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Date: Thu, 27 Sep 2012 20:41:21 -0700
From: Anton Vorontsov <anton.vorontsov@...aro.org>
To: mathieu.poirier@...aro.org
Cc: linux-kernel@...r.kernel.org, dwmw2@...radead.org
Subject: Re: [PATCH 01/57] power: ab8500_bm: Charger current step-up/down
On Tue, Sep 25, 2012 at 10:11:58AM -0600, mathieu.poirier@...aro.org wrote:
> From: Johan Bjornstedt <johan.bjornstedt@...ricsson.com>
>
> There is no state machine in the AB to step up/down
> the charger current to avoid dips and spikes on VBUS
> and VBAT when charging is started.
> Instead this is implemented in SW
Some general comment: the commit messages use random line wrapping length.
It's usually a good idea to make lines no longer than 74 columns (since
'git log' adds some spaces before the message) , but too short or random
is also not pretty.
> Signed-off-by: Johan Bjornstedt <johan.bjornstedt@...ricsson.com>
> Signed-off-by: Mattias Wallin <mattias.wallin@...ricsson.com>
> Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
> Reviewed-by: Karl KOMIEROWSKI <karl.komierowski@...ricsson.com>
> ---
> drivers/power/ab8500_charger.c | 172 +++++++++++++++++++++++++++++++---------
> 1 files changed, 133 insertions(+), 39 deletions(-)
>
> diff --git a/drivers/power/ab8500_charger.c b/drivers/power/ab8500_charger.c
> index d4f0c98..3ceb788 100644
> --- a/drivers/power/ab8500_charger.c
> +++ b/drivers/power/ab8500_charger.c
> @@ -77,6 +77,9 @@
> /* Lowest charger voltage is 3.39V -> 0x4E */
> #define LOW_VOLT_REG 0x4E
>
> +/* Step up/down delay in us */
> +#define STEP_UDELAY 1000
> +
> /* UsbLineStatus register - usb types */
> enum ab8500_charger_link_status {
> USB_STAT_NOT_CONFIGURED,
> @@ -934,6 +937,88 @@ static int ab8500_charger_get_usb_cur(struct ab8500_charger *di)
> }
>
> /**
> + * ab8500_charger_set_current() - set charger current
> + * @di: pointer to the ab8500_charger structure
> + * @ich: charger current, in mA
> + * @reg: select what charger register to set
> + *
> + * Set charger current.
> + * There is no state machine in the AB to step up/down the charger
> + * current to avoid dips and spikes on MAIN, VBUS and VBAT when
> + * charging is started. Instead we need to implement
> + * this charger current step-up/down here.
> + * Returns error code in case of failure else 0(on success)
Random line wrapping...
Sophisticated editors (like vim :-), can format text for you. i.e. 'gqip'
command. I'm sure emacs can do this too.
> + */
> +static int ab8500_charger_set_current(struct ab8500_charger *di,
> + int ich, int reg)
> +{
> + int ret, i;
> + int curr_index, prev_curr_index, shift_value;
One variable per line, please.
> + u8 reg_value;
> +
> + switch (reg) {
> + case AB8500_MCH_IPT_CURLVL_REG:
> + shift_value = MAIN_CH_INPUT_CURR_SHIFT;
> + curr_index = ab8500_current_to_regval(ich);
> + break;
> + case AB8500_USBCH_IPT_CRNTLVL_REG:
> + shift_value = VBUS_IN_CURR_LIM_SHIFT;
> + curr_index = ab8500_vbus_in_curr_to_regval(ich);
> + break;
> + case AB8500_CH_OPT_CRNTLVL_REG:
> + shift_value = 0;
> + curr_index = ab8500_current_to_regval(ich);
> + break;
> + default:
> + dev_err(di->dev, "%s current register not valid\n", __func__);
> + return -ENXIO;
> + }
> +
> + if (curr_index < 0) {
> + dev_err(di->dev, "requested current limit out-of-range\n");
> + return -ENXIO;
> + }
> +
> + ret = abx500_get_register_interruptible(di->dev, AB8500_CHARGER,
> + reg, ®_value);
> + if (ret < 0) {
> + dev_err(di->dev, "%s read failed\n", __func__);
> + return ret;
> + }
> + prev_curr_index = (reg_value >> shift_value);
No need for parenthesis.
