Re: [RESEND PATCH v3 2/2] mfd: lm3533: Support initialization from Device Tree

From: Lee Jones
Date: Mon Apr 11 2016 - 08:30:24 EST

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On Wed, 30 Mar 2016, Bjorn Andersson wrote:

> From: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxx>
>
> Implement Device Tree parsing functions to support initialization of the
> lm3533 drivers.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxx>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> ---
> Changes since v2:
> - Drop vendor prefix of vendor properties
> - Specify unit of various properties
> - Fix reference paths
>
> Changes since v1:
> - Added unit to boost-freq and als-resistance (as the frequency now comes with
> a unit specifier I changed it to be expressed in kHz)
>
> drivers/mfd/lm3533-core.c | 264 ++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 264 insertions(+)
>
> diff --git a/drivers/mfd/lm3533-core.c b/drivers/mfd/lm3533-core.c
> index 5abcbb2e8849..dbf26d86fe85 100644
> --- a/drivers/mfd/lm3533-core.c
> +++ b/drivers/mfd/lm3533-core.c
> @@ -18,6 +18,7 @@
> #include <linux/gpio.h>
> #include <linux/i2c.h>
> #include <linux/mfd/core.h>
> +#include <linux/of_gpio.h>
> #include <linux/regmap.h>
> #include <linux/seq_file.h>
> #include <linux/slab.h>
> @@ -25,6 +26,7 @@
>
> #include <linux/mfd/lm3533.h>
>
> +#define LM3533_DEFAULT_BRIGHTNESS 200

The MFD doesn't care about child specifics. These needs to go into
the child driver.

> #define LM3533_BOOST_OVP_MASK 0x06
> #define LM3533_BOOST_OVP_SHIFT 1
> @@ -588,10 +590,266 @@ static const struct regmap_config regmap_config = {
> .precious_reg = lm3533_precious_register,
> };
>
> +static int lm3533_of_parse_enum(struct device_node *node,
> + const char *propname,
> + const unsigned *match, size_t num_matches)
> +{
> + size_t i;
> + int ret;
> + u32 val;
> +
> + ret = of_property_read_u32(node, propname, &val);
> + if (ret < 0)
> + return ret;
> +
> + for (i = 0; i < num_matches; i++) {
> + if (val == match[i])
> + return i;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int lm3533_of_parse_pwm_zones(struct device_node *node)
> +{
> + const char *propname = "ti,pwm-zones";
> + u32 zones[5];
> + int count;
> + int ret;
> + int i;
> +
> + count = of_property_count_u32_elems(node, propname);
> + if (count == -EINVAL)
> + return 0;
> + if (count <= 0)
> + return count;
> + if (count >= ARRAY_SIZE(zones))
> + return -EINVAL;
> +
> + ret = of_property_read_u32_array(node, propname, zones, count);
> + if (ret < 0)
> + return ret;
> +
> + /* Enable pwm input, and enable the selected zones */
> + ret = BIT(0);
> + for (i = 0; i < count; i++)
> + ret |= BIT(zones[i] + 1);
> +
> + return ret;
> +}

Move to PWM driver.

> +static int lm3533_of_parse_als_node(struct device *dev,
> + struct device_node *node,
> + struct lm3533_platform_data *pdata)
> +{
> + struct lm3533_als_platform_data *als_pdata;
> + int ret;
> + u32 val;
> +
> + als_pdata = devm_kzalloc(dev,
> + sizeof(struct lm3533_als_platform_data),
> + GFP_KERNEL);
> + if (!als_pdata)
> + return -ENOMEM;
> +
> + als_pdata->pwm_mode = of_property_read_bool(node, "ti,pwm-mode");
> +
> + ret = of_property_read_u32(node, "ti,als-resistance-ohm", &val);
> + if (ret < 0 && ret != -EINVAL) {
> + dev_err(dev, "unable to read ti,als-resistance-ohm");
> + return ret;
> + }
> +
> + /* Leave at high-Z, if the property was omitted or specified as 0 */
> + if (!ret && val != 0)
> + als_pdata->r_select = 200000 / val;
> +
> + pdata->als = als_pdata;
> +
> + return 0;
> +}

Move to wherever the ALS driver is.

