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Message-ID: <2by7rakflv22s6uk2e2jk5lw65erjljpwdxdxg3z73furlprj5@2qlacusapkgr>
Date: Sun, 14 Apr 2024 11:05:35 +0200
From: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
To: Trevor Gamblin <tgamblin@...libre.com>
Cc: linux-pwm@...r.kernel.org, linux-kernel@...r.kernel.org,
michael.hennerich@...log.com, nuno.sa@...log.com, devicetree@...r.kernel.org,
robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
dlechner@...libre.com
Subject: Re: [PATCH 2/2] pwm: axi-pwmgen: support version 2.00.a
Hello Trevor,
On Thu, Mar 14, 2024 at 04:47:22PM -0400, Trevor Gamblin wrote:
> This adds support for the AXI PWMGEN v2 IP block. This version is
> nearly identical to v1 other than it supports up to 16 channels instead
> of 4 and a few of the memory mapped registers have moved.
>
> Signed-off-by: Trevor Gamblin <tgamblin@...libre.com>
> ---
> drivers/pwm/pwm-axi-pwmgen.c | 62 ++++++++++++++++++++++++++++--------
> 1 file changed, 49 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/pwm/pwm-axi-pwmgen.c b/drivers/pwm/pwm-axi-pwmgen.c
> index 0c8f7f893a21..539625c404ac 100644
> --- a/drivers/pwm/pwm-axi-pwmgen.c
> +++ b/drivers/pwm/pwm-axi-pwmgen.c
> @@ -32,16 +32,25 @@
> #define AXI_PWMGEN_REG_CORE_MAGIC 0x0C
> #define AXI_PWMGEN_REG_CONFIG 0x10
> #define AXI_PWMGEN_REG_NPWM 0x14
> -#define AXI_PWMGEN_CHX_PERIOD(ch) (0x40 + (12 * (ch)))
> -#define AXI_PWMGEN_CHX_DUTY(ch) (0x44 + (12 * (ch)))
> -#define AXI_PWMGEN_CHX_OFFSET(ch) (0x48 + (12 * (ch)))
> +#define AXI_PWMGEN_CHX_PERIOD(v, ch) ((v)->period_base + (v)->ch_step * (ch))
> +#define AXI_PWMGEN_CHX_DUTY(v, ch) ((v)->duty_base + (v)->ch_step * (ch))
> +#define AXI_PWMGEN_CHX_OFFSET(v, ch) ((v)->offset_base + (v)->ch_step * (ch))
> #define AXI_PWMGEN_REG_CORE_MAGIC_VAL 0x601A3471 /* Identification number to test during setup */
> #define AXI_PWMGEN_LOAD_CONFIG BIT(1)
> #define AXI_PWMGEN_RESET BIT(0)
>
> +struct axi_pwm_variant {
> + u8 period_base;
> + u8 duty_base;
> + u8 offset_base;
> + u8 major_version;
> + u8 ch_step;
> +};
> +
> struct axi_pwmgen_ddata {
> struct regmap *regmap;
> unsigned long clk_rate_hz;
> + const struct axi_pwm_variant *variant;
> };
>
> static const struct regmap_config axi_pwmgen_regmap_config = {
> @@ -50,12 +59,30 @@ static const struct regmap_config axi_pwmgen_regmap_config = {
> .val_bits = 32,
> };
>
> +static const struct axi_pwm_variant pwmgen_1_00_variant = {
> + .period_base = 0x40,
> + .duty_base = 0x44,
> + .offset_base = 0x48,
> + .major_version = 1,
> + .ch_step = 12,
> +};
> +
> +static const struct axi_pwm_variant pwmgen_2_00_variant = {
> + .period_base = 0x40,
> + .duty_base = 0x80,
> + .offset_base = 0xC0,
> + .major_version = 2,
> + .ch_step = 4,
> +};
My first intuition to model the register differences would have been
something like:
#define ..._PERIOD 0
#define ..._DUTY 1
#define ..._OFFSET 2
and then store a "register_step"(?) variable (which is 0x4 for v1 and
0x40 for v2) in the variant struct and then use:
#define AXI_PWMGEN_CHX_PERIOD(v, ch) (0x40 + (v)->ch_step * (ch))
#define AXI_PWMGEN_CHX_DUTY(v, ch) (0x40 + (v)->register_step + (v)->ch_step * (ch))
#define AXI_PWMGEN_CHX_OFFSET(v, ch) (0x40 + 2 * (v)->register_step + (v)->ch_step * (ch))
This saves a tiny bit of memory, not entirely sure this is a good idea.
Pick it up if you like, or keep your approach, I don't care much.
