev, ctrl);
+       if (ret)
+               return dev_err_probe(&pdev->dev, ret,
+                                    "spmi_controller_add failed\n");
+
+       return 0;
+}
+
+static const struct of_device_id apple_spmi_match_table[] = {
+       { .compatible = "apple,spmi", },
+       {}
+};
+MODULE_DEVICE_TABLE(of, apple_spmi_match_table);
+
+static struct platform_driver apple_spmi_driver = {
+       .probe          = apple_spmi_probe,
+       .driver         = {
+               .name   = "apple-spmi",
+               .of_match_table = apple_spmi_match_table,
+       },
+};
+module_platform_driver(apple_spmi_driver);
+
+MODULE_AUTHOR("Jean-Francois Bortolotti <jeff@borto.fr>");
+MODULE_DESCRIPTION("Apple SoC SPMI driver");
+MODULE_LICENSE("GPL");