x86: tangier: pinmux: add API to configure protected pins

This API is going to be used to configure some pins that are protected
for simple modification.

It's not a comprehensive pinctrl driver but can be turned into one
when we need this in the future. Now it is planned to be used only
in one place. So that's why I decided not to pollute the codebase with a
full-blown pinctrl-merrifield nobody will use.

This driver reads corresponding fields in DT and configures pins
accordingly.

The "protected" flag is used to distinguish configuration of SCU-owned
pins from the ordinary ones.

The code has been adapted from Linux work done by Andy Shevchenko
in pinctrl-merrfifield.c

Signed-off-by: Georgii Staroselskii <georgii.staroselskii@emlid.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
[bmeng: fix build warning]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>

diff --git a/arch/x86/cpu/tangier/Makefile b/arch/x86/cpu/tangier/Makefile
index 8274482..68f4a32 100644 (file)
--- a/arch/x86/cpu/tangier/Makefile
+++ b/arch/x86/cpu/tangier/Makefile
@@ -2,5 +2,5 @@
 #
 # Copyright (c) 2017 Intel Corporation
 
-obj-y += car.o tangier.o sdram.o sysreset.o
+obj-y += car.o tangier.o sdram.o sysreset.o pinmux.o
 obj-$(CONFIG_GENERATE_ACPI_TABLE) += acpi.o

