* Which was based on a (non-working) driver which was:
* Copyright (C) 2009-2010 Freescale Semiconductor, Inc. All Rights Reserved.
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- *
+ * SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <malloc.h>
+#include <i2c.h>
#include <asm/errno.h>
#include <asm/io.h>
#include <asm/arch/clock.h>
#define MXS_I2C_MAX_TIMEOUT 1000000
-void mxs_i2c_reset(void)
+static void mxs_i2c_reset(void)
{
struct mxs_i2c_regs *i2c_regs = (struct mxs_i2c_regs *)MXS_I2C0_BASE;
int ret;
+ int speed = i2c_get_bus_speed();
ret = mxs_reset_block(&i2c_regs->hw_i2c_ctrl0_reg);
if (ret) {
&i2c_regs->hw_i2c_ctrl1_clr);
writel(I2C_QUEUECTRL_PIO_QUEUE_MODE, &i2c_regs->hw_i2c_queuectrl_set);
+
+ i2c_set_bus_speed(speed);
}
-void mxs_i2c_setup_read(uint8_t chip, int len)
+static void mxs_i2c_setup_read(uint8_t chip, int len)
{
struct mxs_i2c_regs *i2c_regs = (struct mxs_i2c_regs *)MXS_I2C0_BASE;
writel(I2C_QUEUECTRL_QUEUE_RUN, &i2c_regs->hw_i2c_queuectrl_set);
}
-void mxs_i2c_write(uchar chip, uint addr, int alen,
+static int mxs_i2c_write(uchar chip, uint addr, int alen,
uchar *buf, int blen, int stop)
{
struct mxs_i2c_regs *i2c_regs = (struct mxs_i2c_regs *)MXS_I2C0_BASE;
- uint32_t data;
+ uint32_t data, tmp;
int i, remain, off;
+ int timeout = MXS_I2C_MAX_TIMEOUT;
if ((alen > 4) || (alen == 0)) {
debug("MXS I2C: Invalid address length\n");
- return;
+ return -EINVAL;
}
if (stop)
writel(data >> remain, &i2c_regs->hw_i2c_data);
writel(I2C_QUEUECTRL_QUEUE_RUN, &i2c_regs->hw_i2c_queuectrl_set);
+
+ while (--timeout) {
+ tmp = readl(&i2c_regs->hw_i2c_queuestat);
+ if (tmp & I2C_QUEUESTAT_WR_QUEUE_EMPTY)
+ break;
+ }
+
+ if (!timeout) {
+ debug("MXS I2C: Failed transmitting data!\n");
+ return -EINVAL;
+ }
+
+ return 0;
}
-int mxs_i2c_wait_for_ack(void)
+static int mxs_i2c_wait_for_ack(void)
{
struct mxs_i2c_regs *i2c_regs = (struct mxs_i2c_regs *)MXS_I2C0_BASE;
uint32_t tmp;
{
struct mxs_i2c_regs *i2c_regs = (struct mxs_i2c_regs *)MXS_I2C0_BASE;
uint32_t tmp = 0;
+ int timeout = MXS_I2C_MAX_TIMEOUT;
int ret;
int i;
- mxs_i2c_write(chip, addr, alen, NULL, 0, 0);
+ ret = mxs_i2c_write(chip, addr, alen, NULL, 0, 0);
+ if (ret) {
+ debug("MXS I2C: Failed writing address\n");
+ return ret;
+ }
+
ret = mxs_i2c_wait_for_ack();
if (ret) {
debug("MXS I2C: Failed writing address\n");
for (i = 0; i < len; i++) {
if (!(i & 3)) {
- while (readl(&i2c_regs->hw_i2c_queuestat) &
- I2C_QUEUESTAT_RD_QUEUE_EMPTY)
- ;
+ while (--timeout) {
+ tmp = readl(&i2c_regs->hw_i2c_queuestat);
+ if (!(tmp & I2C_QUEUESTAT_RD_QUEUE_EMPTY))
+ break;
+ }
+
+ if (!timeout) {
+ debug("MXS I2C: Failed receiving data!\n");
+ return -ETIMEDOUT;
+ }
+
tmp = readl(&i2c_regs->hw_i2c_queuedata);
}
buffer[i] = tmp & 0xff;
int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
{
int ret;
- mxs_i2c_write(chip, addr, alen, buffer, len, 1);
+ ret = mxs_i2c_write(chip, addr, alen, buffer, len, 1);
+ if (ret) {
+ debug("MXS I2C: Failed writing address\n");
+ return ret;
+ }
+
ret = mxs_i2c_wait_for_ack();
if (ret)
debug("MXS I2C: Failed writing address\n");
int i2c_probe(uchar chip)
{
int ret;
- mxs_i2c_write(chip, 0, 1, NULL, 0, 1);
- ret = mxs_i2c_wait_for_ack();
+ ret = mxs_i2c_write(chip, 0, 1, NULL, 0, 1);
+ if (!ret)
+ ret = mxs_i2c_wait_for_ack();
mxs_i2c_reset();
return ret;
}
-void i2c_init(int speed, int slaveadd)
+int i2c_set_bus_speed(unsigned int speed)
{
struct mxs_i2c_regs *i2c_regs = (struct mxs_i2c_regs *)MXS_I2C0_BASE;
+ /*
+ * The timing derivation algorithm. There is no documentation for this
+ * algorithm available, it was derived by using the scope and fiddling
+ * with constants until the result observed on the scope was good enough
+ * for 20kHz, 50kHz, 100kHz, 200kHz, 300kHz and 400kHz. It should be
+ * possible to assume the algorithm works for other frequencies as well.