> + /* only update current if it's been changed */
> + if (prev_curr_index == curr_index)
> + return 0;
> +
> + dev_dbg(di->dev, "%s set charger current: %d mA for reg: 0x%02x\n",
> + __func__, ich, reg);
> +
> + if (prev_curr_index > curr_index) {
> + for (i = prev_curr_index - 1; i >= curr_index; i--) {
> + ret = abx500_set_register_interruptible(di->dev,
> + AB8500_CHARGER, reg, (u8) i << shift_value);
> + if (ret) {
> + dev_err(di->dev, "%s write failed\n", __func__);
> + return ret;
> + }
> + usleep_range(STEP_UDELAY, STEP_UDELAY * 2);
> + }
> + } else {
> + for (i = prev_curr_index + 1; i <= curr_index; i++) {
> + ret = abx500_set_register_interruptible(di->dev,
> + AB8500_CHARGER, reg, (u8) i << shift_value);
> + if (ret) {
> + dev_err(di->dev, "%s write failed\n", __func__);
> + return ret;
> + }
> + usleep_range(STEP_UDELAY, STEP_UDELAY * 2);
> + }
> + }
Too much duplication.
Assuming that you need to preserve the order of the writes, i.e. if it
matters to the hw, I guess this (or something alike) will work:
write_current()
{
uint start = prev_curr_index + 1;
uint stop = curr_index + 1;
int direction = 1;
if (prev_curr_index > curr_index) {
start = prev_curr_index - 1;
stop = curr_index - 1;
direction = -1;
}
for (i = start; i != stop; i += direction) {
ret = abx500_set_register_interruptible(di->dev,
AB8500_CHARGER, reg, (u8)i << shift_value);
if (ret) {
dev_err(di->dev, "%s write failed\n", __func__);
return ret;
}
usleep_range(STEP_UDELAY, STEP_UDELAY * 2);
}
}
If the order doesn't matter, it could be even simpler.
> + return ret;
> +}
> +
> +/**
> * ab8500_charger_set_vbus_in_curr() - set VBUS input current limit
> * @di: pointer to the ab8500_charger structure
> * @ich_in: charger input current limit
> @@ -944,8 +1029,6 @@ static int ab8500_charger_get_usb_cur(struct ab8500_charger *di)
> static int ab8500_charger_set_vbus_in_curr(struct ab8500_charger *di,
> int ich_in)
> {
> - int ret;
> - int input_curr_index;
> int min_value;
>
> /* We should always use to lowest current limit */
> @@ -964,19 +1047,38 @@ static int ab8500_charger_set_vbus_in_curr(struct ab8500_charger *di,
> break;
> }
>
> - input_curr_index = ab8500_vbus_in_curr_to_regval(min_value);
> - if (input_curr_index < 0) {
> - dev_err(di->dev, "VBUS input current limit too high\n");
> - return -ENXIO;
> - }
> + return ab8500_charger_set_current(di, min_value,
> + AB8500_USBCH_IPT_CRNTLVL_REG);
> +}
>
> - ret = abx500_set_register_interruptible(di->dev, AB8500_CHARGER,
> - AB8500_USBCH_IPT_CRNTLVL_REG,
> - input_curr_index << VBUS_IN_CURR_LIM_SHIFT);
> - if (ret)
> - dev_err(di->dev, "%s write failed\n", __func__);
> +/**
> + * ab8500_charger_set_main_in_curr() - set main charger input current
> + * @di: pointer to the ab8500_charger structure
> + * @ich_in: input charger current, in mA
> + *
> + * Set main charger input current.
> + * Returns error code in case of failure else 0(on success)
> + */
> +static int ab8500_charger_set_main_in_curr(struct ab8500_charger *di,
> + int ich_in)
> +{
> + return ab8500_charger_set_current(di, ich_in,
> + AB8500_MCH_IPT_CURLVL_REG);
> +}
>
> - return ret;
> +/**
> + * ab8500_charger_set_output_curr() - set charger output current
> + * @di: pointer to the ab8500_charger structure
> + * @ich_out: output charger current, in mA
> + *
> + * Set charger output current.
