summaryrefslogtreecommitdiffstats
path: root/drivers/i2c/algos/i2c-algo-pca.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/i2c/algos/i2c-algo-pca.c')
-rw-r--r--drivers/i2c/algos/i2c-algo-pca.c561
1 files changed, 561 insertions, 0 deletions
diff --git a/drivers/i2c/algos/i2c-algo-pca.c b/drivers/i2c/algos/i2c-algo-pca.c
new file mode 100644
index 000000000..384af88e5
--- /dev/null
+++ b/drivers/i2c/algos/i2c-algo-pca.c
@@ -0,0 +1,561 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters
+ * Copyright (C) 2004 Arcom Control Systems
+ * Copyright (C) 2008 Pengutronix
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/delay.h>
+#include <linux/jiffies.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/i2c-algo-pca.h>
+
+#define DEB1(fmt, args...) do { if (i2c_debug >= 1) \
+ printk(KERN_DEBUG fmt, ## args); } while (0)
+#define DEB2(fmt, args...) do { if (i2c_debug >= 2) \
+ printk(KERN_DEBUG fmt, ## args); } while (0)
+#define DEB3(fmt, args...) do { if (i2c_debug >= 3) \
+ printk(KERN_DEBUG fmt, ## args); } while (0)
+
+static int i2c_debug;
+
+#define pca_outw(adap, reg, val) adap->write_byte(adap->data, reg, val)
+#define pca_inw(adap, reg) adap->read_byte(adap->data, reg)
+
+#define pca_status(adap) pca_inw(adap, I2C_PCA_STA)
+#define pca_clock(adap) adap->i2c_clock
+#define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val)
+#define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON)
+#define pca_wait(adap) adap->wait_for_completion(adap->data)
+
+static void pca_reset(struct i2c_algo_pca_data *adap)
+{
+ if (adap->chip == I2C_PCA_CHIP_9665) {
+ /* Ignore the reset function from the module,
+ * we can use the parallel bus reset.
+ */
+ pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IPRESET);
+ pca_outw(adap, I2C_PCA_IND, 0xA5);
+ pca_outw(adap, I2C_PCA_IND, 0x5A);
+
+ /*
+ * After a reset we need to re-apply any configuration
+ * (calculated in pca_init) to get the bus in a working state.
+ */
+ pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IMODE);
+ pca_outw(adap, I2C_PCA_IND, adap->bus_settings.mode);
+ pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_ISCLL);
+ pca_outw(adap, I2C_PCA_IND, adap->bus_settings.tlow);
+ pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_ISCLH);
+ pca_outw(adap, I2C_PCA_IND, adap->bus_settings.thi);
+
+ pca_set_con(adap, I2C_PCA_CON_ENSIO);
+ } else {
+ adap->reset_chip(adap->data);
+ pca_set_con(adap, I2C_PCA_CON_ENSIO | adap->bus_settings.clock_freq);
+ }
+}
+
+/*
+ * Generate a start condition on the i2c bus.
+ *
+ * returns after the start condition has occurred
+ */
+static int pca_start(struct i2c_algo_pca_data *adap)
+{
+ int sta = pca_get_con(adap);
+ DEB2("=== START\n");
+ sta |= I2C_PCA_CON_STA;
+ sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
+ pca_set_con(adap, sta);
+ return pca_wait(adap);
+}
+
+/*
+ * Generate a repeated start condition on the i2c bus
+ *
+ * return after the repeated start condition has occurred
+ */
+static int pca_repeated_start(struct i2c_algo_pca_data *adap)
+{
+ int sta = pca_get_con(adap);
+ DEB2("=== REPEATED START\n");
+ sta |= I2C_PCA_CON_STA;
+ sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
+ pca_set_con(adap, sta);
+ return pca_wait(adap);
+}
+
+/*
+ * Generate a stop condition on the i2c bus
+ *
+ * returns after the stop condition has been generated
+ *
+ * STOPs do not generate an interrupt or set the SI flag, since the
+ * part returns the idle state (0xf8). Hence we don't need to
+ * pca_wait here.
