Hi Shawn, On Thu, Dec 10, 2020 at 09:51:37AM +0800, Shawn Guo wrote: > On Mon, Dec 07, 2020 at 10:40:22PM -0600, Bjorn Andersson wrote: > > The SN65DSI86 provides the ability to supply a PWM signal on GPIO 4, > > with the primary purpose of controlling the backlight of the attached > > panel. Add an implementation that exposes this using the standard PWM > > framework, to allow e.g. pwm-backlight to expose this to the user. > > > > Special thanks to Doug Anderson for suggestions related to the involved > > math. > > > > Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx> > > --- > > drivers/gpu/drm/bridge/ti-sn65dsi86.c | 202 ++++++++++++++++++++++++++ > > 1 file changed, 202 insertions(+) > > > > diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c > > index f27306c51e4d..43c0acba57ab 100644 > > --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c > > +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c > > @@ -4,6 +4,7 @@ > > * datasheet: https://www.ti.com/lit/ds/symlink/sn65dsi86.pdf > > */ > > > > +#include <linux/atomic.h> > > #include <linux/bits.h> > > #include <linux/clk.h> > > #include <linux/debugfs.h> > > @@ -14,6 +15,7 @@ > > #include <linux/module.h> > > #include <linux/of_graph.h> > > #include <linux/pm_runtime.h> > > +#include <linux/pwm.h> > > #include <linux/regmap.h> > > #include <linux/regulator/consumer.h> > > > > @@ -89,6 +91,11 @@ > > #define SN_ML_TX_MODE_REG 0x96 > > #define ML_TX_MAIN_LINK_OFF 0 > > #define ML_TX_NORMAL_MODE BIT(0) > > +#define SN_PWM_PRE_DIV_REG 0xA0 > > +#define SN_BACKLIGHT_SCALE_REG 0xA1 > > +#define BACKLIGHT_SCALE_MAX 0xFFFF > > +#define SN_BACKLIGHT_REG 0xA3 > > +#define SN_PWM_EN_INV_REG 0xA5 > > #define SN_AUX_CMD_STATUS_REG 0xF4 > > #define AUX_IRQ_STATUS_AUX_RPLY_TOUT BIT(3) > > #define AUX_IRQ_STATUS_AUX_SHORT BIT(5) > > @@ -111,6 +118,8 @@ > > > > #define SN_LINK_TRAINING_TRIES 10 > > > > +#define SN_PWM_GPIO 3 > > So this maps to the GPIO4 described in sn65dsi86 datasheet. I'm > wondering if it's more readable to define the following SHIFT constants > (your code), and use GPIO_MUX_GPIO4_SHIFT >> 2 where you need GPIO > offset? > > #define GPIO_MUX_GPIO1_SHIFT 0 > #define GPIO_MUX_GPIO2_SHIFT 2 > #define GPIO_MUX_GPIO3_SHIFT 4 > #define GPIO_MUX_GPIO4_SHIFT 6 > > If you agree, you may consider to integrate this patch beforehand: > > https://github.com/shawnguo2/linux/commit/7cde887ffb3b27a36e77a08bee3666d14968b586 My preferred way here would be to add a prefix for the other constants. It (IMHO) looks nicer and GPIO_INPUT_SHIFT looks like a quite generic name for a hardware specific definition. (Even if up to now there is no other code location using this name.) Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |
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