> +static int lm3533_of_parse_bl_node(struct device *dev,
> + struct device_node *node,
> + struct lm3533_platform_data *pdata)
> +{
> + struct lm3533_bl_platform_data *bl_pdata;
> + int ret;
> + u32 reg;
> + u32 val;
> +
> + ret = of_property_read_u32(node, "reg", &reg);
> + if (ret < 0 || reg >= ARRAY_SIZE(lm3533_bl_devs)) {
> + dev_err(dev, "invalid reg property\n");
> + return ret;
> + }
> +
> + bl_pdata = &pdata->backlights[reg];
> +
> + /* Increment num_backlights if we're filling a new space */
> + if (reg + 1 > pdata->num_backlights)
> + pdata->num_backlights = reg + 1;
> +
> + ret = of_property_read_string(node, "label",
> + (const char **)&bl_pdata->name);
> + if (ret < 0) {
> + dev_err(dev, "unable to parse label\n");
> + return ret;
> + }
> +
> + ret = of_property_read_u32(node, "led-max-microamp", &val);
> + if (ret < 0) {
> + dev_err(dev, "unable to parse led-max-microamp\n");
> + return ret;
> + }
> + bl_pdata->max_current = val;
> +
> + val = LM3533_DEFAULT_BRIGHTNESS;
> + ret = of_property_read_u32(node, "default-brightness", &val);
> + if (ret < 0 && ret != -EINVAL) {
> + dev_err(dev, "unable to parse default-brightness\n");
> + return ret;
> + }
> + bl_pdata->default_brightness = val;
> +
> + ret = lm3533_of_parse_pwm_zones(node);
> + if (ret < 0) {
> + dev_err(dev, "failed to parse ti,pwm-zones\n");
> + return ret;
> + }
> + bl_pdata->pwm = ret;
> +
> + return 0;
> +}

Move to the Backlight driver.

> +static int lm3533_of_parse_led_node(struct device *dev,
> + struct device_node *node,
> + struct lm3533_platform_data *pdata)
> +{
> + struct lm3533_led_platform_data *led_pdata;
> + int ret;
> + u32 reg;
> + u32 val;
> +
> + ret = of_property_read_u32(node, "reg", &reg);
> + if (ret < 0 || reg >= ARRAY_SIZE(lm3533_led_devs)) {
> + dev_err(dev, "invalid reg property\n");
> + return ret;
> + }
> +
> + led_pdata = &pdata->leds[reg];
> +
> + /* Increment num_leds if we're filling a new space */
> + if (reg + 1 > pdata->num_leds)
> + pdata->num_leds = reg + 1;
> +
> + ret = of_property_read_string(node, "label",
> + (const char **)&led_pdata->name);
> + if (ret < 0) {
> + dev_err(dev, "unable to parse label\n");
> + return ret;
> + }
> +
> + ret = of_property_read_u32(node, "led-max-microamp", &val);
> + if (ret < 0) {
> + dev_err(dev, "unable to parse led-max-microamp\n");
> + return ret;
> + }
> + led_pdata->max_current = val;
> +
> + ret = of_property_read_string(node, "linux,default-trigger",
> + &led_pdata->default_trigger);
> + if (ret < 0 && ret != -EINVAL) {
> + dev_err(dev, "unable to parse default-trigger\n");
> + return ret;
> + }
> +
> + ret = lm3533_of_parse_pwm_zones(node);
> + if (ret < 0) {
> + dev_err(dev, "failed to parse ti,pwm-zones\n");
> + return ret;
> + }
> + led_pdata->pwm = ret;
> +
> + return 0;
> +}

Move to LED driver.

