linux-kernel - [PATCH 7/7] pwm: dwc: add snps,pwm-number to limit pwm count

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Message-Id: <20220712100113.569042-8-ben.dooks@sifive.com>
Date:   Tue, 12 Jul 2022 11:01:13 +0100
From:   Ben Dooks <ben.dooks@...ive.com>
To:     linux-pwm@...r.kernel.org
Cc:     devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Lee Jones <lee.jones@...aro.org>,
        u.kleine-koenig@...gutronix.de,
        Thierry Reding <thierry.reding@...il.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Greentime Hu <greentime.hu@...ive.com>,
        Jude Onyenegecha <jude.onyenegecha@...ive.com>,
        Sudip Mukherjee <sudip.mukherjee@...ive.com>,
        William Salmon <william.salmon@...ive.com>,
        Adnan Chowdhury <adnan.chowdhury@...ive.com>,
        Ben Dooks <ben.dooks@...ive.com>
Subject: [PATCH 7/7] pwm: dwc: add snps,pwm-number to limit pwm count

Add snps,pwm-number property to indicate if the block does not have
all 8 of the PWM blocks.

Not sure if this should be a general PWM property consider optional
for all PWM types, so have added a specific one here (there is only
one other controller with a property for PWM count at the moment)

Signed-off-by: Ben Dooks <ben.dooks@...ive.com>
---
 Documentation/devicetree/bindings/pwm/pwm-synposys.yaml | 5 +++++
 drivers/pwm/pwm-dwc.c                                   | 8 ++++++++
 2 files changed, 13 insertions(+)

diff --git a/Documentation/devicetree/bindings/pwm/pwm-synposys.yaml b/Documentation/devicetree/bindings/pwm/pwm-synposys.yaml
index 38ac0da75272..15bdf764b46a 100644
--- a/Documentation/devicetree/bindings/pwm/pwm-synposys.yaml
+++ b/Documentation/devicetree/bindings/pwm/pwm-synposys.yaml
@@ -30,11 +30,16 @@ properties:
       - items:
         - const: snps,pwm
 
+  snps,pwm-number:
+    $ref: '/schemas/types.yaml#/definitions/uint32'
+    description: u32 value representing the number of PWM devices
+
 required:
   - "#pwm-cells"
   - compatible
   - reg
   - clocks
   - clock-names
+  - snps,pwm-number
 
 additionalProperties: false
diff --git a/drivers/pwm/pwm-dwc.c b/drivers/pwm/pwm-dwc.c
index 6a4364a5d137..abdde83452ad 100644
--- a/drivers/pwm/pwm-dwc.c
+++ b/drivers/pwm/pwm-dwc.c
@@ -328,12 +328,20 @@ static int dwc_pwm_plat_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct dwc_pwm *dwc;
+	u32 nr_pwm;
 	int ret;
 
 	dwc = dwc_pwm_alloc(dev);
 	if (!dwc)
 		return -ENOMEM;
 
+	if (!device_property_read_u32(dev, "snps,pwm-number", &nr_pwm)) {
+		if (nr_pwm > DWC_TIMERS_TOTAL)
+			dev_err(dev, "too many PWMs specified (%d)\n", nr_pwm);
+		else
+			dwc->chip.npwm = nr_pwm;
+	}
+
 	dwc->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(dwc->base))
 		return dev_err_probe(dev, PTR_ERR(dwc->base),
-- 
2.35.1