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    Subject[PATCH 19/24] pm2301: LPN mode control support
    Date
    From: Rupesh Kumar <rupesh.kumar@stericsson.com>

    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: Lee Jones <lee.jones@linaro.org>
    Signed-off-by: Rupesh Kumar <rupesh.kumar@stericsson.com>
    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>
    ---
    drivers/power/pm2301_charger.c | 72 ++++++++++++++++++++++++++++++++++++++--
    drivers/power/pm2301_charger.h | 1 +
    include/linux/pm2301_charger.h | 1 +
    3 files changed, 71 insertions(+), 3 deletions(-)

    diff --git a/drivers/power/pm2301_charger.c b/drivers/power/pm2301_charger.c
    index c7d92b3..14e37b2 100644
    --- 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;
    +}
    +
    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 @@ 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 @@ int pm2xxx_reg_read(struct pm2xxx_charger *pm2, int reg, u8 *val)
    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 @@ 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) {
    @@ -951,7 +1013,8 @@ static int __devinit pm2xxx_wall_charger_probe(struct i2c_client *i2c_client,
    err_deep_debug:
    /* disable interrupt */
    free_irq(pm2->pdata->irq_number, pm2);
    -
    +free_gpio:
    + gpio_free(pm2->lpn_pin);
    unregister_pm2xxx_charger:
    /* unregister power supply */
    power_supply_unregister(&pm2->ac_chg.psy);
    @@ -987,6 +1050,9 @@ 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 5ae3573..c28babc 100644
    --- 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
    --- 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;
    };

    --
    1.7.9.5


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