+ */
+static void pca_stop(struct i2c_algo_pca_data *adap)
+{
+ int sta = pca_get_con(adap);
+ DEB2("=== STOP\n");
+ sta |= I2C_PCA_CON_STO;
+ sta &= ~(I2C_PCA_CON_STA|I2C_PCA_CON_SI);
+ pca_set_con(adap, sta);
+}
+
+/*
+ * Send the slave address and R/W bit
+ *
+ * returns after the address has been sent
+ */
+static int pca_address(struct i2c_algo_pca_data *adap,
+ struct i2c_msg *msg)
+{
+ int sta = pca_get_con(adap);
+ int addr = i2c_8bit_addr_from_msg(msg);
+
+ DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n",
+ msg->addr, msg->flags & I2C_M_RD ? 'R' : 'W', addr);
+
+ pca_outw(adap, I2C_PCA_DAT, addr);
+
+ sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
+ pca_set_con(adap, sta);
+
+ return pca_wait(adap);
+}
+
+/*
+ * Transmit a byte.
+ *
+ * Returns after the byte has been transmitted
+ */
+static int pca_tx_byte(struct i2c_algo_pca_data *adap,
+ __u8 b)
+{
+ int sta = pca_get_con(adap);
+ DEB2("=== WRITE %#04x\n", b);
+ pca_outw(adap, I2C_PCA_DAT, b);
+
+ sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
+ pca_set_con(adap, sta);
+
+ return pca_wait(adap);
+}
+
+/*
+ * Receive a byte
+ *
+ * returns immediately.
+ */
+static void pca_rx_byte(struct i2c_algo_pca_data *adap,
+ __u8 *b, int ack)
+{
+ *b = pca_inw(adap, I2C_PCA_DAT);
+ DEB2("=== READ %#04x %s\n", *b, ack ? "ACK" : "NACK");
+}
+
+/*
+ * Setup ACK or NACK for next received byte and wait for it to arrive.
+ *
+ * Returns after next byte has arrived.
+ */
+static int pca_rx_ack(struct i2c_algo_pca_data *adap,
+ int ack)
+{
+ int sta = pca_get_con(adap);
+
+ sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI|I2C_PCA_CON_AA);
+
+ if (ack)
+ sta |= I2C_PCA_CON_AA;
+
+ pca_set_con(adap, sta);
+ return pca_wait(adap);
+}
+
+static int pca_xfer(struct i2c_adapter *i2c_adap,
+ struct i2c_msg *msgs,
+ int num)
+{
+ struct i2c_algo_pca_data *adap = i2c_adap->algo_data;
+ struct i2c_msg *msg = NULL;
+ int curmsg;
+ int numbytes = 0;
+ int state;
+ int ret;
+ int completed = 1;
+ unsigned long timeout = jiffies + i2c_adap->timeout;
+
+ while ((state = pca_status(adap)) != 0xf8) {
+ if (time_before(jiffies, timeout)) {
+ msleep(10);
+ } else {
+ dev_dbg(&i2c_adap->dev, "bus is not idle. status is "
+ "%#04x\n", state);
+ return -EBUSY;
+ }
+ }
+
+ DEB1("{{{ XFER %d messages\n", num);
+
+ if (i2c_debug >= 2) {
+ for (curmsg = 0; curmsg < num; curmsg++) {
+ int addr, i;
+ msg = &msgs[curmsg];
+
+ addr = (0x7f & msg->addr) ;
+
+ if (msg->flags & I2C_M_RD)
+ printk(KERN_INFO " [%02d] RD %d bytes from %#02x [%#02x, ...]\n",
+ curmsg, msg->len, addr, (addr << 1) | 1);
+ else {
+ printk(KERN_INFO " [%02d] WR %d bytes to %#02x [%#02x%s",
+ curmsg, msg->len, addr, addr << 1,
+ msg->len == 0 ? "" : ", ");
+ for (i = 0; i < msg->len; i++)
+ printk("%#04x%s", msg->buf[i], i == msg->len - 1 ? "" : ", ");
+ printk("]\n");
+ }
+ }
+ }
+
+ curmsg = 0;
+ ret = -EIO;
+ while (curmsg < num) {
+ state = pca_status(adap);
+
+ DEB3("STATE is 0x%02x\n", state);
+ msg = &msgs[curmsg];
+
+ switch (state) {
+ case 0xf8: /* On reset or stop the bus is idle */
+ completed = pca_start(adap);