> +
> static int axi_pwmgen_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> const struct pwm_state *state)
> {
> struct axi_pwmgen_ddata *ddata = pwmchip_get_drvdata(chip);
> unsigned int ch = pwm->hwpwm;
> struct regmap *regmap = ddata->regmap;
> + const struct axi_pwm_variant *variant = ddata->variant;
> u64 period_cnt, duty_cnt;
> int ret;
>
> @@ -70,7 +97,7 @@ static int axi_pwmgen_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> if (period_cnt == 0)
> return -EINVAL;
>
> - ret = regmap_write(regmap, AXI_PWMGEN_CHX_PERIOD(ch), period_cnt);
> + ret = regmap_write(regmap, AXI_PWMGEN_CHX_PERIOD(variant, ch), period_cnt);
> if (ret)
> return ret;
>
> @@ -78,15 +105,15 @@ static int axi_pwmgen_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> if (duty_cnt > UINT_MAX)
> duty_cnt = UINT_MAX;
>
> - ret = regmap_write(regmap, AXI_PWMGEN_CHX_DUTY(ch), duty_cnt);
> + ret = regmap_write(regmap, AXI_PWMGEN_CHX_DUTY(variant, ch), duty_cnt);
> if (ret)
> return ret;
> } else {
> - ret = regmap_write(regmap, AXI_PWMGEN_CHX_PERIOD(ch), 0);
> + ret = regmap_write(regmap, AXI_PWMGEN_CHX_PERIOD(variant, ch), 0);
> if (ret)
> return ret;
>
> - ret = regmap_write(regmap, AXI_PWMGEN_CHX_DUTY(ch), 0);
> + ret = regmap_write(regmap, AXI_PWMGEN_CHX_DUTY(variant, ch), 0);
> if (ret)
> return ret;
> }
> @@ -99,11 +126,12 @@ static int axi_pwmgen_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
> {
> struct axi_pwmgen_ddata *ddata = pwmchip_get_drvdata(chip);
> struct regmap *regmap = ddata->regmap;
> + const struct axi_pwm_variant *variant = ddata->variant;
> unsigned int ch = pwm->hwpwm;
> u32 cnt;
> int ret;
>
> - ret = regmap_read(regmap, AXI_PWMGEN_CHX_PERIOD(ch), &cnt);
> + ret = regmap_read(regmap, AXI_PWMGEN_CHX_PERIOD(variant, ch), &cnt);
> if (ret)
> return ret;
>
> @@ -111,7 +139,7 @@ static int axi_pwmgen_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
>
> state->period = DIV_ROUND_UP_ULL((u64)cnt * NSEC_PER_SEC, ddata->clk_rate_hz);
>
> - ret = regmap_read(regmap, AXI_PWMGEN_CHX_DUTY(ch), &cnt);
> + ret = regmap_read(regmap, AXI_PWMGEN_CHX_DUTY(variant, ch), &cnt);
> if (ret)
> return ret;
>
> @@ -127,7 +155,8 @@ static const struct pwm_ops axi_pwmgen_pwm_ops = {
> .get_state = axi_pwmgen_get_state,
> };
>
> -static int axi_pwmgen_setup(struct regmap *regmap, struct device *dev)
> +static int axi_pwmgen_setup(struct regmap *regmap, struct device *dev,
> + const struct axi_pwm_variant *variant)
> {
> int ret;
> u32 val;
> @@ -146,7 +175,7 @@ static int axi_pwmgen_setup(struct regmap *regmap, struct device *dev)
> if (ret)
> return ret;
>
> - if (ADI_AXI_PCORE_VER_MAJOR(val) != 1) {
> + if (ADI_AXI_PCORE_VER_MAJOR(val) != variant->major_version) {
> return dev_err_probe(dev, -ENODEV, "Unsupported peripheral version %u.%u.%u\n",
Hmm, is it worth to also diagnose a mismatch here? That is if the dt
tells this was a version 2 device but the register says version 1? In
this case
Unsupported peripheral version 1.x.y
might be misleading, because version 1 is supported and the problem is
maybe only a wrong dt?
> ADI_AXI_PCORE_VER_MAJOR(val),
> ADI_AXI_PCORE_VER_MINOR(val),
> @@ -178,9 +207,14 @@ static int axi_pwmgen_probe(struct platform_device *pdev)
> struct pwm_chip *chip;
> struct axi_pwmgen_ddata *ddata;
> struct clk *clk;
> + const struct axi_pwm_variant *variant;
> void __iomem *io_base;
> int ret;
>
> + variant = device_get_match_data(dev);
> + if (!variant)
> + return -EINVAL;
> +
> io_base = devm_platform_ioremap_resource(pdev, 0);
> if (IS_ERR(io_base))
> return PTR_ERR(io_base);
> @@ -190,7 +224,7 @@ static int axi_pwmgen_probe(struct platform_device *pdev)
> return dev_err_probe(dev, PTR_ERR(regmap),
> "failed to init register map\n");
>
> - ret = axi_pwmgen_setup(regmap, dev);
> + ret = axi_pwmgen_setup(regmap, dev, variant);
> if (ret < 0)
> return ret;
>
> @@ -199,6 +233,7 @@ static int axi_pwmgen_probe(struct platform_device *pdev)
> return PTR_ERR(chip);
> ddata = pwmchip_get_drvdata(chip);
> ddata->regmap = regmap;
> + ddata->variant = variant;
>
> clk = devm_clk_get_enabled(dev, NULL);
> if (IS_ERR(clk))
> @@ -224,7 +259,8 @@ static int axi_pwmgen_probe(struct platform_device *pdev)
> }
>
> static const struct of_device_id axi_pwmgen_ids[] = {
> - { .compatible = "adi,axi-pwmgen-1.00.a" },
> + { .compatible = "adi,axi-pwmgen-1.00.a", .data = &pwmgen_1_00_variant },
> + { .compatible = "adi,axi-pwmgen-2.00.a", .data = &pwmgen_2_00_variant },
> { }
> };
> MODULE_DEVICE_TABLE(of, axi_pwmgen_ids);
Otherwise looks fine.
Can you please add the next iteration of this patch together with the
series adding support for v1?
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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