linux/drivers/media/dvb-frontends/isl6421.c
Jemma Denson 214824156c media: isl6421: add checks for current overflow
This Kaffeine's BZ:
	https://bugs.kde.org/show_bug.cgi?id=374693

affects SkyStar S2 PCI DVB-S/S2 rev 3.3 device. It could be due to
a Kernel bug.

While checking the Isil 6421, comparing with its manual, available at:

	http://www.intersil.com/content/dam/Intersil/documents/isl6/isl6421a.pdf

It was noticed that, if the output load is highly capacitive, a different approach
is recomended when energizing the LNBf.

Also, it is possible to detect if a current overload is happening, by checking an
special flag.

Add support for it.

Tested on Skystar S2. Changes respect override_or option so should still work fine
on cx88 based cards which disable dynamic current limit.

Changes since v1:
v2 - fixed incorrect checking of i2c return values
v3 - fix if logic to check if dcl needs re-enabling
   - respect override_or values which aim to disable dcl
   - only do long sleep on overload if dcl enabled
   - add short sleep before re-enabling dcl
   - only check overload and potentially return EINVAL if device is on
v4 - revert v3 sleep logic changes to remove tuning delays

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jemma Denson <jdenson@gmail.com>
2017-08-20 10:20:30 -04:00

235 lines
5.6 KiB
C

/*
* isl6421.h - driver for lnb supply and control ic ISL6421
*
* Copyright (C) 2006 Andrew de Quincey
* Copyright (C) 2006 Oliver Endriss
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* To obtain the license, point your browser to
* http://www.gnu.org/copyleft/gpl.html
*
*
* the project's page is at https://linuxtv.org
*/
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/slab.h>
#include "dvb_frontend.h"
#include "isl6421.h"
struct isl6421 {
u8 config;
u8 override_or;
u8 override_and;
struct i2c_adapter *i2c;
u8 i2c_addr;
bool is_off;
};
static int isl6421_set_voltage(struct dvb_frontend *fe,
enum fe_sec_voltage voltage)
{
int ret;
u8 buf;
bool is_off;
struct isl6421 *isl6421 = (struct isl6421 *) fe->sec_priv;
struct i2c_msg msg[2] = {
{
.addr = isl6421->i2c_addr,
.flags = 0,
.buf = &isl6421->config,
.len = 1,
}, {
.addr = isl6421->i2c_addr,
.flags = I2C_M_RD,
.buf = &buf,
.len = 1,
}
};
isl6421->config &= ~(ISL6421_VSEL1 | ISL6421_EN1);
switch(voltage) {
case SEC_VOLTAGE_OFF:
is_off = true;
break;
case SEC_VOLTAGE_13:
is_off = false;
isl6421->config |= ISL6421_EN1;
break;
case SEC_VOLTAGE_18:
is_off = false;
isl6421->config |= (ISL6421_EN1 | ISL6421_VSEL1);
break;
default:
return -EINVAL;
}
/*
* If LNBf were not powered on, disable dynamic current limit, as,
* according with datasheet, highly capacitive load on the output may
* cause a difficult start-up.
*/
if (isl6421->is_off && !is_off)
isl6421->config |= ISL6421_DCL;
isl6421->config |= isl6421->override_or;
isl6421->config &= isl6421->override_and;
ret = i2c_transfer(isl6421->i2c, msg, 2);
if (ret < 0)
return ret;
if (ret != 2)
return -EIO;
/* Store off status now incase future commands fail */
isl6421->is_off = is_off;
/* On overflow, the device will try again after 900 ms (typically) */
