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Date: Thu, 18 Dec 2014 15:57:22 -0800
From: Bjorn <bjorn@...ymobile.com>
To: Stephen Boyd <sboyd@...eaurora.org>
CC: Rob Herring <robh+dt@...nel.org>, Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>,
Bryan Wu <cooloney@...il.com>,
Richard Purdie <rpurdie@...ys.net>,
Grant Likely <grant.likely@...aro.org>,
"Cavin, Courtney" <Courtney.Cavin@...ymobile.com>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-leds@...r.kernel.org" <linux-leds@...r.kernel.org>,
"linux-arm-msm@...r.kernel.org" <linux-arm-msm@...r.kernel.org>
Subject: Re: [PATCH 2/2] leds: add Qualcomm PM8941 WLED driver
On Tue 16 Dec 17:15 PST 2014, Stephen Boyd wrote:
> On 12/08/2014 04:22 PM, Bjorn Andersson wrote:
> > diff --git a/drivers/leds/leds-pm8941-wled.c b/drivers/leds/leds-pm8941-wled.c
[..]
> > +#include <linux/leds.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +#include <linux/regmap.h>
>
> Missing <linux/kernel.h> for container_of() macro.
>
Thanks
> > +
> > +enum pm8941_wled_reg {
> > + PM8941_WLED_REG_VAL_BASE = 0x40,
> > +#define PM8941_WLED_REG_VAL_MAX 0xFFF
> > +
> > + PM8941_WLED_REG_MOD_EN = 0x46,
> > +#define PM8941_WLED_REG_MOD_EN_BIT BIT(7)
> > +#define PM8941_WLED_REG_MOD_EN_MASK BIT(7)
> > +
> > + PM8941_WLED_REG_SYNC = 0x47,
> > +#define PM8941_WLED_REG_SYNC_MASK 0x07
> > +#define PM8941_WLED_REG_SYNC_LED1 BIT(0)
> > +#define PM8941_WLED_REG_SYNC_LED2 BIT(1)
> > +#define PM8941_WLED_REG_SYNC_LED3 BIT(2)
> > +#define PM8941_WLED_REG_SYNC_ALL 0x07
> > +#define PM8941_WLED_REG_SYNC_CLEAR 0x00
> > +
> > + PM8941_WLED_REG_FREQ = 0x4c,
> > +#define PM8941_WLED_REG_FREQ_MASK 0x0f
> > +
> > + PM8941_WLED_REG_OVP = 0x4d,
> > +#define PM8941_WLED_REG_OVP_MASK 0x03
> > +
> > + PM8941_WLED_REG_BOOST = 0x4e,
> > +#define PM8941_WLED_REG_BOOST_MASK 0x07
> > +
> > + PM8941_WLED_REG_SINK = 0x4f,
> > +#define PM8941_WLED_REG_SINK_MASK 0xe0
> > +#define PM8941_WLED_REG_SINK_SHFT 0x05
> > +
> > +/* Per-'string' registers below */
> > +#define PM8941_WLED_REG_STR_OFFSET 0x10
> > +
> > + PM8941_WLED_REG_STR_MOD_EN_BASE = 0x60,
> > +#define PM8941_WLED_REG_STR_MOD_EN BIT(7)
> > +#define PM8941_WLED_REG_STR_MOD_MASK BIT(7)
> > +
> > + PM8941_WLED_REG_STR_SCALE_BASE = 0x62,
> > +#define PM8941_WLED_REG_STR_SCALE_MASK 0x1f
> > +
> > + PM8941_WLED_REG_STR_MOD_SRC_BASE = 0x63,
> > +#define PM8941_WLED_REG_STR_MOD_SRC_MASK 0x01
> > +#define PM8941_WLED_REG_STR_MOD_SRC_INT 0x00
> > +#define PM8941_WLED_REG_STR_MOD_SRC_EXT 0x01
> > +
> > + PM8941_WLED_REG_STR_CABC_BASE = 0x66,
> > +#define PM8941_WLED_REG_STR_CABC_MASK BIT(7)
> > +#define PM8941_WLED_REG_STR_CABC_EN BIT(7)
> > +};
>
> I don't see any value in this enum. It's never used in a switch
> statement so why not just have #defines for the register offsets. It
> would make reading this a lot easier too.
>
Make sense, I'll rework it.
> > +
> > +static int pm8941_wled_set(struct led_classdev *cdev,
> > + enum led_brightness value)
> > +{
> > + struct pm8941_wled_context *ctx;
> > + struct pm8941_wled *wled;
> > + u8 ctrl = 0;
> > + u16 val;
> > + int rc;
> > + int i;
> > +
> > + wled = container_of(cdev, struct pm8941_wled, cdev);
> > + ctx = container_of(wled, struct pm8941_wled_context, wled);
> > +
> > + if (value != 0)
> > + ctrl = PM8941_WLED_REG_MOD_EN_BIT;
> > +
> > + val = (value * PM8941_WLED_REG_VAL_MAX) / LED_FULL;
>
> Unnecessary parens here.