+ *
+ * Note it was necessary to cap the frequency on both ends as it's not
+ * possible to configure completely arbitrary frequency for the I2C bus
+ * clock.
+ */
+ uint32_t clk = mxc_get_clock(MXC_XTAL_CLK);
+ uint32_t base = ((clk / speed) - 38) / 2;
+ uint16_t high_count = base + 3;
+ uint16_t low_count = base - 3;
+ uint16_t rcv_count = (high_count * 3) / 4;
+ uint16_t xmit_count = low_count / 4;
+
+ if (speed > 540000) {
+ printf("MXS I2C: Speed too high (%d Hz)\n", speed);
+ return -EINVAL;
+ }
- mxs_i2c_reset();
-
- switch (speed) {
- case 100000:
- writel((0x0078 << I2C_TIMING0_HIGH_COUNT_OFFSET) |
- (0x0030 << I2C_TIMING0_RCV_COUNT_OFFSET),
- &i2c_regs->hw_i2c_timing0);
- writel((0x0080 << I2C_TIMING1_LOW_COUNT_OFFSET) |
- (0x0030 << I2C_TIMING1_XMIT_COUNT_OFFSET),
- &i2c_regs->hw_i2c_timing1);
- break;
- case 400000:
- writel((0x000f << I2C_TIMING0_HIGH_COUNT_OFFSET) |
- (0x0007 << I2C_TIMING0_RCV_COUNT_OFFSET),
- &i2c_regs->hw_i2c_timing0);
- writel((0x001f << I2C_TIMING1_LOW_COUNT_OFFSET) |
- (0x000f << I2C_TIMING1_XMIT_COUNT_OFFSET),
- &i2c_regs->hw_i2c_timing1);
- break;
- default:
- printf("MXS I2C: Invalid speed selected (%d Hz)\n", speed);
- return;
+ if (speed < 12000) {
+ printf("MXS I2C: Speed too low (%d Hz)\n", speed);
+ return -EINVAL;
}
- writel((0x0015 << I2C_TIMING2_BUS_FREE_OFFSET) |
- (0x000d << I2C_TIMING2_LEADIN_COUNT_OFFSET),
+ writel((high_count << 16) | rcv_count, &i2c_regs->hw_i2c_timing0);
+ writel((low_count << 16) | xmit_count, &i2c_regs->hw_i2c_timing1);
+
+ writel((0x0030 << I2C_TIMING2_BUS_FREE_OFFSET) |
+ (0x0030 << I2C_TIMING2_LEADIN_COUNT_OFFSET),
&i2c_regs->hw_i2c_timing2);
+ return 0;
+}
+
+unsigned int i2c_get_bus_speed(void)
+{
+ struct mxs_i2c_regs *i2c_regs = (struct mxs_i2c_regs *)MXS_I2C0_BASE;
+ uint32_t clk = mxc_get_clock(MXC_XTAL_CLK);
+ uint32_t timing0;
+
+ timing0 = readl(&i2c_regs->hw_i2c_timing0);
+ /*
+ * This is a reverse version of the algorithm presented in
+ * i2c_set_bus_speed(). Please refer there for details.
+ */
+ return clk / ((((timing0 >> 16) - 3) * 2) + 38);
+}
+
+void i2c_init(int speed, int slaveadd)
+{
+ mxs_i2c_reset();
+ i2c_set_bus_speed(speed);
+
return;
}
projects / karo-tx-uboot.git / blobdiff