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From:   Fabrice Gasnier <fabrice.gasnier@st.com>
To:     <jic23@kernel.org>, <robh+dt@kernel.org>, <alexandre.torgue@st.com>
CC:     <mark.rutland@arm.com>, <mcoquelin.stm32@gmail.com>,
        <lars@metafoo.de>, <knaack.h@gmx.de>, <pmeerw@pmeerw.net>,
        <fabrice.gasnier@st.com>, <linux-iio@vger.kernel.org>,
        <devicetree@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>, <benjamin.gaignard@linaro.org>
Subject: [PATCH v2 2/3] iio: adc: stm32-adc: add support for STM32MP1
Date:   Wed, 2 May 2018 09:44:50 +0200
Message-ID: <1525247091-18143-3-git-send-email-fabrice.gasnier@st.com>
In-Reply-To: <1525247091-18143-1-git-send-email-fabrice.gasnier@st.com>
References: <1525247091-18143-1-git-send-email-fabrice.gasnier@st.com>
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Sender: linux-kernel-owner@vger.kernel.org
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Add support for STM32MP1 ADC. It's quite similar to STM32H7 ADC.
Introduce new compatible to handle variants of this hardware such as
vregready flag, trigger list, interrupts, clock rate.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
---
 drivers/iio/adc/stm32-adc-core.c | 66 +++++++++++++++++++++++++++++-----------
 drivers/iio/adc/stm32-adc.c      | 47 +++++++++++++++++++++++++---
 2 files changed, 91 insertions(+), 22 deletions(-)

diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c
index 40be7d9..ca432e7 100644
--- a/drivers/iio/adc/stm32-adc-core.c
+++ b/drivers/iio/adc/stm32-adc-core.c
@@ -34,9 +34,6 @@
 #define STM32F4_ADC_ADCPRE_SHIFT	16
 #define STM32F4_ADC_ADCPRE_MASK		GENMASK(17, 16)
 
-/* STM32 F4 maximum analog clock rate (from datasheet) */
-#define STM32F4_ADC_MAX_CLK_RATE	36000000
-
 /* STM32H7 - common registers for all ADC instances */
 #define STM32H7_ADC_CSR			(STM32_ADCX_COMN_OFFSET + 0x00)
 #define STM32H7_ADC_CCR			(STM32_ADCX_COMN_OFFSET + 0x08)
@@ -51,9 +48,6 @@
 #define STM32H7_CKMODE_SHIFT		16
 #define STM32H7_CKMODE_MASK		GENMASK(17, 16)
 
-/* STM32 H7 maximum analog clock rate (from datasheet) */
-#define STM32H7_ADC_MAX_CLK_RATE	36000000
-
 /**
  * stm32_adc_common_regs - stm32 common registers, compatible dependent data
  * @csr:	common status register offset
@@ -74,15 +68,17 @@ struct stm32_adc_common_regs {
  * stm32_adc_priv_cfg - stm32 core compatible configuration data
  * @regs:	common registers for all instances
  * @clk_sel:	clock selection routine
+ * @max_clk_rate_hz: maximum analog clock rate (Hz, from datasheet)
  */
 struct stm32_adc_priv_cfg {
 	const struct stm32_adc_common_regs *regs;
 	int (*clk_sel)(struct platform_device *, struct stm32_adc_priv *);
+	u32 max_clk_rate_hz;
 };
 
 /**
  * struct stm32_adc_priv - stm32 ADC core private data
- * @irq:		irq for ADC block
+ * @irq:		irq(s) for ADC block
  * @domain:		irq domain reference
  * @aclk:		clock reference for the analog circuitry
  * @bclk:		bus clock common for all ADCs, depends on part used
@@ -91,7 +87,7 @@ struct stm32_adc_priv_cfg {
  * @common:		common data for all ADC instances
  */
 struct stm32_adc_priv {
-	int				irq;
+	int				irq[STM32_ADC_MAX_ADCS];
 	struct irq_domain		*domain;
 	struct clk			*aclk;
 	struct clk			*bclk;
@@ -133,7 +129,7 @@ static int stm32f4_adc_clk_sel(struct platform_device *pdev,
 	}
 
 	for (i = 0; i < ARRAY_SIZE(stm32f4_pclk_div); i++) {
-		if ((rate / stm32f4_pclk_div[i]) <= STM32F4_ADC_MAX_CLK_RATE)
+		if ((rate / stm32f4_pclk_div[i]) <= priv->cfg->max_clk_rate_hz)
 			break;
 	}
 	if (i >= ARRAY_SIZE(stm32f4_pclk_div)) {
@@ -222,7 +218,7 @@ static int stm32h7_adc_clk_sel(struct platform_device *pdev,
 			if (ckmode)
 				continue;
 