> + * Returns error code in case of failure else 0(on success)
> + */
> +static int ab8500_charger_set_output_curr(struct ab8500_charger *di,
> + int ich_out)
Wrong indentation.
> +{
> + return ab8500_charger_set_current(di, ich_out,
> + AB8500_CH_OPT_CRNTLVL_REG);
> }
>
> /**
> @@ -1088,18 +1190,18 @@ static int ab8500_charger_ac_en(struct ux500_charger *charger,
> return ret;
> }
> /* MainChInputCurr: current that can be drawn from the charger*/
> - ret = abx500_set_register_interruptible(di->dev, AB8500_CHARGER,
> - AB8500_MCH_IPT_CURLVL_REG,
> - input_curr_index << MAIN_CH_INPUT_CURR_SHIFT);
> + ret = ab8500_charger_set_main_in_curr(di,
> + di->bat->chg_params->ac_curr_max);
> if (ret) {
> - dev_err(di->dev, "%s write failed\n", __func__);
> + dev_err(di->dev, "%s Failed to set MainChInputCurr\n",
> + __func__);
> return ret;
> }
> /* ChOutputCurentLevel: protected output current */
> - ret = abx500_set_register_interruptible(di->dev, AB8500_CHARGER,
> - AB8500_CH_OPT_CRNTLVL_REG, (u8) curr_index);
> + ret = ab8500_charger_set_output_curr(di, iset);
> if (ret) {
> - dev_err(di->dev, "%s write failed\n", __func__);
> + dev_err(di->dev,
> + "%s Failed to set ChOutputCurentLevel\n", __func__);
> return ret;
> }
>
> @@ -1156,12 +1258,11 @@ static int ab8500_charger_ac_en(struct ux500_charger *charger,
> return ret;
> }
>
> - ret = abx500_set_register_interruptible(di->dev,
> - AB8500_CHARGER,
> - AB8500_CH_OPT_CRNTLVL_REG, CH_OP_CUR_LVL_0P1);
> + ret = ab8500_charger_set_output_curr(di, 0);
> if (ret) {
> dev_err(di->dev,
> - "%s write failed\n", __func__);
> + "%s Failed to set ChOutputCurentLevel\n",
> + __func__);
Weird, inconsistent indentation.
> return ret;
> }
> } else {
> @@ -1264,10 +1365,11 @@ static int ab8500_charger_usb_en(struct ux500_charger *charger,
> return ret;
> }
> /* ChOutputCurentLevel: protected output current */
> - ret = abx500_set_register_interruptible(di->dev, AB8500_CHARGER,
> - AB8500_CH_OPT_CRNTLVL_REG, (u8) curr_index);
> + ret = ab8500_charger_set_output_curr(di, ich_out);
> if (ret) {
> - dev_err(di->dev, "%s write failed\n", __func__);
> + dev_err(di->dev,
> + "%s Failed to set ChOutputCurentLevel\n",
> + __func__);
Weird indentation.
> return ret;
> }
> /* Check if VBAT overshoot control should be enabled */
> @@ -1364,7 +1466,6 @@ static int ab8500_charger_update_charger_current(struct ux500_charger *charger,
> int ich_out)
> {
> int ret;
> - int curr_index;
> struct ab8500_charger *di;
>
> if (charger->psy.type == POWER_SUPPLY_TYPE_MAINS)
> @@ -1374,18 +1475,11 @@ static int ab8500_charger_update_charger_current(struct ux500_charger *charger,
> else
> return -ENXIO;
>
> - curr_index = ab8500_current_to_regval(ich_out);
> - if (curr_index < 0) {
> - dev_err(di->dev,
> - "Charger current too high, "
> - "charging not started\n");
> - return -ENXIO;
> - }
> -
> - ret = abx500_set_register_interruptible(di->dev, AB8500_CHARGER,
> - AB8500_CH_OPT_CRNTLVL_REG, (u8) curr_index);
> + ret = ab8500_charger_set_output_curr(di, ich_out);
> if (ret) {
> - dev_err(di->dev, "%s write failed\n", __func__);
> + dev_err(di->dev,
> + "%s Failed to set ChOutputCurentLevel\n",
> + __func__);
Weird indentation. No need for the first line wrap.
> return ret;
> }
>
> --
> 1.7.5.4
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