sun6i: Add new p2wi controller driver

The A31 uses a new push-pull two wire interface, which features higher
transfer speeds (upto 6 MHz) in theory. While the hardware can burst 8
bytes each time, this driver will only see very little use and thus is
limited to single byte transmission only.

Signed-off-by: Oliver Schinagl <oliver@schinagl.nl>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>

2 files changed, 118 insertions, 0 deletions

diff --git a/arch/arm/cpu/armv7/sunxi/Makefile b/arch/arm/cpu/armv7/sunxi/Makefile
index 82dbf764e4..b3a3601a27 100644
--- a/arch/arm/cpu/armv7/sunxi/Makefile
+++ b/arch/arm/cpu/armv7/sunxi/Makefile
@@ -13,6 +13,7 @@ obj-y	+= clock.o
 obj-y	+= pinmux.o
 obj-$(CONFIG_MACH_SUN6I)	+= prcm.o
 obj-$(CONFIG_MACH_SUN8I)	+= prcm.o
+obj-$(CONFIG_MACH_SUN6I)	+= p2wi.o
 obj-$(CONFIG_MACH_SUN4I)	+= clock_sun4i.o
 obj-$(CONFIG_MACH_SUN5I)	+= clock_sun4i.o
 obj-$(CONFIG_MACH_SUN6I)	+= clock_sun6i.o
diff --git a/arch/arm/cpu/armv7/sunxi/p2wi.c b/arch/arm/cpu/armv7/sunxi/p2wi.c
new file mode 100644
index 0000000000..48613bd0ea
--- /dev/null
+++ b/arch/arm/cpu/armv7/sunxi/p2wi.c
@@ -0,0 +1,117 @@
+/*
+ * Sunxi A31 Power Management Unit
+ *
+ * (C) Copyright 2013 Oliver Schinagl <oliver@schinagl.nl>
+ * http://linux-sunxi.org
+ *
+ * Based on sun6i sources and earlier U-Boot Allwiner A10 SPL work
+ *
+ * (C) Copyright 2006-2013
+ * Allwinner Technology Co., Ltd. <www.allwinnertech.com>
+ * Berg Xing <bergxing@allwinnertech.com>
+ * Tom Cubie <tangliang@allwinnertech.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <asm/io.h>
+#include <asm/arch/cpu.h>
+#include <asm/arch/gpio.h>
+#include <asm/arch/p2wi.h>
+#include <asm/arch/prcm.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/sys_proto.h>
+
+void p2wi_init(void)
+{
+	struct sunxi_p2wi_reg *p2wi = (struct sunxi_p2wi_reg *)SUNXI_P2WI_BASE;
+
+	/* Enable p2wi and PIO clk, and de-assert their resets */
+	prcm_apb0_enable(PRCM_APB0_GATE_PIO | PRCM_APB0_GATE_P2WI);
+
+	sunxi_gpio_set_cfgpin(SUNXI_GPL(0), SUNXI_GPL0_R_P2WI_SCK);
+	sunxi_gpio_set_cfgpin(SUNXI_GPL(1), SUNXI_GPL1_R_P2WI_SDA);
+
+	/* Reset p2wi controller and set clock to CLKIN(12)/8 = 1.5 MHz */
+	writel(P2WI_CTRL_RESET, &p2wi->ctrl);
+	sdelay(0x100);
+	writel(P2WI_CC_SDA_OUT_DELAY(1) | P2WI_CC_CLK_DIV(8),
+	       &p2wi->cc);
+}
+
+int p2wi_change_to_p2wi_mode(u8 slave_addr, u8 ctrl_reg, u8 init_data)
+{
+	struct sunxi_p2wi_reg *p2wi = (struct sunxi_p2wi_reg *)SUNXI_P2WI_BASE;
+	unsigned long tmo = timer_get_us() + 1000000;
+
+	writel(P2WI_PM_DEV_ADDR(slave_addr) |
+	       P2WI_PM_CTRL_ADDR(ctrl_reg) |
+	       P2WI_PM_INIT_DATA(init_data) |
+	       P2WI_PM_INIT_SEND,
+	       &p2wi->pm);
+
+	while ((readl(&p2wi->pm) & P2WI_PM_INIT_SEND)) {
+		if (timer_get_us() > tmo)
+			return -ETIME;
+	}
+
+	return 0;
+}
+
+static int p2wi_await_trans(void)
+{
+	struct sunxi_p2wi_reg *p2wi = (struct sunxi_p2wi_reg *)SUNXI_P2WI_BASE;
+	unsigned long tmo = timer_get_us() + 1000000;
+	int ret;
+	u8 reg;
+
+	while (1) {
+		reg = readl(&p2wi->status);
+		if (reg & P2WI_STAT_TRANS_ERR) {
+			ret = -EIO;
+			break;
+		}
+		if (reg & P2WI_STAT_TRANS_DONE) {
+			ret = 0;
+			break;
+		}
+		if (timer_get_us() > tmo) {
+			ret = -ETIME;
+			break;
+		}
+	}
+	writel(reg, &p2wi->status); /* Clear status bits */
+	return ret;
+}
+
+int p2wi_read(const u8 addr, u8 *data)
+{
+	struct sunxi_p2wi_reg *p2wi = (struct sunxi_p2wi_reg *)SUNXI_P2WI_BASE;
+	int ret;
+
+	writel(P2WI_DATADDR_BYTE_1(addr), &p2wi->dataddr0);
+	writel(P2WI_DATA_NUM_BYTES(1) |
+	       P2WI_DATA_NUM_BYTES_READ, &p2wi->numbytes);
+	writel(P2WI_STAT_TRANS_DONE, &p2wi->status);
+	writel(P2WI_CTRL_TRANS_START, &p2wi->ctrl);
+
+	ret = p2wi_await_trans();
+
+	*data = readl(&p2wi->data0) & P2WI_DATA_BYTE_1_MASK;
+	return ret;
+}
+
+int p2wi_write(const u8 addr, u8 data)
+{
+	struct sunxi_p2wi_reg *p2wi = (struct sunxi_p2wi_reg *)SUNXI_P2WI_BASE;
+
+	writel(P2WI_DATADDR_BYTE_1(addr), &p2wi->dataddr0);
+	writel(P2WI_DATA_BYTE_1(data), &p2wi->data0);
+	writel(P2WI_DATA_NUM_BYTES(1), &p2wi->numbytes);
+	writel(P2WI_STAT_TRANS_DONE, &p2wi->status);
+	writel(P2WI_CTRL_TRANS_START, &p2wi->ctrl);
+
+	return p2wi_await_trans();
+}