pm2301: LPN mode control support

The AC charger plug-in detection while booting causes I2C read
failure if AC charger is not connected. Now the LPN pin is enabled
for every PM2301 register access, which solves the issue.

Signed-off-by: Rupesh Kumar <rupesh.kumar@stericsson.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Marcus COOPER <marcus.xm.cooper@stericsson.com>
Reviewed-by: Vijaya Kumar K-1 <vijay.kilari@stericsson.com>
Reviewed-by: Rabin VINCENT <rabin.vincent@stericsson.com>
Reviewed-by: Jonas ABERG <jonas.aberg@stericsson.com>
Tested-by: Jonas ABERG <jonas.aberg@stericsson.com>

diff --git a/drivers/power/pm2301_charger.c b/drivers/power/pm2301_charger.c
index 9b2e894..ed48d75 100644 (file)
--- a/drivers/power/pm2301_charger.c
+++ b/drivers/power/pm2301_charger.c
@@ -28,6 +28,7 @@
 #include <linux/mfd/abx500/ab8500-gpadc.h>
 #include <linux/mfd/abx500/ux500_chargalg.h>
 #include <linux/pm2301_charger.h>
+#include <linux/gpio.h>
 
 #include "pm2301_charger.h"
 
@@ -110,9 +111,35 @@ static const struct i2c_device_id pm2xxx_ident[] = {
        { }
 };
 
+static void set_lpn_pin(struct pm2xxx_charger *pm2)
+{
+       if (pm2->ac.charger_connected)
+               return;
+       gpio_set_value(pm2->lpn_pin, 1);
+
+       return;
+}
+
+static void clear_lpn_pin(struct pm2xxx_charger *pm2)
+{
+       if (pm2->ac.charger_connected)
+               return;
+       gpio_set_value(pm2->lpn_pin, 0);
+
+       return;
+}
+
 static int pm2xxx_reg_read(struct pm2xxx_charger *pm2, int reg, u8 *val)
 {
        int ret;
+       /*
+        * When AC adaptor is unplugged, the host
+        * must put LPN high to be able to
+        * communicate by I2C with PM2301
+        * and receive I2C "acknowledge" from PM2301.
+        */
+       mutex_lock(&pm2->lock);
+       set_lpn_pin(pm2);
 
        ret = i2c_smbus_read_i2c_block_data(pm2->config.pm2xxx_i2c, reg,
                                1, val);
@@ -120,6 +147,8 @@ static int pm2xxx_reg_read(struct pm2xxx_charger *pm2, int reg, u8 *val)
                dev_err(pm2->dev, "Error reading register at 0x%x\n", reg);
        else
                ret = 0;
+       clear_lpn_pin(pm2);
+       mutex_unlock(&pm2->lock);
 
        return ret;
 }
@@ -127,6 +156,14 @@ static int pm2xxx_reg_read(struct pm2xxx_charger *pm2, int reg, u8 *val)
 static int pm2xxx_reg_write(struct pm2xxx_charger *pm2, int reg, u8 val)
 {
        int ret;
+       /*
+        * When AC adaptor is unplugged, the host
+        * must put LPN high to be able to
+        * communicate by I2C with PM2301
+        * and receive I2C "acknowledge" from PM2301.
+        */
+       mutex_lock(&pm2->lock);
+       set_lpn_pin(pm2);
 
        ret = i2c_smbus_write_i2c_block_data(pm2->config.pm2xxx_i2c, reg,
                                1, &val);
@@ -134,6 +171,8 @@ static int pm2xxx_reg_write(struct pm2xxx_charger *pm2, int reg, u8 val)
                dev_err(pm2->dev, "Error writing register at 0x%x\n", reg);
        else
                ret = 0;
+       clear_lpn_pin(pm2);
+       mutex_unlock(&pm2->lock);
 
        return ret;
 }
@@ -850,6 +889,14 @@ static int __devinit pm2xxx_wall_charger_probe(struct i2c_client *i2c_client,
 
        pm2->bat = pl_data->battery;
 
+       /*get lpn GPIO from platform data*/
+       if (!pm2->pdata->lpn_gpio) {
+               dev_err(pm2->dev, "no lpn gpio data supplied\n");
+               ret = -EINVAL;
+               goto free_device_info;
+       }
+       pm2->lpn_pin = pm2->pdata->lpn_gpio;
+
        if (!i2c_check_functionality(i2c_client->adapter,
                        I2C_FUNC_SMBUS_BYTE_DATA |
                        I2C_FUNC_SMBUS_READ_WORD_DATA)) {
@@ -929,10 +976,25 @@ static int __devinit pm2xxx_wall_charger_probe(struct i2c_client *i2c_client,
                goto unregister_pm2xxx_charger;
        }
 
+       /*Initialize lock*/
+       mutex_init(&pm2->lock);
+
        /*
-        * I2C Read/Write will fail, if AC adaptor is not connected.
-        * fix the charger detection mechanism.
+        * Charger detection mechanism requires pulling up the LPN pin
+        * while i2c communication if Charger is not connected
+        * LPN pin of PM2301 is GPIO60 of AB9540
         */
+       ret = gpio_request(pm2->lpn_pin, "pm2301_lpm_gpio");
+       if (ret < 0) {
+               dev_err(pm2->dev, "pm2301_lpm_gpio request failed\n");
+               goto unregister_pm2xxx_charger;
+       }
+       ret = gpio_direction_output(pm2->lpn_pin, 0);
+       if (ret < 0) {
+               dev_err(pm2->dev, "pm2301_lpm_gpio direction failed\n");
+               goto free_gpio;
+       }
+
        ret = pm2xxx_charger_detection(pm2, &val);
 
        if ((ret == 0) && val) {
@@ -944,6 +1006,8 @@ static int __devinit pm2xxx_wall_charger_probe(struct i2c_client *i2c_client,
 
        return 0;
 
+free_gpio:
+       gpio_free(pm2->lpn_pin);
 unregister_pm2xxx_charger:
        /* unregister power supply */
        power_supply_unregister(&pm2->ac_chg.psy);
@@ -977,6 +1041,9 @@ static int __devexit pm2xxx_wall_charger_remove(struct i2c_client *i2c_client)
 
        power_supply_unregister(&pm2->ac_chg.psy);
 
+       /*Free GPIO60*/
+       gpio_free(pm2->lpn_pin);
+
        kfree(pm2);
 
        return 0;

diff --git a/drivers/power/pm2301_charger.h b/drivers/power/pm2301_charger.h
index 3531cc5..e6319cd 100644 (file)
--- a/drivers/power/pm2301_charger.h
+++ b/drivers/power/pm2301_charger.h
@@ -493,6 +493,7 @@ struct pm2xxx_charger {
        int old_vbat;
        int failure_case;
        int failure_input_ovv;
+       unsigned int lpn_pin;
        struct pm2xxx_interrupts *pm2_int;
        struct ab8500_gpadc *gpadc;
        struct regulator *regu;

diff --git a/include/linux/pm2301_charger.h b/include/linux/pm2301_charger.h
index 16bb1d3..fc3f026 100644 (file)
--- a/include/linux/pm2301_charger.h
+++ b/include/linux/pm2301_charger.h
@@ -49,6 +49,7 @@ struct pm2xxx_charger_platform_data {
        int i2c_bus;
        const char *label;
        int irq_number;
+       unsigned int lpn_gpio;
        int irq_type;
 };