+ break;
+
+ case 0x08: /* A START condition has been transmitted */
+ case 0x10: /* A repeated start condition has been transmitted */
+ completed = pca_address(adap, msg);
+ break;
+
+ case 0x18: /* SLA+W has been transmitted; ACK has been received */
+ case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */
+ if (numbytes < msg->len) {
+ completed = pca_tx_byte(adap,
+ msg->buf[numbytes]);
+ numbytes++;
+ break;
+ }
+ curmsg++; numbytes = 0;
+ if (curmsg == num)
+ pca_stop(adap);
+ else
+ completed = pca_repeated_start(adap);
+ break;
+
+ case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */
+ DEB2("NOT ACK received after SLA+W\n");
+ pca_stop(adap);
+ ret = -ENXIO;
+ goto out;
+
+ case 0x40: /* SLA+R has been transmitted; ACK has been received */
+ completed = pca_rx_ack(adap, msg->len > 1);
+ break;
+
+ case 0x50: /* Data bytes has been received; ACK has been returned */
+ if (numbytes < msg->len) {
+ pca_rx_byte(adap, &msg->buf[numbytes], 1);
+ numbytes++;
+ completed = pca_rx_ack(adap,
+ numbytes < msg->len - 1);
+ break;
+ }
+ curmsg++; numbytes = 0;
+ if (curmsg == num)
+ pca_stop(adap);
+ else
+ completed = pca_repeated_start(adap);
+ break;
+
+ case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */
+ DEB2("NOT ACK received after SLA+R\n");
+ pca_stop(adap);
+ ret = -ENXIO;
+ goto out;
+
+ case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */
+ DEB2("NOT ACK received after data byte\n");
+ pca_stop(adap);
+ goto out;
+
+ case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */
+ DEB2("Arbitration lost\n");
+ /*
+ * The PCA9564 data sheet (2006-09-01) says "A
+ * START condition will be transmitted when the
+ * bus becomes free (STOP or SCL and SDA high)"
+ * when the STA bit is set (p. 11).
+ *
+ * In case this won't work, try pca_reset()
+ * instead.
+ */
+ pca_start(adap);
+ goto out;
+
+ case 0x58: /* Data byte has been received; NOT ACK has been returned */
+ if (numbytes == msg->len - 1) {
+ pca_rx_byte(adap, &msg->buf[numbytes], 0);
+ curmsg++; numbytes = 0;
+ if (curmsg == num)
+ pca_stop(adap);
+ else
+ completed = pca_repeated_start(adap);
+ } else {
+ DEB2("NOT ACK sent after data byte received. "
+ "Not final byte. numbytes %d. len %d\n",
+ numbytes, msg->len);
+ pca_stop(adap);
+ goto out;
+ }
+ break;
+ case 0x70: /* Bus error - SDA stuck low */
+ DEB2("BUS ERROR - SDA Stuck low\n");
+ pca_reset(adap);
+ goto out;
+ case 0x78: /* Bus error - SCL stuck low (PCA9665) */
+ case 0x90: /* Bus error - SCL stuck low (PCA9564) */
+ DEB2("BUS ERROR - SCL Stuck low\n");
+ pca_reset(adap);
+ goto out;
+ case 0x00: /* Bus error during master or slave mode due to illegal START or STOP condition */
+ DEB2("BUS ERROR - Illegal START or STOP\n");
+ pca_reset(adap);
+ goto out;
+ default:
+ dev_err(&i2c_adap->dev, "unhandled SIO state 0x%02x\n", state);
+ break;
+ }
+
+ if (!completed)
+ goto out;
+ }
+
+ ret = curmsg;
+ out:
+ DEB1("}}} transferred %d/%d messages. "
+ "status is %#04x. control is %#04x\n",
+ curmsg, num, pca_status(adap),
+ pca_get_con(adap));
+ return ret;
+}
+
