i2c-algo-pca: Add PCA9665 support

Add support for the PCA9665 I2C controller.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 166 insertions, 14 deletions

diff --git a/drivers/i2c/algos/i2c-algo-pca.c b/drivers/i2c/algos/i2c-algo-pca.c
index 943d70ee5d59..a8e51bd1a4f5 100644
--- a/drivers/i2c/algos/i2c-algo-pca.c
+++ b/drivers/i2c/algos/i2c-algo-pca.c
@@ -46,6 +46,14 @@ static int i2c_debug;
 #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.
  *
@@ -333,27 +341,171 @@ static const struct i2c_algorithm pca_algo = {
         .functionality  = pca_func,
 };
 
-static int pca_init(struct i2c_adapter *adap)
+static unsigned int pca_probe_chip(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;
+        /* 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)
+{
+        struct i2c_algo_pca_data *pca_data = adap->algo_data;
 
         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;
+
+                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_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);
 
-        clock = pca_clock(pca_data);
-        printk(KERN_INFO "%s: Clock frequency is %dkHz\n", adap->name,
-               freqs[clock]);
+                printk(KERN_INFO
+                     "%s: Clock frequency is %dHz\n", adap->name, clock * 100);
 
-        pca_set_con(pca_data, I2C_PCA_CON_ENSIO | clock);
+                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;
@@ -388,7 +540,7 @@ EXPORT_SYMBOL(i2c_pca_add_numbered_bus);
 
 MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>, "
         "Wolfram Sang <w.sang@pengutronix.de>");
-MODULE_DESCRIPTION("I2C-Bus PCA9564 algorithm");
+MODULE_DESCRIPTION("I2C-Bus PCA9564/PCA9665 algorithm");
 MODULE_LICENSE("GPL");
 
 module_param(i2c_debug, int, 0);