misc: tps6594-esm: Disable ESM for rev 1 PMIC

Due to a silicon bug, ESM on TPS6594 PMIC revision 1 is not working
properly. This patch keeps SOC ESM disabled for such PMIC.

Fixes: 875fdd0 ("misc: tps6594-esm: Add driver for TI TPS6594 ESM")
Co-developed-by: Julien Panis <jpanis@baylibre.com>
Signed-off-by: Julien Panis <jpanis@baylibre.com>
Signed-off-by: Esteban Blanc <eblanc@baylibre.com>
Link: https://lore.kernel.org/r/20230726-tps6594_fix_esm_for_v1-v1-1-2adfdcad31c2@baylibre.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Skallwar

drivers/misc/tps6594-esm.c

@@ -13,6 +13,8 @@
 
 #include <linux/mfd/tps6594.h>
 
+#define TPS6594_DEV_REV_1 0x08
+
 static irqreturn_t tps6594_esm_isr(int irq, void *dev_id)
 {
 	struct platform_device *pdev = dev_id;
@@ -32,11 +34,26 @@ static int tps6594_esm_probe(struct platform_device *pdev)
 {
 	struct tps6594 *tps = dev_get_drvdata(pdev->dev.parent);
 	struct device *dev = &pdev->dev;
+	unsigned int rev;
 	int irq;
 	int ret;
 	int i;
 
-	for (i = 0 ; i < pdev->num_resources ; i++) {
+	/*
+	 * Due to a bug in revision 1 of the PMIC, the GPIO3 used for the
+	 * SoC ESM function is used to power the load switch instead.
+	 * As a consequence, ESM can not be used on those PMIC.
+	 * Check the version and return an error in case of revision 1.
+	 */
+	ret = regmap_read(tps->regmap, TPS6594_REG_DEV_REV, &rev);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to read PMIC revision\n");
+	if (rev == TPS6594_DEV_REV_1)
+		return dev_err_probe(dev, -ENODEV,
+			      "ESM not supported for revision 1 PMIC\n");
+
+	for (i = 0; i < pdev->num_resources; i++) {
 		irq = platform_get_irq_byname(pdev, pdev->resource[i].name);
 		if (irq < 0)
 			return dev_err_probe(dev, irq, "Failed to get %s irq\n",