+static u32 pca_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm pca_algo = {
+ .master_xfer = pca_xfer,
+ .functionality = pca_func,
+};
+
+static unsigned int pca_probe_chip(struct i2c_adapter *adap)
+{
+ struct i2c_algo_pca_data *pca_data = adap->algo_data;
+ /* The trick here is to check if there is an indirect register
+ * available. If there is one, we will read the value we first
+ * wrote on I2C_PCA_IADR. Otherwise, we will read the last value
+ * we wrote on I2C_PCA_ADR
+ */
+ pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR);
+ pca_outw(pca_data, I2C_PCA_IND, 0xAA);
+ pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ITO);
+ pca_outw(pca_data, I2C_PCA_IND, 0x00);
+ pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR);
+ if (pca_inw(pca_data, I2C_PCA_IND) == 0xAA) {
+ printk(KERN_INFO "%s: PCA9665 detected.\n", adap->name);
+ pca_data->chip = I2C_PCA_CHIP_9665;
+ } else {
+ printk(KERN_INFO "%s: PCA9564 detected.\n", adap->name);
+ pca_data->chip = I2C_PCA_CHIP_9564;
+ }
+ return pca_data->chip;
+}
+
+static int pca_init(struct i2c_adapter *adap)
+{
+ struct i2c_algo_pca_data *pca_data = adap->algo_data;
+
+ adap->algo = &pca_algo;
+
+ if (pca_probe_chip(adap) == I2C_PCA_CHIP_9564) {
+ static int freqs[] = {330, 288, 217, 146, 88, 59, 44, 36};
+ int clock;
+
+ if (pca_data->i2c_clock > 7) {
+ switch (pca_data->i2c_clock) {
+ case 330000:
+ pca_data->i2c_clock = I2C_PCA_CON_330kHz;
+ break;
+ case 288000:
+ pca_data->i2c_clock = I2C_PCA_CON_288kHz;
+ break;
+ case 217000:
+ pca_data->i2c_clock = I2C_PCA_CON_217kHz;
+ break;
+ case 146000:
+ pca_data->i2c_clock = I2C_PCA_CON_146kHz;
+ break;
+ case 88000:
+ pca_data->i2c_clock = I2C_PCA_CON_88kHz;
+ break;
+ case 59000:
+ pca_data->i2c_clock = I2C_PCA_CON_59kHz;
+ break;
+ case 44000:
+ pca_data->i2c_clock = I2C_PCA_CON_44kHz;
+ break;
+ case 36000:
+ pca_data->i2c_clock = I2C_PCA_CON_36kHz;
+ break;
+ default:
+ printk(KERN_WARNING
+ "%s: Invalid I2C clock speed selected."
+ " Using default 59kHz.\n", adap->name);
+ pca_data->i2c_clock = I2C_PCA_CON_59kHz;
+ }
+ } else {
+ printk(KERN_WARNING "%s: "
+ "Choosing the clock frequency based on "
+ "index is deprecated."
+ " Use the nominal frequency.\n", adap->name);
+ }
+
+ clock = pca_clock(pca_data);
+ printk(KERN_INFO "%s: Clock frequency is %dkHz\n",
+ adap->name, freqs[clock]);
+
+ /* Store settings as these will be needed when the PCA chip is reset */
+ pca_data->bus_settings.clock_freq = clock;
+
+ pca_reset(pca_data);
+ } else {
+ int clock;
+ int mode;
+ int tlow, thi;
+ /* Values can be found on PCA9665 datasheet section 7.3.2.6 */
+ int min_tlow, min_thi;
+ /* These values are the maximum raise and fall values allowed
+ * by the I2C operation mode (Standard, Fast or Fast+)
+ * They are used (added) below to calculate the clock dividers
+ * of PCA9665. Note that they are slightly different of the
+ * real maximum, to allow the change on mode exactly on the
+ * maximum clock rate for each mode
+ */
+ int raise_fall_time;
+
+ if (pca_data->i2c_clock > 1265800) {
+ printk(KERN_WARNING "%s: I2C clock speed too high."
