Re: [PATCH v5 3/3] backlight: lm3630a: add firmware node support

Dan Murphy
2019-04-23T13:49:20Z

Hello

On 4/18/19 10:11 AM, Brian Masney wrote:
> Add fwnode support to the lm3630a driver and optionally allow
> configuring the label, default brightness level, and maximum brightness
> level. The two outputs can be controlled by bank A and B independently
> or bank A can control both outputs.
>
> If the platform data was not configured, then the driver defaults to
> enabling both banks. This patch changes the default value to disable
> both banks before parsing the firmware node so that just a single bank
> can be enabled if desired. There are no in-tree users of this driver.
>
> Driver was tested on a LG Nexus 5 (hammerhead) phone.
>
> Signed-off-by: Brian Masney <masneyb@onstation.org>
> ---
> Changes since v4
> - Added new function lm3630a_parse_bank()
> - Renamed seen variable to seen_led_sources
> - Use the bitmask returned from lm3630a_parse_led_sources() to compare
> against the seen_led_sources rather than just the control bank. This
> eliminated another if statement that was previously present that
> checked to see if control bank A should control both sinks.
> - #define LM3630A_BANK_0, LM3630A_BANK_1, LM3630A_SINK_0,
> LM3630A_SINK_1, and LM3630A_NUM_SINKS and use where appropriate.
> - Changed all occurances of
> 'if (bank == 0) { BANK_A_WORK } else { BANK_B_WORK }' to
> 'if (bank) { BANK_B_WORK } else { BANK_A_WORK }'
> - Dropped unnecessary 'ret = 0' from lm3630a_parse_led_sources().
> - Changed 'if (ret < 0)' to 'if (ret)' in lm3630a_parse_node().
> - Dropped kerneldoc from lm3630a_parse_led_sources().
>
> Changes since v3
> - Add support for label
> - Changed lm3630a_parse_node() to return -ENODEV if no nodes were found
> - Remove LM3630A_LED{A,B}_DISABLE
> - Add two additional newlines for code readability
> - Remove extra newline
>
> Changes since v2
> - Separated out control banks and outputs via the reg and led-sources
> properties.
> - Use fwnode instead of of API
> - Disable both banks by default before calling lm3630a_parse_node()
> - Add lots of error handling
> - Check for duplicate source / bank definitions
> - Remove extra ;
> - Make probe() method fail if fwnode parsing fails.
>
> drivers/video/backlight/lm3630a_bl.c | 149 ++++++++++++++++++++++-
> include/linux/platform_data/lm3630a_bl.h | 4 +
> 2 files changed, 148 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/video/backlight/lm3630a_bl.c b/drivers/video/backlight/lm3630a_bl.c
> index ef2553f452ca..75d996490cf0 100644
> --- a/drivers/video/backlight/lm3630a_bl.c