> +static int lm3533_pdata_from_of_node(struct device *dev)
> +{
> + struct lm3533_platform_data *pdata;
> + struct device_node *node;
> + int ret;
> + const unsigned freqs[] = {
> + [LM3533_BOOST_FREQ_500KHZ] = 500000,
> + [LM3533_BOOST_FREQ_1000KHZ] = 1000000,
> + };
> + const unsigned ovps[] = {
> + [LM3533_BOOST_OVP_16V] = 16000,
> + [LM3533_BOOST_OVP_24V] = 24000,
> + [LM3533_BOOST_OVP_32V] = 32000,
> + [LM3533_BOOST_OVP_40V] = 40000,
> + };
> +
> + pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
> + if (!pdata)
> + return -ENOMEM;
> +
> + pdata->backlights = devm_kcalloc(dev,
> + ARRAY_SIZE(lm3533_bl_devs),
> + sizeof(struct lm3533_bl_platform_data),
> + GFP_KERNEL);
> + if (!pdata->backlights)
> + return -ENOMEM;

These needs to go into the Backlight driver.

> + pdata->leds = devm_kcalloc(dev,
> + ARRAY_SIZE(lm3533_led_devs),
> + sizeof(struct lm3533_led_platform_data),
> + GFP_KERNEL);
> + if (!pdata->leds)
> + return -ENOMEM;

This needs to go into the LED driver.

> + pdata->gpio_hwen = of_get_named_gpio(dev->of_node, "hwen-gpios", 0);
> + if (pdata->gpio_hwen < 0)
> + return pdata->gpio_hwen;
> +
> + ret = lm3533_of_parse_enum(dev->of_node, "ti,boost-freq-hz", freqs, 2);
> + if (ret < 0) {
> + dev_err(dev, "failed to parse ti,boost-freq-hz\n");
> + return ret;
> + }

I'm not a big fan of this abstraction method, but at the very least
you should place the error message into the function.

> + pdata->boost_freq = ret;
> +
> + ret = lm3533_of_parse_enum(dev->of_node, "ti,boost-ovp-mv", ovps, 4);
> + if (ret < 0) {
> + dev_err(dev, "failed to parse ti,boost-ovp-mv\n");
> + return ret;
> + }
> + pdata->boost_ovp = ret;
> +
> + for_each_child_of_node(dev->of_node, node) {

The MFD driver shouldn't have to care what child nodes are present.
Just regiser them as devices in their own right via mfd_add_devices()
or of_platform_populate.

> + if (!strcmp(node->name, "als"))
> + ret = lm3533_of_parse_als_node(dev, node, pdata);
> + else if (!strcmp(node->name, "backlight"))
> + ret = lm3533_of_parse_bl_node(dev, node, pdata);
> + else if (!strcmp(node->name, "led"))
> + ret = lm3533_of_parse_led_node(dev, node, pdata);
> +
> + if (ret < 0) {
> + of_node_put(node);
> + return ret;
> + }
> + }
> +
> + dev->platform_data = pdata;
> +
> + return 0;
> +}
> +
> static int lm3533_i2c_probe(struct i2c_client *i2c,
> const struct i2c_device_id *id)
> {
> struct lm3533 *lm3533;
> + int ret;
>
> dev_dbg(&i2c->dev, "%s\n", __func__);
>
> @@ -608,6 +866,12 @@ static int lm3533_i2c_probe(struct i2c_client *i2c,
> lm3533->dev = &i2c->dev;
> lm3533->irq = i2c->irq;
>
> + if (i2c->dev.of_node) {
> + ret = lm3533_pdata_from_of_node(lm3533->dev);
> + if (ret < 0)
> + return ret;
> + }
> +
> return lm3533_device_init(lm3533);
> }
>

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org â Open source software for ARM SoCs
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Next in thread: Bjorn Andersson: "Re: [RESEND PATCH v3 2/2] mfd: lm3533: Support initialization from Device Tree"
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