Re: [RFC PATCH v2 1/2] drm/bridge: parade-ps8640: Use regmap APIs

From: Doug Anderson
Date: Mon Sep 13 2021 - 20:32:20 EST


Hi,

On Mon, Sep 13, 2021 at 2:33 PM Philip Chen <philipchen@xxxxxxxxxxxx> wrote:
>
> diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
> index 685e9c38b2db..1b2414601538 100644
> --- a/drivers/gpu/drm/bridge/parade-ps8640.c
> +++ b/drivers/gpu/drm/bridge/parade-ps8640.c
> @@ -9,6 +9,7 @@
> #include <linux/i2c.h>
> #include <linux/module.h>
> #include <linux/of_graph.h>
> +#include <linux/regmap.h>
> #include <linux/regulator/consumer.h>
>
> #include <drm/drm_bridge.h>
> @@ -31,6 +32,11 @@
>
> #define NUM_MIPI_LANES 4
>
> +#define COMMON_PS8640_REGMAP_CONFIG \
> + .reg_bits = 8, \
> + .val_bits = 8, \
> + .cache_type = REGCACHE_NONE

At some point we should see if we get any speed gains by actually
caching, but that could be done later and isn't terribly high
priority.


> +
> /*
> * PS8640 uses multiple addresses:
> * page[0]: for DP control
> @@ -64,12 +70,48 @@ struct ps8640 {
> struct drm_bridge *panel_bridge;
> struct mipi_dsi_device *dsi;
> struct i2c_client *page[MAX_DEVS];
> + struct regmap *regmap[MAX_DEVS];
> struct regulator_bulk_data supplies[2];
> struct gpio_desc *gpio_reset;
> struct gpio_desc *gpio_powerdown;
> bool powered;
> };
>
> +static const struct regmap_config ps8640_regmap_config[] = {
> + [PAGE0_DP_CNTL] = {
> + COMMON_PS8640_REGMAP_CONFIG,
> + .max_register = 0xbf
> + },
> + [PAGE1_VDO_BDG] = {
> + COMMON_PS8640_REGMAP_CONFIG,
> + .max_register = 0xff
> + },
> + [PAGE2_TOP_CNTL] = {
> + COMMON_PS8640_REGMAP_CONFIG,
> + .max_register = 0xff
> + },
> + [PAGE3_DSI_CNTL1] = {
> + COMMON_PS8640_REGMAP_CONFIG,
> + .max_register = 0xff
> + },
> + [PAGE4_MIPI_PHY] = {
> + COMMON_PS8640_REGMAP_CONFIG,
> + .max_register = 0xff
> + },
> + [PAGE5_VPLL] = {
> + COMMON_PS8640_REGMAP_CONFIG,
> + .max_register = 0x7f
> + },
> + [PAGE6_DSI_CNTL2] = {
> + COMMON_PS8640_REGMAP_CONFIG,
> + .max_register = 0xff
> + },
> + [PAGE7_SPI_CNTL] = {
> + COMMON_PS8640_REGMAP_CONFIG,
> + .max_register = 0xff
> + }

nit: stylistically it's nice to add a "," after the last brace too.
It's not technically needed but it makes diffs cleaner if another
config is later added.


> @@ -362,6 +390,10 @@ static int ps8640_probe(struct i2c_client *client)
>
> ps_bridge->page[PAGE0_DP_CNTL] = client;
>
> + ps_bridge->regmap[PAGE0_DP_CNTL] = devm_regmap_init_i2c(client, ps8640_regmap_config);
> + if (IS_ERR(ps_bridge->regmap[PAGE0_DP_CNTL]))
> + return PTR_ERR(ps_bridge->regmap[PAGE0_DP_CNTL]);

I'm a huge fan of dev_err_probe(). I wonder if it makes sense to use
it here? Untested:

if (IS_ERR(ps_bridge->regmap[PAGE0_DP_CNTL]))
return dev_err_probe(dev, PTR_ERR(ps_bridge->regmap[PAGE0_DP_CNTL]),
"Error initting page 0 regmap\n");


All of that is just nits, so:

Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx>