Hello, just a few small details left to criticize ...
On Sat, Apr 10, 2021 at 08:08:37AM +0900, Nobuhiro Iwamatsu wrote:
> diff --git a/drivers/pwm/pwm-visconti.c b/drivers/pwm/pwm-visconti.c
> new file mode 100644
> index 000000000000..99d83f94ed86
> --- /dev/null
> +++ b/drivers/pwm/pwm-visconti.c
> @@ -0,0 +1,188 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Toshiba Visconti pulse-width-modulation controller driver
> + *
> + * Copyright (c) 2020 TOSHIBA CORPORATION
> + * Copyright (c) 2020 Toshiba Electronic Devices & Storage Corporation
> + *
> + * Authors: Nobuhiro Iwamatsu <nobuhiro1.iwama...@toshiba.co.jp>
> + *
> + */
> +
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +
> +#define PIPGM_PCSR(ch) (0x400 + 4 * (ch))
> +#define PIPGM_PDUT(ch) (0x420 + 4 * (ch))
> +#define PIPGM_PWMC(ch) (0x440 + 4 * (ch))
> +
> +#define PIPGM_PWMC_PWMACT BIT(5)
> +#define PIPGM_PWMC_CLK_MASK GENMASK(1, 0)
> +#define PIPGM_PWMC_POLARITY_MASK GENMASK(5, 5)
> +
> +struct visconti_pwm_chip {
> + struct pwm_chip chip;
> + void __iomem *base;
> +};
> +
> +static inline struct visconti_pwm_chip *to_visconti_chip(struct pwm_chip
> *chip)
> +{
> + return container_of(chip, struct visconti_pwm_chip, chip);
> +}
> +
> +static int visconti_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> + const struct pwm_state *state)
> +{
> + struct visconti_pwm_chip *priv = to_visconti_chip(chip);
> + u32 period, duty_cycle, pwmc0;
> +
> + /*
> + * pwmc is a 2-bit divider for the input clock running at 1 MHz.
> + * When the settings of the PWM are modified, the new values are
> shadowed in hardware until
> + * the period register (PCSR) is written and the currently running
> period is completed. This
> + * way the hardware switches atomically from the old setting to the new.
> + * Also, disabling the hardware completes the currently running period
> and keeps the output
> + * at low level at all times.
Can you please put a paragraph analogous to the one in pwm-sifive in the
same format. This simplified keeping an overview about the oddities of
the various supported chips.
> + */
> + if (!state->enabled) {
> + writel(0, priv->base + PIPGM_PCSR(pwm->hwpwm));
> + return 0;
> + }
> +
> [...]
> +
> +static void visconti_pwm_get_state(struct pwm_chip *chip, struct pwm_device
> *pwm,
> + struct pwm_state *state)
> +{
> + struct visconti_pwm_chip *priv = chip_to_priv(chip);
> + u32 period, duty, pwmc0, pwmc0_clk;
> +
> + period = readl(priv->base + PIPGM_PCSR(pwm->hwpwm));
> + if (period)
> + state->enabled = true;
> + else
> + state->enabled = false;
If PIPGM_PCSR is 0 the hardware is still active and setting a new
configuration completes the currently running period, right? Then I
think having always state->enabled = true is a better match.
> + duty = readl(priv->base + PIPGM_PDUT(pwm->hwpwm));
> + pwmc0 = readl(priv->base + PIPGM_PWMC(pwm->hwpwm));
> + pwmc0_clk = pwmc0 & PIPGM_PWMC_CLK_MASK;
> +
> + state->period = (period << pwmc0_clk) * NSEC_PER_USEC;
> + state->duty_cycle = (duty << pwmc0_clk) * NSEC_PER_USEC;
> + if (pwmc0 & PIPGM_PWMC_POLARITY_MASK)
> + state->polarity = PWM_POLARITY_INVERSED;
> + else
> + state->polarity = PWM_POLARITY_NORMAL;
> +}
> +
> [...]
> +
> +static int visconti_pwm_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct visconti_pwm_chip *priv;
> + int ret;
> +
> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(priv->base))
> + return PTR_ERR(priv->base);
> +
> + platform_set_drvdata(pdev, priv);
> +
> + priv->chip.dev = dev;
> + priv->chip.ops = &visconti_pwm_ops;
> + priv->chip.npwm = 4;
> +
> + ret = pwmchip_add(&priv->chip);
> + if (ret < 0)
> + return dev_err_probe(&pdev->dev, ret, "Cannot register visconti
> PWM\n");
Thierry told to have picked up my patch to add the function
devm_pwmchip_add. I just double checked and it didn't made it into his
for-next branch yet. When you respin this series please check if the
patch landed in the mean time and then make use of it.
> + return 0;
> +}
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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