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Date: Wed, 26 Sep 2012 16:57:42 +0530
From: "Philip, Avinash" <avinashphilip@...com>
To: <thierry.reding@...onic-design.de>, <grant.likely@...retlab.ca>,
<rob.herring@...xeda.com>, <rob@...dley.net>
CC: <linux-kernel@...r.kernel.org>,
<devicetree-discuss@...ts.ozlabs.org>, <linux-doc@...r.kernel.org>,
<nsekhar@...com>, <gururaja.hebbar@...com>,
"Philip, Avinash" <avinashphilip@...com>
Subject: [PATCH 1/2] pwm: pwm-tiecap: Add device-tree binding support for APWM driver
Add support for device-tree binding and of_xlate for ECAP APWM driver.
of_xlate provides ECAP APWM polarity configuration from client driver
device-tree.
Also size of pwm-cells set to 3 to support pwm channel number, pwm
period & polarity configuration from device tree.
Add platform data with has_configspace as member. Set has_configspace as
true for platforms which has common config space for enabling clock
gating.
Signed-off-by: Philip, Avinash <avinashphilip@...com>
---
:000000 100644 0000000... e93745d... A Documentation/devicetree/bindings/pwm/pwm-tiecap.txt
:100644 100644 081471f... 776b7ca... M drivers/pwm/pwm-tiecap.c
:000000 100644 0000000... 0c19dcb... A include/linux/platform_data/ti-pwmss.h
.../devicetree/bindings/pwm/pwm-tiecap.txt | 26 +++++
drivers/pwm/pwm-tiecap.c | 105 ++++++++++++++++++++
include/linux/platform_data/ti-pwmss.h | 23 +++++
3 files changed, 154 insertions(+), 0 deletions(-)
diff --git a/Documentation/devicetree/bindings/pwm/pwm-tiecap.txt b/Documentation/devicetree/bindings/pwm/pwm-tiecap.txt
new file mode 100644
index 0000000..e93745d
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/pwm-tiecap.txt
@@ -0,0 +1,26 @@
+TI SOC ECAP based APWM controller
+
+Required properties:
+- compatible: Must be "ti,am33xx-ecap"
+- #pwm-cells: Should be 3. Number of cells being used to specify PWM property.
+ First cell specifies the per-chip index of the PWM to use, the second
+ cell is the period cycle in nanoseconds and the third cell is the polarity
+ of PWM output. Polarity 0 gives normal polarity and 1 gives inversed
+ polarity (inverse duty cycle)
+- reg: physical base address and size of the registers map. For am33xx,
+ 2 register maps are present (ECAP register space & PWM subsystem common
+ config space). Order should be maintained with ECAP register map as first
+ entry & PWM subsystem common config space as second entry.
+
+Optional properties:
+- ti,hwmods: Name of the hwmod associated to the ECAP:
+ "ecap<x>", <x> being the 0-based instance number from the HW spec
+
+Example:
+
+ecap0: ecap@0 {
+ compatible = "ti,am33xx-ecap";
+ #pwm-cells = <3>;
+ reg = <0x48300100 0x80 0x48300000 0x10>;
+ ti,hwmods = "ecap0";
+};
diff --git a/drivers/pwm/pwm-tiecap.c b/drivers/pwm/pwm-tiecap.c
index 081471f..776b7ca 100644
--- a/drivers/pwm/pwm-tiecap.c
+++ b/drivers/pwm/pwm-tiecap.c
@@ -25,6 +25,9 @@
#include <linux/clk.h>
#include <linux/pm_runtime.h>
#include <linux/pwm.h>
+#include <linux/of_device.h>
+#include <linux/platform_data/ti-pwmss.h>
+#include <linux/pinctrl/consumer.h>
/* ECAP registers and bits definitions */
#define CAP1 0x08
@@ -37,10 +40,16 @@
#define ECCTL2_SYNC_SEL_DISA (BIT(7) | BIT(6))
#define ECCTL2_TSCTR_FREERUN BIT(4)
+#define PWMSS_CLKCONFIG 8
+#define PWMSS_ECAP_CLK_EN BIT(0)
+
+#define PWM_CELL_SIZE 3
+
struct ecap_pwm_chip {
struct pwm_chip chip;
unsigned int clk_rate;
void __iomem *mmio_base;
+ void __iomem *config_base;
};
static inline struct ecap_pwm_chip *to_ecap_pwm_chip(struct pwm_chip *chip)
@@ -184,12 +193,60 @@ static const struct pwm_ops ecap_pwm_ops = {
.owner = THIS_MODULE,
};
+static struct pwm_device *of_ecap_xlate(struct pwm_chip *chip,
+ const struct of_phandle_args *args)
+{
+ struct pwm_device *pwm;
+
+ if (chip->of_pwm_n_cells < PWM_CELL_SIZE)
+ return ERR_PTR(-EINVAL);
+
+ if (args->args[0] >= chip->npwm)