>
Agreed
> > +
> > + rc = regmap_update_bits(ctx->regmap,
> >
> > +
> > +static int pm8941_wled_configure(struct pm8941_wled *wled, struct device *dev)
> > +{
> [...]
> > +
> > + if (dev->of_node == NULL) {
> > + dev_err(dev, "no OF node!\n");
> > + return -EINVAL;
> > + }
>
> Seems like an unnecessary check. Everything's DT so far.
>
Agreed.
> > +
> > + rc = of_property_read_u32(dev->of_node, "reg", &val);
> > + if (rc || val > 0xffff) {
> > + dev_err(dev, "invalid IO resources\n");
> > + return rc ? rc : -EINVAL;
> > + }
> > + wled->addr = val;
> > +
> > + rc = of_property_read_string(dev->of_node, "label", &wled->cdev.name);
> > + if (rc)
> > + wled->cdev.name = dev->of_node->name;
> > +
> > + wled->cdev.default_trigger = of_get_property(dev->of_node,
> > + "linux,default-trigger", NULL);
> > +
> > + *cfg = pm8941_wled_config_defaults;
> > + for (i = 0; i < ARRAY_SIZE(u32_opts); ++i) {
> > + u32 sel, c;
> > + int j, rj;
> > +
> > + rc = of_property_read_u32(dev->of_node, u32_opts[i].name, &val);
> > + if (rc) {
> > + if (rc != -EINVAL) {
> > + dev_err(dev, "error reading '%s'\n",
> > + u32_opts[i].name);
> > + return rc;
> > + }
> > + continue;
> > + }
> > +
> > + sel = UINT_MAX;
> > + rj = -1;
> > + c = pm8941_wled_values(u32_opts[i].cfg, 0);
> > + for (j = 0; c != UINT_MAX; ++j) {
> > + if (c <= val && (sel == UINT_MAX || c >= sel)) {
> > + sel = c;
> > + rj = j;
> > + }
> > + c = pm8941_wled_values(u32_opts[i].cfg, j + 1);
> > + }
> > + if (sel == UINT_MAX) {
> > + dev_err(dev, "invalid value for '%s'\n",
> > + u32_opts[i].name);
> > + return rc;
> > + }
> > + if (sel != val) {
> > + dev_warn(dev, "rounding '%s' down to %u\n",
> > + u32_opts[i].name, sel);
> > + }
>
> Do we really want to do all this complicated rounding and checking?
> Can't we just assume the DT is correct?
>
We could remove the printout about rounding, but the logic turns human-readable
values into register values (indices), so we need something for that.
> > + dev_dbg(dev, "'%s' = %u\n", u32_opts[i].name, sel);
> > + *u32_opts[i].val_ptr = rj;
> > + };
> > +
> > + for (i = 0; i < ARRAY_SIZE(bool_opts); ++i) {
> > + if (of_property_read_bool(dev->of_node, bool_opts[i].name))
> > + *bool_opts[i].val_ptr = true;
> > + }
> > +
> > + cfg->num_strings = cfg->num_strings + 1;
> > +
> > + return 0;
> > +}
> > +
> > +static int pm8941_wled_probe(struct platform_device *pdev)
> > +{
> > + struct pm8941_wled_context *ctx;
> > + struct regmap *regmap;
> > + int rc;
> > +
> > + regmap = dev_get_regmap(pdev->dev.parent, NULL);
> > + if (!regmap) {
> > + dev_err(&pdev->dev, "Unable to get regmap\n");
> > + return -EINVAL;
> > + }
> > +
> > + ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
> > + if (ctx == NULL)
>
> Nitpick only because it doesn't match the !regmap style above. Please
> use the !ctx style here as well.
>
Agreed
> > + return -ENOMEM;
> > +
> > + ctx->regmap = regmap;
> > +
> > + rc = pm8941_wled_configure(&ctx->wled, &pdev->dev);
> > + if (rc)
> > + return rc;
> > +
> > + rc = pm8941_wled_setup(&ctx->wled);
> > + if (rc)
> > + return rc;
> > +
> > + ctx->wled.cdev.brightness_set = pm8941_wled_set_brightness;
> > +
> > + rc = led_classdev_register(&pdev->dev, &ctx->wled.cdev);
> > + if (rc)
> > + return rc;
> > +
> > + platform_set_drvdata(pdev, ctx);
> > + dev_info(&pdev->dev, "registered led \"%s\"\n", ctx->wled.cdev.name);
>
> Please don't spam the log with "I'm alive!" messages.
>
Ok
> > +
> > + return 0;
> > +};
> > +
[..]
> > +
> > +static const struct of_device_id pm8941_wled_match_table[] = {
> > + { .compatible = "qcom,pm8941-wled" },
> > + {}
> > +};
>
> MODULE_DEVICE_TABLE?
>
Indeed
Thanks for the review Stephen.
Regards,
Bjorn
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