linux-kernel - Re: [PATCH v2] PM: AVS: qcom-cpr: Use nvmem_cell_read_variable_le

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Message-ID: <YKx2VGxuPg3EPSMA@yoga>
Date:   Mon, 24 May 2021 23:00:20 -0500
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Douglas Anderson <dianders@...omium.org>
Cc:     "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Niklas Cassel <niklas.cassel@...aro.org>,
        Akhil P Oommen <akhilpo@...eaurora.org>,
        linux-arm-msm@...r.kernel.org,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Andy Gross <agross@...nel.org>,
        Niklas Cassel <nks@...wful.org>, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org
Subject: Re: [PATCH v2] PM: AVS: qcom-cpr: Use
 nvmem_cell_read_variable_le_u32()

On Fri 21 May 15:44 CDT 2021, Douglas Anderson wrote:

> Let's delete the private function cpr_read_efuse() since it does the
> basically the same thing as the new API call
> nvmem_cell_read_variable_le_u32().
> 
> Differences between the new API call and the old private function:
> * less error printing (I assume this is OK).
> * will give an error if the value doesn't fit in 32-bits (the old code
>   would have truncated silently).
> 

Reviewed-by: Bjorn Andersson <bjorn.andersson@...aro.org>

Regards,
Bjorn

> Signed-off-by: Douglas Anderson <dianders@...omium.org>
> ---
> I haven't done any more than compile-test this. Mostly I'm just
> writing this patch because it helped provide inspiration for the
> general API function.
> 
> Changes in v2:
> - Resending v1 as a singleton patch; dependency is merged in mainline.
> 
>  drivers/soc/qcom/cpr.c | 43 +++++-------------------------------------
>  1 file changed, 5 insertions(+), 38 deletions(-)
> 
> diff --git a/drivers/soc/qcom/cpr.c b/drivers/soc/qcom/cpr.c
> index b24cc77d1889..4ce8e816154f 100644
> --- a/drivers/soc/qcom/cpr.c
> +++ b/drivers/soc/qcom/cpr.c
> @@ -801,38 +801,6 @@ static int cpr_set_performance_state(struct generic_pm_domain *domain,
>  	return ret;
>  }
>  
> -static int cpr_read_efuse(struct device *dev, const char *cname, u32 *data)
> -{
> -	struct nvmem_cell *cell;
> -	ssize_t len;
> -	char *ret;
> -	int i;
> -
> -	*data = 0;
> -
> -	cell = nvmem_cell_get(dev, cname);
> -	if (IS_ERR(cell)) {
> -		if (PTR_ERR(cell) != -EPROBE_DEFER)
> -			dev_err(dev, "undefined cell %s\n", cname);
> -		return PTR_ERR(cell);
> -	}
> -
> -	ret = nvmem_cell_read(cell, &len);
> -	nvmem_cell_put(cell);
> -	if (IS_ERR(ret)) {
> -		dev_err(dev, "can't read cell %s\n", cname);
> -		return PTR_ERR(ret);
> -	}
> -
> -	for (i = 0; i < len; i++)
> -		*data |= ret[i] << (8 * i);
> -
> -	kfree(ret);
> -	dev_dbg(dev, "efuse read(%s) = %x, bytes %zd\n", cname, *data, len);
> -
> -	return 0;
> -}
> -
>  static int
>  cpr_populate_ring_osc_idx(struct cpr_drv *drv)
>  {
> @@ -843,8 +811,7 @@ cpr_populate_ring_osc_idx(struct cpr_drv *drv)
>  	int ret;
>  
>  	for (; fuse < end; fuse++, fuses++) {
> -		ret = cpr_read_efuse(drv->dev, fuses->ring_osc,
> -				     &data);
> +		ret = nvmem_cell_read_variable_le_u32(drv->dev, fuses->ring_osc, &data);
>  		if (ret)
>  			return ret;
>  		fuse->ring_osc_idx = data;
> @@ -863,7 +830,7 @@ static int cpr_read_fuse_uV(const struct cpr_desc *desc,
>  	u32 bits = 0;
>  	int ret;
>  
> -	ret = cpr_read_efuse(drv->dev, init_v_efuse, &bits);
> +	ret = nvmem_cell_read_variable_le_u32(drv->dev, init_v_efuse, &bits);
>  	if (ret)
>  		return ret;
>  
> @@ -932,7 +899,7 @@ static int cpr_fuse_corner_init(struct cpr_drv *drv)
>  		}
>  
>  		/* Populate target quotient by scaling */
> -		ret = cpr_read_efuse(drv->dev, fuses->quotient, &fuse->quot);
> +		ret = nvmem_cell_read_variable_le_u32(drv->dev, fuses->quotient, &fuse->quot);
>  		if (ret)
>  			return ret;
>  
> @@ -1001,7 +968,7 @@ static int cpr_calculate_scaling(const char *quot_offset,
>  	prev_fuse = fuse - 1;
>  
>  	if (quot_offset) {
> -		ret = cpr_read_efuse(drv->dev, quot_offset, &quot_diff);
> +		ret = nvmem_cell_read_variable_le_u32(drv->dev, quot_offset, &quot_diff);
>  		if (ret)
>  			return ret;
>  
> @@ -1701,7 +1668,7 @@ static int cpr_probe(struct platform_device *pdev)
>  	 * initialized after attaching to the power domain,
>  	 * since it depends on the CPU's OPP table.
>  	 */
> -	ret = cpr_read_efuse(dev, "cpr_fuse_revision", &cpr_rev);
> +	ret = nvmem_cell_read_variable_le_u32(dev, "cpr_fuse_revision", &cpr_rev);
>  	if (ret)
>  		return ret;
>  
> -- 
> 2.31.1.818.g46aad6cb9e-goog
>