i2c-algo-pca: Add PCA9665 support

Add support for the PCA9665 I2C controller.

Signed-off-by: Wolfram Sang <[e-mail]>
Signed-off-by: Jean Delvare <[e-mail]>

drivers/i2c/algos/i2c-algo-pca.c

···
 #define pca_wait(adap) adap->wait_for_completion(adap->data)
 #define pca_reset(adap) adap->reset_chip(adap->data)
 
+static void pca9665_reset(void *pd)
+{
+	struct i2c_algo_pca_data *adap = pd;
+	pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IPRESET);
+	pca_outw(adap, I2C_PCA_IND, 0xA5);
+	pca_outw(adap, I2C_PCA_IND, 0x5A);
+}
+
 /*
  * Generate a start condition on the i2c bus.
  *
···
 	.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);
+		return I2C_PCA_CHIP_9665;
+	} else {
+		printk(KERN_INFO "%s: PCA9564 detected.\n", adap->name);
+		return I2C_PCA_CHIP_9564;
+	}
+}
+
 static int pca_init(struct i2c_adapter *adap)
 {
-	static int freqs[] = {330,288,217,146,88,59,44,36};
-	int clock;
 	struct i2c_algo_pca_data *pca_data = adap->algo_data;
-
-	if (pca_data->i2c_clock > 7) {
-		printk(KERN_WARNING "%s: Invalid I2C clock speed selected. Trying default.\n",
-			adap->name);
-		pca_data->i2c_clock = I2C_PCA_CON_59kHz;
-	}
 
 	adap->algo = &pca_algo;
 
-	pca_reset(pca_data);
+	if (pca_probe_chip(adap) == I2C_PCA_CHIP_9564) {
+		static int freqs[] = {330, 288, 217, 146, 88, 59, 44, 36};
+		int clock;
 
-	clock = pca_clock(pca_data);
-	printk(KERN_INFO "%s: Clock frequency is %dkHz\n", adap->name,
-	       freqs[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);
+		}
 
-	pca_set_con(pca_data, I2C_PCA_CON_ENSIO | clock);
+		pca_reset(pca_data);
+
+		clock = pca_clock(pca_data);
+		printk(KERN_INFO "%s: Clock frequency is %dkHz\n",
+		     adap->name, freqs[clock]);
+
+		pca_set_con(pca_data, I2C_PCA_CON_ENSIO | clock);
+	} 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;
+
+		struct i2c_algo_pca_data *pca_data = adap->algo_data;
+
+		/* Ignore the reset function from the module,
+		 * we can use the parallel bus reset
+		 */
+		pca_data->reset_chip = pca9665_reset;
+
+		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 > 10000) {
+			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 > 4000) {
+			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 > 1000) {
+			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;
+		}
+
+		pca_reset(pca_data);
+
+		printk(KERN_INFO
+		     "%s: Clock frequency is %dHz\n", adap->name, clock * 100);
+
+		pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IMODE);
+		pca_outw(pca_data, I2C_PCA_IND, mode);
+		pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLL);
+		pca_outw(pca_data, I2C_PCA_IND, tlow);
+		pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLH);
+		pca_outw(pca_data, I2C_PCA_IND, thi);
+
+		pca_set_con(pca_data, I2C_PCA_CON_ENSIO);
+	}
 	udelay(500); /* 500 us for oscilator to stabilise */
 
 	return 0;
···
 
 MODULE_AUTHOR("Ian Campbell <[e-mail]>, "
 	"Wolfram Sang <[e-mail]>");
-MODULE_DESCRIPTION("I2C-Bus PCA9564 algorithm");
+MODULE_DESCRIPTION("I2C-Bus PCA9564/PCA9665 algorithm");
 MODULE_LICENSE("GPL");
 
 module_param(i2c_debug, int, 0);

drivers/i2c/busses/Kconfig

···
 	  will be called i2c-elektor.
 
 config I2C_PCA_ISA
-	tristate "PCA9564 on an ISA bus"
+	tristate "PCA9564/PCA9665 on an ISA bus"
 	depends on ISA
 	select I2C_ALGOPCA
 	default n
 	help
-	  This driver supports ISA boards using the Philips PCA9564
+	  This driver supports ISA boards using the Philips PCA9564/PCA9665
 	  parallel bus to I2C bus controller.
 
 	  This driver can also be built as a module.  If so, the module
···
 	  time).  If unsure, say N.
 
 config I2C_PCA_PLATFORM
-	tristate "PCA9564 as platform device"
+	tristate "PCA9564/PCA9665 as platform device"
 	select I2C_ALGOPCA
 	default n
 	help
-	  This driver supports a memory mapped Philips PCA9564
+	  This driver supports a memory mapped Philips PCA9564/PCA9665
 	  parallel bus to I2C bus controller.
 