-			if ((rate / div) <= STM32H7_ADC_MAX_CLK_RATE)
+			if ((rate / div) <= priv->cfg->max_clk_rate_hz)
 				goto out;
 		}
 	}
@@ -242,7 +238,7 @@ static int stm32h7_adc_clk_sel(struct platform_device *pdev,
 		if (!ckmode)
 			continue;
 
-		if ((rate / div) <= STM32H7_ADC_MAX_CLK_RATE)
+		if ((rate / div) <= priv->cfg->max_clk_rate_hz)
 			goto out;
 	}
 
@@ -328,11 +324,24 @@ static int stm32_adc_irq_probe(struct platform_device *pdev,
 			       struct stm32_adc_priv *priv)
 {
 	struct device_node *np = pdev->dev.of_node;
+	unsigned int i;
+
+	for (i = 0; i < STM32_ADC_MAX_ADCS; i++) {
+		priv->irq[i] = platform_get_irq(pdev, i);
+		if (priv->irq[i] < 0) {
+			/*
+			 * At least one interrupt must be provided, make others
+			 * optional:
+			 * - stm32f4/h7 shares a common interrupt.
+			 * - stm32mp1, has one line per ADC (either for ADC1,
+			 *   ADC2 or both).
+			 */
+			if (i && priv->irq[i] == -ENXIO)
+				continue;
+			dev_err(&pdev->dev, "failed to get irq\n");
 
-	priv->irq = platform_get_irq(pdev, 0);
-	if (priv->irq < 0) {
-		dev_err(&pdev->dev, "failed to get irq\n");
-		return priv->irq;
+			return priv->irq[i];
+		}
 	}
 
 	priv->domain = irq_domain_add_simple(np, STM32_ADC_MAX_ADCS, 0,
@@ -343,8 +352,12 @@ static int stm32_adc_irq_probe(struct platform_device *pdev,
 		return -ENOMEM;
 	}
 
-	irq_set_chained_handler(priv->irq, stm32_adc_irq_handler);
-	irq_set_handler_data(priv->irq, priv);
+	for (i = 0; i < STM32_ADC_MAX_ADCS; i++) {
+		if (priv->irq[i] < 0)
+			continue;
+		irq_set_chained_handler(priv->irq[i], stm32_adc_irq_handler);
+		irq_set_handler_data(priv->irq[i], priv);
+	}
 
 	return 0;
 }
@@ -353,11 +366,17 @@ static void stm32_adc_irq_remove(struct platform_device *pdev,
 				 struct stm32_adc_priv *priv)
 {
 	int hwirq;
+	unsigned int i;
 
 	for (hwirq = 0; hwirq < STM32_ADC_MAX_ADCS; hwirq++)
 		irq_dispose_mapping(irq_find_mapping(priv->domain, hwirq));
 	irq_domain_remove(priv->domain);
-	irq_set_chained_handler(priv->irq, NULL);
+
+	for (i = 0; i < STM32_ADC_MAX_ADCS; i++) {
+		if (priv->irq[i] < 0)
+			continue;
+		irq_set_chained_handler(priv->irq[i], NULL);
+	}
 }
 
 static int stm32_adc_probe(struct platform_device *pdev)
@@ -497,11 +516,19 @@ static int stm32_adc_remove(struct platform_device *pdev)
 static const struct stm32_adc_priv_cfg stm32f4_adc_priv_cfg = {
 	.regs = &stm32f4_adc_common_regs,
 	.clk_sel = stm32f4_adc_clk_sel,
+	.max_clk_rate_hz = 36000000,
 };
 
 static const struct stm32_adc_priv_cfg stm32h7_adc_priv_cfg = {
 	.regs = &stm32h7_adc_common_regs,
 	.clk_sel = stm32h7_adc_clk_sel,
+	.max_clk_rate_hz = 36000000,
+};
+
+static const struct stm32_adc_priv_cfg stm32mp1_adc_priv_cfg = {
+	.regs = &stm32h7_adc_common_regs,
+	.clk_sel = stm32h7_adc_clk_sel,
+	.max_clk_rate_hz = 40000000,
 };
 
 static const struct of_device_id stm32_adc_of_match[] = {
@@ -512,6 +539,9 @@ static int stm32_adc_remove(struct platform_device *pdev)
 		.compatible = "st,stm32h7-adc-core",
 		.data = (void *)&stm32h7_adc_priv_cfg
 	}, {
+		.compatible = "st,stm32mp1-adc-core",
+		.data = (void *)&stm32mp1_adc_priv_cfg
+	}, {
 	},
 };
 MODULE_DEVICE_TABLE(of, stm32_adc_of_match);
diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index 9a2583ca..3784118 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -84,6 +84,7 @@
 #define STM32H7_ADC_CALFACT2		0xC8
 
