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Message-ID: <alpine.DEB.2.02.1306070920010.32163@utopia.booyaka.com>
Date: Fri, 7 Jun 2013 09:38:10 +0000 (UTC)
From: Paul Walmsley <pwalmsley@...dia.com>
To: Mark Brown <broonie@...nel.org>
cc: Liam Girdwood <lgirdwood@...il.com>, linux-kernel@...r.kernel.org,
linux-tegra@...r.kernel.org, Andrew Chew <achew@...dia.com>,
Matthew Longnecker <mlongnecker@...dia.com>
Subject: Re: [PATCH] regulator: core: add regulator_get_linear_step()
Hi Mark,
On Fri, 7 Jun 2013, Mark Brown wrote:
> On Fri, Jun 07, 2013 at 08:06:56AM +0000, Paul Walmsley wrote:
>
> > Applies on v3.10-rc4. Will be used by the upcoming Tegra DFLL clocksource
> > driver, which will build its own table of voltage-to-VSEL values by
> > querying the regulator framework.
>
> Can you show the code please?
The driver isn't 100% ready to post yet. Still wrapping up a few last
tweaks (in an unrelated part of the driver). But here are the parts of
the code that use that regulator function.
This is the immediate caller:
+/**
+ * tegra_dfll_init_pmic_data - initialize PMIC regulator data
+ * @pdev: DFLL instance
+ *
+ * Read the PMIC integration data, including regulator data, from DT
+ * and the the regulator framework. Build the voltage map from
+ * regulator data. Returns 0 upon success or -EINVAL upon error.
+ */
+static int __must_check tegra_dfll_init_pmic_data(struct platform_device *pdev)
+{
+ struct tegra_dfll *td = dev_get_drvdata(&pdev->dev);
+ int r;
+
+ td->vdd = regulator_get(&pdev->dev, "vdd");
+ if (IS_ERR(td->vdd)) {
+ dev_err(&pdev->dev, "couldn't locate regulator\n");
+ return -EINVAL;
+ }
+
+ td->vdd_step = regulator_get_linear_step(td->vdd);
+ if (!td->vdd_step) {
+ dev_err(&pdev->dev, "only linear map regulators supported\n");
+ goto tdipd_err;
+ }
+
+ r = parse_of_dfll_pmic_integration(pdev, pdev->dev.of_node);
+ if (r) {
+ dev_err(&pdev->dev, "DFLL PMIC integration parse error\n");
+ goto tdipd_err;
+ }
+
+ r = tegra_dfll_regulator_probe_voltages(pdev);
+ if (r) {
+ dev_err(&pdev->dev, "couldn't probe regulator voltages\n");
+ goto tdipd_err;
+ }
+
+ return 0;
+
+tdipd_err:
+ regulator_put(td->vdd);
+ return -EINVAL;
+}
... and here's the code that uses td->vdd_step:
+static int get_cvb_voltage(struct platform_device *pdev, int c0, int c1,
+ int c2)
+{
+ struct tegra_dfll *td = dev_get_drvdata(&pdev->dev);
+ /* apply only speedo scale: output mv = cvb_mv * v_scale */
+ int mv;
+
+ /* combined: apply voltage scale and round to cvb alignment step */
+ mv = DIV_ROUND_CLOSEST(c2 * td->speedo_value, td->cvb_speedo_scale);
+ mv = DIV_ROUND_CLOSEST((mv + c1) * td->speedo_value,
+ td->cvb_speedo_scale) + c0;
+
+ /* XXX Bring back cvb_alignment_uv; put it in the board dfll DT */
+ return DIV_ROUND_UP(mv * 1000,
+ td->cvb_voltage_scale * td->vdd_step) *
+ td->vdd_step / 1000;
+}
But, maybe you're more interested in the voltage probing code:
+/**
+ * tegra_dfll_regulator_probe_voltages - build vdd_map[] from the regulator
+ * @pdev: DFLL instance
+ *
+ * Build the vdd_map from regulator framework and DFLL DT data.
+ * Returns 0 upon success, or -ENOSPC on a memory allocation failure.
+ */
+static int tegra_dfll_regulator_probe_voltages(struct platform_device *pdev)
+{
+ struct tegra_dfll *td = dev_get_drvdata(&pdev->dev);
+ int c, i, j, vdd_uv, vdd_mv;
+ struct tegra_dfll_voltage_reg_map *vdd_map;
+
+ c = regulator_count_voltages(td->vdd);
+ if (c < 0)
+ return c;
+
+ vdd_map = kzalloc(sizeof(struct tegra_dfll_voltage_reg_map) * c,
+ GFP_KERNEL);
+ if (!vdd_map)
+ return -ENOMEM;
+
+ j = 0;
+ for (i = 0; i < c; i++) {
+ vdd_uv = regulator_list_voltage(td->vdd, i);
+ if (vdd_uv <= 0)
+ continue;
+
+ if (vdd_uv < td->dfll_min_microvolt)
+ continue;
+
+ if (vdd_uv > td->dfll_max_microvolt)
+ break;
+
+ vdd_mv = vdd_uv / 1000;
+
+ vdd_map[j].reg_value = i;
+ vdd_map[j].reg_uv = vdd_uv;
+ vdd_map[j].reg_mv = vdd_mv;
+ j++;
+ }
+
+ td->vdd_map_size = j;
+ td->vdd_map = vdd_map;
+
+ return 0;
+}
If you've got a different approach in mind, I'm happy to switch to it.
- Paul
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