 	  This driver can also be built as a module.  If so, the module

drivers/i2c/busses/i2c-pca-isa.c

···
 
 /* Data sheet recommends 59kHz for 100kHz operation due to variation
  * in the actual clock rate */
-static int clock  = I2C_PCA_CON_59kHz;
+static int clock  = 59000;
 
 static wait_queue_head_t pca_wait;
 
···
 static struct i2c_adapter pca_isa_ops = {
 	.owner          = THIS_MODULE,
 	.algo_data	= &pca_isa_data,
-	.name		= "PCA9564 ISA Adapter",
+	.name		= "PCA9564/PCA9665 ISA Adapter",
 	.timeout	= 100,
 };
 
···
 }
 
 MODULE_AUTHOR("Ian Campbell <[e-mail]>");
-MODULE_DESCRIPTION("ISA base PCA9564 driver");
+MODULE_DESCRIPTION("ISA base PCA9564/PCA9665 driver");
 MODULE_LICENSE("GPL");
 
 module_param(base, ulong, 0);
···
 module_param(irq, int, 0);
 MODULE_PARM_DESC(irq, "IRQ");
 module_param(clock, int, 0);
-MODULE_PARM_DESC(clock, "Clock rate as described in table 1 of PCA9564 datasheet");
+MODULE_PARM_DESC(clock, "Clock rate in hertz.\n\t\t"
+		"For PCA9564: 330000,288000,217000,146000,"
+		"88000,59000,44000,36000\n"
+		"\t\tFor PCA9665:\tStandard: 60300 - 100099\n"
+		"\t\t\t\tFast: 100100 - 400099\n"
+		"\t\t\t\tFast+: 400100 - 10000099\n"
+		"\t\t\t\tTurbo: Up to 1265800");
 
 module_init(pca_isa_init);
 module_exit(pca_isa_exit);

drivers/i2c/busses/i2c-pca-platform.c

···
 
 	i2c->adap.nr = pdev->id >= 0 ? pdev->id : 0;
 	i2c->adap.owner = THIS_MODULE;
-	snprintf(i2c->adap.name, sizeof(i2c->adap.name), "PCA9564 at 0x%08lx",
-		(unsigned long) res->start);
+	snprintf(i2c->adap.name, sizeof(i2c->adap.name),
+		 "PCA9564/PCA9665 at 0x%08lx",
+		 (unsigned long) res->start);
 	i2c->adap.algo_data = &i2c->algo_data;
 	i2c->adap.dev.parent = &pdev->dev;
 	i2c->adap.timeout = platform_data->timeout;
···
 e_alloc:
 	release_mem_region(res->start, res_len(res));
 e_print:
-	printk(KERN_ERR "Registering PCA9564 FAILED! (%d)\n", ret);
+	printk(KERN_ERR "Registering PCA9564/PCA9665 FAILED! (%d)\n", ret);
 	return ret;
 }
 
···
 }
 
 MODULE_AUTHOR("Wolfram Sang <[e-mail]>");
-MODULE_DESCRIPTION("I2C-PCA9564 platform driver");
+MODULE_DESCRIPTION("I2C-PCA9564/PCA9665 platform driver");
 MODULE_LICENSE("GPL");
 
 module_init(i2c_pca_pf_init);

include/linux/i2c-algo-pca.h

···
 #ifndef _LINUX_I2C_ALGO_PCA_H
 #define _LINUX_I2C_ALGO_PCA_H
 
-/* Clock speeds for the bus */
+/* Chips known to the pca algo */
+#define I2C_PCA_CHIP_9564	0x00
+#define I2C_PCA_CHIP_9665	0x01
+
+/* Internal period for PCA9665 oscilator */
+#define I2C_PCA_OSC_PER		3 /* e10-8s */
+
+/* Clock speeds for the bus for PCA9564*/
 #define I2C_PCA_CON_330kHz	0x00
 #define I2C_PCA_CON_288kHz	0x01
 #define I2C_PCA_CON_217kHz	0x02
···
 #define I2C_PCA_ADR		0x02 /* OWN ADR Read/Write */
 #define I2C_PCA_CON		0x03 /* CONTROL Read/Write */
 
+/* PCA9665 registers */
+#define I2C_PCA_INDPTR          0x00 /* INDIRECT Pointer Write Only */
+#define I2C_PCA_IND             0x02 /* INDIRECT Read/Write */
+
+/* PCA9665 indirect registers */
+#define I2C_PCA_ICOUNT          0x00 /* Byte Count for buffered mode */
+#define I2C_PCA_IADR            0x01 /* OWN ADR */
+#define I2C_PCA_ISCLL           0x02 /* SCL LOW period */
+#define I2C_PCA_ISCLH           0x03 /* SCL HIGH period */
+#define I2C_PCA_ITO             0x04 /* TIMEOUT */
+#define I2C_PCA_IPRESET         0x05 /* Parallel bus reset */
+#define I2C_PCA_IMODE           0x06 /* I2C Bus mode */
+
+/* PCA9665 I2C bus mode */
+#define I2C_PCA_MODE_STD        0x00 /* Standard mode */
+#define I2C_PCA_MODE_FAST       0x01 /* Fast mode */
+#define I2C_PCA_MODE_FASTP      0x02 /* Fast Plus mode */
+#define I2C_PCA_MODE_TURBO      0x03 /* Turbo mode */
+
+
 #define I2C_PCA_CON_AA		0x80 /* Assert Acknowledge */
 #define I2C_PCA_CON_ENSIO	0x40 /* Enable */
 #define I2C_PCA_CON_STA		0x20 /* Start */
···
 	int  (*read_byte)		(void *data, int reg);
 	int  (*wait_for_completion)	(void *data);
 	void (*reset_chip)		(void *data);
-	/* i2c_clock values are defined in linux/i2c-algo-pca.h */
+	/* For PCA9564, use one of the predefined frequencies:
+	 * 330000, 288000, 217000, 146000, 88000, 59000, 44000, 36000
+	 * For PCA9665, use the frequency you want here. */
 	unsigned int			i2c_clock;
 };