GK SDK 源码库: XMIPCLinuxV100R005C00SPC030 (kernel/tools/open_source excluded)

source/bootloader/u-boot-2020.01/arch/arm/mach-imx/i2c-mxv7.c

@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2012 Boundary Devices Inc.
+ */
+#include <common.h>
+#include <malloc.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/imx-regs.h>
+#include <linux/errno.h>
+#include <asm/gpio.h>
+#include <asm/mach-imx/mxc_i2c.h>
+#include <watchdog.h>
+
+int force_idle_bus(void *priv)
+{
+	int i;
+	int sda, scl;
+	ulong elapsed, start_time;
+	struct i2c_pads_info *p = (struct i2c_pads_info *)priv;
+	int ret = 0;
+
+	gpio_direction_input(p->sda.gp);
+	gpio_direction_input(p->scl.gp);
+
+	imx_iomux_v3_setup_pad(p->sda.gpio_mode);
+	imx_iomux_v3_setup_pad(p->scl.gpio_mode);
+
+	sda = gpio_get_value(p->sda.gp);
+	scl = gpio_get_value(p->scl.gp);
+	if ((sda & scl) == 1)
+		goto exit;		/* Bus is idle already */
+
+	printf("%s: sda=%d scl=%d sda.gp=0x%x scl.gp=0x%x\n", __func__,
+		sda, scl, p->sda.gp, p->scl.gp);
+	/* Send high and low on the SCL line */
+	for (i = 0; i < 9; i++) {
+		gpio_direction_output(p->scl.gp, 0);
+		udelay(50);
+		gpio_direction_input(p->scl.gp);
+		udelay(50);
+	}
+	start_time = get_timer(0);
+	for (;;) {
+		sda = gpio_get_value(p->sda.gp);
+		scl = gpio_get_value(p->scl.gp);
+		if ((sda & scl) == 1)
+			break;
+		WATCHDOG_RESET();
+		elapsed = get_timer(start_time);
+		if (elapsed > (CONFIG_SYS_HZ / 5)) {	/* .2 seconds */
+			ret = -EBUSY;
+			printf("%s: failed to clear bus, sda=%d scl=%d\n",
+					__func__, sda, scl);
+			break;
+		}
+	}
+exit:
+	imx_iomux_v3_setup_pad(p->sda.i2c_mode);
+	imx_iomux_v3_setup_pad(p->scl.i2c_mode);
+	return ret;
+}
+
+static void * const i2c_bases[] = {
+	(void *)I2C1_BASE_ADDR,
+	(void *)I2C2_BASE_ADDR,
+#ifdef I2C3_BASE_ADDR
+	(void *)I2C3_BASE_ADDR,
+#endif
+#ifdef I2C4_BASE_ADDR
+	(void *)I2C4_BASE_ADDR,
+#endif
+};
+
+/* i2c_index can be from 0 - 3 */
+int setup_i2c(unsigned i2c_index, int speed, int slave_addr,
+	      struct i2c_pads_info *p)
+{
+	char name[9];
+	int ret;
+
+	if (i2c_index >= ARRAY_SIZE(i2c_bases))
+		return -EINVAL;
+
+	snprintf(name, sizeof(name), "i2c_sda%01d", i2c_index);
+	ret = gpio_request(p->sda.gp, name);
+	if (ret)
+		return ret;
+
+	snprintf(name, sizeof(name), "i2c_scl%01d", i2c_index);
+	ret = gpio_request(p->scl.gp, name);
+	if (ret)
+		goto err_req;
+
+	/* Enable i2c clock */
+	ret = enable_i2c_clk(1, i2c_index);
+	if (ret)
+		goto err_clk;
+
+	/* Make sure bus is idle */
+	ret = force_idle_bus(p);
+	if (ret)
+		goto err_idle;
+
+#ifndef CONFIG_DM_I2C
+	bus_i2c_init(i2c_index, speed, slave_addr, force_idle_bus, p);
+#endif
+
+	return 0;
+
+err_idle:
+err_clk:
+	gpio_free(p->scl.gp);
+err_req:
+	gpio_free(p->sda.gp);
+
+	return ret;
+}