diff --git a/arch/x86/cpu/tangier/pinmux.c b/arch/x86/cpu/tangier/pinmux.c
new file mode 100644 (file)
index 0000000..fdd6530
--- /dev/null
+++ b/arch/x86/cpu/tangier/pinmux.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2018 Emlid Limited
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <dm/pinctrl.h>
+#include <dm/read.h>
+#include <regmap.h>
+#include <syscon.h>
+#include <asm/cpu.h>
+#include <asm/scu.h>
+#include <linux/io.h>
+
+#define BUFCFG_OFFSET                          0x100
+
+#define MRFLD_FAMILY_LEN                       0x400
+
+/* These are taken from Linux kernel */
+#define MRFLD_PINMODE_MASK                     0x07
+
+#define pin_to_bufno(f, p)                     ((p) - (f)->pin_base)
+
+struct mrfld_family {
+       unsigned int family_number;
+       unsigned int pin_base;
+       size_t npins;
+       void __iomem *regs;
+};
+
+#define MRFLD_FAMILY(b, s, e)                          \
+       {                                               \
+               .family_number = (b),                   \
+               .pin_base = (s),                        \
+               .npins = (e) - (s) + 1,                 \
+       }
+
+/* Now we only support I2C family of pins */
+static struct mrfld_family mrfld_families[] = {
+       MRFLD_FAMILY(7, 101, 114),
+};
+
+struct mrfld_pinctrl {
+       const struct mrfld_family *families;
+       size_t nfamilies;
+};
+
+static const struct mrfld_family *
+mrfld_get_family(struct mrfld_pinctrl *mp, unsigned int pin)
+{
+       const struct mrfld_family *family;
+       unsigned int i;
+
+       for (i = 0; i < mp->nfamilies; i++) {
+               family = &mp->families[i];
+               if (pin >= family->pin_base &&
+                   pin < family->pin_base + family->npins)
+                       return family;
+       }
+
+       pr_err("failed to find family for pin %u\n", pin);
+       return NULL;
+}
+
+static void __iomem *
+mrfld_get_bufcfg(struct mrfld_pinctrl *pinctrl, unsigned int pin)
+{
+       const struct mrfld_family *family;
+       unsigned int bufno;
+
+       family =  mrfld_get_family(pinctrl, pin);
+       if (!family)
+               return NULL;
+
+       bufno = pin_to_bufno(family, pin);
+
+       return family->regs + BUFCFG_OFFSET + bufno * 4;
+}
+
+static void
+mrfld_setup_families(void *base_addr,
+                    struct mrfld_family *families, unsigned int nfam)
+{
+       for (int i = 0; i < nfam; i++) {
+               struct mrfld_family *family = &families[i];
+
+               family->regs = base_addr +
+                              family->family_number * MRFLD_FAMILY_LEN;
+       }
+}
+
+static int mrfld_pinconfig_protected(unsigned int pin, u32 mask, u32 bits)
+{
+       struct mrfld_pinctrl *pinctrl;
+       struct udevice *dev;
+       void __iomem *bufcfg;
+       u32 v, value;
+       int ret;
+
+       ret = syscon_get_by_driver_data(X86_SYSCON_PINCONF, &dev);
+       if (ret)
+               return ret;
+
+       pinctrl = dev_get_priv(dev);
+
+       bufcfg = mrfld_get_bufcfg(pinctrl, pin);
+       if (!bufcfg)
+               return -EINVAL;
+
+       value = readl(bufcfg);
+
+       v = (value & ~mask) | (bits & mask);
+
+       debug("scu: v: 0x%x p: 0x%x bits: %d, mask: %d bufcfg: 0x%p\n",
+             v, (u32)bufcfg, bits, mask, bufcfg);
+
+       ret = scu_ipc_raw_command(IPCMSG_INDIRECT_WRITE, 0, &v, 4,
+                                 NULL, 0, (u32)bufcfg, 0);
+       if (ret)
+               pr_err("Failed to set mode via SCU for pin %u (%d)\n",
+                      pin, ret);
+
+       return ret;
+}
+
+static int mrfld_pinctrl_cfg_pin(ofnode pin_node)
+{
+       bool is_protected;
+       int pad_offset;
+       int mode;
+       u32 mask;
+       int ret;
+
+       /* For now we only support just protected Family of pins */
+       is_protected = ofnode_read_bool(pin_node, "protected");
+       if (!is_protected)
+               return -ENOTSUPP;
+
+       pad_offset = ofnode_read_s32_default(pin_node, "pad-offset", -1);
+       if (pad_offset == -1)
+               return -EINVAL;
+
+       mode = ofnode_read_s32_default(pin_node, "mode-func", -1);
+       if (mode == -1)
+               return -EINVAL;
+
+       mask = MRFLD_PINMODE_MASK;
+
+       /* We don't support modes not in range 0..7 */
+       if (mode & ~mask)
+               return -ENOTSUPP;
+
+       ret = mrfld_pinconfig_protected(pad_offset, mask, mode);
+
+       return ret;
+}
+
+static int tangier_pinctrl_probe(struct udevice *dev)
+{
+       void *base_addr = syscon_get_first_range(X86_SYSCON_PINCONF);
+       struct mrfld_pinctrl *pinctrl = dev_get_priv(dev);
+       ofnode pin_node;
+       int ret;
+
+       mrfld_setup_families(base_addr, mrfld_families,
+                            ARRAY_SIZE(mrfld_families));
+
+       pinctrl->families = mrfld_families;
+       pinctrl->nfamilies = ARRAY_SIZE(mrfld_families);
+
+       ofnode_for_each_subnode(pin_node, dev_ofnode(dev)) {
+               ret = mrfld_pinctrl_cfg_pin(pin_node);
+               if (ret) {
+                       pr_err("%s: invalid configuration for the pin %ld\n",
+                              __func__, pin_node.of_offset);
+               }
+       }
+
+       return 0;
+}
+
+static const struct udevice_id tangier_pinctrl_match[] = {
+       { .compatible = "intel,pinctrl-tangier", .data = X86_SYSCON_PINCONF },
+       { /* sentinel */ }
+};
+
+U_BOOT_DRIVER(tangier_pinctrl) = {
+       .name = "tangier_pinctrl",
+       .id = UCLASS_SYSCON,
+       .of_match = tangier_pinctrl_match,
+       .probe = tangier_pinctrl_probe,
+       .priv_auto_alloc_size = sizeof(struct mrfld_pinctrl),
+};