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);