[Intel-gfx] [PATCH v2 3/3] acpi: lpss: call pwm_add_table() for bsw PWM device

Thierry Reding thierry.reding at gmail.com
Mon Jan 30 08:18:39 UTC 2017


On Sun, Jan 22, 2017 at 05:14:09PM +0100, Hans de Goede wrote:
> On x86 we do not have devicetree to link the PWM controller and
> the display controller together. So someone needs to call
> pwm_add_table() to create the link, so that the i915 driver's
> pwm_get(dev, "pwm_backlight") call returns the lpss' pwm0.
> 
> The PWM subsystem does not want to have pwm_add_table() calls
> directly in PWM drivers (this leads to probe ordering issues),
> so lets do it here since the acpi-lpss code is always builtin.
> 
> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
> Acked-by: Thierry Reding <thierry.reding at gmail.com>
> ---
> Changes in v2:
> -Set new pwm_lookup module_name field in the table
> ---
>  drivers/acpi/acpi_lpss.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)

Rafael, do you mind if I take this through the PWM tree to resolve the
build-time dependency?

Thanks,
Thierry

> 
> diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
> index 8ea836c..794be64 100644
> --- a/drivers/acpi/acpi_lpss.c
> +++ b/drivers/acpi/acpi_lpss.c
> @@ -20,6 +20,7 @@
>  #include <linux/platform_data/clk-lpss.h>
>  #include <linux/pm_domain.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/pwm.h>
>  #include <linux/delay.h>
>  
>  #include "internal.h"
> @@ -154,6 +155,17 @@ static void byt_i2c_setup(struct lpss_private_data *pdata)
>  	writel(0, pdata->mmio_base + LPSS_I2C_ENABLE);
>  }
>  
> +/* BSW PWM used for backlight control by the i915 driver */
> +static struct pwm_lookup bsw_pwm_lookup[] = {
> +	PWM_LOOKUP_MODNAME("80862288:00", 0, "0000:00:02.0", "pwm_backlight",
> +			   0, PWM_POLARITY_NORMAL, "pwm-lpss-platform"),
> +};
> +
> +static void bsw_pwm_setup(struct lpss_private_data *pdata)
> +{
> +	pwm_add_table(bsw_pwm_lookup, ARRAY_SIZE(bsw_pwm_lookup));
> +}
> +
>  static const struct lpss_device_desc lpt_dev_desc = {
>  	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_LTR,
>  	.prv_offset = 0x800,
> @@ -191,6 +203,7 @@ static const struct lpss_device_desc byt_pwm_dev_desc = {
>  
>  static const struct lpss_device_desc bsw_pwm_dev_desc = {
>  	.flags = LPSS_SAVE_CTX | LPSS_NO_D3_DELAY,
> +	.setup = bsw_pwm_setup,
>  };
>  
>  static const struct lpss_device_desc byt_uart_dev_desc = {
> -- 
> 2.9.3
> 
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