> +++ b/drivers/video/backlight/lm3630a_bl.c
> @@ -35,6 +35,14 @@
> #define REG_MAX 0x50
>
> #define INT_DEBOUNCE_MSEC 10
> +
> +#define LM3630A_BANK_0 0
> +#define LM3630A_BANK_1 1
> +
> +#define LM3630A_NUM_SINKS 2
> +#define LM3630A_SINK_0 0
> +#define LM3630A_SINK_1 1
> +
> struct lm3630a_chip {
> struct device *dev;
> struct delayed_work work;
> @@ -329,15 +337,17 @@ static const struct backlight_ops lm3630a_bank_b_ops = {
>
> static int lm3630a_backlight_register(struct lm3630a_chip *pchip)
> {
> - struct backlight_properties props;
> struct lm3630a_platform_data *pdata = pchip->pdata;
> + struct backlight_properties props;
> + const char *label;
>
> props.type = BACKLIGHT_RAW;
> if (pdata->leda_ctrl != LM3630A_LEDA_DISABLE) {
> props.brightness = pdata->leda_init_brt;
> props.max_brightness = pdata->leda_max_brt;
> + label = pdata->leda_label ? pdata->leda_label : "lm3630a_leda";
> pchip->bleda =
> - devm_backlight_device_register(pchip->dev, "lm3630a_leda",
> + devm_backlight_device_register(pchip->dev, label,
> pchip->dev, pchip,
> &lm3630a_bank_a_ops, &props);
> if (IS_ERR(pchip->bleda))
> @@ -348,8 +358,9 @@ static int lm3630a_backlight_register(struct lm3630a_chip *pchip)
> (pdata->ledb_ctrl != LM3630A_LEDB_ON_A)) {
> props.brightness = pdata->ledb_init_brt;
> props.max_brightness = pdata->ledb_max_brt;
> + label = pdata->ledb_label ? pdata->ledb_label : "lm3630a_ledb";
> pchip->bledb =
> - devm_backlight_device_register(pchip->dev, "lm3630a_ledb",
> + devm_backlight_device_register(pchip->dev, label,
> pchip->dev, pchip,
> &lm3630a_bank_b_ops, &props);
> if (IS_ERR(pchip->bledb))
> @@ -364,6 +375,123 @@ static const struct regmap_config lm3630a_regmap = {
> .max_register = REG_MAX,
> };
>
> +static int lm3630a_parse_led_sources(struct fwnode_handle *node,
> + int default_led_sources)
> +{
> + u32 sources[LM3630A_NUM_SINKS];
> + int ret, num_sources, i;
> +
> + num_sources = fwnode_property_read_u32_array(node, "led-sources", NULL,
> + 0);
> + if (num_sources < 0)
> + return default_led_sources;
> + else if (num_sources > ARRAY_SIZE(sources))
> + return -EINVAL;
> +
> + ret = fwnode_property_read_u32_array(node, "led-sources", sources,
> + num_sources);
> + if (ret)
> + return ret;
> +
> + for (i = 0; i < num_sources; i++) {
> + if (sources[i] < LM3630A_SINK_0 || sources[i] > LM3630A_SINK_1)
> + return -EINVAL;
> +
> + ret |= BIT(sources[i]);
> + }
> +
> + return ret;
> +}
> +
> +static int lm3630a_parse_bank(struct lm3630a_platform_data *pdata,
> + struct fwnode_handle *node, int *seen_led_sources)