 /* STM32H7_ADC_ISR - bit fields */
+#define STM32MP1_VREGREADY		BIT(12)
 #define STM32H7_EOC			BIT(2)
 #define STM32H7_ADRDY			BIT(0)
 
@@ -249,6 +250,7 @@ struct stm32_adc_regspec {
  * @adc_info:		per instance input channels definitions
  * @trigs:		external trigger sources
  * @clk_required:	clock is required
+ * @has_vregready:	vregready status flag presence
  * @selfcalib:		optional routine for self-calibration
  * @prepare:		optional prepare routine (power-up, enable)
  * @start_conv:		routine to start conversions
@@ -261,6 +263,7 @@ struct stm32_adc_cfg {
 	const struct stm32_adc_info	*adc_info;
 	struct stm32_adc_trig_info	*trigs;
 	bool clk_required;
+	bool has_vregready;
 	int (*selfcalib)(struct stm32_adc *);
 	int (*prepare)(struct stm32_adc *);
 	void (*start_conv)(struct stm32_adc *, bool dma);
@@ -695,8 +698,12 @@ static void stm32h7_adc_stop_conv(struct stm32_adc *adc)
 	stm32_adc_clr_bits(adc, STM32H7_ADC_CFGR, STM32H7_DMNGT_MASK);
 }
 
-static void stm32h7_adc_exit_pwr_down(struct stm32_adc *adc)
+static int stm32h7_adc_exit_pwr_down(struct stm32_adc *adc)
 {
+	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
+	int ret;
+	u32 val;
+
 	/* Exit deep power down, then enable ADC voltage regulator */
 	stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_DEEPPWD);
 	stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADVREGEN);
@@ -705,7 +712,20 @@ static void stm32h7_adc_exit_pwr_down(struct stm32_adc *adc)
 		stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_BOOST);
 
 	/* Wait for startup time */
-	usleep_range(10, 20);
+	if (!adc->cfg->has_vregready) {
+		usleep_range(10, 20);
+		return 0;
+	}
+
+	ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_ISR, val,
+					   val & STM32MP1_VREGREADY, 100,
+					   STM32_ADC_TIMEOUT_US);
+	if (ret) {
+		stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_DEEPPWD);
+		dev_err(&indio_dev->dev, "Failed to exit power down\n");
+	}
+
+	return ret;
 }
 
 static void stm32h7_adc_enter_pwr_down(struct stm32_adc *adc)
@@ -888,7 +908,9 @@ static int stm32h7_adc_selfcalib(struct stm32_adc *adc)
 	int ret;
 	u32 val;
 
-	stm32h7_adc_exit_pwr_down(adc);
+	ret = stm32h7_adc_exit_pwr_down(adc);
+	if (ret)
+		return ret;
 
 	/*
 	 * Select calibration mode:
@@ -952,7 +974,10 @@ static int stm32h7_adc_prepare(struct stm32_adc *adc)
 {
 	int ret;
 
-	stm32h7_adc_exit_pwr_down(adc);
+	ret = stm32h7_adc_exit_pwr_down(adc);
+	if (ret)
+		return ret;
+
 	stm32_adc_writel(adc, STM32H7_ADC_DIFSEL, adc->difsel);
 
 	ret = stm32h7_adc_enable(adc);
@@ -1944,9 +1969,23 @@ static int stm32_adc_remove(struct platform_device *pdev)
 	.smp_cycles = stm32h7_adc_smp_cycles,
 };
 
+static const struct stm32_adc_cfg stm32mp1_adc_cfg = {
+	.regs = &stm32h7_adc_regspec,
+	.adc_info = &stm32h7_adc_info,
+	.trigs = stm32h7_adc_trigs,
+	.has_vregready = true,
+	.selfcalib = stm32h7_adc_selfcalib,
+	.start_conv = stm32h7_adc_start_conv,
+	.stop_conv = stm32h7_adc_stop_conv,
+	.prepare = stm32h7_adc_prepare,
+	.unprepare = stm32h7_adc_unprepare,
+	.smp_cycles = stm32h7_adc_smp_cycles,
+};
+
 static const struct of_device_id stm32_adc_of_match[] = {
 	{ .compatible = "st,stm32f4-adc", .data = (void *)&stm32f4_adc_cfg },
 	{ .compatible = "st,stm32h7-adc", .data = (void *)&stm32h7_adc_cfg },
+	{ .compatible = "st,stm32mp1-adc", .data = (void *)&stm32mp1_adc_cfg },
 	{},
 };
 MODULE_DEVICE_TABLE(of, stm32_adc_of_match);
-- 
1.9.1