+ " Using 1265.8kHz.\n", adap->name);
+ pca_data->i2c_clock = 1265800;
+ }
+
+ if (pca_data->i2c_clock < 60300) {
+ printk(KERN_WARNING "%s: I2C clock speed too low."
+ " Using 60.3kHz.\n", adap->name);
+ pca_data->i2c_clock = 60300;
+ }
+
+ /* To avoid integer overflow, use clock/100 for calculations */
+ clock = pca_clock(pca_data) / 100;
+
+ if (pca_data->i2c_clock > I2C_MAX_FAST_MODE_PLUS_FREQ) {
+ mode = I2C_PCA_MODE_TURBO;
+ min_tlow = 14;
+ min_thi = 5;
+ raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */
+ } else if (pca_data->i2c_clock > I2C_MAX_FAST_MODE_FREQ) {
+ mode = I2C_PCA_MODE_FASTP;
+ min_tlow = 17;
+ min_thi = 9;
+ raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */
+ } else if (pca_data->i2c_clock > I2C_MAX_STANDARD_MODE_FREQ) {
+ mode = I2C_PCA_MODE_FAST;
+ min_tlow = 44;
+ min_thi = 20;
+ raise_fall_time = 58; /* Raise 29e-8s, Fall 29e-8s */
+ } else {
+ mode = I2C_PCA_MODE_STD;
+ min_tlow = 157;
+ min_thi = 134;
+ raise_fall_time = 127; /* Raise 29e-8s, Fall 98e-8s */
+ }
+
+ /* The minimum clock that respects the thi/tlow = 134/157 is
+ * 64800 Hz. Below that, we have to fix the tlow to 255 and
+ * calculate the thi factor.
+ */
+ if (clock < 648) {
+ tlow = 255;
+ thi = 1000000 - clock * raise_fall_time;
+ thi /= (I2C_PCA_OSC_PER * clock) - tlow;
+ } else {
+ tlow = (1000000 - clock * raise_fall_time) * min_tlow;
+ tlow /= I2C_PCA_OSC_PER * clock * (min_thi + min_tlow);
+ thi = tlow * min_thi / min_tlow;
+ }
+
+ /* Store settings as these will be needed when the PCA chip is reset */
+ pca_data->bus_settings.mode = mode;
+ pca_data->bus_settings.tlow = tlow;
+ pca_data->bus_settings.thi = thi;
+
+ pca_reset(pca_data);
+
+ printk(KERN_INFO
+ "%s: Clock frequency is %dHz\n", adap->name, clock * 100);
+ }
+ udelay(500); /* 500 us for oscillator to stabilise */
+
+ return 0;
+}
+
+/*
+ * registering functions to load algorithms at runtime
+ */
+int i2c_pca_add_bus(struct i2c_adapter *adap)
+{
+ int rval;
+
+ rval = pca_init(adap);
+ if (rval)
+ return rval;
+
+ return i2c_add_adapter(adap);
+}
+EXPORT_SYMBOL(i2c_pca_add_bus);
+
+int i2c_pca_add_numbered_bus(struct i2c_adapter *adap)
+{
+ int rval;
+
+ rval = pca_init(adap);
+ if (rval)
+ return rval;
+
+ return i2c_add_numbered_adapter(adap);
+}
+EXPORT_SYMBOL(i2c_pca_add_numbered_bus);
+
+MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
+MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
+MODULE_DESCRIPTION("I2C-Bus PCA9564/PCA9665 algorithm");
+MODULE_LICENSE("GPL");
+
+module_param(i2c_debug, int, 0);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 09:05:59 +0000