Why is seen_led_sources passed in here?
It is initialized on the stack in lm3630a_parse_node but the variable is never referenced in that API.

Dan

> +{
> + int led_sources, ret;
> + const char *label;
> + u32 bank, val;
> + bool linear;
> +
> + ret = fwnode_property_read_u32(node, "reg", &bank);
> + if (ret)
> + return ret;
> +
> + if (bank < LM3630A_BANK_0 || bank > LM3630A_BANK_1)
> + return -EINVAL;
> +
> + led_sources = lm3630a_parse_led_sources(node, BIT(bank));
> + if (led_sources < 0)
> + return led_sources;
> +
> + if (*seen_led_sources & led_sources)
> + return -EINVAL;
> +
> + *seen_led_sources |= led_sources;
> +
> + linear = fwnode_property_read_bool(node,
> + "ti,linear-mapping-mode");
> + if (bank) {
> + if (led_sources & BIT(LM3630A_SINK_0) ||
> + !(led_sources & BIT(LM3630A_SINK_1)))
> + return -EINVAL;
> +
> + pdata->ledb_ctrl = linear ?
> + LM3630A_LEDB_ENABLE_LINEAR :
> + LM3630A_LEDB_ENABLE;
> + } else {
> + if (!(led_sources & BIT(LM3630A_SINK_0)))
> + return -EINVAL;
> +
> + pdata->leda_ctrl = linear ?
> + LM3630A_LEDA_ENABLE_LINEAR :
> + LM3630A_LEDA_ENABLE;
> +
> + if (led_sources & BIT(LM3630A_SINK_1))
> + pdata->ledb_ctrl = LM3630A_LEDB_ON_A;
> + }
> +
> + ret = fwnode_property_read_string(node, "label", &label);
> + if (!ret) {
> + if (bank)
> + pdata->ledb_label = label;
> + else
> + pdata->leda_label = label;
> + }
> +
> + ret = fwnode_property_read_u32(node, "default-brightness",
> + &val);
> + if (!ret) {
> + if (bank)
> + pdata->ledb_init_brt = val;
> + else
> + pdata->leda_init_brt = val;
> + }
> +
> + ret = fwnode_property_read_u32(node, "max-brightness", &val);
> + if (!ret) {
> + if (bank)
> + pdata->ledb_max_brt = val;
> + else
> + pdata->leda_max_brt = val;
> + }
> +
> + return 0;
> +}
> +
> +static int lm3630a_parse_node(struct lm3630a_chip *pchip,
> + struct lm3630a_platform_data *pdata)
> +{
> + int ret = -ENODEV, seen_led_sources = 0;
> + struct fwnode_handle *node;
> +
> + device_for_each_child_node(pchip->dev, node) {
> + ret = lm3630a_parse_bank(pdata, node, &seen_led_sources);
> + if (ret)
> + return ret;
> + }
> +
> + return ret;
> +}
> +
> static int lm3630a_probe(struct i2c_client *client,
> const struct i2c_device_id *id)
> {
> @@ -396,13 +524,18 @@ static int lm3630a_probe(struct i2c_client *client,
> GFP_KERNEL);
> if (pdata == NULL)
> return -ENOMEM;
> +
> /* default values */
> - pdata->leda_ctrl = LM3630A_LEDA_ENABLE;
> - pdata->ledb_ctrl = LM3630A_LEDB_ENABLE;
> pdata->leda_max_brt = LM3630A_MAX_BRIGHTNESS;
> pdata->ledb_max_brt = LM3630A_MAX_BRIGHTNESS;
> pdata->leda_init_brt = LM3630A_MAX_BRIGHTNESS;
> pdata->ledb_init_brt = LM3630A_MAX_BRIGHTNESS;
> +
> + rval = lm3630a_parse_node(pchip, pdata);
> + if (rval) {
> + dev_err(&client->dev, "fail : parse node\n");
> + return rval;
> + }
> }
> pchip->pdata = pdata;
>
> @@ -470,11 +603,17 @@ static const struct i2c_device_id lm3630a_id[] = {
> {}
> };
>
> +static const struct of_device_id lm3630a_match_table[] = {
> + { .compatible = "ti,lm3630a", },
> + { },
> +};
> +
> MODULE_DEVICE_TABLE(i2c, lm3630a_id);
>
> static struct i2c_driver lm3630a_i2c_driver = {
> .driver = {
> .name = LM3630A_NAME,
> + .of_match_table = lm3630a_match_table,
> },
> .probe = lm3630a_probe,
> .remove = lm3630a_remove,
> diff --git a/include/linux/platform_data/lm3630a_bl.h b/include/linux/platform_data/lm3630a_bl.h
> index 7538e38e270b..762e68956f31 100644
> --- a/include/linux/platform_data/lm3630a_bl.h
> +++ b/include/linux/platform_data/lm3630a_bl.h
> @@ -38,9 +38,11 @@ enum lm3630a_ledb_ctrl {
>
> #define LM3630A_MAX_BRIGHTNESS 255
> /*
> + *@leda_label : optional led a label.
> *@leda_init_brt : led a init brightness. 4~255
> *@leda_max_brt : led a max brightness. 4~255
> *@leda_ctrl : led a disable, enable linear, enable exponential
> + *@ledb_label : optional led b label.
> *@ledb_init_brt : led b init brightness. 4~255
> *@ledb_max_brt : led b max brightness. 4~255
> *@ledb_ctrl : led b disable, enable linear, enable exponential
> @@ -50,10 +52,12 @@ enum lm3630a_ledb_ctrl {
> struct lm3630a_platform_data {
>
> /* led a config. */
> + const char *leda_label;
> int leda_init_brt;
> int leda_max_brt;
> enum lm3630a_leda_ctrl leda_ctrl;
> /* led b config. */
> + const char *ledb_label;
> int ledb_init_brt;
> int ledb_max_brt;
> enum lm3630a_ledb_ctrl ledb_ctrl;
>