+ return ERR_PTR(-EINVAL);
+
+ pwm = pwm_request_from_chip(chip, args->args[0], NULL);
+ if (IS_ERR(pwm))
+ return pwm;
+
+ pwm_set_period(pwm, args->args[1]);
+ pwm_set_polarity(pwm, args->args[2]);
+ return pwm;
+}
+
+static struct pwmss_platform_data am33xx_data = {
+ .has_configspace = true,
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id ecap_of_match[] = {
+ {
+ .compatible = "ti,am33xx-ecap",
+ .data = &am33xx_data,
+ },
+ {},
+};
+MODULE_DEVICE_TABLE(of, ecap_of_match);
+#endif
+
static int __devinit ecap_pwm_probe(struct platform_device *pdev)
{
int ret;
struct resource *r;
struct clk *clk;
struct ecap_pwm_chip *pc;
+ struct pwmss_platform_data *pdata = pdev->dev.platform_data;
+ const struct of_device_id *match;
+ u16 regval;
+ struct pinctrl *pinctrl;
+
+ match = of_match_device(of_match_ptr(ecap_of_match), &pdev->dev);
+
+ if (match)
+ pdata = (struct pwmss_platform_data *)match->data;
+
+ pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
+ if (IS_ERR(pinctrl))
+ dev_warn(&pdev->dev, "failed to configure pins from driver\n");
pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
if (!pc) {
@@ -211,6 +268,8 @@ static int __devinit ecap_pwm_probe(struct platform_device *pdev)
pc->chip.dev = &pdev->dev;
pc->chip.ops = &ecap_pwm_ops;
+ pc->chip.of_xlate = of_ecap_xlate;
+ pc->chip.of_pwm_n_cells = PWM_CELL_SIZE;
pc->chip.base = -1;
pc->chip.npwm = 1;
@@ -231,13 +290,56 @@ static int __devinit ecap_pwm_probe(struct platform_device *pdev)
}
pm_runtime_enable(&pdev->dev);
+
+ /*
+ * Some platform has extra PWM-subsystem common config space
+ * and requires special handling of clock gating.
+ */
+ if (pdata && pdata->has_configspace) {
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+ if (!r) {
+ dev_err(&pdev->dev, "no memory resource defined\n");
+ ret = -ENODEV;
+ goto err_disable_clock;
+ }
+
+ pc->config_base = devm_ioremap(&pdev->dev, r->start,
+ resource_size(r));
+ if (!pc->config_base) {
+ dev_err(&pdev->dev, "failed to ioremap() registers\n");
+ ret = -EADDRNOTAVAIL;
+ goto err_disable_clock;
+ }
+
+ /* Enable ECAP clock gating at PWM-subsystem common config */
+ pm_runtime_get_sync(&pdev->dev);
+ regval = readw(pc->config_base + PWMSS_CLKCONFIG);
+ regval |= PWMSS_ECAP_CLK_EN;
+ writew(regval, pc->config_base + PWMSS_CLKCONFIG);
+ pm_runtime_put_sync(&pdev->dev);
+ }
+
platform_set_drvdata(pdev, pc);
return 0;
+
+err_disable_clock:
+ pm_runtime_disable(&pdev->dev);
+ return ret;
}
static int __devexit ecap_pwm_remove(struct platform_device *pdev)
{
struct ecap_pwm_chip *pc = platform_get_drvdata(pdev);
+ u16 regval;
+
+ if (pc->config_base) {
+ /* Disable ECAP clock gating at PWM-subsystem common config */
+ pm_runtime_get_sync(&pdev->dev);
+ regval = readw(pc->config_base + PWMSS_CLKCONFIG);
+ regval &= ~PWMSS_ECAP_CLK_EN;
+ writew(regval, pc->config_base + PWMSS_CLKCONFIG);
+ pm_runtime_put_sync(&pdev->dev);
+ }
pm_runtime_put_sync(&pdev->dev);
pm_runtime_disable(&pdev->dev);
@@ -247,6 +349,9 @@ static int __devexit ecap_pwm_remove(struct platform_device *pdev)
static struct platform_driver ecap_pwm_driver = {
.driver = {
.name = "ecap",
+#ifdef CONFIG_OF
+ .of_match_table = of_match_ptr(ecap_of_match),
+#endif
},
.probe = ecap_pwm_probe,
.remove = __devexit_p(ecap_pwm_remove),
diff --git a/include/linux/platform_data/ti-pwmss.h b/include/linux/platform_data/ti-pwmss.h
new file mode 100644
index 0000000..0c19dcb
--- /dev/null
+++ b/include/linux/platform_data/ti-pwmss.h
@@ -0,0 +1,23 @@
+/*
+ * TI PWM subsystem
+ *
+ * Copyright (C) {2012} Texas Instruments Incorporated - http://www.ti.com/
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef _TI_PWMSS_H
+#define _TI_PWMSS_H
+
+struct pwmss_platform_data {
+ bool has_configspace; /* set true for platforms has config space */
+};
+
+#endif
--
1.7.0.4
--
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