if (!is_off && (buf & ISL6421_OLF1))
msleep(1000);
/* Re-enable dynamic current limit */
if ((isl6421->config & ISL6421_DCL) &&
!(isl6421->override_or & ISL6421_DCL)) {
isl6421->config &= ~ISL6421_DCL;
ret = i2c_transfer(isl6421->i2c, msg, 2);
if (ret < 0)
return ret;
if (ret != 2)
return -EIO;
}
/* Check if overload flag is active. If so, disable power */
if (!is_off && (buf & ISL6421_OLF1)) {
isl6421->config &= ~(ISL6421_VSEL1 | ISL6421_EN1);
ret = i2c_transfer(isl6421->i2c, msg, 1);
if (ret < 0)
return ret;
if (ret != 1)
return -EIO;
isl6421->is_off = true;
dev_warn(&isl6421->i2c->dev,
"Overload current detected. disabling LNBf power\n");
return -EINVAL;
}
return 0;
}
static int isl6421_enable_high_lnb_voltage(struct dvb_frontend *fe, long arg)
{
struct isl6421 *isl6421 = (struct isl6421 *) fe->sec_priv;
struct i2c_msg msg = { .addr = isl6421->i2c_addr, .flags = 0,
.buf = &isl6421->config,
.len = sizeof(isl6421->config) };
if (arg)
isl6421->config |= ISL6421_LLC1;
else
isl6421->config &= ~ISL6421_LLC1;
isl6421->config |= isl6421->override_or;
isl6421->config &= isl6421->override_and;
return (i2c_transfer(isl6421->i2c, &msg, 1) == 1) ? 0 : -EIO;
}
static int isl6421_set_tone(struct dvb_frontend *fe,
enum fe_sec_tone_mode tone)
{
struct isl6421 *isl6421 = (struct isl6421 *) fe->sec_priv;
struct i2c_msg msg = { .addr = isl6421->i2c_addr, .flags = 0,
.buf = &isl6421->config,
.len = sizeof(isl6421->config) };
switch (tone) {
case SEC_TONE_ON:
isl6421->config |= ISL6421_ENT1;
break;
case SEC_TONE_OFF:
isl6421->config &= ~ISL6421_ENT1;
break;
default:
return -EINVAL;
}
isl6421->config |= isl6421->override_or;
isl6421->config &= isl6421->override_and;
return (i2c_transfer(isl6421->i2c, &msg, 1) == 1) ? 0 : -EIO;
}
static void isl6421_release(struct dvb_frontend *fe)
{
/* power off */
isl6421_set_voltage(fe, SEC_VOLTAGE_OFF);
/* free */
kfree(fe->sec_priv);
fe->sec_priv = NULL;
}
struct dvb_frontend *isl6421_attach(struct dvb_frontend *fe, struct i2c_adapter *i2c, u8 i2c_addr,
u8 override_set, u8 override_clear, bool override_tone)
{
struct isl6421 *isl6421 = kmalloc(sizeof(struct isl6421), GFP_KERNEL);
if (!isl6421)
return NULL;
/* default configuration */
isl6421->config = ISL6421_ISEL1;
isl6421->i2c = i2c;
isl6421->i2c_addr = i2c_addr;
fe->sec_priv = isl6421;
/* bits which should be forced to '1' */
isl6421->override_or = override_set;
/* bits which should be forced to '0' */
isl6421->override_and = ~override_clear;
/* detect if it is present or not */
if (isl6421_set_voltage(fe, SEC_VOLTAGE_OFF)) {
kfree(isl6421);
fe->sec_priv = NULL;
return NULL;
}
isl6421->is_off = true;
/* install release callback */
fe->ops.release_sec = isl6421_release;
/* override frontend ops */
fe->ops.set_voltage = isl6421_set_voltage;
fe->ops.enable_high_lnb_voltage = isl6421_enable_high_lnb_voltage;
if (override_tone)
fe->ops.set_tone = isl6421_set_tone;
return fe;
}
EXPORT_SYMBOL(isl6421_attach);
MODULE_DESCRIPTION("Driver for lnb supply and control ic isl6421");
MODULE_AUTHOR("Andrew de Quincey & Oliver Endriss");
MODULE_LICENSE("GPL");